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Home My WebLink AboutAPA5851 l ~l l ~ l 'l l l .l 1 1 ] 1 . 1 ] 1 1 v ,....... _I!) -C'\1 v _v "' 0 ~ 0 -0 ~ -,....... _M M SUSITNA HYDRO AQUATIC STUDIES Pr~SE II BASIC DATA REPORT Volume 4: Aquatic Habitat and Instream Flow Studies, 1982. Parts I and II "'~-'""''~ Resources Library Inforrnatwn .,;., -3 .. rvtces Anchorage, At~ska SUSITNA HYDRO AQUATIC STUDIES Pr~SE II BASIC DATA REPORT Volume 4: Aquatic HabitAt Hnn Instream Flow Studies, 1982. Parts I and II -by- ALASKA DEPARTMENT OF FISH AND GAME Susitna Hydro Aquatic Studies 2207 Spenard Road Anchorage, Alaska 99503 1983 or;;t ,...... lO N or;;t or;;t 0 0 0 lO lO ,...... (\") (\") PREFACE This report is part of a five volume presentation of the fisheries, aquatic habitat, and instream flow data collected by the Alaska Depart- ment of Fish and Game (ADF&G) Susitna Hydroelectric (Su Hydro) Feasibility Aquatic Studies Program during the 1981-82 (October-May) ice-covered and 1982 open water (May-October) seasons. It is one of a series of reports prepared for the Alaska Power Authority (APA) and its principal contractor, Acres American (Acres), by the ADF&G and other contractors to evaluate the feasibility of the proposed Susitna Hydroelectric Project. This report is intended for data transmittal to other Susitna Hydroelectric Feasibility Study participants. A preliminary draft was circulated for review in February. The topics discussed in Volumes Two through Five are illustrated in Figure A. Volume One presents a synopsis of the information contained in the other four volumes. Volume Two also includes a comparison of 1981 and 1982 adult anadromous fisheries data. An ADF&G data analysis report will include an analysis of the pre-project fishery and habitat relationships derived from this and related reports prepared by other study participants. A review draft will be circulated to study participants in May 1983. The final report will be submitted to the APA on June 30, 1983 for formal distribution to study participants, state and federal agencies, and the public. Also scheduled for completion on June 30, 1983 is the first draft of the ADF&G 1982-83 ice-covered season basic data report. It will include a presentation of 1982-83 incubation and other fishery and habitat data. These and other ADF&G reports (197 4, 1976, 1977, 1978, 1979, 1981a, b, c, d, e, f, 1982) and information reported by others will be summarized and analyzed by the Arctic Environmental Information and Data Center (AEIDC) to evaluate post-project conditions within the overall study area of the proposed project (Figure B). Woodward Clyde I Factors Influencing Aquatic Habitat River Morphology Vol.4, Vol. 5 Chemical Vol. 4, Vol. 5 Fish Life Phases Influenced by Habitat Timing, Oiatributlon and Population Val. 2, Vol. 4 Spawning Vol. 2, Vol. 4, Vol. 5 Rearing Vol. 3 i---Food Hoblta -------Vol. 3 ~Outmlgrotlon ~ Vol. 3 Spawning Vol. 3, Vol. 5 Rearing Vol. 3, Vol. 4, Vol. 5 Olatrlbutlon Vol. 3, Vol.4, Vol. 5 Figure A. Integration of and relationships among the program elements presented in Volumes Two through Five. Consultants will, in turn, use this information to support the preparation of the Federal Energy Regulatory Commission License Appli- cation for Acres. The five year (Acres 1980) ADF&G Su Hydro Aquatic Studies program was initiated in November 1980. It is subdivided into three study sections: Adult Anadromous Fish Studies (AA), Resident and Juvenile Anadromous Fish Studies (RJ), and Aquatic Habitat and Instream Flow Studies (AH). Specific objectives of the three sections are: 1. AA -determine the seasonal distribution and relative abun- dance of adult anadromous fish populations produced within the study area (Figure B); 2. RJ -determine the seasonal distribution and relative abun- dance of selected resident and juvenile anadromous fish populations within the study area; and 3. AH characterize the seasonal habitat requirements of selected anadromous and resident fish species within the study area and the relationship between the availability of these habitat conditions and the mainstem discharge of the Susitna River. The 1981-82 ice-covered and 1982 open-water ADF&G study areas (Figures C and D) were limited to the mainstem Susitna River, associated sloughs and side channels, and the mouths of major tributaries. Portions of tributaries which will be inundated by the proposed Watana and Devil Canyon reservoirs were also evaluated. Descriptions of study sites are presented in each of these volumes including the ADF&G reports (ADF&G 1981a, b, c, d, e, f). The Susitna River is approximately 275 miles long from its sources in the Alaska Mountain Range to its point of discharge into Cook Inlet. Its drainage encompasses an area of 19,400 square miles. The mainstem III ·-C) ..... , ....... < 0 I 25 I • ADF 8G FIELD CAMPS Figure B. Overall study area of the Susitna Hydroelectric Feasib·ility Study Progra;n. < ' 0 25 miles ' ' .............. ...... , .....- ...... ...... , ' \ \ \ I I I I I I I I I / .,-"' 1982 OPEN WATER SEASON STUDY AREAS I] ~~~E~ ~~v~R ~ LOWER RIVER ~ STUDY AREA --DRAINAGE BOUNDARY Figure C. 1982 ADF&G open water season (May through October) study area. ., 0 ' ' ...... , -...... ...... ""-...... ...... \ \ ' ' I I I I I I ~~ / / 1981-82 ICE-COVERED SEASON STUDY AREAS LOWER RIVER STUDY AREA UPPER RIVER STUDY AREA Figure D. 1981-82 ADF&G ice-covered season (October through May) study area. and major tributaries of the Susitna River, including the Chulitna, Talkeetna and Yentna rivers, originate in glaciers and carry a heavy load of glacial flour during the ice-free months (approximately May .through October). There are many smaller tributaries which are perennially clear. Questions concerning these reports should be directed to: Thomas W. Trent Aquatic Studies Coordinator Alaska Department of Fish & Game Su Hydro Aquatic Studies Program 2207 Spenard Road Anchorage, Alaska 99503 Telephone (907) 274-7583 VII PREFACE REFERENCES Acres American, Inc. (Acres) 1980. Susitna Hydroelectric Project Plan of Study. Prepared for the Alaska Power Authority. Anchorage, Alaska. Alaska Department of Fish and Game (ADF&G). 197 4. An assessment of the anadromous fish populations in the Upper Susitna River Watershed between Devil Canyon and the Chulitna River. Anchorage, Alaska. 1976. Fish and Wildlife studies related to the Corps of Engineers Devil Canyon, Watana Reservoir Hydroelectric Project. ADF&G. Anchorage, Alaska. 1977. Preauthorization assessment of the proposed Susitna Hydroelectric Projects: preliminary investigations of water quality and aquatic species composition. ADF&G. Anchorage, Alaska. 1978. Preliminary environmental assessment of hydroelectric development on the Susitna River. Anchorage, Alaska. 19 7 9 . Preliminary proposed by the ADF&G. final plan of study fish and ADF&G. Anchorage, Alaska. studies 1981a. Aquatic studies procedures manual. Phase I. Final Draft. Subtask 7 .10. Prepared for Acres American, Incorporated, by the Alaska Department of Fish and Game/Su Hydro. Anchorage, Alaska. 1981b. Adult anadromous fisheries project. Phase I. Final Draft. Subtask 7 .10. Prepared for Acres American, Incorporated, by the Alaska Department of Fish and Game/Su Hydro. Anchorage, Alaska. VIII PREFACE REFERENCES (Continued) 198lc. Aquatic habitat and instream flow project. Phase I. Final Draft. Prepared for Acres American, Incorporated, by the Alaska Department of Fish and Game/Su Hydro. Anchorage, Alaska. 1981d. Resident fish investigation on the lower Susitna River. Phase I. Final Draft. Prepared for Acres American, Incorporated by Alaska Department of Fish and Game/Su Hydro. Anchorage, Alaska. 1981e. Resident fish investigations on the lower Susitna River. Phase I. Final Draft. ADF&G Su Hydro Aquatic Studies Program. Anchorage, Alaska. 1981f. Resident fish investigations on the upper Susitna River. Phase I. Final Draft. ADF&G Su Hydro Aquatic Studies Program. Anchorage, Alaska. 1982. Aquatic Studies Program. Phase I. Final Draft. Subtask 7 .10. Prepared for Acres American, Incorporated by the Alaska Department of Fish and Game/Su Hydro. Anchorage, Alaska. IX FOREWARD This volume of the Aquatic Studies Draft Basic Data Report is divided into two parts. Part I, the "Hydrologic and ~Jater Quality Investigations," is a compilation of the physical and chemical data collected by the ADF&G Su Hydro Aquatic Studies team during 1982. These data are arranged by individual variables and geographic location for ease of access to user agencies. The combined data set represents the available physical habitat of the study area within the Cook Inlet to Oshetna River reach of the Susitna River. Part II, the 11 Lower River Fisheries Habitat Investigations," describes the subset of available habitat compiled in Part I that is utilized by the various species and life phases of fish studied in the lower Susitna River (Cook Inlet to Devil Canyon) study area. It represents the first stage of development for a fisheries and habitat relationships analysis report which will be completed in the spring 1983 (refer to Preface). A similar treatment of habitat and fishing data for the upper Susitna River impoundment (Devil Canyon to Oshetna River) study area is presented in Volume 5. X VOLUME PART ONE Factors Influencing Aquatic Habitat R lver Morphology -,- 1 I I FOUR PART TWO Fish Life Phases Influenced by Habitat Timing, Distribution and Population ~ Spawning~ --1 _____ _ Outmlgration Spawning Temperature Figure 4-1. Organization of Volume Four. TABLE OF CONTENTS PREFACE. ••. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I FOREWORD ..••••••. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X LIST OF FIGURES. XVIII LIST OF TABLES .. XXV LIST OF PLATES •• ................................................. .XXVII I LIST OF APPENDIX FIGURES, TABLES, AND PLATES •• CONTRIBUTORS ..•.•.. ACKNOWLEDGEMENTS .• MAP LEGEND •••...•• PART 1 1. OBJECTIVES. 2. METHODS ...• 2.1 Hydrological Investigations •• 2.2 2 .1.1 2 .1. 2 2 .1. 3 Stage and Discharge. 2.1.1.1 2.1.1.2 Thalweg Stage .................................. . 2.1.1.1.1 2.1.1.1.2 Discharge. Profi 1 es .• Mainstem Staff Gage Locations Non-mainstem Staff Gage Locations .••......••. Other Hydrological Components 2.1.3.1 2.1.3.2 Backwater Areas ... Open Channel. Water Quality Investigations ....• XI XXX LXXI LXXIV LXXV 1 5 5 5 5 6 10 12 15 16 16 19 20 TABLE OF CONTENTS (Continued) 2.2.1 Temperatures..................................... 20 2.2.1.1 Surface Water Temperature............... 20 2.2.1.1.1 Instantaneous Surface Water Temperature............... 20 2.2.1.1.2 Continuous Surface Water Temperature............... 21 2.2.1.2 Intragravel Water Temperature........... 24 2.2.1.2.1 Instantaneous Intragravel Water Temperature......... 25 2.2.1.2.2 Continuous Intragravel Water Temperature......... 26 2.2.2 Other Basic Field Parameters..................... 28 2.2.3 Total Dissolved Gases............................ 30 3. RESULTS .•.••.••.•••••••.....•....••..•.•••.•••...••.•.....•.• 34 3.1 Hydrological Investigations ................ ·.•.......•... 34 3.1.1 Stage and Discharge.............................. 34 3.1.1.1 Mainstem Sites Between Talkeetna and Devil Canyon......................... 34 3.1.1.2 Sloughs in the Talkeetna to Devil Canyon of the Susitna River.......... 36 3.1.1.2.1 Upland Sloughs............... 37 3.1.1.2.2 Side Sloughs................. 43 3.1.1.3 Tributaries Between Talkeetna and Devil Canyon..................... 66 3.1.1.4 Mainstem, Sloughs and Tributaries Downstream of Talkeetna.............. 79 3.1.1.4.1 Mainstem Sites............... 85 3.1.1.4.2 Tributaries.................. 89 3.1.1.4.3 Sloughs...................... 100 3.1.1.5 Upstream of Devil Canyon................ 106 3.1.2 Thalweg Profiles................................. 106 3.1.3 Other Hydrological Components.................... 113 XII TABLE OF CONTENTS (Continued) Page 3.1.3.1 Backwater Areas......................... 113 3.1.3.2 Open Channels........................... 141 3.2 Water Quality Investigations............................ 141 3.2.1 Temperature...................................... 141 3.2.1.1 Mainstem Between Talkeetna and Devil Canyon..................... 143 3.2.1.1.1 Surface Water Temperature.... 143 3.2.1.1.2 Intragravel Water Temperature 144 3.2.1.2 Sloughs Between Talkeetna and Devil Canyon......................... 144 3.2.1.2.1 Surface Water Temperature.... 144 3.2.1.2.2 Intragravel Water Temperature 146 3.2.1.3 Tributaries Between Talkeetna and De vi 1 Canyon. • • . • . . . . . . . • . • . . . . . • 148 3.2.1.3.1 Surface Water Temperature.... 148 3.2.1.3.2 Intragravel Water Temperature 149 3.2.1.4 Mainstem, Sloughs and Tributaries Downstream of Talkeetna.............. 150 3.2.1.4.1 Surface Water Temperature.... 150 3.2.1.4.2 Intragravel Water Temperature 153 3.2.1.5 Locations Upstream of Devil Canyon...... 153 3.2.1.5.1 Surface Water Temperature.... 153 3.2.1.5.2 Intragravel Water Temperature 154 3.2.2 Other Basic Field Parameters..................... 154 3.2.2.1 Mainstem and Side Channels Between Talkeetna and Devil Canyon........... 155 3.2.2.2 Sloughs Between Talkeetna and Devil Canyon......................... 155 3.2.2.2.1 Upland Sloughs............... 156 3.2.2.2.2 Side Sloughs................. 157 3.2.2.3 Tributaries Between Talkeetna and Devil Canyon..................... 161 3.2.2.4 Mainstem and Side Channels Downstream of Talkeetna.............. 164 XIII TABLE OF CONTENTS (Continued) Page 3.2.2.5 Sloughs Downstream of Talkeetna......... 165 3.2.2.6 Tributaries Downstream of Talkeetna..... 167 3.2.2.7 Locations Upstream of Devil Canyon...... 169 3.2.3 Total Dissolved Gases............................ 170 4. DISCUSSION................................................... 175 4.1 Hydrological Investigations............................. 175 4.1.1 Stage and Discharge.............................. 175 4.1.2 Thalweg Profiles................................. 180 4.1.3 Other Hydrological Components.................... 180 4.1.3.1 Backwater Areas......................... 180 4.1.3.2 Open Channels........................... 186 4.2 Water Quality Investigations............................ 186 4.2.1 Temperature...................................... 186 4.2.2 Other Basic Field Parameters •....... ~............ 189 4.2.3 Total Dissolved Gases............................ 197 XIV TABLE OF CONTENTS (Continued) PART II 1. OBJECTIVES..................................................... 203 1.1 Adult Anadromous Fish Habitat Investigations ..•••...••••. 203 1.1.1 Salmon Habitat •...•••..•..••••••..•••..••..•..•.•• 204 1.1.1.1 Mainstem ................................. 204 1.1.1.2 Slough ................................... 204 1.1.2 Eulachon Habitat .•.•..•••....•.•••••...••..•.•..•• 205 1.1.3 Bering Cisco Habitat •••••..•...•••••....••..•••... 206 1.2 Juvenile Anadromous Fish Habitat Investigations ••...••.•. 207 1.3 Resident Fish Habitat Investigation •••....••••.••.•••.... 208 2. METHODS •.•••••••••.•...••...••••.•...•.•.•••.••....•••...••.•• 210 2.1 Adult Anadromous Fish Habitat Investigations ••••.•..••.•. 210 2.1.1 General Mainstem and Lower River Studies ........•. 210 2.1.1.1 Mainstem Salmon •.••••....•••.••••..••.•.. 210 2.1.1.2 Eulachon ................................. 213 2.1.1.3 Bering Cisco ..•.••••.•.••••••••.•...•.•.. 216 2.1.2 General Slough and Tributary Studies ...•••••.••.•. 218 2.1.3 Specific Slough Studies •.•..••••..••..•.••..•.•... 219 2. 1. 3 .1 Mode 1 i ng. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220 2.1.3.2 Habitat Availability and Utilization ...•• 221 2.1.3.2.1 Availability .•......•...••...• 221 2.1.3.2.2 Utilization .....••.••..••..... 222 2.1.3.2.3 Water Quality .•....•.••....... 222 2.2 Juvenile Anadromous Fish Habitat Investigations •..•...... 223 2.3 Resident Fish Habitat Investigations .....•..........•.... 232 2.3.1 Mainstem .......................................... 232 2.3.1.1 Radio Telemetry Studies .................. 232 2.3.3.2 Miscellaneous Spawning Fish ........•..... 233 2.3.2 Slough and Tributary .......•....•.....•........... 233 3. RESULTS. . . . • . . . • . . • . . . . • . . . • • . . . . . . . . • • . . . . . . . • . . . . . . . . . . . . . . . 234 3.1 Adult Anadromous Fish Habitat Investigations ............. 234 XV TABLE OF CONTENTS (Continued) 3.1.1 Chum Salmon ....................................... 234 3.1.1.1 Mainstem •....•.....••.••••..••••••.•••... 234 3.1.1.2 Slough ................................... 236 3.1.1.2.1 Modeling .••.••.•.•..••.•...... 236 3.1.1.2.2 Habitat Summaries •...•..••.... 242 3.1.1.2.3 Water Quality .••••....•.•.•... 248 3.1.1.2.4 Available and Utilized Habitats •..•.•.... 259 3.1.1.2.5 General Slough ..••.•••.••..•.. 267 3.1.2 Sockeye Salmon .................................... 267 3.1.3 Pink Salmon; ...................................... 268 3.1.4 Coho Salmon ....................................... 268 3.1.5 Chinook Salmon ..••.•.......••..••...••...•....•.•. 268 3.1.6 Eulachon .......................................... 269 3.1.7 Bering Cisco •..•...•..•.•••.•.•.••.•.....•.••..... 277 3.2 Juvenile Anadromous Fish Habitat Investigations .••....•.. 285 3.3 Resident Fish Habitat Investigations .•••.•.••...••.••..•• 285 3.3.1 Rainbow Trout ...•••..•....•..•.••..••.•...•••..•.. 285 3.3.2 Burbot............................................ 288 3.3.3 Other ............................................. 288 4. DISCUSSION.................................................... 292 4.1 Adult Anadromous Fish Habitat Investigations ............. 292 4.1.1 Salmon Species 292 4.1.1.1 Mainstem ................................. 292 4.1.1.2 Slough ................................... 294 4.1.1.2.1 Spawning Site Selection •...... 294 4.1.1.2.2 Timing of Spawning .........•.• 295 4.1.1.2.3 Access ........................ 301 4.1.1.2.4 Modeling ..••.........••...•... 313 4.1.2 Eulachon .......................................... 315 4.1.3 Bering Cisco •.......•.•...•...••.....••..•........ 323 4.2 Juvenile Anadromous Fish Habitat Investigations .•........ 326 4.2.1 Chum Salmon ....................................... 329 4.2.2 Sockeye Salmon .................................... 333 4. 2. 3 Coho Sa 1 man. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 334 4.2.4 Chinook Salmon ................•..•.•...•.......... 337 XVI TABLE OF CONTENTS (Continued) 4.3 Resident Fish Habitat Investigations .•.••...•.•...•.•••.. 339 4.3.1 Rainbow Trout ••.••.••••••••••.•••.....••..•...••.. 341 4.3.2 Arctic Grayling................................... 345 4.3.3 Burbot ............................................ 348 4.3.4 Round Whitefish ..•••••••••.••......•••...••••.•••• 351 4.3.5 Humpback Whitefish •••.•••••.•••....•••.•••••...••• 354 4.3.6 Longnose Sucker ..........................•........ 356 4.3.7 Other Species •.•.•.••••••••....••....•••..••••••.. 358 4.3.7.1 Dolly Varden .••••••.•..•••.•..•••••..•••. 358 4.3.7.2 Threespine Stickleback ••...•••••..••..••• 359 4.3:7.3 Slimy Sculpin •••••..•....•••••.•••••..•.• 360 4.3.7.4 Arctic Lamprey ........................... 361 5. LITERATURE CITED •.•.••..••...••.•••••.•.••••..•..••.•••••.•••. 362 6. APPENDICES Appendix A Stage/Discharge Data .••..••••....•.••.•••••....••• 4-A-1 Appendix B Slough Availability and Utilization Data •••••.•.•• 4-B-1 Appendix C Temperature Data ••....••.•••...•••..•.....••...... 4-C-1 Appendix D Water Quality Data ••.••••..••......• · ••....••.•... .4-D-1 Appendix E Survey Data ....................................... 4-E-1 Appendix F Habitat Location Description and Photos •..•••...•. 4-F-1 Appendix G Catch Data ........................................ 4-G-1 Appendix H CPUE Data ......•....•.••.•.......•.••....•......•• 4-H-1 Appendix I Habitat Data .....•••.••.•.••..•....•...•.•.•.•.... 4-I-1 Appendix J Ice-Covered Season (1981-82) Habitat Data .••..•.•. 4-J-1 XVI I LIST OF FIGURES Figure 4I-1-1 Figure 4I-2-1 Figure 4I-2-2 Figure 4I-2-3 Figure 4I-2-4 Figure 4I-3-1 Figure 4I-3-2 Figure 4I-3-3 Figure 4I-3-4 Figure 4I-3-5 Figure 4I-3-6 Figure 4I-3-7 Figure 4I-3-8 Figure 4I-3-9 Figure 4I-3-10 General habitat categories of the Susitna River - a conceptual diagram (adapted from AEIDC 1982; Trihey 1982) •••••..•..••.•.•...••. ADF&G staff gage identification system .•••••.• Mainstem and Yentna River staff gage locations in the Cook Inlet to Talkeetna reach (RM 103.0) of the Susitna River ...•.•.•• Mainstem staff gage locations in the Talkeetna (RM 103.0) to Devil Canyon (RM 148.8) reach of the 2 7 8 Susitna River................................. 9 Susitna River mainstem and tributary thermograph locations......................... 22 Gradient of the Susitna River from Talkeetna to Portage Creek.................... 35 Planimetric site map of Slough 6A, RM 112.3, GC S28N05W13CAC..................... 38 Planimetric site map of Slough 19, RM 140.0, GC S31N02W10DBB..................... 40 Planimetric site map of Whiskers Creek/ Slough, RM 101.2, GC S26N05W03AAC............. 44 Whiskers Creek Slough stage-discharge rating curve................................. 47 Planimetric site map of Lane Creek/ Slough, RM 113.6, GC S28N05W12ADD............. 48 Lane Creek Slough stage-discharge rating curve.................................. 50 Slough 9 stage-discharge rating surve......... 51 Planimetric site map of Slough 11, RM 135.3, GC S31N02W19DDD..................... 53 Planimetric site map of Slough 16B, RM 138.0, GC S31N02W17 ABC. . . . . . . . . . . • • • . . . . . . . 55 XVIII LIST OF FIGURES (Continued) Figure 4I-3-ll Figure 4I-3-12 Figure 4I-3-13 Figure 4I-3-14 Figure 4I-3-15 Figure 4I-3-16 Figure 4I-3-17 Figure 4I-3-18 Figure 4I-3-19 Figure 4I-3-20 Figure 4I-3-21 Figure 4I-3-22 Figure 4I-3-23 Figure 4I-3-24 Figure 4I-3-25 Figure 41-3-26 Figure 4I-3-27 Figure 4I-3-28 Slough 168 stage-discharge rating curve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Planimetric site map of Slough 20, RM 140.1, GC S31N02W11BBC..................... 58 Slough 20 stage-discharge rating curve........ 60 Planimetric site map of Slough 21, RM 142.0, GC S31N02W02AAA..................... 61 Slough 21 stage-discharge rating curve....... 63 Planimetric site map of Slough 22 RM 144.3, GC S32N02W32BBD..................... 65 Slough 22 stage-discharge rating curve....... 67 Whiskers Creek stage-discharge rating curve... 70 Planimetric site map of Gash Creek, RM 111.5, GC S28N02W24ADA..................... 72 Stage-discharge rating curve for Lane and Gash Creeks................................... 73 Planimetric site map of Fourth of July Creek, RM 131.1, GC S30N03W03DAC.............. 75 Stage-discharge rating curve for unnamed tributary at the head of Slough 20........... 76 Planimetric site map of Indian River, RM 138.6, GC S31N02W09CDA..................... 77 Planimetric site map of Portage Creek, RM 148.8, GC S32N01W25CDB..................... 78 Stage-discharge rating curves for Indian River and Portage Creek....................... 84 Gradient of the Susitna River from Cook Inlet to Talkeetna............................ 86 Planimetric site map of Goose Creek 2/ Slough, RM 73.1, GC S23N04W30DBC.............. 91 Stage-discharge rating curve for Goose Creek 2. . . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 XIX LIST OF FIGURES (Continued) Figure 4I-3-29 Figure 4I-3-30 Figure 4I-3-31 Figure 4I -3-32 Figure 4I-3-33 Figure 4I-3-34 Figure 4I-3-35 Figure 4I-3-36 Figure 4I-3-37 Figure 4I-3-38 Figure 4I-3-39 Figure 4I-3-40 Figure 4I-3-41 Figure 4I-3-42 Figure 4!-3-43 Figure 4I-3-44 Figure 4I-3-45 Planimetric site map of Rabideux Creek/Slough RM 83.1 GC S24N05W16ADC....................... 94 Stage-discharge rating curves for Rabideux and Sunshine Creeks........................... 95 Planimetric site map of Sunshine Creek/Slough, RM 85.7, GC S24N05W14AAB...................... 96 Planimetric site map of Birch Creek/Slough, RM 88.4, GC S25N05W25DCC...................... 98 Stage-discharge rating curves for Birch Creek and Birch Creek Slough........................ 99 Planimetric site map of Whitefish Slough, RM 78.7, GC S23N05W01BBC ••••••••.•....•..•.... 102 Stage-discharge rating curve for Whitefish Slough........................................ 103 Streambed Profile for Slough 8A .......••.•...• Streambed Profile for Slough 9 ................ Streambed Profile for Slough 11 ............... Streambed Profile for Slough 21 Complex ..•.... Aggregate type II water surface area at Slough 21 versus mainstem 107 108 109 110 discharge at Gold Creek ....................... 115 Aggregate type II water surface area at Slough 20 versus mainstem discharge at Gold Creek ....••••••••.•••..•.•.. 118 Aggregate type II water surface area at Slough 19 versus mainstem discharge at Gold Creek ....••.•.............•• 119 Aggregate type II water surface area at Slough 11 versus mainstem discharge at Gold Creek ..............•......•. 121 Aggregate type II water surface area at Slough 9 versus mainstem discharge at Gold Creek ...•..•.......•..•..... 122 Aggregate type II water surface area at Slough 8A versus mainstem discharge at Gold Creek .•••.•....••...•..•...• 124 XX LIST OF FIGURES Figure 4I-3-46 Figure 4I-3-47 Figure 4I-3-48 Figure 4I-3-49 Figure 4I-3-50 Figure 4I-3-51 Figure 4I-3-52 Figure 4I-3-53 Figure 4I-3-54 Figure 4I-3-55 Figure 4I-3-56 Figure 4I-4-1 (Continued) Aggregate type II water surface area at Lane Creek versus mainstem discharge at Gold Creek ....•...•••.•• Aggregate type II water surface area at Slough 6A versus mainstem discharge at Gold Creek •••••...••••••.••...••• Aggregate type II water surface area at Whiskers Creek/Sidechannel versus mainstem discharge at Gold Creek .••.....••.•.. Aggregate type II water surface area at Birch Creek/Slough versus mainstem discharge at Sunshine •..•..•..•.•••.. Aggregate type II water surface area at Sunshine Creek/Sidechannel versus mainstem discharge at Sunshine .••...••• Aggregate type II water surface area at Rabideux Creek/Slough Page 126 128 129 132 134 versus mainstem discharge at Sunshine .•.•••.•. 136 Aggregate type II water surface area at Whitefish Slough versus mainstem discharge at Sunshine ......••......•• 138 Aggregate type II water surface area at Goose Creek 2/Sidechannel versus mainstem discharge at Sunshine ••.•..... 140 Percent concentration of total dissolved gas versus distance below the Devil Canyon proposed dam site .....•.••... 171 Concentrations of dissolved gases in Devil Canyon rapids complex ..••....•.•.•.•. 173 Mean daily discharge versus saturometer readings below Devil Canyon........................................ 174 Total surface area of aggregate type II water within the study boundaries of nine upper reach sites versus Susitna River discharge at Gold Creek (USGS Provision a 1 Data).. . • . . . . . . . . . . . . . . . . . • . 184 XXI LIST OF FIGURES (Continued) Figure 4I-4-2 Figure 4I-4-3 Figure 4II-2-1 Figure 4II-2-2 Figure 4II-3-1 Figure 4II-3-2 Figure 4II-3-3 Figure 4II-3-4 Figure 4II-3-5 Figure 4II-3-6 Figure 4II-3-7 Total surface area of aggregate type II water within the study boundaries of five lower reach sites versus Susitna River discharge at Sunshine (USGS Provisional Data) .•••.•••••.•.•••••••••• 185 Dissolved gas decay rates versus Gold Creek discharge with dissolved gas data below Libby Dam, Kootenai River, Montana, provided as a comparison (Source U.S. Army Corps of Engineers, T. Bonde, Seattle, WA) .•.•.•.•.. 200 Hypothetical slough, with associated tributary, showing hydraulic zones present at three different levels of mainstem discharge ............................ 226 Location of Designated Fish Habitat sites on the Susitna River, Goose Creek 2 to Portage Creek ••.•••.••.•..•.• 228 Location of the mainstem chum salmon spawning sites on the upper Susitna River: September 4-15, 1982 ..••••••..••••.... 235 Water depths and velocities (mean and range) of Chum Channel transects at three discharges in 1982 •.....••...••.....•.•.•..... 260 Water depths and velocities (mean and range) of Rabideux Slough transects at two discharges in 1982 ...•••.......•••••...•••...• 261 Water depths and velocities (mean and range) of Slough 8A transects at three dis- charges in 1982 .••..•••••..•••..••...•••...•.. 262 Water depths and velocities (mean and range) of Slough 9 transects at four dis- charges in 1982 ...••.••••..•...........•.....• 263 Water depths and velocities (mean and range) of Slough 21 transects at three dis- charges in 1982 ........•.•..••...............• 265 Water depths and velocities (mean and range) available (A) and utilized (U) for chum salmon redds in three sloughs during August 25-26 (Q 1 ) and September 2-7 (02), 1982 .......•..•••..........••........... 266 XXII LIST OF FIGURES (Continued) Figure 4II-3-8 Figure 4II-3-9 Figure 4II-3-10 Figure 4II-3-11 Figure 4II-3-12 Figure 4II-3-13 Figure 4II-3-14 Figure 4II-3-15 Figure 4II-3-16 Eulachon spawning sites surveyed for habitat characteristics on the Susitna River: May 24-June 7, 1982 ..•.•..•. 270 Surface water temperature, pH, specific conductance and dissolved oxygen at 20 eulachon spawning areas on the Susitna River: May 24-June 7, 1982 ••••..... 274 Water depths and velocities (mean and range) at 20 eulachon spawning sites on the Susitna River: May 24 - June 7, 1982.................................. 275 Water temperatures for the Susitna River at Susitna Station (RM 25.5): May 16-June 10, 1982 .•••....•...••••...•.••. 278 Provisional discharge (USGS 1982b) and daily mean water temperatures for the Susitna River at Susitna Station (RM 25.5) compared with CPUE (catch/minute/net) for the gill net set at RM 5.0: May 17-June 10, 1982 ..•.••.....••.••.•..••.• 279 Bering cisco catch per day at the Sunshine fishwheel compared with daily mean surface water temper- atures of the Susitna River at Sunshine (RM 84.0) and provisional discharge at Sunshine (USGS 1982b): September 1982 ..•••....••..••.....••....•....• 283 Bering cisco catch per day at the Sunshine fishwheel compared with daily mean surface water temper- ature of the Susitna River above Montana Creek (RM 77.5) and pro- visional discharge (USGS 1982a) at Sunshine (RM 84.0): August 25 - September 30, 1981 ...•••..•.••................ 284 Movement of five radio-tagged rainbow trout in the Susitna River: October 1981 through April 1982 ........•..•.•• 286 Movement of five radio-tagged burbot in the Susitna River: October 1981 through April 1982.................................... 289 XXIII LIST OF FIGURES {Continued) Figure 4II-4-1 Figure 4II-4-2 Figure 4II-4-3 Figure 4II-4-4 Figure 4II-4-5 Figure 4II-4-6 Numbers of live salmon counted in August and September, 1982 in Sloughs SA, 9, 11, 21 and others ( 1, 2, 3A, 38, 4, 5, 6, 6A, 7, 8, 88, 8C, 8D, A, 9A, 98, 10, 12, 13, 14, 15, 16, 17, 18, 19, 20) •••••••.•••.•••..•. 297 Factors limiting salmon spawning in sloughs ... 302 Backwater profiles at the entrance to Slough 9 for selected mainstem streamflows at Gold Creek ...••••••..•.••..•.•. 307 Water surface elevation and depths of Slough 9 (Figure 4II-4-3) versus mainstem discharge (Provisional USGS 1982b) at Gold Creek .••.••..•....•••.••....••••.•.... 309 Rainbow trout catch per unit of trotline effort by aggregate water source zones at Designated Fish Habitat (DFH) sites on the Susitna River between Goose Creek 2 and · Portage Creek: June through September, 1982 ............................... 343 Burbot catch per unit of trotline effort by aggregate water source zones at Designated Fish Habitat (DFH) sites on the Susitna River between Goose Creek 2 and Portage Creek: June through September, 1982.......................................... 350 XXIV LIST OF TABLES Table 4I-3-1 Table 4I-3-2 Table 4I-3-3 Table 4I-3-4 · Table 4I-3-5 Table 4I-3-6 Table 4I-3-7 Table 4I-4-1 Comparison of periodic measurements of slough flow at selected sloughs upstream of Talkeetna to the corresponding mean daily mainstem discharge at Gold Creek (USGS gaging station 15292000)................ 41 Determination of the mainstem dis- charge at Gold Creek (cfs) required to breach the upstream end (head) of selected side sloughs in the Talkeetna to Devil Canyon Reach............... 45 A comparison of water surface elevation (WSEL) and discharge measurements at selected tributary streams upstream of Talkeetna to the mean daily Susitna River discharge recorded at Gold Creek (USGS gaging station 1529200).............................. 68 Daily mean streamflow and surface water temperature record for Indian River, Alaska................................. 80 Daily mean streamflow and surface water temperature record for Portage Creek, Alaska................................. 82 A comparison of water surface elevation (WSEL) at Sunshine Fishwheel Camp (RM 79.2) to the mean daily Susitna River discharge recorded at Sunshine (USGS gaging station 15292780)............................ 87 A comparison of the relative water surface elevation (WSEL) at the Yentna Fishwheel Camp to the mean daily Yentna River and Susitna River discharge (cfs)............................... 90 Total surface areas of type II hydraulic zones within the boundaries of nine study areas on the upper Susitna River versus Gold Creek discharge, June through September, 1982.......................................... 182 XXV LIST OF TABLES (Continued) Table 41-4-2 Table 4II-2-1 Table 4II-3-1 Table 4II-3-2 Table 4II-3-3 Table 4II-3-4 Table 411-3-5 Table 411-3-6 Table 4II-3-7 Total surface areas of type II hydraulic zones within the boundaries of five study areas on the lower Susitna River versus Sunshine station discharge, June through September, 1982....... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183 Description of hydraulic zones sampled at Designated Fish Habitat sites: June-September, 1982.......................................... 225 Water quality at chum salmon spawning sites on the Susitna River: September 4-14, 1982 •••••••••••....•.. 239 Water depths, velocities and substrates at chum salmon spawning sites on the Susitna River: September 4-14, 1982 ••.................•••.... 240 Data summary of intragravel temperatures obtained at 1982 ADF&G study transects (Sloughs 8A, 9, 21) and specified locations (Sloughs 9B and 11) from September 30 to October 5, 1982 .•••.•.......••••.•..•...••••.. 250 Data summary for surface water temperatures (°C) at specified locations in Sloughs 8A, 9, 9B and 11 collected during October 1-5, 1982 (raw data in Appendix D) ••.••...•............. 251 Data summary for substrate/water interface temperatures (°C) collected at specified locations in Sloughs 8A, 9, 98, 11 and 21 during October 1-5, 1982 (raw data in Appendix D) ............•.... 252 Data summary for intragravel tempera- tures (°C) collected at specified locations in Sloughs 8A, 9B, 11 and 21 during October 1-5, 1982 (raw data in Appendix D) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254 Data summary for specific conductance (umhos/cm), collected at specified locations in Sloughs 8A and 9 during October 3-5, 1982 (raw data in Appendix D) ....•....•........••............... 256 XXVI LIST OF TABLES (Continued) Table 4II-3-8 Table 4II-3-9 Table 4II-3-10 Tab 1 e 4II-3-11 Table 4!!-3-12 Table 4II-3-13 Tab 1 e 4!!-3-14 Table 4!!-4-1 Table 4II-4-2 Table 4!1-4-3 Eulachon spawning site evaluations on the Susitna River: May 24 - June 7, 1982. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272 Miscellaneous eulachon spawning site habitat evaluations on the Susitna River: May 16 - June 12, 1982 .....••..•.••••••••.••••••••..••• 276 Bering cisco spawning site habitat evaluations for RM 76.8-77.6 on the Susitna River: October 14, 1982 •....••.....•• 281 Water temperatures and discharges at Bering cisco spawning sites: 1981-1982..................................... 282 Water quality and quantity and substrate at overwintering areas utilized by radio tagged rainbow trout during 1981 ..••..•.•••.••••••..••••..••• 287 Water quality and quantity at overwintering areas utilized by radio tagged burbot during 1981 •••.....•..••.. 290 Spawning site habitat evaluations for longnose sucker and arctic lamprey: 1982................................ 291 Comparison of Slough 9 discharge with the average daily mainstem discharge at Gold Creek .....•..•....•.•....... 305 Comparison of water surface elevations (WSEL) at the entrance to Slough 9 and the average daily mainstem dis- charge at Gold Creek, 1982 ••..••.....••....•.. 308 Entrance conditions at the mouth of Slough 9 at various mainstem discharges at Gold Creek when slough discharge was 3 cfs ......................................... 311 XXVII LIST OF PLATES Plate 4II-2-1 Plate 4II-3-1 Plate 4II-3-2 Plate 4II-3-3 Plate 4II-3-4 Plate 4II-4-1 Plate 4II-4-2 Plate 4II-4-3 Plate 4II-4-4 Plate 4II-4-5 Plate 4II-4-6 Plate 4II-4-7 Electroshocking on the mainstem Susitna River •..•.•••..•.•...••••.•.•••••..••. 211 Chum salmon spawning area on the Susitna River at RM 114.4 (GC S28N04W06CAB): September 9, 1982 .•.•••••.•..• 237 Chum salmon spawning area on the Susitna River at RM 128.6 (GC S30N03W16BCA): September 7, 1982 •••••••...••. 238 Seepage of ground water sources into Slough 21 •.•••••••.•.••••••••...••.•••.•. 246 Upwelling ground water in silted area of Slough 21 .••••••.••••.••.••..•••..•.•. 247 Chum salmon spawning in silted area of Slough 21. Note: fish have fanned silt from spawning area •.•.••..... 296 Chum salmon stranded in riffle during low flow condition in Slough 9, inhibiting access to spawning areas ..••••.••.....•.•..•.. 312 Male and female eulachon taken from the Susitna River at RM 21.4: June 1, 1982.................................. 316 Upstream movement of eulachon along the west bank of the Susitna River at RM 16.5: June 1, 1982 •.......••......••.•.• 318 Upstream movement of eulachon creating a visible surface wave along the east bank of the Susitna River at RM 15.0: June 6, 1982 .................................. 319 Milling fish in what appeared to be spawning behavior along the east bank of the Susitna River at RM 15.0: June 6, 1982 ........•..••.....•.. 320 Milling fish in what appears to be spawning behavior along the east bank of the Susitna River at RM 15.0: June 6, 1982 •.....•........•.•••• 321 XXV I II LIST OF PLATES (Continued) Plate 4II-4-8 Accumulation of dead eulachon along the east bank of the Susitna River at RM 15.0: June 6, 1982.................................. 322 XXIX LIST OF FIGURES Figure 4-A-1 Figure 4-A-2 Figure 4-A-3 Figure 4-A-4 Figure 4-A-5 Figure 4-A-6 Figure 4-A-7 Figure 4-A-8 Figure 4-A-9 APPENDIX A Mainstem discharge (Provisional USGS 1982b) versus mainstem water surface elevation at left bank of LRX-6 and Whiskers Creek Slough .•.......••.. 4-A-3 Mainstem discharge (Provisional USGS 1982b) versus mainstem water surface elevation at Talkeetna Fishwheel Camp and right bank of LRX-9 ••..•..•..•.•.•..•..• 4-A-4 Mainstem discharge (Provisional USGS 1982b) versus mainstem water surface elevation at side channel of Gash Creek and head of Gash Creek side channel ..••.••.• 4-A-5 Mainstem discharge (Provisional USGS 1982b) versus mainstem water surface elevation at Slough 6A and right bank of LRX-18 •••.•..••.•....•....•••..•••••.••.. 4-A-6 Mainstem discharge (Provisional USGS 1982b) versus mainstem water surface elevation at Curry Fishwheel Camp and right bank of LRX-24 .•.•.••...••.•••........ 4-A-7 Mainstem discharge (Provisional USGS 1982b) versus mainstem water surface elevation at right bank of LRX-28 and right bank of LRX-29 ....••...•............•• 4-A-8 Mainstem discharge (Provisional USGS 1982b) versus mainstem water surface elevation at right bank of LRX-31 and right bank of LRX-35 •••.••.•....••.......... 4-A-9 Mainstem discharge (Provisional USGS 1982b) versus mainstem water surface elevation at Fourth of July Creek and left bank of LRX-40 .•..•••.....•.......•.... 4-A-10 Mainstem discharge (Provisional USGS 1982b) versus mainstem water surface elevation at side channel below mouth of Slough 11 and side channel above mouth of Slough 11 .....•.•..•......••....... 4-A-11 XXX LIST OF FIGURES (Continued) Figure 4-A-10 Figure 4-A-11 Figure 4-A-12 Figure 4-A-13 Figure 4-A-14 Figure 4-A-15 Figure 4-A-16 Figure 4-A-17 Figure 4-A-18 Figure 4-A-19 Figure 4-A-20 Mainstem discharge (Provisional USGS 1982b) versus mainstem water surface elevation at Slough 168 mouth and head •...•• 4-A-12 Mainstem discharge (Provisional USGS 1982b) versus mainstem water surface elevation at left bank of LRX-50 and left bank of LRX-51 .•.•.•.•.•..•••..•••...•. 4-A-13 Mainstem discharge (Provisional USGS 1982b) versus mainstem water surface elevation at Slough 19 and right bank of LRX-53 .............................. 4-A-14 Mainstem discharge (Provisional USGS 1982b) versus mainstem water surface elevation at head of Slough 20 and at LRX-54 ...................•.................. 4-A-15 Mainstem discharge (Provisional USGS 1982b) versus mainstem water surface elevation at right bank of LRX-56 and right bank of LRX-57 ...•.••....• ~ ••••.....•• 4-A-16 Mainstem discharge (Provisional USGS 1982b) versus mainstem water surface elevation at head of Slough 22 and left bank of LRX-61 •.•••.•.•...•....••.••..• 4-A-17 Mainstem discharge (Provisional USGS 1982b) versus mainstem water surface elevation at left bank of LRX-62 •.•.••....•• 4-A-18 Mainstem discharge (Provisional USGS 1982b) versus the water surface elevation at Slough 6A mouth and Slough 19 mouth ............................. 4-A-19 Mainstem discharge (Provisional USGS 1982b) versus the water surface elevation at Whiskers Slough mouth and mid-slough .............................. 4-A-20 Mainstem discharge (Provisional USGS 1982b) versus the water surface elevation at head of Whiskers Creek Slough .•.•....•...•..........••.........•.. 4-A-21 Mainstem discharge (Provisional USGS 1982b) versus the water surface elevation at Lane Creek Slough mid-slough and head .................•....... 4-A-22 XXXI LIST OF FIGURES (Continued) Figure 4-A-21 Figure 4-A-22 Figure 4-A-23 Figure 4-A-24 Figure 4-A-25 Figure 4-A-26 Figure 4-A-27 Figure 4-A-28 Figure 4-A-29 Figure 4-A-30 Figure 4-A-31 Mainstem discharge (Provisional USGS 1982b) versus the water surface elevation at Slough 11 mouth and mid-slough .............................. 4-A-23 Mainstem discharge (Provisional USGS 1982b) versus the water surface elevation at head of Slough 11 •.•.••••••••• 4-A-24 Mainstem discharge (Provisional USGS 1982b) versus the water surface elevation at Slough 16B mouth and mid-slough •............................. 4-A-25 Mainstem discharge (Provisional USGS 1982b) versus the water surface elevation at head of Slough 16B ..•••••.••.• 4-A-26 Mainstem discharge (Provisional USGS 1982b) versus the water surface elevation at Slough 20 mouth and mid-slough .............................. 4-A-27 Mainstem discharge (Provisional USGS 1982b) versus the water surface elevation at head of Slough 20 •••..•.•••••. 4-A-28 Mainstem discharge (Provisional USGS 1982b) versus the water surface elevation at Slough 21 mouth and mid-slough .............................. 4-A-29 Mainstem discharge (Provisional USGS 1982b) versus the water surface elevation at the NW and NE heads of Slough 21 ................................... 4-A-30 Mainstem discharge (Provisional USGS 1982b) versus the water surface elevation at Slough 22 mouth and mid-slough ••.•.•....••..•.•...••..••.... 4-A-31 Mainstem discharge (Provisional USGS 1982b) versus the water surface elevation at head of Slough 22 .....••••..•. 4-A-32 Cross sections of the head, mid- slough and mouth of Whiskers Creek Slough depicting the water surface elevation corresponding to the slough and mainstem discharge .......•...•.......... 4-A-33 XXXII LIST OF FIGURES (Continued) Figure 4-A-32 Figure 4-A-33 Figure 4-A-34 Figure 4-A-35 Figure 4-A-36 Figure 4-A-37 Figure 4-A-38 Figure 4-A-39 Figure 4-A-40 Figure 4-A-41 Cross sections of the head and mid- slough of Lane Creek Slough depicting the water surface elevation corresponding to the slough and mainstem discharge .•••...• 4-A-34 Cross sections of the head, mid-slough and mouth of Slough 11 depicting the water surface elevation corresponding to the slough and mainstem discharge •••...•• 4-A-35 Cross sections of the head, mid-slough, mouth and access to Slough 168 depicting the water surface elevation corresponding to the slough and mainstem discharge ..•..•.. 4-A-36 Cross sections of the head, mid-slough and mouth of Slough 20 depicting the water surface elevation corresponding to the slough and mainstem discharge •.•....•.••..•. 4-A-37 Cross sections of the head, mid-slough and mouth of Slough 22 depicting the water surface elevation corresponding to the slough and mainstem discharge .••...•.••. ~ •.. 4-A-38 Cross sections of Slough 8A at 1982 ADF&G survey transects at three discharges: A= 20 cfs, B = 7 cfs, C = 4 cfs .•.....••....•...•••.••...••••...•• 4-A-39 Cross sections of Slough 9 at 1982 ADF&G survey transects at four discharges: A= 232 cfs, B = 145 cfs, C = 8 cfs, D = 3 cfs ..•.•...•••••....•..•••. 4-A-41 Cross sections of Slough 21 at 1982 ADF&G survey transects at three discharges: A= 157 cfs, B = 10 cfs, C = 5 cfs ................................... 4-A-43 Cross sections of Rabideux Slough at 1982 ADF&G survey transects at two discharges: A= 281 cfs, B = 0.3 cfs ••..... 4-A-44 Cross sections of Chum Channel at 1982 ADF&G survey transects at three discharges: A= 90 cfs, B = 7 cfs, C = 0.4 cfs .••..•.....•.•••....•....•.....•• 4-A-45 XXX II I LIST OF TABLES Table 4-A-1 Table 4-A-2 Table 4-A-3 Table 4-A-4 Table 4-A-5 Table 4-A-6 Table 4-A-7 APPENDIX A Discharge measurements obtained in sloughs and tributaries during the open water season of 1982 from within the Susitna River Basin ••••.•....••••....• 4-A-46 Comparison of mainstem water surface elevation to mean daily mainstem discharge (cfs), obtained at the USGS gaging station at Gold Creek .•.••.•••••..••...••• 4-A-56 Comparison of periodic water surface elevations (WSEL) at selected sloughs upstream of Talkeetna to the correspond- ing average daily mainstem discharge at Gold Creek .•.••••....•••••••..•.•••••.. 4-A-66 Continuous hourly streamflow and surface water temperature record· for Indian River, Alaska •••••••••...••••... 4-A-75 Continuous hourly streamflow and surface water temperature record for Portage Creek, Alaska ••••.•.•........•• 4-A-124 Comparison of periodic water surface elevations (WSEL) and measured flow at selected sites located downstream of Talkeetna to the corresponding average daily mainstem discharge at Sunshine (USGS gaging station 15292780) •••.••.•••.• 4-A-173 Surface area of aggregate type II hydraulic zones at Designated Fish Habitat sites and mainstem Susitna River discharges, June through September, 1982 ••••.••••••.•..••..••....•. 4-A-179 XXXIV LIST OF TABLES Table 4-B-1. Table 4-B-2. Table 4-B-3. Table 4-B-4. Table 4-B-5. Table 4-B-6. Table 4-B-7 Table 4-B-8. Table 4-B-9. Table 4-B-10. Table 4-B-11. Table 4-B-12. APPENDIX B Velocities (ft/sec) and depths (ft) in Chum Channel at three different discharges, 1982 .................. Velocities (ft/sec) and depths (ft) in Rabideux Slough at three different discharges, 1982 .................. Velocities (ft/sec) and depths (ft) in Slough 8A at three different discharges, 1982 •••....•••••••.... Velocities (ft/sec) and depths (ft) in Slough 9 at three different discharges, 1982 •••••..•....••...• Velocities (ft/sec) and depths (ft) in Slough 21 at three different discharges, 1982 ..•..• ~ ••.••••.... Hydraulic habitat variables collected at transects in Slough 8A, August 22, 1982 .•••••••...•.••.•......•••..• Hydraulic habitat variables collected at transects in Page 4-B-2 4-B-3 4-B-4 4-B-5 4-B-6 4-B-7 Slough 8A, August 26, 1982 ••..••......••...• 4-B-16 Hydraulic habitat variables collected at transects in Slough 8A, September 7, 1982 ••.•.•..••••.... 4-B-18 Hydraulic habitat variables collected at transects in Slough 8A, September 19, 1982 ••.•••..•.•••.. 4-B-28 Hydraulic habitat variables collected at transects in Slough 9, August 12, 1982 •...•••.••..•.....• 4-B-37 Hydraulic habitat variables collected at transects in Slough 9, August 25, 1982 .•...........•....• 4-B-44 Hydraulic habitat variables collected at transects in Slough 9, September 4, 1982 .....•...••.•.... 4-B-52 XXXV LIST OF TABLES (Continued) Table 4-B-13. Table 4-B-14. Table 4-B-15. Table 4-B-16. Table 4-B-17. Table 4-B-18. Table 4-B-19. Table 4-B-20. Table 4-B-21. Table 4-B-22. Hydraulic habitat variables collected at transects in Slough 9, September 18, 1982 ..•••..•..•••••. 4-B-61 Hydraulic habitat variables collected at transects in Slough 9, September 20, 1982 •••••....•••..•• 4-B-67 Hydraulic habitat variables collected at transects in Slough 21, September 2, 1982 •••••....•.••••. 4-B-72 Hydraulic habitat variables collected at transects in Slough 21, September 17, 1982 •.•••....••••.. 4-B-78 Hydraulic habitat variables collected at transects in Slough 21, September 19, 1982 .••..•..•.••••. 4-B-84 Depths (ft) and velocities (ft/sec) associated with chum salmon redds in four sloughs at three discharges (Q, cfs) in 1982 ••..••....••••.••....•.•.•.. 4-B-90 Depths (ft) and velocities (ft/sec) associated with pink salmon and sockeye salmon redds in three sloughs at three discharges (Q, cfs) in 1982 ..................................... 4-B-91 Hydraulic habitat variables collected at chum redds. (Transect number indicates the transect area in which the redd was located) ....•....•.... 4-B-92 Hydraulic habitat variables collected at sockeye redds. (Transect number indicates the transect area in which the redd was located) ...••.......••••...••.• 4-B-98 Hydraulic habitat variables collected at pink redds. (Transect number indicates the transect area in which the redd was located) ..•......•.•..•...•............ 4-B-100 XXXVI LIST OF TABLES Table 4-C-1 Table 4-C-2 Table 4-C-3 Table 4-C-4 Table 4-C-5 Table 4-C-6 Table 4-C-7 Table 4-C-8 Table 4-C-9 Table 4-C-10 Table 4-C-11 APPENDIX C ADF&G Susitna River Basin continuous temperature data index, 1981-1982 •••••••... 4-C-2 Thermograph data summary, summer surface water temperature (C), Su Station, RM 25.8, GC S17N07W22DCD ....•••••... 4-C-7 Thermograph data summary, summer surface water temperature (C), Yentna Fishwheel, RM 30.1, TRM 4.0 GC S18N07W34DBC •••...••••••••.•••••••••..•••• 4-C-9 Thermograph data summary, summer surface water temperature (C), Susitna River-Upstream of Yentna River, RM 29.5, GC S17N06W07CAD ...••....•••• 4-C-14 Thermograph data summary, summer surface water temperature (C), · Parks Highway Bridge West, RM 83.9 GC S24N05W15BAB •...•.•.•..•••.••..•••••••••• 4-C-19 Thermograph data summary, summer surface water temperature (C), Parks Highway Bridge East, RM 83.9 GC S24N05W15BAD •••.•....•••••••..•••••••.... 4-C-21 Thermograph data summary, summer surface water temperature (C), LRX 1, RM 97.0, GC S26N05W23DCB •...••..•••.. 4-C-24 Thermograph data summary, summer surface water temperature (C), Talkeetna River, RM 97.2, TRM 1.5, GC S26N05W24BDA •••.•..•..•.•.•......•..•.•.. 4-C-25 Thermograph data summary, summer surface water temperature (C), Chulitna River, RM 98.6, TRM 0.6, GC S26N05W14CBC •....••...•...•••.........•.. 4-C-30 Thermograph data summary, summer surface water temperature (C), Talkeetna Fishwheel, RM 103.0, GC S27N05W26DDD .........•.•....•............ 4-C-34 Thermograph data summary, summer surface water temperature (C), LRX 18, RM 113.0, GC S28N04W12DAB .......•••• 4-C-39 XXXVII LIST OF TABLES (Continued) Table 4-C-12 Table 4-C-13 Table 4-C-14 Table 4-C-15 Table 4-C-16 Table 4-C-17 Table 4-C-18 Table 4-C-19 Table 4-C-20 Table 4-C-21 Table 4-C-22 Thermograph data summary, summer surface water temperature (C), Curry Fishwheel, RM 120.7, GC S29N04W10CBB •..•.••..•••••.•••.••••.••.•• 4-C-43 Thermograph data summary, summer surface water temperature (C), Slough SA-Area of R&M Stage Recorder, RM 126.0, GC S30N03W30BCA ••....••• 4-C-46 Thermograph data summary, summer surface water temperature (C), LRX 29, RM 126.1, GC S30N03W19DCA~ ••••..•... 4-C-50 Thermograph data summary, summer surface water temperature (C), Slough 9-Area of R&M Stage Recorder, RM 129.2, GC S30N03W16ACB .•.•••..• 4-C-54 Thermograph data summary, summer surface water temperature (C), LRX 35, RM 130.8, GC S30N03W03DCA ••••....••• 4-C-58 Thermograph data summary, summer surface water temperature (C), Indian River, RM 138.6, GC S31N02W09CDA ....• 4-C-59 Thermograph data summary, summer surface water temperature (C), LRX 53, RM 140.1, GC S31N11W10AAC ....••....• 4-C-62 Thermograph data summary, summer surface water temperature (C), Slough 21-Area of R&M Stage Recorder, RM 142.0, GC S32N02W36CCC •....•.•. 4-C-64 Thermograph data summary, summer surface water temperature (C), Portage Creek, RM 148.8, TRM 0.1, GC S32N01W25CAB ....••...•.•..••.....•••••.•. 4-C-68 Thermograph data summary, summer surface water temperature (C), Tsusena Creek, RM 181.3, GC S32N04E36ADB .....•...••..••.............. 4-C-71 Thermograph data summary, summer surface water temperature (C), Watana Creek, RM 194.1, GC S32N06E25CCA ....................••....••. 4-C-76 XXXVIII LIST OF TABLES Table 4-C-23 Table 4-C-24 Table 4-C-25 Table 4-C-26 Table 4-C-27 Table 4-C-28 Table 4-C-29 Table 4-C-30 Table 4-C-31 (Continued) Thermograph data summary, summer surface water temperature (C), Kosina Creek, RM 206.8, GC S31N08E15BAB •....•••••.•••••.•.••..••••• Thermograph data summary, summer surface water temperature (C), Goose Creek, RM 231.3, GC S30N11E32DBC .••.•••..••••••.•......••••. Thermograph data summary, summer surface water temperature (C), Oshetna River, RM 233.4, GC S30N11E34CCD .•....•...••••.••••..••••... Weekly minimum, mean and maximum summer surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Su Station, RM 25.8, GC S17N07W22DCD .•.••........••.•. Weekly minimum, mean and maximum summer surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Yentna Fishwheel RM 28.0, TRM 4.0, GC S18N07W34DBC .•••••... Weekly minimum, mean and maximum summer surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Susitna River- Upstream of Yentna River, RM 29.5, GC S17N06W07CAD ........••••••....•..•••..• Weekly minimum, mean and maximum summer surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Parks Highway Bridge-West, RM 83.9, GC Page 4-C-81 4-C-86 4-C-91 4-C-95 . 4-C-96 4-C-97 S24N05W15BAB ...•.......••••....•.•....•... 4-C-98 Weekly minimum, mean and maximum summer surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Parks Highway Bridge-East, RM 83.9, GC S24N05W15BAD ..... 4-C-99 Weekly minimum, mean and maximum summer surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, LRX 1, RM 97.0, GC S26N05W23DCB .•.......•..••..... 4-C-100 XXXIX LIST OF TABLES (Continued) Table 4-C-32 Table 4-C-33 Table 4-C-34 Table 4-C-35 Table 4-C-36 Table 4-C-37 Table 4-C-38 Table 4-C-39 Weekly minimum, mean and maximum summer surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Talkeetna River, RM 97.2, TRM 1.5, GC S26N05W24BDA .•. 4-C-101 Weekly minimum, mean and maximum summer surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Chulitna River, RM 98.6, TRM 0.6, GC S26N05W14CBC ... 4-C-102 Weekly minimum, mean and maximum summer surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Talkeetna Fishwheel, RM 103.0, GC S27N05W26DDD ••..... 4-C-103 Weekly minimum, mean and maximum summer surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, LRX 18, RM 113.0, GC S28N04W12DAB .••...••.••....••• 4-C-104 Weekly minimum, mean and maximum summer surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Curry Fishwheel, RM 120.7, GC S29N04W10CBB ....••• 4-C-105 Weekly minimum, mean and maximum summer surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Slough SA- Area of R&M Stage Recorder, RM 126.0, GC S30N03W30BCA ••••..•••••••••............. 4-C-106 Weekly minimum, mean and maximum summer surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, LRX 29, RM 126.1, GC S30N03W19DCA ••.••...••....••.• 4-C-107 Weekly minimum, mean and maximum summer surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Slough 9- Area of R&M Stage Recorder, RM 129.2, GC S30N03W16ACB .•.••.•.....•...•.......•...... 4-C-108 XL LIST OF TABLES (Continued) Table 4-C-40 Table 4-C-41 Table 4-C-42 Table 4-C-43 Table 4-C-44 Table 4-C-45 Table 4-C-46 Table 4-C-47 Weekly minimum, mean and maximum summer surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, LRX 35, RM 130.8, GC S30N03W03DCA •••..•.....•.•••.• 4-C-109 Weekly minimum, mean and maximum summer surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Indian River, RM 138.6, GC S31N02W09CDA •.••••..•.• 4-C-110 Weekly minimum, mean and maximum summer surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, LRX 53, RM 140.1, GC S31N11W10AAC .•....•.•.•.....•• 4-C-111 Weekly minimum, mean and maximum summer surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Slough 21- Area of R&M Stage Recorder, RM 142.0, GC S32N02W36CCC ..••••••..•.••••.•.....••.....• 4-C-112 Weekly minimum, mean and maximum summer surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Portage Creek, RM 148.8, TRM 0.1, GC S32N01W25CAB .• 4-C-113 Weekly minimum, mean and maximum summer surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Tsusena Creek, RM 181.3, GC S32N04E36ADB ......•.•.• 4-C-114 Weekly minimum, mean and maximum summer surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Watana Creek, RM 194.1, GC S32N06E25CCA ....•...•.. 4-C-115 Weekly minimum, mean and maximum summer surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Kosina Creek, RM 206.8, GC S31N08E15BAB ....•..•.....•.... 4-C-116 XLI LIST OF TABLES (Continued) Table 4-C-48 Table 4-C-49 Table 4-C-50 Table 4-C-51 Table 4-C-52 Table 4-C-53 Table 4-C-54 Table 4-C-55 Table 4-C-56 Table 4-C-57 Weekly minimum, mean and maximum summer surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Goose Creek, RM 231.3, GC S30N11E32DBC •.••..•.••.••....• 4-C-117 Weekly minimum, mean and maximum summer surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Oshetna River, RM 233.4, GC S30N11E34CCD .•••••...•.••••••• 4-C-118 Datapod intragravel and surface water temperature (C) continuous record, at Slough 8A-Mouth, RM 125.4, GC S30N03W30BCD .•....•..••••••• 4-C-119 Datapod intragravel and surface water temperature (C) continuous record, at Slough 8A-Upper, RM 126.4, GC S30N03W20CDD ...••••..•...••• 4-C-129 Datapod intragravel and surface water temperature (C) continuous record, at Slough 9, RM 128.7, GC S30N03W09DBC •..•...•.....•.•••.•...••• 4-C-139 Datapod intragravel and surface water temperature (C) continuous record, at Slough 11, RM 135.7, GC S31N02W30ADC ....••.....•..••..•...•.•• 4-C-152 Datapod intragravel and surface water temperature (C) continuous record, at Slough 168, RM 138.0, GC S31N02W10AAA •..•.•......•..••...••.•.. 4-C-162 Datapod intragravel and surface water temperature (C) continuous record, at Slough 19, RM 140.0, GC S31N02W02DBA ...•....•.•..•.......•••.. 4-C-172 Datapod intragravel and surface water temperature (C) continuous record, at Slough 21-Mouth, RM 141.8, GC S31N02W02AAB .............•........•••• 4-C-182 Datapod intragravel and surface water temperature (C) continuous record, at Slough 21-Upper, RM 142.0, GC S32N02W36CCC .•.....•..•....••••....... 4-C-188 XLII LIST OF TABLES (Continued) Table 4-C-58 Mean intragravel and surface water temperature (C) datapod data summary at Slough 8A-Mouth~ RM 125.4~ GC S30N03W30BCD .....•••.•••.•.••.•....••• 4-C-198 Table 4-C-59 Mean intragravel and surface water temperature (C) datapod data summary at Slough 8A-Upper~ RM 126.4~ GC S30N03W20CDD ...•.......•.••••••.••.•..•.• 4-C-201 Table 4-C-60 Mean intragravel and surface water temperature (C) datapod data summary at Slough 9, RM 128.7, GC S30N03W09DBC .•• 4-C-204 Table 4-C-61 Mean intragravel and surface water temperature (C) datapod data summary at Slough 11, RM 135.7, GC S31N02W30ADC •. 4-C-208 Table 4-C-62 Mean intragravel and surface water temperature (C) datapod data summary at Slough 16B, RM 138.0, GC S31N02W17AAA .. 4-C-211 Table 4-C-63 Mean intragravel and surface water temperature (C) datapod data summary at Slough 19, RM 140.0, GC S31N02W10DBA .• 4-C-214 Table 4-C-64 Mean intragravel and surface water temperature (C) datapod data summary at Slough 21-Mouth, RM 141.8~ GC S31N02W02AAB .•.......•••••.•..•••.••.•... 4-C-217 Table 4-C-65 Mean intragravel and surface water temperature (C) datapod data summary at Slough 21-Upper~ RM 142.0~ GC S32N02W36CCC .......•..•.•••.•.•...•.•••.. 4-C-219 Table 4-C-66 Thermograph data summary~ winter surface water temperature (C), Whiskers Creek Slough~ RM 101.2~ GC S26N05W03ADB .......•..••....••.......• 4-C-222 Table 4-C-67 Thermograph data summary, winter surface water temperature (C), Slough 9B, RM 129.0, GC S30N03W16ABB •.•..•..•...•... 4-C-226 Table 4-C-68 Thermograph data summary, winter surface water temperature (C), Slough 9-Below Tributary B, RM 129.0, GC S30N03W16ABC •..•.....•...... 4-C-230 XLIII LIST OF TABLES Table 4-C-69 Table 4-C-70 Table 4-C-71 Table 4-C-72 Table 4-C-73 Table 4-C-74 Table 4-C-75 Table 4-C-76 Table 4-C-77 Table 4-C-78 Table 4-C-79 (Continued) Thermograph data summary, winter surface water temperature (C), Slough 11, RM 135.3, GC S31N02W19DDD ..••...••••• Thermograph data summary, winter surface water temperature (C), Slough 19, RM 140.0, GC S31N11W10DBB ••...••.•••. Thermograph data summary, winter surface water temperature (C), Slough 21-Mouth, RM 142.0, GC S31N11W12AAA •...•• Thermograph data summary, winter surface water temperature (C), Slough 21-Middle, RM 142.0, GC S31N11W02AAA •••••••..•••••••••••••..•. Thermograph data summary, winter intragravel water temperature (C), Slough 9-Below Tributary B, RM 129.0, GC S30N03W16ABC .••••••..•••.•.•.••.••••.• Thermograph data summary, winter· intragravel water temperature (C), Slough 98, RM 129.0, GC S30N03W16ABB ..••• Thermograph data summary, winter intragravel water temperature (C), Slough 19, RM 140.0, GC S31N11W10DBB •.... Thermograph data summary, winter intragravel water temperature (C), Slough 21-Mouth, RM 142.0, GC S31N11W02AAA ••.••...••••..••.••••••..• Weekly minimum, mean and maximum winter surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Whiskers Page 4-C-233 4-C-236 4-C-240 4-C-244 4-C-247 4-C-251 4-C-255 4-C-258 Creek Slough, RM 101.2, S26N05W03ADB ...•.. 4-C-261 Weekly minimum, mean and maximum winter surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Slough 98, RM 129.0, GC S30N03W16ABB .••..........•.•. 4-C-262 Weekly minimum, mean and maximum winter surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Slough 9- Below Tributary B, RM 129.0, GC S30N03W16ABC ....••....•.....•............• 4-C-263 XLIV LIST OF TABLES (Continued) Table 4-C-80 Table 4-C-81 Table 4-C-82 Table 4-C-83 Table 4-C-84 Table 4-C-85 Table 4-C-86 Table 4-C-87 Table 4-C-88 Weekly minimum, mean and maximum winter surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Slough 11, RM 135.3, GC S31N02W19DDD •••....••....••.. 4-C-264 Weekly minimum, mean and maximum winter surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Slough 19, RM 140.0, GC S31N11W10DBB .....•.•....•••.• 4-C-265 Weekly minimum, mean and maximum winter surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Slough 21- Mouth, RM 142.0, GC S31N11W02AAA •.....•... 4-C-266 Weekly minimum, mean and maximum winter surface water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Slough 21- Middle, RM 142.0, GC S31N11W02AAA .....•..• 4-C-267 Weekly minimum, mean and maximum winter intragravel water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Slough 9- Below Tributary B, RM 129.0, GC S30N03W16ABC .........••.••...••.•••..•. 4-C-268 Weekly minimum, mean and maximum winter intragravel water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Slough 98, RM 129.0, GC S30N03W16ABB •••......•......• 4-C-269 Weekly minimum, mean and maximum winter intragravel water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Slough 19, RM 140.0, GC S31N11W10DBB ••.....•..•.••... 4-C-270 Weekly minimum, mean and maximum winter intragravel water temperature (C) obtained from 2-hour Ryan thermograph readings and listed by USGS water year week, Slough 21- Mouth, RM 142.0, GC S31N11W02AAA .......... 4-C-271 Instantaneous intragravel water temperatures obtained at salmon spawning redds in Slough 8A, Susitna River, Alaska, 1982 ...•..•.•...••......... 4-C-272 XLV LIST OF TABLES (Continued) Table 4-C-89 Table 4-C-90 Table 4-C-91 Instantaneous intragravel water temperatures obtained at salmon spawning redds in Slough 9, Susitna River, Alaska, 1982 ••.•.•••••••••.•••••••. 4-C-273 Instantaneous intragravel water temperatures obtained at salmon spawning redds in Slough 11, Susitna River, Alaska, 1982 •..••••..••••••.•••.••. 4-C-275 Instantaneous intragravel water temperatures obtained at salmon spawning redds in Slough 21, Susitna River, Alaska, 1982 •....••••.••.•.••..•••. 4-C-276 XLVI LIST OF TABLES Table 4-D-1 Table 4-D-2 Table 4-D-3 Table 4-D-4 Table 4-D-5 Table 4-D-6 Table 4-D-7 Table 4-D-8 Table 4-D-9 Table 4-D-10 Table 4-D-11 APPENDIX D Listing of dissolved gas decay data. • • • • . . . . . . . • • • . • . . • . • • • • • • • • . . . • • • . . • . 4-D-2 Dissolved gas analytical methods Appendix •••..••..••..•.••....••••.. 4-D-3 Dissolved gases statistical analysis................................... 4-D-4 Dissolved gas data -continuous record ••••...•••••••..•.•.••••..•..•••.•..• 4-D-11 Water Quality Summary Table .....••.•...•... 4-D-44 Summary of provisional water quality data for Sloughs 8A, 9, 168, 19 and 21, and mainstem Susitna River at Gold Creek, collected by ADF&G and USGS in June, July and September, 1981, and in January and February, 1982 .......... 4-D-69 Temperature (°C), specific conductance (umhos/cm), and depth (ft) collected at specified locations in Slough 8A, October 5, 1982 .•.....••.•••..•••••.•••.... 4-D-85 Temperature (°C), specific conductance (umhos/cm), and depth (ft) collected at specified locations in Slough 9, October 4 and 5, 1982 ....•.•..•••.•.•••...• 4-D-87 Temperature (°C), specific conductance (umhos/cm), and depth (ft) collected at specified locations in Slough 9B, October 4, 1982 ....•.••......•••.........•. 4-D-90 Temperature (°C), specific conductance (umhos/cm), and depth (ft) collected at specified locations in Slough 11, October 3, 1982 ••••.......•....•..........• 4-D-91 Temperature (°C), specific conductance (umhos/cm), and depth (ft) collected at specified locations in Slough 21, October 1-2, 1982 ........•........•......•• 4-D-92 XLVII LIST OF TABLES Table 4-D-12 Table 4-D-13 Table 4-D-14 Surface and intragravel temperatures (°C) and related data (ft) collected along study transects in Slough 8A, October 5, 1982 ••...••••••••••.•••...•••••. 4-D-93 Surface and intragravel temperatures (°C) and related data (ft) collected along study transects in Slough 9, October 4-5, 1982 •••••.••..•••.•••..•••••.• 4-D-94 Surface and intragravel temperatures (°C) and related data (ft) collected along study transects in Slough 21, October 1-2, 1982 •••..•.•...••••..••••••.•. 4-D-95 XLVIII LIST OF TABLES Table 4-E-1. Table 4-E-2. Table 4-E-3. Table 4-E-4. Table 4-E-5. Table 4-E-6. Table 4-E-7. Table 4-E-8. APPENDIX E Head pin elevations in Chum Channel surveyed July 30, 1982 (see pages E-1 to E-3 for definitions of terms) ••••.•.....•••.•.••.•.• 4-E-5 Cross section elevations in transect 1 of Chum Channel surveyed August 11, 1982 (see pages E-1 to E-3 for definitions of terms) ................................... 4-E-6 Cross section elevations in transect 2 of Chum Channel surveyed August 11, 1982 (see pages E-1 to E-3 for definitions of terms) ................................... 4-E-7 Cross section elevations in transect 3 of Chum Channel surveyed August 11, 1982 (see pages E-1 to E-3 for definitions of terms) ................................... 4-E-8 Cross section elevations in transect 4 of Chum Channel surveyed August 11, 1982 (see pages E-1 to E-3 for definitions of terms) ................................... 4-E-9 Cross section elevations in transect 5 of Chum Channel surveyed August 11, 1982 (see pages E-1 to E-3 for definitions of terms) ................................... 4-E-10 Cross section elevations in transect 6 of Chum Channel surveyed August 11, 1982 (see pages E-1 to E-3 for definitions of terms) ................................... 4-E-11 Cross section elevations in transect 7 of Chum Channel surveyed August 11, 1982 (see pages E-1 to E-3 for definitions of terms) ................................... 4-E-12 XLIX LIST OF TABLES (Continued) Table 4-E-9. Table 4-E-10. Table 4-E-11. Table 4-E-12. Table 4-E-13. Table 4-E-14. Table 4-E-15. Table 4-E-16. Table 4-E-17. Table 4-E-18. Cross section elevations in transect 8 of Chum Channel surveyed August 11, 1982 (see pages E-1 to E-3 for definitions of terms) ...................................... 4-E-13 Head pin elevations in Rabideux Slough surveyed August 10, 1982 (see pages E-1 to E-3 for definitions of terms) ................................... 4-E-14 Cross section elevations in transect 0 of Rabideux Slough surveyed August 10, 1982 (see pages E-1 to E-3 for definitions of terms) ................................... 4-E-15 Cross section elevations in transect 1 of Rabideux Slough surveyed August 10, 1982 (see pages E-1 to E-3 for definitions of terms) ................................... 4-E-16 Cross section elevations in transect 2 of Rabideux Slough surveyed August 10, 1982 (see pages E-1 to E-3 for definitions of terms) ................................... 4-E-17 Cross section elevations in transect 3 of Rabideux Slough surveyed August 10, 1982 (see pages E-1 to E-3 for definitions of terms) ................................... 4-E-18 Cross section elevations in transect 4 of Rabideux Slough surveyed August 10, 1982 (see pages E-1 to E-3 for definitions of terms) ................................... 4-E-19 Cross section elevations in transect 5 of Rabideux Slough surveyed August 10, 1982 (see pages E-1 to E-3 for definitions of terms) ................................... 4-E-20 Cross section elevations in transect 6 of Rabideux Slough surveyed August 10, 1982 (see pages E-1 to E-3 for definitions of terms) ................................... 4-E-21 Cross section elevations in transect 7 of Rabideux Slough surveyed August 10, 1982 (see pages E-1 to E-3 for definitions of terms) ................................... 4-E-22 L LIST OF TABLES (Continued) Table 4-E-19. Table 4-E-20. Tab 1 e 4-E-21. Table 4-E-22. Table 4-E-23. Table 4-E-24. Table 4-E-25. Table 4-E-26. Table 4-E-27. Head pin elevations in Slough SA surveyed August 23, 19S2 (see pages E-1 to E-3 for definitions of terms) ...................................... 4-E-23 Cross section elevations in transect 1 of Slough SA surveyed August 22, 19S2 (see pages E-1 to E-3 for definitions of terms) ...................................... 4-E-24 Cross section elevations in transect 2 of Slough SA surveyed August 22, 19S2 (see pages E-1 to E-3 for definitions of terms) ...................................... 4-E-25 Cross section elevations in transect 3 of Slough SA surveyed August 22, 19S2 (see pages E-1 to E-3 for definitions of terms) ...................................... 4-E-26 Cross section elevations in transect 4 of Slough SA surveyed by R & M Consultants (see pages E-1 to E-3 for definitions of terms) ...................................... 4-E-27 Cross section elevations in transect 5 of Slough SA surveyed August 22, 19S2 (see pages E-1 to E-3 for definitions of terms) ...................................... 4-E-28 Cross section elevations in transect 6 of Slough SA surveyed August 22, 19S2 (see pages E-1 to E-3 for definitions of terms) ...................................... 4-E-29 Cross section elevations in transect 7 of Slough SA surveyed August 22, 19S2 (see pages E-1 to E-3 for definitions of terms) ...................................... 4-E-30 Cross section elevations in transect S of Slough SA surveyed August 22, 19S2 (see pages E-1 to E-3 for definitions of terms) ...................................... 4-E-31 li LIST OF TABLES (Continued) Table 4-E-2S. Table 4-E-29. Table 4-E-30. Tab 1 e 4-E-31. Table 4-E-32. Table 4-E-33. Table 4-E-34. Table 4-E-35. Table 4-E-36. Cross section elevations in transect 9 of Slough SA surveyed August 22, 19S2 (see pages E-1 to E-3 for definitions of terms) ...................................... 4-E-33 Cross section elevations in transect 10 of Slough SA surveyed August 22, 19S2 (see pages E-1 to E-3 for definitions of terms) ...................................... 4-E-34 Cross section elevations in transect 11 of Slough SA surveyed August 22, 19S2 (see pages E-1 to E-3 for definitions of terms) ....................................... 4-E-35 Data (ft) for streambed (thalweg) profile of Slough SA, 19S2 (see pages E-3 and E-4 for definitions of terms) .......................... -............ 4-E-37 Head pin elevations in Slough 9 surveyed August 23, 19S2 (see pages E-1 to E-3 for definitions of terms) ...................................... 4-E-41 Cross section elevations in transect 1 of Slough 9 surveyed August 11, 19S2 (see pages E-1 to E-3 for definitions of terms) ...................................... 4-E-42 Cross section elevations in transect 2 of Slough 9 surveyed August 11, 19S2 (see pages E-1 to E-3 for definitions of terms) ...................................... 4-E-43 Cross section elevations in transect 3 of Slough 9 surveyed August 11, 19S2 (see pages E-1 to E-3 for definitions of terms) ............................. ~ ........ 4-E-44 Cross section elevations in transect 4 of Slough 9 surveyed August 11, 19S2 (see pages E-1 to E-3 for definitions of terms) ...................................... 4-E-45 LII LIST OF TABLES (Continued) Table 4-E-37. Table 4-E-38. Table 4-E-39. Table 4-E-40. Tab 1 e 4-E-41. Table 4-E-42. Table 4-E-43. Table 4-E-44. Table 4-E-45. Table 4-E-46. Cross section elevations in transect 5 of Slough 9 surveyed August 11, 1982 (see pages E-1 to E-3 for definitions of terms) ...................................... 4-E-46 Cross section elevations in transect 6 of Slough 9 surveyed August 11, 1982 {see pages E-1 to E-3 for definitions of terms) ...................................... 4-E-47 Cross section elevations in transect 7 of Slough 9 surveyed by R & M Consultants (see pages E-1 to E-3 for definitions of terms) .••••••••.•••..•... 4-E-48 Cross section elevations in transect 8 of Slough 9 surveyed August 11, 1982 (see pages E-1 to E-3 for definitions of terms) ...................................... 4-E-49 Cross section elevations in transect 9 of Slough 9 surveyed August 11, 1982 (see pages E-1 to E-3 for definitions of terms) ....................................... 4-E-50 Cross section elevations in transect 10 of Slough 9 surveyed August 11, 1982 (see pages E-1 to E-3 for definitions of terms) .................•.................... 4-E-51 Data (ft) for streambed {thalweg) profile of Slough 9 {see pages E-3 and E-4 for definitions of terms) ...•..••••.... 4-E-52 Data (ft) for streambed (thalweg) profile of Slough 11, 1982 (see pages E-3 and E-4 for definitions of terms) ..................................... 4-E-55 Head pin elevations in Slough 21 surveyed September 2, 1982 (see pages E-1 to E-3 for definitions of terms) .•.... 4-E-57 Cross section elevations in transect 1 of Slough 21 surveyed September 22, 1982 (see pages E-1 to E-3 for definitions of terms) ..................................... 4-E-58 LIII LIST OF TABLES (Continued) Table 4-E-47. Table 4-E-48. Table 4-E-49. Table 4-E-50. Tab 1 e 4-E-51. Table 4-E-52. Table 4-E-53. Table 4-E-54. Table 4-E-55. Cross section elevations in transect 2 of Slough 21 surveyed September 22, 1982 (see pages E-1 to E-3 for definitions of terms) ...................................... 4-E-59 Cross section elevations in transect 3 of Slough 21 surveyed by September 22, 1982 (see pages E-1 to E-3 for definitions of terms) ...................................... 4-E-60 Cross section elevations in transect 4 of Slough 21 surveyed September 22, 1982 (see pages E-1 to E-3 for definitions of terms) ...................................... 4-E-61 Cross section elevations in transect 5 of Slough 21 surveyed September 22, 1982 (see pages E-1 to E-3 for definitions· of terms) ...................................... 4-E-62 Cross section elevations in transect 6 of Slough 21 surveyed September 22, 1982 (see pages E-1 to E-3 for definitions of terms) .•.................................... 4-E-63 Cross section elevations in transect 7 of Slough 21 surveyed September 22, 1982 (see pages E-1 to E-3 for definitions of terms) ...................................... 4-E-64 Cross section elevations in transect 8 of Slough 21 surveyed September 22, 1982 (see pages E-1 to E-3 for definitions of terms) ...................................... 4-E-65 Data (ft) for streambed (thalweg) profile of Slough 21, 1982 (see pages E-3 and E-4 for definitions of terms) ...................................... 4-E-66 Data (ft) for streambed (thalweg) profile of side-channel of Slough 21, 1982 (see pages E-3 and E-4 for definitions of terms) .•.....••........••..•• 4-E-70 LIV LIST OF TABLES (Continued) Table 4-E-56. Data (ft) for streambed (thalweg) profile of right fork of Slough 21, 1982 (see pages E-3 and E-4 for definitions of terms) ..•.••••..••••.•..••••• 4-E-71 LV APPENDIX F LIST OF TABLES Page Table 4-F-1 Description of habitat zones sampled at Designated Fish Habitat sites, June through September, 1982 ...................................... 4-F-96 Table 4-F-2 Hydraulic zones, mainstem discharges at the Parks Highway bridge, and the status of the controlling streambed elevation at the upstream entrance (head) of Goose side channel at the Goose Creek 2 and Side Channel site, for sampling dates from June to September, 1982 ........................... 4-F-100 Table 4-F-3 Hydraulic zones mainstem discharges at the Parks Highway bridge for the Whitefish Slough site, for sampling dates from June to September, 1982 .•••..•. 4-F-108 Table 4-F-4 Hydraulic zones, mainstem discharges at the Parks Highway bridge, and the status of the controlling streambed elevation at the upstream entrance (head) of Rabideux Slough at the Rabideux Creek and Slough site, for sampling dates from June to September, 1982 ...................................... 4-F-116 Table 4-F-5 Hydraulic zones, mainstem discharges at the Parks Highway bridge, and the status of the controlling streambed elevation at the upstream entrance (head) of Sunshine side channel at the Sunshine Creek and Side Channel site, for sampling dates from June to September, 1982 .•••..•••..•••••.••..••..•• 4-F-123 Table 4-F-6 Hydraulic zones, mainstem discharges at the Parks Highway bridge, and the status of the controlling streambed elevation at the upstream entrance (head) of Birch Slough at the Birch Creek and Slough site, for sampling dates from June to September, 1982 ...•.... 4-F-130 LVI LIST OF TABLES Table 4-F-7 Table 4-F-8 Table 4-F-9 Table 4-F-10 Table 4-F-11 Table 4-F-12 Table 4-F-13 (Continued) Hydraulic zones, mainstem discharges at the Parks Highway bridge, and the status of the controlling streambed elevation at the upstream entrance (head) of Whiskers Slough at the Whiskers Creek and Slough site, for sampling dates f~om June to September, 1982 ...................................... Hydraulic zones and mains~em discharges at the Gold Creek Station for the Slough 6A site for sampling dates from June to September, 1982 ...••••••••.•.•••.• Hydraulic zones and mains~em discharges at the Gold Creek Station , and the status of the controlling streambed elevation at the upstream entrance (head) of Slough 8 at the Lane Creek and Slough 8 site, for sampling dates from June to September, 1982 ••••••....•.•• Hydraulic zones and mains~em discharges at the Gold Creek Station , and the status of the controlling streambed elevation at the upstream entrance (head) of Slough 8A for the Slough 8A site for sampling dates from June to September, 1982 ....•.••.•.•••.••..•..••.•• Hydraulic zones and mains~em discharges at the Gold Creek Station , and the status of the controlling streambed elevation at the upstream entrance (head) of Slough 9 for the Slough 9 site for sampling dates from June to September, 1982 ........................... Hydraulic zones and mains~em discharges at the Gold Creek station for the Fourth of July Creek mouth site for sampling dates from June to September, 1982 ...................................... Hydraulic zones and mains~em discnarges at the Gold Creek Station , and the status of the controlling streambed elevation at the upstream entrance (head) of Slough 11 at the Slough 11 site for sampling dates from June to Page 4-F-138 4-F-145 4-F-153 4-F-159 4-F-167 4-F-173 September, 1982 •...••.....•..•..••....••.. 4-F-181 LVII LIST OF TABLES (Continued) Page Table 4-F-14 Hydraulic zones and mains~em discharges at the Gold Creek station for the Indian River mouth site for sampling dates from June to September, 1982 •.•.••..•.••••••••. 4-F-187 Table 4-F-15 Hydraulic zones and mains~em discharges at the Gold Creek station for the Slough 19 site for sampling dates from June to September, 1982 ....••••••..•...•.• 4-F-193 Table 4-F-16 Hydraulic zones and mains~em discharges at the Gold Creek station , and the status of the controlling streambed elevation at the upstream entrance (head) of Slough 20 at the Slough 20 site for sampling dates from June to September, 1982 ..•••.•..•••...•...•••..... 4-F-199 Table 4-F-17 Hydraulic zones and mains~em discharges at the Gold Creek station , and the status of the controlling streambed elevation at the upstream entrance (head) of Slough 21 at the Slough 21 site for sampling dates from June to September, 1982 ...................................... 4-F-206 Table 4-F-18 Hydraulic zones and mains~em discharges at the Gold Creek station for the Portage Creek mouth side for sampling from June to September, 1982 ..••....•....• 4-F-212 LVIII APPENDIX F LIST OF FIGURES Page Figure 4-F-1 Water quality sampling locations in Slough 8A •••••••••••••••••••••••••••••• 4-F-2 Figure 4-F-2 Water quality sampling locations in lower Slough 9 •.•••••••••...•••.•.••••. 4-F-3 Figure 4-F-3 Water quality sampling locations in upper Slough 9 ••••••...••••••••....••.. 4-F-4 Figure 4-F-4 Chum salmon spawning area on the Susitna River at RM 114.4 (GC S28N04W06CAB): September 9, 1982 .••..••.. 4-F-5 Figure 4-F-5 Chum salmon spawning area on the Susitna River at RM 136.0 (GC S31N02W19AD): September 4, 1982 •...•••••• 4-F-6 Figure 4-F-6 Chum salmon spawning area on the Susitna River at RM 148.2 (GC S32N01W26DCA): September 5, 1982 •...•••.. 4-F-7 Figure 4-F-7 Chum salmon spawning area on the Susitna River at RM 138.9 (GC S31N02W09DBD): September 6, 1982 ••..•••.. 4-F-8 Figure 4-F-8 Chum salmon spawning area on the Susitna River at RM 137.4 (GC S31N02W17DBB): September 6, 1982 .•...•... 4-F-9 Figure 4-F-9 Chum salmon spawning area on the Susitna River at RM 128.6 (GC S30N03Wl6BCA): September 7, 1982 ...•.•••• 4-F-10 Figure 4-F-10 Chum salmon spawning area on the Susitna River at RM 131.3 (GC S30N03W03DAD) : September 4-8, 1982 ....... 4-F-11 Figure 4-F-11 Chum salmon spawning area on the Susitna River at RM 129.8 (GC S30N03W09DAB): September 14, 1982. Chum salmon were also observed spawning on September 12, 1982, when the water was clear at the site ••.... 4-F-12 Figure 4-F-12 Rabideux Slough transects, 1982 .....•..•.• 4-F-13 Figure 4-F-13 Chum Channel transects, 1982 .......•...... 4-F-14 LIX LIST OF FIGURES (Continued) Figure 4-F-14 Figure 4-F-15 Figure 4-F-16 Figure 4-F-17 Figure 4-F-18 Figure 4-F-19 Figure 4-F-20 Figure 4-F-21 Figure 4-F-22 Figure 4-F-23 Figure 4-F-24 Figure 4-F-25 Figure 4-F-26 Figure 4-F-27 Figure 4-F-28 Figure 4-F-29 Figure 4-F-30 Figure 4-F-31 Figure 4-F-32 Figure 4-F-33 Figure 4-F-34 Figure 4-F-35 Figure 4-F-36 Figure 4-F-37 Whiskers Creek Slough sampling sites, 1982. 4-F-15 Whiskers Creek Slough substrate, 1982 ..•..• 4-F-16 Whiskers Creek Slogh ice-free areas, winter 1982-83 .•••••••••..••••••••••••••••••.••••• 4-F-17 Slough 6A sampling sites, 1982 .•••.••••.•.• 4-F-18 Slough 6A substrate, 1982 ••••.•...•.••••••. 4-F-19 Slough 6A ice-free areas, winter 1982-83 •• 4-F-20 Lane Creek Slough sampling sites, 1982 .•... 4-F-21 Lane Creek Slough substrate, 1982 •.••...•.. 4-F-22 Lane Creek Slough upwelling/seepage, 1982 .• 4-F-23 Lane Creek Slough ice-free areas, winter 1982-83 .•....••.•••••....•••.•••.•.••••.•.. 4-F-24 Slough 8A sampling sites, 1982 .•••..••.••. 4-F-25 Slough 8A substrate, 1982 .•....•..•......• 4-F-26 Slough 8A upwelling/seepage 1982 •••.••.... 4-F-27 Slough 8A ice-free areas, winter 1982-83 •. 4-F-28 Slough 8A spawning areas, 1982 .....•••...• 4-F-29 Slough 8A redd locations, 1982 ••...•..•..• 4-F-30 Slough 9 sampling sites, 1982 .........•.•• 4-F-31 Slough 9 substrate, 1982 •••..••....••.•... 4-F-32 Slough 9 upwelling/seepage, 1982 ••..•...•. 4-F-33 Slough 9 ice-free areas, winter 1982-83 .... 4-F-34 Slough 9 spawning areas, 1982 •..•.......•. 4-F-35 Slough 9 redd locations, 1982 ..•.•........ 4-F-36 Slough 9A sampling site, 1982 ...........•.. 4-F-37 Slough 9A substrate, 1982 ..........•...•... 4-F-38 LX LIST OF FIGURES (Continued) Page Figure 4-F-38 Slough 9A upwelling/seepage, 1982 ...••.•... 4-F-39 Figure 4-F-39 Slough 9A ice-free areas, winter 1982-83 •.• 4-F-40 Figure 4-F-40 Slough 10 sampling sites, 1982 ............. 4-F-41 Figure 4-F-41 Slough 10 substrate, 1982 •.••.••....•••.••.• 4-F-42 Figure 4-F-42 Slough 10 ice-free areas, winter 1982-83 •... 4-F-43 Figure 4-F-43 Slough 11 sampling sites, 1982 ••..•.••...• 4-F-44 Figure 4-F-44 Slough 11 substrate, 1982 ................. 4-F-45 Figure 4-F-45 ' Slough 11 upwe 11 i ng/ seepage, 1982 •.•..•••• 4-F-46 Figure 4-F-46 Slough 11 ice-free areas, winter 1982-83 •. 4-F-47 Figure 4-F-47 Slough 11 spawning areas, 1982 ............ 4-F-48 Figure 4-F-48 Slough 11 redd locations, 1982 ............ 4-F-49 Figure 4-F-49 Slough 168 sampling sites, 1982 ............ 4-F-50 Figure 4-F-50 Slough 168 substrate, 1982 ................. 4-F-51 Figure 4-F-51 Slough 168 ice-free areas, winter 1982-83 .• 4-F-52 Figure 4-F-52 Slough 19 sampling sites, 1982 ............. 4-F-53 Figure 4-F-53 Slough 19 substrate, 1982 •....••...••••••.. 4-F-54 Figure 4-F-54 Slough 19 upwelling/seepage, 1982 .......... 4-F-55 Figure 4-F-55 Slough 19 ice-free areas, winter 1982-83 ..• 4-F-56 Figure 4-F-56 Slough 20 samp 1 i ng sites, 1982 ............. 4-F-57 Figure 4-F-57 Slough 20 substrate, 1982 ....•.•....••..... 4-F-58 Figure 4-F-58 Slough 20 ice-free areas, winter 1982-83 ... 4-F-59 Figure 4-F-59 Slough 21 sampling sites, 1982 •....•..•... 4-F-60 Figure 4-F-60 Slough 21 substrate, 1982 •....••...••..... 4-F-61 Figure 4-F-61 Slough 21 upwelling/seepage, 1982 ....•.... 4-F-62 Figure 4-F-62 Slough 21 ice-free areas, winter 1982-83 .. 4-F-63 LXI LIST OF FIGURES (Continued) Figure 4-F-63 Figure 4-F-64 Figure 4-F-65 Figure 4-F-66 Figure 4-F-67 Figure 4-F-68 Figure 4-F-69 Figure 4-F-70 Figure 4-F-71 Figure 4-F-72 Figure 4-F-73 Figure 4-F-74 Figure 4-F-75 Figure 4-F-76 Figure 4-F-77 Figure 4-F-78 Slough 21 Complex ice-free areas, winter 1982-83................................... 4-F-64 Slough 21 spawning areas, 1982 ••••.•..•••. 4-F-65 Slough 21 redd locations, 1982 .••••...•.•• 4-F-66 Slough 22, sampling sites, 1982 ••.•••••.... 4-F-67 Slough 22, substrate, 1982 ••.•.••.•.•••••.. 4-F-68 Slough 22, upwelling/seepage, 1982 •.•••.... 4-F-69 Slough 22, ice-free areas, winter 1982-83 •• 4-F-70 Eulachon spawning area on the Susitna River at RM 26.0 (GC S17N07W22DAA): May 31, 1982 ...• :......... 4-F-71 Eulachon spawning area on the Susitna River at RM 25.9 (GC S17N07W22DDA): May 31, 1982 ...• ~ ..•••..•. 4-F-72 Eulachon spawning area on the Susitna River at RM 26.3 (GC S17N07W23CAB): May 31, 1982 •..•.••......• 4-F-73 Eulachon spawning area on the Susitna River at RM 25.5 (GC S17N07W22CAA): May 31, 1982 .......•...•.. 4-F-74 Eulachon spawning area on the Susitna River at RM 25.8 {GC S17N07W22DCD): June 1, 1982 ••••...••....• 4-F-75 Eulachon spawning area on the Susitna River at RM 21.4 (GC S16N07W04CAC): June 1, 1982 ••...•.••..... 4-F-76 Eulachon spawning area on the Susitna River at RM 18.2 (GC S16N07W15CDB): June 1, 1982 .•....•..•.••• 4-F-77 Eulachon spawning area on the Susitna River at RM 16.5 (GC S16N07W22DCD): June 1, 1982 •.......••..•• 4-F-78 Eulachon spawning area on the Susitna River at RM 44.0 (GC S19N05W20CAC): June 3, 1982 .......••..... 4-F-79 LXII LIST OF FIGURES (Continued) Figure 4-F-79 Figure 4-F-80 Figure 4-F-81 Figure 4-F-82 Figure 4-F-83 Figure 4-F-84 Figure 4-F-85 Fi'gure 4-F-86 Figure 4-F-87 Figure 4-F-88 Figure 4-F-89 Figure 4-F-90 Eulachon spawning area on the Susitna River at RM 41.3 (GC S19N06W25CCD): June 4, 1982 .•.•...••...•. 4-F-80 Eulachon spawning area on the Susitna River at RM 28.0 (GC S17N07W13DBB): June 5, 1982 ..••....•..... 4-F-81 Eulachon spawning area on the Susitna River at RM 31.1 (GC S17N06W18BAA): June 5, 1982 .......•..•... 4-F-82 Eulachon spawning area on the Susitna River at RM 31.8 (GC S17N06W05ABA): June 5, 1982 ...•...••••.•• 4-F-83 Eulachon spawning area on the Susitna River at RM 15.0 (GC S16N07W35BDD): June 6, 1982 ..•.•..•...•.. 4-F-84 Eulachon spawning area on the Susitna River at RM 35.5 (GC S18N06W15CCC): June 7, 1982 .••.••••....•• 4-F-85 Eulachon spawning area on the Susitna River at RM 22.8 (GC S16N07W04BBA): May 30, 1982 ..•..........• 4-F-86 Eulachon spawning area on the Susitna River at RM 43.3 (GC S19N06W24ACC): May 24, 1982 ..•....•...... 4-F-87 Eulachon spawning area on the Susitna River at RM 8.5 (GC S14N07W22ACA): May 26, 1982 ..•.....•..... 4-F-88 Eulachon spawning area on the Susitna River at RM 11.0 (GC S15N07W10DCC): May 26, 1982 .......••..... 4-F-89 Eulachon spawning area on the Susitna River at RM 18.3 (GC S16N07W15CDB): May 26, 1982 .............. 4-F-90 The Lower Montana Bering cisco spawning area on the Susitna River at RM 76.8 -77.3 (GC S23N04W06ADD): October 14, 1982 ........•.............. LXII I 4-F-91 LIST OF FIGURES (Continued) Figure 4-F-91 Figure 4-F-92 Figure 4-F-93 Figure 4-F-94 Figure 4-F-95 Figure 4-F-96 The Upper Montana Bering cisco spawning area on the Susitna River at RM 77.3-77.6 (GC S23N04W06CBB): October 14, 1982....... 4-F-92 Hypothetical slough with associated tributary showing presence of hydraulic zones at three different mainstem discharges .•.••••.••.... 4-F-95 Map of surface areas and zone types at Whitefish Slough (RM 78.7) on two sampling dates. Discharges (cfs) at Sunshine (USGS Provisional Data, 1982, 15292780) ••••..••••••...••••.••...... 4-F-111 Map of surface areas and zone types at Whiskers Creek and Slough (RM 101.2) on two sampling dates. Discharges at Gold Creek (USGS Provisional Data, 1982, 1529200) •..••..•.• 4-F-139 Map of surface areas and zone types at Slough 6A (RM 112.3) on two sampling dates. Discharges (cfs) at Gold Creek (USGS Provisional Data, 1982, 1529200) .......•.••••...•.•..•••.... 4-F-147 Map of surface areas and zone types at Slough 21 (RM 142.0) on two sampling dates. Discharges (cfs) at Gold Creek (USGS Provisional Data, 1982, 1529200) ....••.••.••..•.••..•.••..•• 4-F-207 LXIV LIST OF PLATES Plate 4-F-1 Plate 4-F-2 Plate 4-F-3 Place 4-F-4 Plate 4-F-5 Plate 4-F-6 Plate 4-F-7 Plate 4-F-8 Plate 4-F-9 APPENDIX F August 1980 aerial photo~raph of Goose Creek 2 and Sidechannel (RM 73.1). The Susitna River flows from right to left in this photo ••..••.•..•••••••..••••••••••.•••.. 4-F-99 May 1982 aerial photograph of Whitefish Slough (RM 78.7). The Susitna River flows towards the upper left corner in this photo ....•••••.... 4-F-107 Hydraulic changes at a designated fish habitat site caused by fluctuations in the discharge of the mainstem Susitna River •..•.•.••.•.••...••...•..•..•••.... 4-F-110 August 1982 aerial photograph of Rabideux Creek and Slough (RM 83.1). The Susitna River flows from top to bottom in this photo ..••••••..•••••.. ~ .....•••.. 4-F-115 August 1980 aerial photograph of Sunshine Creek and Side Channel (RM 85.7). The lakes and tributaries above the study area provide water to Sunshine Creek. The Susitna River flows from top to bottom in this photo .•...••......•.• 4-F-122 August 1980 aerial photograph of Birch Creek and Slough (RM 88.4). The Susitna River flows from right to left in this photo ••.•.•.••...•••...•..•..•.. 4-F-129 May 1982 aerial photograph of Whiskers Creek and Slough (RM 101.2). The Susitna River flows from right to left in this photo .....•......•••....•••••••.... 4-F-136 May 1982 aerial photograph of Slough 6A (RM 112.3). The Susitna River flows from right to left in this photo ••.•..•......•........••....•. ; •.••.•. 4-F-144 August 1982 aerial photograph of Lane Creek mouth and Slough 8 (RM 113.6). The Susitna River flows from right to left in this photo ..•........•.•....•.•....•....•.... 4-F-151 LXV LIST OF PLATES (Continued) Plate 4-F-10 Plate 4-F-11 Plate 4-F-12 Plate 4-F-13 Plate 4-F-14 Plate 4-F-15 Plate 4-F-16 Plate 4-F-17 Plate 4-F-18 August 1980 aerial photograph of Slough 8A (RM 125.3). The Susitna River flows from right to left in this photo ••••••••••••.••••••••....•.••.•••••••• 4-F-158 August 1980 aerial photograph of Slough 9 (RM 129.1). The Susitna River flows from right to left in this photo ..•••.•••••••••.•••••••.••••••••••.••• 4-F-165 May 1982 aerial photograph of the mouth of 4th of July Creek (RM 131.1). The Susitna River flows from right to left in this photo .•....••••••••..••.•..••..•••. 4-F-172 August 1980 aerial photograph of Slough 11 (RM 135.3). The Susitna River flows from right to left in this photo .••••.••.•.•..•••...•.•••••..•••••.••. 4-F-179 August 1982 aerial photograph of the mouth of Indian River (RM 138.6).· The Susitna River flows from right to left in this photo •.....••.••...•.••••.••.•..•.• 4-F-186 May 1982 aerial photograph of Slough 19 (RM 140.0). The Susitna River flows from right to left in this photo ..•••.•..•...•••....•...•....•••..•... 4-F-192 August 1982 aerial photograph of Slough 20 (RM 140.1). The Susitna River flows from right to left in this photo .•..•••...•••.....•..•••.•....•.••••.. 4-F-198 August 1980 aerial photograph of Slough 21 (RM 142.0). The Susitna River flows from right to left in this photo .......••.••.•.••••...•..•..••.•••.••• 4-F-204 August 1980 aerial photograph of the mouth of Portage Creek (RM 148.8) and the Susitna River. The Susitna River flows from right to left in this photo .....••.•. 4-F-211 LXVI LIST OF TABLES Table 4-G APPENDIX G Catch data for Designated Fish Habitat Sites, 1982. Units for gear 002 are minutes shocked, for gear 009 are hours fished, and for all other gears are pieces of gear fished •.........................•.........•• 4-G-3 LXVII LIST OF TABLES Table 4-H APPENDIX H Catch per unit effort for Designated Fish Habitat sites, 1982. Units for gear 002 are minutes shocked, for gear 009 are hours fished, and for all other gears are pieces of gear fished ..•••. 4-H-3 LXVI II APPENDIX I LIST OF TABLES Table 4-I Habitat data for Designated Fish Habitat sites, 1982 ...••••••••...•••..••••.• 4-I-2 LXIX .. LIST OF TABLES Table 4-J-1 APPENDIX J Selected physicochemical data collected during the ice-covered study season, 1982 ••.•••.••.••••.....••••..•••.•.••.•.••.. 4-J-2 LXX CONTRIBUTORS Aquatic Habitat and Instream Flow Studies (AH) Project Leader and Principal Contact AH Sub-project Leaders (contributing to Volume 4) Electrofishing and Radio Telemetry Section Instream Flow Evaluation Section Fish Habitat Utilization Section Impoundment Section Data Reduction and Transfer Section AH Data Reduction, Transfer, and Laboratory Operations Staff Resident and Juvenile Anadromous Studies (RJ) Project Leader RJ Sub-project Leaders (contributing to Volume 4) Fish Distribution Study Electrofishing and Radio Telemetry Hydraulic Engineer Data Processing Project Leader Data Processing Staff Graphics Typing Staff Editors LXXI Christopher Estes Doug Lang Tim Quane Andy Hoffmann Joe Sautner Camille Stephens Theresa Keklak Mark Willette Troya Bogard Dana Schmidt Larry Dugan Rich Sundet E. Woody Trihey Allen Bingham Kathy Rowe 11 Gail Heineman Donna Bucholtz Katrine Zozel Carol Kerkvliet Sally Donovan Carol Kerkvl iet Anne Reilly Peggy Skeers Joyce Godin Lynn Watson Christopher Estes Doug Lang Tim Quane Andy Hoffmann Stephen Hale Dana Schmidt CONTRIBUTORS (Continued) Part I Coordinator Hydrological Investigations Stage -Discharge Thalweg Profiles Backwater Areas Open Channel Water Quality Investigations Temperature Basic Field Parameters Dissolved Gas Part II Coordinator Adult Anadromous Habitat Salmon Species Mainstem LXXII Tim Quane Tim Quane Tommy Withrow Jody Miller Pat Morrow Patricia Harris Len Vining Don Seagren Bob Marsha 11 Rick Sinnott Kim Sylvester Tim Quane Jody Miller Pat Morrow Tommy Withrow Tim Quane Pat Morrow Jody Mi 11 er Tommy Withrow Len Vining Dana Schmidt Andy Hoffmann Doug Lang Kathy Sheehan Craig Richards CONTRIBUTORS (Continued) Slough Eulachon Bering Cisco Juvenile Anadromous Habitat Resident Habitat LXXI I I Andy Hoffmann Len Vining Kim Sylvester Rick Sinnott Don Seagren Sheryl Sa 1 a sky Jeff Blakley Don Volk Dean Beers Doug Lang Doug Lang Kathy Sheehan Stephen Hale Larry Dugan Karl Kuntz Bob Marshall Dave Sterritt Rich Sundet Doug Lang Paul Suchanek ACKNOWLEDGEMENTS Special appreciation is extended to Nikki Newcome (ADF&G) for providing technical support to the computer modeling portion of the hydraulic studies; Beverly Valdez (Arctic Environmental Information and Data Center) for computer plotting stage/discharge curves; Dave Wangaard (U.S. Fish and Wildlife Service), James Dryden (Dryden and LaRue, Inc.) and Terrestri a 1 Envi ronmenta 1 Specia 1 i sts, Inc. for their assistance with the dissolved gas study. We would like to also thank Marilyn Barker (Anchorage Community College) and Bjartmar Sveinbjornsson (University of Alaska) for their help with identification of aquatic plants; and the local residents and property owners who have assisted us and expressed interest in our work: Harold and Nancy Larson, Bill Blakeley, Roy Bloomfield, Dr. Clifford H. Driskell, and Doug and Marie Dunn. The authors wish to thank Acres American, Inc.; Air Logistics; Akland Helicopter; the Alaska Railroad; R&M Consultants, Inc.; Gene and Rose Jenne (Three Rivers Union); and the U.S. Geological Survey for their support services. Appreciation is also extended to the Alaska Power Authority for funding this project and to T. Trent, L. Bartlett, R. Dieryck, K. Watson, R. Logan, L. Heckart, M. Mi 11 s and other staff of the ADF&G for their administrative services support. LXXIV VOLUME FOUR MAP SYMBOLS LEGEND Silt (SI) Sand (SA) Gravel (GR) Rubble (RU) Cobble (CO) Boulder (BO) R & M Stage Recorder !IIIII Staff Gage I I II I * Intragravel Temperature Site 2299911 ® Intragravel Temperature Site (Apparent Up we 11 i ng Area) (@ Spring -z- -···-···-Small Tributary -·-·-::..;_ :·~:~ ·.::-Dewatered Channel f------1 LXXV River Mile (RM) Water Quality Measurement Site Datapod Site Thermograph Site Eddy Log Cut Bank Railroad Mixing Zone Riffle True North Transect (ADF & G, R & M) Q Station (ADF & G, R & M) PART I HYDRAULIC MD WATER QJAUTY INVESTIGA.TIONS 1. OBJECTIVES Aquatic Habitat and 1nstream Flow Project (AH) hydrological and water quality investigations were continued and expanded in 1982 to further characterize: 1) the influence of mainstem Susitna River discharge on the hydrological and water quality characteristics of selected slough, tributary and mainstem habitats (Figure 41-1-1) downstream of Devil Canyon; and 2) the baseline hydrological and water quality characteristics of fishery habitats (Figure 41-1-1) within the boundaries of the proposed impoundment areas (see Volume 5)1• Tasks designed to meet objective one were to: 1) determine water surface elevations associated with various discharges of the Susitna River at selected mainstem, slough, and tributary locations from river mile (RM) 73.1 (Lower Goose 2) to RM 148.8 (Portage Creek); 10bjective two is discussed in Volume 5. 1 N Figure 41-1-l. I) 2) 3) 4) 5) 6) 7) GENERAL HABITAT CATEGORIES OF TilE SUSITHA RIVER Hainstem llabitat consists of those portions of the Susitna River that nor111aliy convey streamflow throughout the year. Both single and multiple channel reaches are Included tn this habitat category. Groundwater and tributary Inflow appear to be Inconsequential contributors to the overall characteristics of ma1nstem habitat. Hatnstem habitat Is typically characterized by htgh water velocities and well armored streambeds. Substrates generally consist of boulder and cobble she materials wtth lntersttt1a1 spaces filled with a grout~l1ke mixture of small gravels and glacial sands. Suspended sediment concentrations and turbidity are high during surrmer due to the influence of glacial melt~water. Streamflows recede 1n early fall and the mainstem clears appreciably in October. An ice cover forms on the river in late Novettber or Decen~ber. Stde Channel llabttat consists of those portfons of the Susttna Rher that MnMlly convey streamflow during the open water season but become appreciably dewatered durtng periods of low flow. Side channel habitat may exist either fn welt 'defined overflow channels. or fn poorly defined water courses flowing through putfalty submerged gravel bars and Islands along the margins of the matnstem river. Side channel streambed ele- vations are typically lower than the mean monthly water surface ele- vations of the mainstem Susttna River observed during June. July and August. Side channel habitats are characterized by shallower depths, lower velocities and smaller streambed materials than the adjacent habitat of the mafnstem river. Side Slough Uabttat fs located in spring fed overflow channels between the edge of the floodplain and the mafnstem and side channels of the Susttna River and 1s usually separated from the mafnstem and side channels by well vegetated bars. An exposed alluvial berm often separates the head of the slough from mafnstem or side channel flows. The controlling streambed/streambank elevations at the upstream end of the side sloughs are slightly less than the watf!r surface elevations of the mean monthly flows of the mafnstem Susitna River observed for June, July. and August. At Intermediate and low-flow periods. the side sloughs convey clear water from small trtbutarfes and/or upwellfng groundwater (ADF&G }g8lc. Jg82b). These clear water inflows are essenttal con- trthutors to the existence of this habitat type. The water surface elevatton of the Susftna River generally causes a backwater to extend well up Into the slough from its lower end (AOF&G tgSic, tg82b). Even though this substantial backwater exists. the sloughs function hydrau- lically very lll.ICh lfke small stream systems and several hundred feet of the slough channel often conveys water independent of matnstem backwater effects. At high flows the water surface elevation of the mainsten1 river 1s sufficient to overtop the upper end of the slough (AOF&G }gatc. Jg82b). Surface water temperatures in the side sloughs during sunrner months are principally a function of atr temperature. solar radtatfon. and the temperature of the loca 1 runoff. ~~!t~:a;1~3ho/'arh1etas\o~~~fe[ss n~~~ni~~c~~~:cte13u;ft:a:h~tastur~:c~h~~t!~: of the mainstem Susftna River or fts side channels. These sloughs are characterized by the presence of beaver dams and an accuA'MJlatlon of silt covering the substrate resulting from the absence of mainstem scouring flows. Tributary Habitat consists of the full complement of hydraulic and morphologic conditions that occur In the tributaries. Their seasonal streamflow. sediment. and thermal regt~s r·cflect the integration of the hydrology, geology. and clim.1te of the tributary drainage. The physical attributes of tributary habitat are not dependent on malnstem conditions. Tributary Hauth llabttat extends from the uppermost point In the tributary influenced by mainstem Susttna River or slough backwater effects to the downstream extent of the tributary plume whtch extends into the n~alnstem Sus1tna River or slough (AOF&G l98lc. lg82b). Lake llab1tat conststs of various hmtlc environments that occur wtthfn the Susitna River drainage. These habitats range from small, sha11ow. Isolated lakes perched on the tundra to larger. deeper lakes which connect to the mafnstem Susltna River through well defined tributary systems. The lakes receive their water from springs, surface runoff and/or tributaries. General habitat categories of the Susitna River -a cnnceptual diagram (adapted from AEIDC 1982; Trihey 1982). These data were collected to support analyses of the effects of mainstem Susitna River discharge on the availability of habitat for fish passage, rearing and spawning in slough, mainstem, and tributary habitats (e.g., stage-discharge and stage-surface area rel ati onshi ps of hydraulic zones in sloughs, etc.); 2) obtain baseline discharge data of tributaries in the Talkeetna to De vi 1 Canyon reach to quantify their contributions to the Susitna River; 3) monitor variations in seasonal surface water temperature of the mainstem Susitna River downstream of Devil Canyon to support the analysis of discharge and temperature relation- ships and relationships of temperature to fish passage and spawning; 4) monitor variations in seasonal surface and intragravel water temperatures at selected sloughs within the Talkeetna to Devil Canyon reach of the Sus i tna river to eva 1 uate their relationship to mainstem discharge and support analyses of their relationships to fish passage and spawning; 5) obtain baseline water quality data to characterize the water chemistry of surface waters within selected sites of the Susitna River basin and support the analysis of the influence 3 of discharge on water quality conditions and their relationships to fish passage, spawning and rearing; and 6) establish the baseline condition of supersaturation of dissolved gases in the vicinity of the Devil Canyon rapids and the influence that changes in discharge have upon those conditions. These investigations were initiated in 1981 to describe the physical and chemical characteristics of seasonal habitats utilized by juvenile and adult anadromous and resident fish within the Susitna River Basin (Preface Figures B, C and D). Studies conducted during 1981 provided baseline hydrological and water quality data for the various habitats (i.e., mainstem, side channel, slough and tributary) present in the Susitna River and the relationships of these habitat characteristics to changes in discharge of the mainstem Susitna River (ADF&G 1982b). This information used to describe the seasonal habitat requirements of adult and juveni 1 e anadromous and resident fish of the Susi tna River and to evaluate the accuracy of hydrological and temperature models which will be used to predict discharge influenced impacts on fisheries habitat (ADF&G 1982a). The data co 11 ected during 1981 demonstrated the importance of these studies and the need to expand the data base during 1982 if the goals of defining discharge-influenced impacts to fishery habitats by the proposed project (as well as designing discharge-related mitigation options) are to be achieved. 4 2. METHODS 2.1 Hydrological Investigations 2.1.1 Stage and Discharge 2 .1.1.1 Stage Detailed methods pertaining to the collection of stage and discharge data are presented in the ADF&G procedure manuals (ADF&G 1981a, 1982a). The following discussion is a summary of those methods used in these investigations. Measurements of stage were obtained at least twice monthly at various mainstem and non-mainstem (i.e., slough and tributary) sites in the Susitna River basin during the 1982 open water field season. Stage was determined to the nearest one-hundredth of a foot through observations of staff gages at all sites with the exception of Indian River and Portage Creek where an automatic recorder and associated pressure transducer was used to continuously monitor stage (ADF&G 1981a, 1982a). At each staff gage placement site, staff gages were tiered to the high water marks to provide for the range of flows expected during 1982 as indicated from field observations during 1981 and the 31 year flow record (USGS 1977, 1978a, 1978b, 1979, 1980, 1981) obtained from the U.S. Geological Survey (USGS) gaging station at Gold Creek (15292000). Depending on the gradient of the streambank, each staff gage placement 5 site was composed of a series of at least two to five individual staff gages (ADF&G 1982b). An assume5l elevation, which was referenced to a temporary bench mark (TBM), was determined for each staff gage using basic survey techniques of differential leveling (ADF&G 1981, 1982). All TBWs were surveyed to a known elevation (project datum) so that resultant stage readings could be converted to true water surface elevations (with the exception of the staff gage placement site on the Yentna River). A continuous stage record was obtained at Indian River and Portage Creek with a pressure transducer installed on the streambed and connected to a recorder. This instrumentation system recorded an average water column depth every hour. These hourly stage recordings were used to calculate a mean daily stage. Periodically, the depth of flow over the pressure transducer was directly measured as a check on the accuracy of recorded values. The corresponding depth readings were recorded to determine the offset required to convert the depth of flow over the pressure trans- ducer into equivalent stage readings. Placement of staff gages varied, depending on the specific tasks of the various studies involved. Generally, staff gage placements consisted of mainstem and non-mainstem staff gage locations (Figure 41-2-1). 2.1.1.1.1 Mainstem Staff Gage Locations Staff gages were installed in the mainstem Susitna River (Figures 4!-2-2 and 41-2-3) for the purpose of correlating the relationships between 6 S Iough Mouth Gage 100. 2W I A,B,C --- A -- I I I I I I I I I I I Tributary Gao• Sift 100.!5T2 A,B,C I I I I I I I I I • .. .. : :. ';:· ,. ~! .. :. ., ... '• .~: j Figure 4!-2-1. ADF&G staff gage identification system. ··:. :·, ~I :~ .·. ... . , STAFF GAGE NUMBERING FORMAT CD I ---·-, RIVER MILE I ® River Mile (RM) is determined for all of the staff gage sites within the same study area at the most downstream point of the study areas. The Study areas are defined by the Aquatic Habitat and lnstream Flow Project biologists. Placement Type Codes Mainstem "' t1 Mid-slough = S Slough Mouth = W Slough Head = H Tributary = T Staff gage site number withir. an assigned river mile reach study area. Gage letters for each site assigned from shore outward. River Mile Staff Gage Site Study Area PARKS HIGHWAY-- BRIDGE BIRCH CREEK SLOUGH (RM 88.4) SUNSHINE STATION (RM 79.2) ere Montana e14 GOOSE CREEK 2 SLOUGH (RM 73.1) MAINSTEM SUSITNA RIVER and YENTNA RIVER STAFF GAGE LOCATIONS (COOK INLET TO TALKEETNA) 6 AD FaG STAFF GAGE SITE 0 10 MILES Figure 41-2-2. Mainstem and Yentna River staff gage locations in the Cook Inlet to Talkeetna (RM 103.0) reach of the Susitna River. 8 MAP AREA· ./ ABOVE SLOUGH II MOUTH BELOW SLOUGH II MOUTH LRX 40 MAINSTEM AT 4th of JULY CREEK LRX 35 MAINSTEM SUSITNA Rl VER STAFF GAGE LOCATIONS (TALKEETNA TO DEVIL CANYON) 0 10 FEET L A oF a G STAFF GAGE SITE Figure 4I-2-3. Mainstem staff gage locations in the Talkeetna (RM 103.0) to Devil Canyon (RM 148.0) reach of the Susitna River. 9 water surface elevations and stage of the mainstem Susitna River to mainstem discharge recorded at USGS gaging stations. Mainstem staff gages 1 ocated in the Ta 1 keetna to De vi 1 Canyon reach of the Sus i tna River are correlated to discharge data obtained at the USGS gaging station at Gold Creek (15292000). Mainstem staff gages located downstream of Talkeetna are correlated to discharge data obtained at the USGS gaging station at the Parks Highway bridge (15292780). Mainstem staff gages were installed and monitored daily at each ADF&G Su Hydro fishwheel and sonar site. Mainstem staff gages were also instal- led at specific lower river cross section (LRX) sites established by R&M Consultants and were monitored on an irregular basis. Other mainstem staff gages were installed adjacent to study sloughs and tributaries and monitored periodically to determine the influence of mainstem stage and discharge on these study areas (see 2.1.1.1.2). 2.1.1.1.2 Non-Mainstem Staff Gage Locations Staff gages were installed to monitor specific habitat characteristics in sloughs, side channels, and tributaries. These staff gages were located in various hydraulic zones of sloughs and tributaries and monitored a minimum of two times per month. Staff gages located at the mouths (downstream end) of selected sloughs and side channels were monitored to evaluate the influence of mainstem discharge on the availability of fish rearing habitat in the lower end 10 of sloughs and fish passage to and from sloughs. Staff gages were also 1 ocated in the free-flowing portions of these study areas and were monitored to evaluate local stage-slough flow relationships. Other staff gages were located at the head (upstream end) portions of sloughs or side channels to determine the mainstem discharge required to breach the heads of these areas. The ADF&G should be consulted for the interpretation of these data. The following discussion describes the methods used for determining the mainstem discharges at which breaching of selected side sloughs and side channels situated in the reach of the Susitna River between Talkeetna and Devil Canyon occurred. Cross section surveys, staff gage readings and on-site observations were used in conjunction to determine the mainstem discharges at which breaching of a slough began to occur. The lowest representative elevation, on a cross-section, surveyed across the head of a slough is called the "point of zero flow" (PZF). It is assumed the cross section at the head of a slough was surveyed at the point where streambed elevations control flow into the slough. The water surface elevation of the mainstem at the head of the slough must be greater than the PZF before mainstem water can enter the head of the slough. PzF•s were determined for selected sloughs in the Susitna River basin from cross section survey data conducted by R&M Consultants, Inc. 11 Staff gages were installed at the head of study sloughs and side chan- nels as near as possible to the upstream point that controlled mainstem flow into these areas so that the elevation of the bottom of the staff gage provided a good check on the accuracy of the PZF determined from the cross-section surveys. Mainstem water surface elevations necessary for breaching were obtained from staff gages installed in the mainstem near the head of the slough and surveyed to project datum. Periodic field observations were made to document the mainstem dis- charges required to breach selected study slough and side channel areas. However, even if field crews were fortunate enough to observe a site just as it was breached, this did not mean that the exact mainstem discharge required for breaching of that slough had been identified. Observations of slough breaching and staff gage readings obtained to determine breaching flows were referenced to the average daily mainstem streamflow at Gold Creek (USGS 1982). This gaging station is located up to 20 miles from various sloughs where breaching data were collected. Since the accuracy of the relationship between breaching and Gold Creek discharge was dependent on the rate that the river was rising or fall- ing, the range of flows required for breaching were determined from a combination of the above methods. 2.1.1.2 Discharge Measurements of discharge were obtained at selected sloughs and tribu- taries downstream of Devil Canyon to determine the range of discharges which occur under an annual flow regime and to thereby develop simple 12 stage-discharge relationships in the form of rating curves. Discharge measurements were also obtained at six tributary locations upstream of Devil Canyon to monitor flow conditions and provide baseline flow data for future reservoir modeling. In addition, discharge measurements were obtained as a byproduct of a series of depth and velocity measurements primarily intended to quantify potentially available fish habitat at several slough sites (refer to Volume 4, Part II, Section 2.1.3.2.1). Downstream of Devil Canyon Discharge sites (gaging stations) were placed within study locations in areas where conditions for obtaining stage and discharge measurements were maximized. Stream morphology was thus the major criteria used to establish gaging stations. Gaging stations were located in a free- flowing portion of the stream, removed from any backwater influences created by the mainstem, within a uniform channel with a stable sub- strate where water column velocities paralleled each other and were at right angles to the cross section. Discharge measurements were made by the current-meter method as outlined in the Procedures Manual (ADF&G 1981a), using standard USGS techniques (USGS 1977) employing either a Price AA or Pygmy meter. Cross sections at gaging stations were divided into a minimum of 20 cells to ensure that each velocity obtained measured no more than five percent of the total flow. The observed depth at each cell was determined using a four foot top setting wading rod graduated into one-tenth foot increments. Mean water column velocities, measured as feet/second (fps), were 13 obtained at each cell using a two point or a six-tenths depth method. At depths less than or equal to 2.5 feet, mean cell water column velocity was measured at six-tenths of the depth from the surface while at depths exceeding 2.5 feet, water column velocities were measured at two-tenths and eight-tenths of the depth from the surface and then averaged to yield a mean cell water column velocity. At depths less than six-tenths of a foot or velocities less than 2.5 fps, the Pygmy meter was utilized while at greater depths and velocities a Price AA meter was used. When velocities were observed not to be at right angles to the discharge transect, the velocity vector component normal to the measuring section was determined as described in the Procedures Manual (ADF&G 1981a). Total discharge was then determined as the summation of the products of cell area and mean cell column velocity. If sufficient discharge and corresponding stage data were collected at a gaging station, simple rating curves were developed. Depth and velocity measurements were also obtained at specific intervals along each transect in the FHU study sites using a Marsh-McBirney model 201 electronic flow meter and methods outlined in the Procedures Manual (ADF&G 1981a). From these data, discharge was computed to estimate the range and quantity of habitat available to fish and to calibrate the IFG computer model for each study site (Milhous, et al. 1981). Upstream of Devil Canyon Discharge measurements were obtained in six tributaries located upstream of Devil Canyon employing techniques outlined above and in the 14 Procedures Manual (ADF&G 1981a). Refer to Volume 5, Section 2.2.3 for specific discharge methods employed upstream of Devil Canyon. 2.1.2 Thalweg Profiles Thalweg is defined as "the line following the deepest part or middle of the bed or channel of a river or stream" (Arnette 1975). To determine the thalweg of sloughs SA, 9, 11 and 21, surveys were conducted using the standard surveying techniques of differential leveling. After establishing a temporary bench mark (the elevation of which was later tied into project datum), the survey progressed from one end of the slough through its entire length. Based on visual observation during a low flow period, low points at areas of significant·change in gradient (tops and bottoms of riffles, bottoms of pools, etc.) were selected as tha 1 weg points. Distances between these points were measured to the nearest foot using a survey tape or by reading the stadia on the survey level. The data was then plotted with elevation as the ordinate and distance as the abscissa. In some sloughs, elevations obtained from previous surveys (i.e., study area transects or cross sections at slough head and mouth) were used for part of the plot to save time and dupli- cation of effort. The area referred to as the mouth of a slough is a hydraulically dynamic zone, dependent on the stage of the mainstem Susitna River and the streambed morphology of a slough. As such, an exact geographical location of a slough mouth is only an approximation (see Trihey 1982 for a more detailed description of slough morphology). 15 For the purpose of constructing thalweg profiles for sloughs 8A, 9, 11 and 21, the mouth of each slough was defined by R&M transects #125.2W1, 128.4W1, 135.5W1 and 141.8S7, respectively (R&M 1982). 2.1.3 Other Hydrological Components 2.1.3.1 Backwater Areas Backwater areas are zones of low velocity water which result from hydraulic barriers created by mainstem stage effects. Data was collect- ed twice monthly at 17 slough and tributary habitat locations from June through September, 1982 to describe the relationshi-p between mainstem Susitna River discharge and backwater areas. The data base consists of a series of maps, one for each sampling period at each site, depicting the prevailing hydraulic features of the surface waters. To map hydraulic conditions, nine different hydrological "zones" were defined to represent various conditions of water surface velocity, water source (tributary or mainstem) and hydraulic influence from mainstem water surface elevations present at the mouth of a study site. After the hydraulic conditions at a study area were categorized using the zone codes (numbers 1-9), maps of the wetted surface and zone boundaries were drawn. Susitna River discharge data used in the presentation of these results was provided by the USGS as provisional data (USGS 1982). The June 16 discharges for the upper river were estimated by the USGS from support- ing data because the Gold Creek Gaging station (15292000) was inopera- tive during June. Additional correction to these discharges were made for the June 19-30, 1982 period after the 1st Draft Data Report was distributed. Descriptions of the field program and zone codes are presented in Volume 3, Section 2.1.3 and are discussed in detail in Part II, Section 2.2 of this volume. A narrative description of each habitat site is also given in Volume 4 (Appendix 4-F). Included in these descriptions are traced reductions of blueline zone-boundary maps (see Slough 21, Slough 6A, Whitefish Slough, and Whiskers Creek and Sidechannel) which illustrate the mapping procedures. Mapping Aerial photographs of each habitat location were taken on May 31 and August 20, 1982 under contracts with R&M Consultants and North Pacific Aerial Surveys, Inc. These were printed as blueline copies at a scale of 1"=50 1 for use as reference maps. At the time of each sampling, the observed boundaries of wetted surfaces and the 1 ocati on of zones were drawn on the b 1 ue 1 i ne maps. During the June samp 1 i ngs, b 1 ue 1 i ne maps were not available thus the June data compilations were constructed in Anchorage from sketches, measurements and photographs taken in the field. In general, wetted edge locations and zone boundaries were located on the blueline maps using natural points of reference (e.g., deadfall, trees, geographic features) and measurements made using 17 a survey tape. Wetted edge boundaries were typically mapped without a great amount of precision. Ground truth measurements were made at most sites to check and/or adjust the scales on the blueline photographs. Surface Area Measurements Surface areas were measured from the blueline maps (or direct tracings of the maps) with a NumonicsR model 2400 Digitizer. Several random and systematic errors are associated with the measured surface areas. Random errors were introduced during various steps of map construction. Specific sources of random errors include inaccurately 1 ocati ng the wetted edge boundary and inaccurately locating the boundary between hydraulic zones (for more on this see Part II, section 2.2). Systematically, deviations as large as 7 percent were found between indicated linear distances (map scale) and measured ground features at some sites. Unfortunately, some sites had no natural features to check map scales against. Deviations also appeared across the surface of maps as a result of photographic image distortion {parallax). Scales on blueline maps made from the May and August flights for some sites were also found to differ by several percent. A combined estimate of system- atic error might reasonably approach 15 percent in some of the surface areas measured. 18 Precise surface area measurements were not the objective of this study, rather the goal was to document trends in the distribution of hydraulic conditions to relate to the fish distribution. Finer resolution in the maps was not practical within the constraints of the 1982 program. 2.1.3.2 Open Channel Segments of sloughs SA, 9 and 21, Rabideux Slough and Chum Channel were selected for computer modeling using hydraulic simulation programs developed by the Instream Flow Group (Milhous et. al. 1981). Provided with channel depths, velocities, widths and water surface elevations from transects at known mainstem discharges, these models extrapolate and predict hydraulic parameters including depth; velocity, width, wetted perimeter and water surface elevation at unobserved streamflows. Data from actual field observations are used to calibrate the model. When predicted hydraulic parameters at known discharges closely approximate observed parameters and when predicted hydraulic parameters at hypothetical discharges fit a realistic pattern based on past hydrological experience, the models are calibrated. Data collected during one field season will not necessarily include a sufficient range of conditions to calibrate the model at all potential discharges. Thus, the models are being developed from data collected in 1982 and are reli- able only at streamflows within specified limits. The results of modeling will be presented in the Fisheries and Habitat Relationships report. 19 2.2 Water Quality Investigations Water quality data were collected throughout the study area as discussed below. 2.2.1 Temperatures Surface and intragravel water temperatures were measured on an instan- taneous and continuous basis at various locations in the Susitna River basin. Several types of temperature monitoring instruments were em- ployed. 2.2.1.1 Surface Water Temperature Surface water temperature was measured on an instantaneous and contin- uous basis at various locations in the Susitna River basin. Instantan- eous surface water temperature measurements were obtained at various locations in the water column from the streambed to the water surface. Continuous monitoring of the surface water temperature was confined to the portion of the water column adjacent to the stream bed upon which the temperature sensor rested, usually 0.5 feet or less above the stream bed, or upon the stream bed itself. 2.2.1.1.1 Instantaneous Surface Water Temperature Instantaneous water temperatures were obtained at each study site in the process of collecting the basic water quality field parameters. The 20 measurements were collected with either a calibrated Brooklyn mercury thermometer or Hydrolab model 4041 electronic multiparameter unit using procedures outlined in the Procedures Manual (ADF&G 1981a). 2.2.1.1.2 Continuous Surface Water Temperature Surface water temperature was measured during the 1982 open-water field season on a continuous basis at 23 stations within the Susitna River basin, including 10 mainstem sites (located from RM 5.0 to RM 140.0), 10 major tributaries from the Yentna River (RM 28.4) to the Oshetna River (RM 233.4) (Figure 41-2-4), and of 3 sloughs above Talkeetna (sloughs 8A, 9 and 21). The two types of instruments employed in the continuous measurement of temperature were the Peabody-Ryan model J-90 submersible thermograph and the Omnidata recorder (datapod) with associated thermis- tors. For both the thermograph and the datapod, the temperature sensor was placed on the bottom of the stream to record the water temperature of the lower portion of the water column adjacent to the stream bed. Peabody-Ryan model J-90 thermographs continuously monitor and record temperature with an error of 0.6°C on 90-day charts. Thermographs, after installation, were monitored and serviced (if necessary) twice monthly, except those located above Devil Canyon which were monitored on a monthly basis. To ensure accuracy of temperature data collected, each thermograph was screened at two temperatures (0°C and between 11-16°C) prior to installation using a calibrated Brooklyn or American Society for Testing and Manufacturing (ASTM) thermometer as a standard. Thermo- graphs found to be in error by more than 3°C at either screening temper- 21 Figure 4!-2-4. c'' ·Y SUSITNA RIVER MAINSTEM and TRIBUTARY THERMOGRAPH LOCATIONS 1982 <f)-THERMOGRAPH SITE SCALE • I: 500,000 ALASKA DEPT. OF FISH AND GAME SU HYDRO AQUATIC STUDIES PROGRAM 10 miles Susitna River mainstem and tributary thermograph locations. 22 ature were not used and were returned to the manufacturer for ca 1 i- bration. To ensure proper calibration of temperature readings, surface water temperatures were obtained using a calibrated thermometer at the time of installation and removal of the thermograph from each site. A unique calibration factor was then determined for each thermograph, calculated as the difference in the readings between the surface water temperature obtained with the thermograph and the calibrated thermometer at the time of thermograph removal. The calibration factor was deter- mined from data at the time of thermograph removal rather than the time of installation because response time after installation varied for each thermograph. The ca 1 i brati on factor was then used to correct 2-hour point temperature readings from each recording chart. From these corrected 2-hour point temperatures mean, maximum and minimum temper- atures were computer calculated for each 6-hour period. The instal- lation and service methods are outlined in the Procedures Manual (ADF&G 1981a). The data pods and associ a ted thermi stars used to continuously monitor surface water temperatures were capable of simultaneously recording both surface and intragravel water temperature with an error of O.l°C. The datapod incorporates a non-volatile, ultraviolet (UV) erasable, solid state data storage module (DSM) to record data. The DSM is capable of approximately three months data storage recorded in 6 hour intervals as minimum, maximum and mean water temperatures. The units were virtually maintenance-free but were peri odi ca lly checked for 1 ow battery charge and disturbance by wildlife. 23 To obtain surface water temperatures with a datapod, the associated thermistor was attached to a weight and placed upon the substrate of the stream channel. Each thermistor probe was calibrated prior to field installation by Dryden and LaRue Consulting Engineers (distributors of the instruments) and assigned a calibration factor. The surface water temperature probe was placed immediately adjacent to an intragravel temperature probe (see Section 2.2.1.2.2) associated with the same recorder. Immediately after installation of the recorder and prior to removal of the DSM, a surface water temperature was obtained with a ca 1 i bra ted mercury thermometer. In addition, surface water temperature was obtained from a 11 Short data dump 11 which the recorder is programmed to yield. The 11 Short data dump 11 is a listing of data which also includes errors accumulated, numbers of data points ·stored, minutes to next recording and intragravel water temperature. The two temperatures were compared, taking into consideration probe calibration factors, to ensure accuracy of the instrument. The data was retrieved from the DSM via an Omnidata model 217 Datapod/Cassette Reader and printed as 6-hour maximum, minimum and mean temperatures. 2.2.1.2 Intragravel Water Temperature Intragravel water temperature measurements were obtained on an instan- taneous and continuous basis in the Susitna River basin during the 1982 open-water fie 1 d season using Peabody-Ryan thermographs and Omni data recorders (datapods) for the continuous measurements and Digi-Sense recorders for the instantaneous measurements. 24 2.2.1.2.1 Instantaneous Intragravel Water Temperature Instantaneous intragravel water temperatures were obtained at salmon and Bering cisco mainstem spawning sites and in Sloughs 8A, 9, 11, and 21 using a Digi-Sense temperature recorder and associated Yellow Springs Instruments (YSI) series 400 insertion probe. The following procedure was utilized to obtain an instantaneous intragravel temperature using a Digi-Sense temperature meter and associated YSI insertion probe. 1) The wire lead was attached from the insertion probe to the Digi-Sense unit. 2) The insertion probe was pushed into substrate to a depth of at least six inches. 3) The unit was turned on for a period long enough to allow the digital readout to stabilize (usually within 30-60 seconds). 4) The water temperature was recorded. Variations in measurements of up to 0.2°C associated with drift and damp field conditions usually resulted in erroneous values making it neces- sary to check instruments in the field with a calibrated ASTM mercury thermometer (verified accuracy ±0.2°C) before and after a series of readings. A calibration factor was then determined for each set of readings as the difference between the mercury thermometer reading and Digi-Sense readings and was later used to correct the recorded readings. 25 2.2.1.2.2 Continuous Intragravel Water Temperature Intragravel water temperature was continuously monitored and recorded at various sites in the Susitna River basin during 1982 using both the Peabody-Ryan model J-90 submersible thermographs and the datapods with associated thermistor. Peabody-Ryan model J-90 thermographs were used for determining intragravel water temperatures only during the 1981-82 ice covered period. Refer to Appendix Table 4-C-1 for a list of the continuous surface and intragravel water temperature data collected during 1981 and 1982. Peabody-Ryan model J-90 thermographs were buried 1· to 3 feet in the substrate. The i nsta 11 ati on procedure for these thermographs is the same as for the surface water temperature thermographs, with the excep- tion that the thermographs monitoring intragravel water temperature were checked within 90 days and full 90 day recording charts were used (ADF&G 1981a). Methods of data reduction are the same as those presented in Section 2.2.1.1.2 for the continuous measurements of surface water temperature data by Peabody-Ryan model J-90 thermographs, except that the thermographs were not screened and ca 1 i bra ted according to proce- dures described in Section 2.2.1.1.2. Calibration factors were de- termined (for each thermograph) by a 11 owing each thermograph to reach equilibrium in a water bath at soc (as determined by a calibrated Brooklyn thermometer) and then following procedures outlined in Section 2.2.1.1.2 for computing calibration factors. 26 Datapods was also used to record intragravel water temperatures during the 1982 field season. Datapods were found to be advantageous over the Peabody-Ryan thermographs because of several unique features the units incorporate to record intragravel water temperatures including: (1) an ability to measure temperature to an accuracy of 0.1°C, (2) a minimal amount of effort is expended in calibrating the probes, (3) only the Data Storage Module (DSM) must be removed for data retrieval and not the entire instrument thus allowing for a continuous flow of temperature data, (4) the recorder can be secured out of the water on a safe loca- tion with the risk of only losing the temperature probe during periods of flooding and bank erosion, (5) two probes can be used simultaneously to record both intragravel and surface water temperatures on the same DSM, and (6) there is considerably less data reduction time in compari- son to the Peabody-Ryan thermograph. Each datapod was equipped to simultaneously monitor the intragravel and surface water temperature at a placement site. The associated intragravel thermistor was secured within a steel, slotted tube and inserted approximately 18 inches into the substrate. The thermistor probe wires were connected to the Omnidata recorder which was stored in a waterproof container secured on the stream bank out of the range of flood flows and eroding banks. The surface water temperature probe was weighted and placed adjacent to the intragravel probe (see section 2.2.1.1.2 for details). Field installation procedures and data reduction techniques are the same as described in Section 2.2.1.1.2. 27 2.2.2 Other Basic Field Parameters The dissolved oxygen (DO), pH, temperature, and specific conductance of surface water were collected throughout the Susitna River basin during 1982 by Instream Flow Eva 1 uation Study, Fishery Habitat Uti 1 i zation Study, Fishery Distribution Study, Electrofishing Study and Impoundment Study personnel. The basic field parameters of DO, pH, water tempera- ture, and specific conductance were measured in the field using a Hydrolab model 4041 portable multiparameter meter. The four parameters were measured simultaneously at the Sonde unit (underwater unit) and the readings were displayed in an indicator unit. Each hydrolab was cali- brated prior to entering the field (see Procedures Manual (ADF&G 1981a) for methods of calibration) except for temperature which was calibrated by the manufacturer. Measurement of the basic field parameters varied, depending on the specific tasks of the various studies involved. The basic field parameters were obtained at each discharge transect within each Resident Fish Designated Habitat site at intervals necessary to characterize the water quality present. The basic field parameters were collected to determine the overall differences in water quality within each Adult Anadromous Fish Habitat Investigation Slough site. Sites for measurement of water quality were located at the head and mouth of the FHU study slough and in, above and below any tributary (sufficiently far downstream to allow mixing) or other water sources (spring or upwelling) within the site. 28 Twice monthly, hydraulic zones were determined within each Resident Fish Designated Habitat site. To characterize the water quality present within each zone, the basic field parameters were collected in an area of the zone considered representative for the entire zone. Measurements of the basic field parameters gathered in conjunction with the mainstem Fish Habitat investigations were collected at spawning sites of resident and anadromous fish species (refer to Vol. 4, Part II for specific information concerning site selection and data collection techniques). The basic field parameters were obtained at least once per month at designated tributary, mainstem and lake sampling sites in the impound- ment zone (see Vol. 5 for details). Additional sites, including minor tributaries and tributary study sections, were also sampled on irregular intervals. Water samples for turbidity analysis were collected by the Fish Distribution Study (FDS), Downstream Migrant Study and the Impoundment Study personnel. Turbidity samples were collected in 250 ml bottles and stored for a maximum of 18 days in a cool, dark location prior to analysis. Samples were obtained within each FDS zone twice monthly and analyzed in the field on a HF Instruments DRT-15 turbidity meter accord- ; ng to procedures described in the Procedures Manu a 1 (ADF&G 1981a). Turbidity samples were obtained daily from the mainstem at the smolt trap (located at the Talkeetna Fishwheel camp) for the Downstream Migrant Study and also analyzed in the field on a HF instruments DAT-15 29 turbidity meter. Turbidity samples were collected by Impoundment Study personnel on a monthly basis at designated tributary and mainstem sampling sites (see Impoundment WQ site selection Vol. 5). Analysis was performed on a Hach 2100A turbidity meter immediately upon returning from the field using procedures described in the Procedures Manual (ADF&G 1982a). ·Turbidity values, reported as Nephelometric turbidity units (NTUs) were measured to the sensitivity of the turbidimeter calibrated with the appropriate standard. Measured turbidity values less than 1 NTU are reported as less than 1 NTU. Values equal to or less than 100 NTUs are reported to the nearest whole number. Values greater than 100 NTUs are reported to two significant figures. 2.2.3 Total Dissolved Gases A study of dissolved gases was conducted in the Susitna River between the Chulitna River confluence and the upper extent of the Devil Canyon rapids. The uppermost sampling site was located approximately one quarter mile above the mouth of Devil Creek (RM 161.4). Dissolved gas concentrations were measured at several points through the 10 mile reach of the proposed Devil Canyon rapids and downstream to approximately 50 miles below the Devil Canyon dam site. During the summer of 1982, a continuous recording monitor was installed approximately two miles below the Devil Canyon dam site. Most of the decay data was collected between this monitor and the Alaska Railroad bridge at Gold Creek. Precise 30 locations are indicated in the Appendix Tables by river mile (Appendix 4-D-1) . . Dissolved gas measurements were taken approximately one meter below the . surface, although this varied somewhat depending on conditions. Very minor variations in dissolved gas pressures were recorded with depth. Sampling was usually done from a river boat drifting with the current in the river below Devil Canyon. Above the Devil Canyon dam site, gas measurements were often made by suspending the probe from a hovering helicopter. Because of the high velocities, this was generally done in eddies below the rapids. Where possible in the canyon, measurements were made from shore by landing on islands or rock outcroppings. Approximately 15 to 30 minutes was allowed for the dissolved gas read- ings to stabilize before the probe readings were recorded. Temperature and tensionometer pressure readings were recorded at each site. Because of the difficulties in sampling in the canyon, these values are somewhat less precise than those in the lower river. Two types of instruments were used to measure dissolved gas pressure during this study. A saturometer described by Bouck (1982) was used for the initial measurements during the 1981 field season. However, because of the lack of portability of this instrument, a saturometer developed by Common Sensing was used for all subsequent measurements. This instrument was modified for continuous recording of dissolved gas pressure and was dep 1 oyed from August 4 through October 10, 1982. A Datapod solid state recorder was connected to the saturometer and used 31 to record temperature and dissolved gas pressure hourly throughout this period. Dissolved oxygen was also recorded during the initial sampling periods of 1981 to determine the relative contribution of dissolved oxygen to the overall gas supersaturation. Measurements were made in the field with a YSI dissolved oxygen probe with duplicate measurements at some sites by use of the Winkler method. Because the dissolved oxygen levels closely para 11 el ed tota 1 gas supersaturation, further measurements of dissolved oxygen during the remainder of the study were not conducted. Barometric pressure readings were recorded by use of the saturometer when point measurements were made. The Talkeetna weather station barometric pressure data from the U.S. Weather Bureau was used for ca 1 i brati on of the continuous recording di sso 1 ved gas concentrations, using standard correction factors for altitude differences. Discharge data used are the provisional records of the U.S. Geological Survey from the Gold Creek gaging station (15292000). Hourly stream- flows were obtained by digitizing copies of the USGS gage traces and converting the hourly gage heights to discharge by use of the current rating table for this gage. Dissolved gas supersaturation and all other values were calculated using the formula of Bouck (1982). These formula are duplicated in Appendix Table 4-D-2 of this report. All statistics were calculated using micro- computer statistical programs or by use of programmable calculators. 32 Further references in addition to details of statistical analysis are included in Appendix Table 4-D-3. 33 3. RESULTS 3.1 Hydrological Investigations 3.1.1 Stage and Discharge Stage and discharge measurements were obtai ned during the 1982 open- water season at various mainstem, slough and tributary sites within the Susitna River basin (Appendix Table 4-A-1). 3.1.1.1 Mainstem Sites Between Talkeetna and Devil Canyon Periodic stage readings (converted to water surface elevations) were obtained at 31 mainstem locations between Talkeetna and Devil Canyon during the 1982 open-water season. These data, along with corresponding average daily discharges of the mainstem recorded at Gold Creek (USGS provisional data, 1982), are presented in Appendix Table 4-A-2. Plots of these data (Appendix Figures 4-A-1 -4-A-16) indicate the relation- ship between water surface elevation and mainstem discharge is relative- ly well defined at most of the 31 locations for the range of flows from 8,000 to 30,000 cubic feet/second (cfs). The water surface elevation of the river rises approximately 1.5 to 2.0 feet as discharge increases from 10,000 to 20,000 cfs. A mainstem gradient map (Figure 4!-3-1) shows a drop of 10.6 ft/mi from Portage Creek to Curry and 7.8 ft/mi from Curry to Whiskers Creek Slough. 34 900 800 700 -Q) Q) -z 0 ;:: 600 <( > w w ..J U1 w w 500 ::::> 0:: 1- 400 300 98 100 SUStTNA RIVER TALKEETNA TO PORTAGE CREEK WHISKERS f SLOUGH/ CREEK 105 110 115 120 125 RIVER MILE 130 4th of [ PORTAGE CREEK SUSITNA RIVER To I keetna to Portage Creek L_J Distance from Slough Head to Mouth Relative to Susitna River Mile 135 140 145 150 Figure 41-3-l. Gradient of the Susitna River from Talkeetna to Portage Creek. 155 At the onset of the 1982 field season, it was intended to define the relationship between stage and discharge for the mainstem upstream of Talkeetna for the full range of discharges that normally occur during . the open water season. However, abnormally low discharges this past summer, followed by high fall flows and an early freeze-up, precluded our ability to obtain the necessary field data to define water surface profiles for mainstem discharges in the 5,000 to 8,000 cfs or 30,000 to 45,000 cfs ranges. 3.1.1.2 Sloughs in the Talkeetna to Devil Canyon Reach of the Susitna River Periodic staff gage readings and discharge measurements were obtained during the 1982 open water field season at eleven sloughs located between Talkeetna and Devil Canyon (Whiskers and Lane Creek Sloughs and Sloughs 6A, 8A, 9, 11, 168, 19, 20, 21 and 22). Information for Sloughs 8A, 9, 11 and 21 is presented in Part II, Section 3.1.1.2.2. Data collected from Whiskers and Lane Creek Sloughs and Sloughs 6A, 168, 19, 20 and 22 and additional information on Sloughs 9, 11 and 21 is presented below. Baseline data from Whiskers and Lane Creek Sloughs and Sloughs 9, 168, 20, 21 and 22 have been used to construct preliminary rating curves. Insufficient data at the other sloughs prevented the development of rating curves. 36 Plots were made comparing mainstem discharge to the observed water surface elevation within sloughs 6A, 11, 168, 19, 20, 21, 22, Whiskers and Lane (Appendix Figures 4-A-17 to 4-A-30)L Cross sections were made for Whiskers and Lane Creek Sloughs and Sloughs 11, 168, 20 and 22, (Appendix Figures 4-A-31 to 4-A-36). Additional cross section data were developed utilizing ADF&G survey data obtained in 1982 for Sloughs 8A, 9 and 21 (Appendix Figures 4-A-37 to 4-A-39). Sloughs were characterized as either upland or side sloughs. Upland sloughs were defined as those having no connection to the mainstem other than at their mouth, with their water sources consisting primarily of ground water and/or surface water. Side sloughs were defined as those connected to the mainstem at their mouth and, during periods of high mainstem flow, at their upstream juncture (head) with the mainstem. 3.1.1.2.1 Upland Sloughs Slough 6A Slough 6A (Figure 41-3-2) is an area of clear backwater characterized by extremely low velocities. Water sources are primarily composed of ground water and surface runoff from a beaver dam in its upstream portion. Twelve staff gage readings were obtained at the mouth of Slough 6A showing a range of 3.2 feet of water surface elevation change over a corresponding range of mainstem flows from 8,440 to 32,000 cfs (Appendix Table 4-A-3). Water surface elevations obtained at the mouth of the slough were within 0.25 feet of the corresponding water surface 37 w ():) MOUTH 0 S I gt'l o" . ~ .... : _.:-;··· .. ::~. ,, .. . ;: . . ..... .. .. , ...... ::·~ . •• # :··· • ... ·~~~~6 Q STATION ....... ·i····.··· ··~·.,·: ....... ,., ..... ; .. ;, ..•... ··::··"··,·.:· .. · ... ,,.; .. :.; ... :.··:·:·::.·.::'· : ..• ·-. .• ····:·::.:.·.:,,-, i.· .... ···': .. 500 SUSITNA RIVER-- FEET ( approx. seale) ·: ...... J<! ,. : ···,·::. ,-, ••••• ·, •• ;.-.-... .:-. ·:: t:• :·!· .... ~ ....... /o: .... t' ... ·· .... ............ 6 STAFF GAGE Figure 4!-3-2. Planimetric site map of Slough 6A, RM 112.3, GC S28N05Wl3CAC. elevations obtained in the mainstem (Appendix Table 4-A-2) for mainstem flows in the range of 14,000 to 32,000 cfs, indicating that a backwater effect occurs at the slough mouth over this range of mainstem flows. A single slough discharge, measured at 0.6 cfs, was obtained at the mouth of the slough when the corresponding mainstem discharge was 24,200 cfs (Table 41-3-1). Slough 19 Slough 19 (Figure 41-3-3) is a relatively short slough that, during periods of high mainstem flow, exhibits an area of backwater in its lower reaches. The primary sources of clear water in this slough, based on visual observations, appears to be ground water. and surface water runoff. Nineteen water surface elevations obtained at the downstream point of access (small side channel below the mouth) to Slough 19 exhibited a range of 3.27 feet over a corresponding range of mainstem flows from 11,700 to 31,800 cfs (Appendix Table 4-A-3). Water surface elevations, obtained in the mainstem adjacent to Slough 19, exhibited a range of 3.54 feet during mainstem flows of 6,900 to 31,900 cfs (Appendix Table 4-A-2). A single slough discharge, measured at 0.4 cfs, was obtained at the mouth of Slough 19 (Table 41-3-1) when the mainstem discharge was 13,300 cfs. 39 ,., .. 0 500 FEET (a pprox. s co I e) sustTNA Rl vER ,,;, ... , ... •.:: .... ,:,, ·.•. ;·.· .. ::, !·:.r,.: ··.: .. ' . "; .. ·.:::·· :j: !" ••• ·: .' •• ~ .• ·~ ~""' • ' ~ 0 ~. ' ••• 6 STAFF GAGE IQI DATAPOD (f) THERMOGRAPH : ::,. ":·.,.:\:::·::~--~::···''; Figure 4!-3-3. Planimetric site map of Slough 19, RM 140.0, GC S3lN02WlODBB. Table 41-3-1. Comparison of periodic measurements of slough flow at selected sloughs upstream of Talkeetna to the corresponding mean daily mainstem discharge at Gold Creek (USGS gaging station 15292000).a Location Date Whiskers Creek Slough 821009 (RM 101.4) 820903 820816 820920 Slough 6A (RM 112.3) 820921 Lane Creek Slough 820903 (RM 113.6) 820920 820917 Slough 9 820825 (RM 129.2) 820909 820720 820715 820623 Slough 11 820830 (RM 135. 7) 820918 Slough 16B 820902 (RM 138.0) 820919 820801 820915 Slough 19 (RM 139.8) 820819 aUSGS Provisional Data, 1982. bTrue water surface elevation. Time 1145 1625 1445 1530 1040 1456 1333 1517 1244 1010 1212 1617 1551 1412 1730 Slough WSELb Discharge (cfs) (ft) 2.0 365.58 0.7 365.65 0.2 365.81 35.1 366.22 0.6 457.61 2.0 468.28 9.9 469.41 20.7 470.75 c 593.51~ 1. 7 c 3.0c 593.56 28.0c 593.92c 108.0c 594.10c 182.0 594.27c 3.1 670.72 5.5 670.80 0.9e 23.5 700.58 54.8 700.85 257.6 701.69 0.4 718.79 cDischarge and water surface elevations obtained by R&M Consultants. Main stem Dischar}e (cfs 8,470 14,600 15,600 24,000 24,200 14,600 24,000 32,000 13,400 13,400 22,900 25,600d 26,000 13,100 27,500 16,000 24,100 26,400 28,200 13,300 dGold Creek stream gage malfunction. USGS estimated value used in plotting stage-discharge curve. eDischarge measurement was not used in plotting the stage-discharge curve due to the location of the measurement which was outside the reach of the stream necessary to develop a stage-discharge relationship. 41 Table 41-3-1. (Continued) Slough WSELa Mainstem Discharge Discharge Location Date Time (cfs) (ft) (cfs) Slough 20 820820 1120 2.6 726.76 12,500 (RM 140.2) 820901 1643 11.6 726.89 17,900 820802 1220 16.5 726.99 22,500 820918 1825 44.8 727.27 27,500 820916 1415 158.8 728.06 32,500 Slough 21 820831 1518 3.3 744.90 16,000 (RM 141.9) 820802 1400 5.0 744.93 22,500 820916 1024 59.2 746.52 32,500 Slough 22 820919 1124 5.1 783.84 24,100 (RM 144.6) 820918 1425 31.2 784.28 27,500 820915 1642 118.5 785.08 28,200 aTrue water surface elevation 42 3.1.1.2.2 Side Sloughs Whiskers Creek Slough Whiskers Creek Slough has a relatively unobstructed channel that has as its primary water source, when it is not breached by the mainstem, Whiskers Creek, which empties into the slough approximately midway between its head and mouth (Figure 41-3-4). Six staff gage readings were obtained at the head of Whiskers Creek Slough which joins a side channel of the Susitna River. A water surface elevation range of 0.80 feet for corresponding mainstem flows of 13,600 to 31,900 cfs (Appendix Table 4-A-3) was observed. At mainstem discharges of 13,600 and 15,600 cfs, the head was not breached and the staff gage site was dewatered. At mainstem discharges of 24,000 and greater, the head was breached (Table 41-3-2). Four discharge measurements, obtained in Whiskers Creek Slough above its confluence with Whiskers Creek (at the mid-slough gaging site), ranged from 0.2 to 35.1 cfs (Table 41-3-1). The highest discharge measured (35.1 cfs) was recorded during a period when the head of the slough was breached and the mainstem discharge was 24,000 cfs (Table 41-3-2). The lower three flow measurements ranged from 0.2 to 2.0 cfs. The main water sources contributing to the slough above the Whiskers Creek confluence during the unbreached period appeared to be ground water and surface water runoff. Corresponding water surface elevations obtai ned during the low flows at the mid-slough gaging site, showed a range of 43 6 STAFF GAGE 0 2!50 FEET ( approx. scale) ADF6G Q STATION -1" .---- .:.: -.. ~ .. : ....... : ... ~ :-: .. : t:: .... ·~··.; .. ·.-.; .. ~ ... ~ .. ;,_,/_ · ... :! •. · .. SUS!TNA R.-- Figure 41-3-4. Planimetric site map of Whiskers Creek/Slough, RM 101.2, GC S26N05W03AAC. .p. c:..n Table 41-3-2 Determination of the mainstem discharge at Gold Creek (cfs) required to breach the upstream end (head) of selected side sloughs in the Talkeetna to Devil Canyon Reach. Analytical Determination from Staff Gage at Slough Head Field Observations PZFa at Mainstem Flowb Mainstem Flow Location Slough Head at Gold Creek Date at Gold Creek Whiskers Creek Slough 367.3 18,000 820816 15,600 RM 101.2 820710 23,000 820920 24,000 Lane Creek Slough (Slough 8) 472.9 24,000 820920 24,000 RM 113.6 820607 25,000c Slough SA 820707 16,600 RM 125.3 820711 24,000 820712 26,500c 820608 28,000 Slough 9 820923 19,400 RM 129.2 820722 22,400 820610 26,000c (31,500)d 820622 26,000c Slough 11 684.0 Never breached in 1982 Estimated breaching RM 135.3 flow @ 42,000 Slough 16B 703.0 19,000 820708 18' 100 RM 138.0 J 820914 20,200 Slough 20 730.75 20,000 820914 20,200 RM 140.1 820709 21,500 Slough 21, NW Channel 754.6 24,000 820720 22,900 RM 142.0 820711 24,000 820728 25,600 Slough 21, NE Channel 755.5 26,000 820728 25,600 (31,500)d RM 142.0 820622 26,000c Slough 22 787.8 21,000 820914 20,200 RM 144.3 820919 24,100 aPZF = Point of zero flow. bMainstem flow at Gold Creek necessary to breach slough head as determined from point of zero flow (PZF). cUSGS gaging station was inoperable in June, mainstem discharges are estimates. dAmended mainstem discharge at Gold Creek as determined from ADFG stage-discharge curve. Status of Slough Not breached Barely breached Breached Almost breached Breached Not breached Not breached Not breached Breached Not breached Breached Breached Breached Not breached Breached Not breached Breached Not breached Barely breached Breached Not breached Breached Barely breached Breached 0.12 feet, with the overall range of water surface elevations observed being 2.03 feet (Appendix Table 4-A-3) and corresponding ranges of mainstem flows of 8,440 to 28,000 cfs. These slough stage-discharge data were used to construct and a preliminary rating curve (Figure 41-3-5). Fourteen water surface elevations from the mouth of the slough were found to have a range of 3. 96 feet corresponding to rna i nstem flows ranging from 8,440 to 31,900 cfs (Appendix Table 4-A-3). The water surface elevation of the mainstem, adjacent to the mouth of vJhiskers Creek Slough (Figure 41-3-4), ranged 2.50 feet over mainstem flows from 8,440 to 24,000 cfs (Appendix Table 4-A-2). Water surface elevations obtained at the mouth of the slough were within· 0.03 feet of the corresponding mainstem water surface elevations over the range of mainstem flows from 8,400 to 24,000 cfs (non-breaching mainstem flows), indicating that a backwater effect occurred at the mouth of the slough over these range of mainstem flows. Lane Creek Slough Lane Creek Slough (Figure 41-3-6) is an unobstructed, meandering slough which empties into the mouth of Lane Creek. The mainstem was observed to breach the head of Lane Creek STough at mainstem flows of approximately 25,000 cfs (Table 41-3-2). Of the three staff gage readings obtained at the head of the slough, two were dry at mainstem flows of 14,000 and 24,000 cfs and one showed a water surface 46 -IJ) .... 0 l&l <!) a:: <( :::c (.) U) Q 50 10 1.0 WHISKERS CREEK SLOUGH Q =10 -24.ose~ WSEL -360) 31 •6166 ~ • • 5 10 WSEL-360 (feet) Figure 41-3-5. Whiskers Creek Slough stage- discharge rating curve. 47 I· ·' .. .. ., :~ ~. ·~ RIVER- ADF a G Q STATION "i ~ .... 0 FEET (opprox. scale) 250 6 STAFF GAGE ++++RAILROAD Figure 41-3-6. Planimetric site map of Lane Creek/Slough, RM 113.6, GC S28N05Wl2ADD. elevation of 474.30 feet at a mainstem discharge of 32,000 cfs. Seven water surface elevations obtained at the mid-slough gaging station showed a range of 2.5 feet over a corresponding range of mainstem flows from 10,500 to 32,100 cfs (Appendix Table 4-A-3). Three discharge measurements were also obtained at the mid-slough gaging station (Table 4I-3-1), and were used to construct a preliminary rating curve (Figure 4I-3-7). Flow during the two lowest discharges (2.0 and 9.9 cfs) appeared to result primarily from ground water seepage and surface water runoff. Flow during the highest measured discharge (20.7 cfs), taken when the mainstem flow was 32,000 cfs, appeared to be primarily from the mainstem. Water surface elevations were not determined at the mouth of Lane Creek Slough. However, a small backwater area was noted at the mouth of the slough over all ranges of mainstem flows observed in 1982. Slough 9 Five discharge measurements (Table 4I-3-1) obtained by R&M Consultants ranged from 1.7 to 182.0 cfs over a corresponding range of water surface elevation of 0.76 feet. These measurements were obtained within the vicinity of the R&M Consultants' stage recorder (Appendix Figure 4-F-30). The mainstem discharge recorded during the period of slough discharge measurements ranged from 13,400 to 26,000 cfs. These discharge and stage measurements obtained in Slough 9 were used to construct a preliminary rating curve (Figure 4I-3-8). Additional 49 100 80 60 40 -In 20 -(.') IJJ (.!) a:: <( :I: 10 u CJ) 0 5 LANE CREEK SLOUGH Q= 10-'·•o,. ( WSEL-460)0~ !5 10 20 WSEL -460 {feet) Figure 41-3-7. Lane Creek Slough stage-discharge rating curve. 50 1000 LIJ (.!) a:: <( :I: (.) (/) 0 100 10 SLOUGH 9 Q = 10"12.11111 ( WSEL-590) 24.20414 ~ 1.0 2.0 5.0 IQO W S E L-590 (feet) Figure 4I-3-8. Slough 9 stage-discharge rating curve. 51 measurements of stage and discharge are presented in Part II, Section 4.1.1.2.3. Slough 11 Slough 11 (Figure 4I-3-9) is a relatively long, unforked side slough with a head and mouth which juncture side channels of the mainstem. The slough head during the 1982 period of observation was never breached by the mainstem. Six water surface elevations obtained from gages at the mid-slough gaging station were found to vary only 0.05 feet (Appendix Table 4-A-3). A rating curve was not developed for this slough. Due to the limited range of flows available in Slough 11 in 1982, only two discharge measurements (3.1 and 5.5 cfs) were obtained at the mid-slough gaging station (Table 4I-3-1). The main sources of water contributing to the flow in Slough 11 during the open water season of 1982 appeared to be from ground water and surface water runoff. At the mouth, fifteen water surface e 1 evati ons showed a range of 3. 65 feet over a corresponding range of mainstem flows from 11,700 to 28,000 cfs. Water surface elevations of the mainstem, adjacent to the mouth, during this period had a range of 3.14 feet (Appendix Table 4-A-2). Backwater effects were observed to be limited to the immediate area of the mouth, increasing with increased mainstem discharge. Staff gages located at the head of Slough 11 were observed to be dry throughout the 1982 open winter season and 684.0 feet was determined as the point of 52 ()1 w 0 500 6 STAFF GAGE • R8M STAGE RECORDER 1m DATAPOD Figure 41-3-9. Planimetric site map of Slough 11, RM 135.3, GC S31N02Wl9DDD. zero flow for the head. Refer to Part II, Section 3.1.1.2.2 for addi- tional information on this slough. Slough 168 Slough 168 (Figure 4I-3-10) consists of a relatively unobstructed, free-flowing channel which head and mouth juncture with the mainstem. Slough 168 was observed to be breached by the mainstem at the head of the slough when mainstem flows were 20,200 cfs (Table 4!-3-2). From five water surface elevations determined from staff gages placed at the head of Slough 168, it was found that during a range of flows in the mainstem from 20,200 to 31,900 cfs, the water surface·at the head ranged 1.4 feet. Eight water surface elevations obtained at the mid-slough gaging station showed a range of 1.4 feet (Appendix Table 4-A-3). Three discharge measurements were also obtained at the mid-slough gaging station, rang- ing from 23.5 to 257.6 cfs (Table 4!-3-1). These data were used to con- struct a preliminary rating curve for this slough (Figure 4!-3-11). All discharge measurements measured at the mid-slough gaging station were obtained while the slough was breached by the mainstem. Corresponding mainstem flows ranged from 24,100 to 28,200 cfs. A single discharge measurement was made during a low flow, unbreached period near the mouth of the slough when the mainstem flow was 16,000 cfs. The flow was measured at 0.9 cfs and appeared to consist primarily of groundwater and 54 (J1 (J1 0 250 FEET ( opprox. scale) ....-SUSITNA Rl VER 6 STAFF GAGE [Q] DATAPOD A R 8 M STAGE RECORDER Figure 41-3-10. Planimetric site map of Slough l6B, RM 138.0, GC S31N02Wl7ABC. 1000 SLOUGH 16 8 500 -(/) -(.') Q=IO '·••••(WSEL-700)2 ·406 ~ LLI (.!) a:: <( ::I: (.) 100 CJ) 0 !50 10~--------r---~--~--~,-,-~rT--------~--~ .I .!5 1.0 2.0 3.0 WSEL-700 (feet) Figure 4!-3-11. Slough 168 stage-discharge rating curve. 56 surface water runoff. This flow measurement was obtained outside the reach of slough used to develop the rating curve and was not plotted. The overall range of water surface elevations measured at the mouth of the slough was 2.88 feet over a corresponding range of mainstem dis- charges from 11,700 to 31,900 cfs. Thirteen water surface elevations of the mainstem, adjacent to the mouth of Slough 168, ranged 5.83 feet over a range of mainstem discharges from 7,950 to 31,900 cfs. No pooling or backwater effect caused by the mainstem was apparent at the mouth of this slough during 1982. Slough 20 Slough 20 (Figure 41-3-12) is a relatively unobstructed, free-flowing channel which is fed by two clear water tributaries. Both its head and mouth juncture the mainstem Susitna River. Fourteen staff gage readings were obtained at the head of the slough, of these, three were observed dry at mainstem flows ranging from 12,500 to 20,200 cfs. The other eleven gage readings ranged from 0.40 to 1.39 feet over mainstem flows ranging from 21,500 to 32,500 cfs (Appendix Table 4-A-3). These data indicate the slough breaches between a mainstem discharge of 20,200 and 21,500 cfs (Table 41-3-2). Thirteen water surface elevations, obtained at the mid-slough gaging station varied 1.28 feet (Appendix Table 4-A-3). Five discharge mea- surements, taken at the mid-slough gaging station, ranged from 2.6 to 57 U1 ():) :r:.·., ••.• ·.· •• ,. '"· ~ .: ... • ,. ·.•. ••·.• '•:' ·'.":'*>'•'::.,\,'.',:.;.;.·.-::·-.•·. •:.•, .• , .• •. • o/ • o •, • •'• '' '\ •, • ''•,••; •• • • '• '• ~. '• o ': .., :,.. •: • ." ~ ... •,• '• I;, o ,• •'• f:;) ~ • ,: '•/ " o •,' •:,•,• '•:.~ .. , •,, • 0 500 FEET ( opprox. seale) STAFF GAGE THERMOGRAPH .,. SUSITNA Rl VER- :-~ :; ~ Woftlrfo/1 Cr. :~\ .. Figure 4!-3-12. Planimetric site map of Slough 20, RM 140.1, GC S31N02WllBBC. 158.8 cfs (Table 41-3-1). These data were used to construct a prelim- inary rating curve for this slough (Figure 41-3-13). Corresponding mainstem flows during the period of slough discharge measurements ranged from 12,500 to 32,500 cfs. Water surface elevations obtained at the mid-slough gaging station during breached and non-breached conditions varied 1.10 and 0.17 feet, respectively; while corresponding discharge measurements ranged from 16.4 to 158.8 cfs (breached period), and 2.6 to 11.6 cfs, (non-breached period). Mai nstem flows during these periods ranged from 22,500 to 32,500 cfs, (breached period) and 12,500 to 17,900 cfs, (non-breached period). Twenty water surface elevations recorded at the mouth of Slough 20 ranged 2.44 feet during corresponding mainstem flows from 8,480 to 32,500 cfs (Appendix Table 4-A-3). Mainstem water surface elevations recorded adjacent to the mouth of Slough 20 for this same period ranged 2.48 feet (Appendix Table 4-A-2). These data indicate a backwater effect takes place in the vicinity of the mouth of the slough for these ranges of mainstem flows. Observations in 1982 substantiate this conclusion. Slough 21 In this report, Slough 21 has been defined to include the slough proper and the extended access channel oriented parallel to the mainstem Susitna River. The slough portion of the Slough 21 complex (Figure 41-3-14) is a relatively long slough which parallels the mainstem Susitna River. The upper portion of Slough 21 forks into two channels 59 -(/) -() -LLI (!:) a:: <( J: (.) en Cl 200 10 5 SLOUGH 20 5 10 WSEL -720 (feet) Figure 4I-3-13. Slough 20 stage-discharge rating curve. 60 Figure 4!-3-14. Planimetric site map of Slough 21, RM 142.0, GC S31N02W02AAA. 500 FEET ( opprox. seale) 6 STAFF GAGE A RSM STAGE RECORDER @I DATAPOD CD THERMOGRAPH and both heads juncture the mainstem. The mouth of the slough drains into a side channel of the mainstem. The NW (left channel looking upstream) head was observed to be breached by the mainstem at mainstem flows greater than 24,000 cfs (Table 41-3- 2). Of the 12 staff gage readings obtained at the NW head, four were dry at mainstem flows between 16,000 and 22,900 cfs and eight had a range of 0.66 feet over mainstem flows from 24,000 to 32,500 cfs. Mainstem flows of at least 26,000 cfs, however, are required to breach the NE head. Of the nine staff gage readings obtained at the NE head of Slough 21, five were dry at mainstem flows ranging from 16,000 and 26,000 cfs and four had a range of 0.46 feet over mainstem flows from 26,000 to 31,900 cfs (Appendix Table 4-A-3). With ·a mainstem flow of 32,500 cfs on September 16, both heads were breached by the mainstem. Seventeen water surface elevations obtained at the gaging station located downstream of the forks varied 2.10 feet (Appendix Table 4-A-3). Three discharge measurements were also obtained at this gaging station ranging from 3.2 to 59.2 cfs (Table 41-3-1). These data were used to construct a preliminary rating curve for this slough (Figure 41-3-15). Corresponding mainstem discharges over the period of measurement ranged from 11,000 to 32,500 cfs. The two lowest discharge measurements, 3.2 and 5.0 cfs, were recorded during non-breaching mainstem flows of 16,000 and 22,500. The highest recorded slough discharge measured 59.2 cfs and was recorded during a breaching mainstem flow of 32,500 cfs. The primary sources of water to the slough flow during times of non-breach- ing mainstem flows appeared to be ground water and surface water runoff. 62 -.. - 2 () -1.1.1 (!) cr <t ::r 0 I 0 U) 8 6 SLOUGH 21 Q = 10-&.9626 ( WSEL -740) 9 ·&0115 "" 5 10 WSEL-740 (feet) Figure 4!-3-15. Slough 21 stage-discharge rating curve. 63 Seventeen water surface e 1 evati ons obtai ned at the mouth of Slough 21 (Appendix Table 4-A-3) had a range of 0.25 feet for mainstem flows from 12,200 to 24,100 cfs and a range of 1. 42 feet for rna i nstem flows from 25,600 to 32,500 cfs. Very 1 ittl e backwater effects caused by the mainstem were observed in the vicinity of the mouth of Slough 21 in 1982. Refer to Part II, Section 3.1.1.2.2 for additional information concern- ing this slough. Slough 22 Slough 22 has a relatively long, unobstructed channel which head and mouth both juncture the mainstem Susitna River (Figure 4I-3-16). Mainstem water was observed to begin to breach the head of Slough 22 at mainstem flows of 22,500 cfs (Table 4I-3-2). For mainstem flows in the range of 22,500 to 28,200 cfs, the water surface elevation of the slough at the head varied 1.40 feet. Three dry staff gage readings were obtained under non-breaching mainstem flows of 18,100, 16,000 and 13,600 cfs. Nine water surface elevations obtained at the mid-slough gaging station had a range of 1.72 (feet) (Appendix Table 4-A-3). Three discharge measurements obtained at this gaging station ranged from 5.1 to 118.5 cfs (Table 41-3-1). These data were used to construct a preliminary 64 ... ··" ... : ... \ ~ .. · .. • . .....: SUSITNA Rl VER Figure 41-3-16. Planimetric site map of Slough 22, RM 144.3, GC S32N02W32BBD. 0 250 FEET (approx.. scale) f:::. STAFF GAGE rating curve for Slough 22 (Figure 41-3-17). Corresponding mai nstem discharges over the periods of measurement ranged from 13,600 to 28,200 cfs. All slough discharges were measured under mainstem breaching conditions. Water surface elevations obtained at the mouth of Slough 22 varied 0.44 feet for mainstem flows ranging from 11,000 to 24,000 cfs and 0.99 feet for mainstem flows ranging from 24,100 to 28,200 cfs. For mainstem flows of 24,100 to 28,200 cfs, water depths over the head of Slough 22 ranged from 0.51 to 1.63 feet. No backwater effects caused by mainstem water influence were observed in 1982 in the vicinity of the mouth of Slough 22. 3.1.1.3 Tributaries Between Talkeetna and Devil Canyon Staff gage readings and discharge measurements were obtai ned at seven tributaries located between Talkeetna and Devil Canyon during the 1982 open water field season. For all of these tributaries except Fourth of July Creek preliminary rating curves were developed. A rating curve could not be developed at Fourth of July Creek due to insufficient data. Whiskers Creek Four discharge measurements were obtained on Whiskers Creek (Figure 41-3-4) ranging from 16.9 to 142.5 cfs over a corresponding change in water surface elevation of 1.54 feet (Table 41-3-3). These data were used to develop a preliminary rating curve (Figure 41-3-18). Eleven 66 en -0 200 SLOUGH 22 • "'-..Q=IO·s.s22!i(WSEL -780) 10.8416 5 WSEL-780(feet) 10 Figure 4I-3-17. Slough 22 stage-discharge rating curve. 67 Table 41-3-3. A comparison of water surface elevation {WSEL) and discharge measurements at selected tributary streams upstream of Talkeetna to the mean daily Susitna River dis~harge recorded at Gold Creek {USGS gaging station 15292000). WSELb Measured Mainstem Streamflow Discharge Location Date Time (ft) (cfs) (cfs) Whiskers Creek 821009 1145 366.51 31.8 7,080 (R.M. 101.4) 821006 1300 366.59 7,500 gage 101.2T2 820822 1400 366.21 _12,200 820928 1715 366.84 12,900 820909 1315 366.39 13,400 820813 1405 366.48 13,600 820903 1550 366.87 54.7 14,600 820816 1700 366.37 16.9 15,600 820808 1930 366.12 16,600c 820611 366.06 24,000 820920 1615 367.91 142.5 24,000 820715 1320 365.49 25,600 d 820622 0930 367.07 26,000c (31,500)d 820621 1300 367.40 28,000c (37,000) 820725 1525 368.47 31,900 Gash Creek 821009 1545 453.32 5.9 8,440 (R.M. 111.5) 821004 1430 453.34 10,500 gage 111. 5Tl 820813 1320 453.10 13,600 820818 1150 453.18 1.3 14,200 820920 1707 453.69 16.6 24,000 820921 1240 453.34 24,200 Lane Creek 821004 1228 472.03 10,500 (R.M. 113.6) 820909 1100 471.94 13,400 gage 113.6T3 820926 1335 472.11 14,400 820910 1630 471.91 14,400 820903 1450 472.23 14,600 820925 1640 472.14 15,000 820817 1425 475.79 27.5 15,100 820816 475.44 35.3 15,600 820902 475.79 51.7 16,000 820831 475.94 56.7 16,000 820808 1430 471.95 16,600 820917 1645 472.58 32,000 aUSGS provisional data, 1982. bTrue water surface elevation. cGold Creek stream gage malfunctioned, USGS estimated value. dAmended mainstem discharge at Gold Creek as determined from ADFG stage-dis- charge curve. 68 Table 4!-3-3 (continued). WSELa Measured Mainstem Streamflow Discharge Location Date Time (ft) (cfs) (cfs) 4th of July Creek 820907 1745 625.29 11,700 (R.M. 131.1) 820908 1345 625.24 11 ,900 gage 131.1Tl 820822 1315 624.99 12,200 821001 1524 625.53 12,400 820813 1220 625.18 13,600 820818 1805 625.18 14,200 820903 1130 625.81 14,600 820811 1015 625.33 15,400 820902 1640 625.67 16,000 820810 1835 625.38 16,700 820924 1750 625.53 17,100 820803 1625 625.35 38.3 19,800 820920 1030 626.28 24,000 820919 1026 626.28 24,100 820728 1625 625.52 25,600 820917 1050 626.17 32,000 Tributary at 821003 1715 731.23 11,000 head of Slough 20 820820 1145 730.16 12,500 ( R. M. 140. 6) 820813 1005 730.19 13,600 gage 140 .1T3 820901 1540 730.22 0.7 17,900 820804 1220 730.04 18,500 820914 1447 730.52 20,200 820802 1230 730.37 22,500b 820619 730.77 25,000b (28,500)c 820623 1015 730.61 26,000b (26,500)c 820622 1145 730.98 26,000 (31,500)c 820918 1217 730.74 9.3 27,500 820727 1205 730.84 29,100 820916 1230 731.39 23.5 32,500 aTrue water surface elevation. bGold Creek stream gage malfunctioned, USGS estimated value. cAmended mainstem discharge at Gold Creek as determined from ADFG stage-dis- charge curve. 69 VI -(.) 200 100 LLJ 50 (!) a:: <t :t: (.) U) 0 20 WHISKERS CREEK 5 10 WSEL-365 (feet) Figure 4!-3-18. Whiskers Creek stage-discharge rating curve. 70 water surface elevations collected in addition to the stage/discharge data showed an overa 11 range of water surface e 1 evati on during the period of June to early October of 2.41 feet. Gash Creek Three discharge measurements were obtained on Gash Creek (Figure 41-3- 19) ranging from 1.3 to 16.6 cfs over a corresponding change in water surface elevation of 0.51 feet (Table 41-3-3). These data were used to develop a preliminary rating curve (Figure 41-3-20). Three water surface elevations collected in addition to the stage/discharge measure- ments had a range of 0. 59 feet during the period August to October, 1982. Flows in Gash Creek are influenced by a culvert located upstream of the gaging station. Lane Creek Four discharge measurements were obtained on Lane Creek (Figure 41-3-6) ranging from 27.5 to 56.7 cfs over a corresponding change in water surface elevation of 0.50 feet (Table 41-3-3). These data were used to develop a preliminary rating curve (Figure 41-3-20). Eight water surface elevations collected in addition to the stage/discharge data showed an overall range of 4.03 feet during the period August to Octo- ber, 1982. 71 I .· ,, :· :. • . . , .. .; III.&T I AOFSG \ Q STATION ... . ·.-·:·.··::·:·· .... -··" ·~ .. 0 50 FEET (approx. scale) 6. STAFF GAGE 1111 RAILROAD Figure 4!-3-19. Planimetric site map of Gash Creek, RM 111.5, GC S28N02W24ADA. -• .... C) -LLI ~ a: < ::c (,) fJ) Q 100 LANE CREEK • Q = IO"I.e7u( WSEL-470)4.z079 101~--------~--------~----r-~~~~~ I 20 10 5 5 WSEL-470 (feet) GASH CREEK • 10 --Q = 10-7.6457( WSEL _450 ) 15.7438 5 WSEL -450 (feet) 10 Figure 41-3-20. Stage-discharge rating curves for Lane and Gash Creeks. 73 Fourth of July Creek Due to high water velocities which made wading hazardous during most of 1982, only a single discharge measurement of 38.3 cfs corresponding to a water surface elevation of 625.35 feet was obtained on Fourth of July Creek (Figure 41-3-21). Because of this limited data base, a rating curve was not developed for this site. Fifteen water surface elevations collected in addition to the stage/discharge data showed an overall change in water surface elevation of 1.29 feet during the period July to October, 1982 (Table 41-3-3). Unnamed Tributary at the Head of Slough 20 Three discharge measurements were obtained on the unnamed tributary located at the head of Slough 20 (Figure 41-3-12), ranging from 0.7 to 23.5 cfs over a corresponding change in water surface elevation of 1.17 feet (Table 41-3-3). These data were used to develop a preliminary rating curve (Figure 41-3-22). Ten water surface elevations collected in conjunction with stage/discharge data showed an overall change in water surface of 1.35 feet during the period of June to October, 1982. Indian River and Portage Creek Continuous streamflow records for Indian River (Figure 41-3-23) and Portage Creek (Figure 41-3-24) were obtained from August 9 through October 22, 1982 (Appendix Tables 4-A-4 and 4-A-5). Streamflows gener- ally ranged between 100 and 400 cfs over a corresponding change in water 74 .... · .. -::· ·.::: '{;:!· ...... ·.·: (Side Channel) ··.;·::,: .. ·.:::: •.. : ·.: ·.; :; .. :;~·: ;·:-:·:::: · ... 0 FEET (approx. scale) 6. STAFF GAGE Figure 41-3-21. Planimetric site map of Fourth of July Creek, RM 131.1, GC S30N03W03DAC. 25 en -(.) LLI (!) a:: <t :I: () CJ) c 50 TRIBUTARY AT HEAD 10 .I OF SLOUGH 20 Q = IO 1.1448(WSEL-?3 0) 1.9363 .5 WSEL-730 (feet) 1.0 2.0 Figure 4!-3-22. Stage-discharge rating curve for unnamed tributary at the head of Slough 20. 76 SUSITNA RIVER 138.11r.ll Figure 41-3-23. Planimetric site map of Indian River, RM 135.6, GC S31N02W09CDA. '---===----'190 FEET (a pprox. scale) 6 STAFF GAGE <!) THERMOGRAPH .. i• ) ·:· ·.· '.: {~ 0 250 FEET ( opprox. a cole) [Q) DATAPOD (!) THERMOGRAPH Figure 41-3-24. Planimetric site map of Portage Creek, RM 148.8, GC S32N01W25CDB. surface elevation of 1.82 ft at Indian River (Table 41-3-4) and 200 to 600 cfs over a corresponding change in water surface elevation of 2.79 ft at Portage Creek (Table 41-3-5). Due to prevailing weather condi- tions during the measurement period of 1982, these streamflows may be considerably less than normally expected for this period. The peak runoff recorded from early August through October was 1,815 cfs on September 15 at Indian River and 1,673 cfs on September 16 in Portage Creek. These streamflows were the effect of a 3-day rainstorm during which 2.7 inches of precipitation was recorded at Devil Canyon (R&M, 1982 observations). A cursory review of monthly precipitation values at Talkeetna indicate that this was a fairly large, but not uncommon, amount of precipitation for September. Preliminary .rating curves were developed utilizing stage-discharge data collected by R&M Consultants (Figure 4I~3-25). 3.1.1.4 Mainstem, Sloughs and Tributaries Downstream of Talkeetna Measurements of water surface elevation and discharge were obtained at four tributaries (Goose, Rabideux, Sunshine and Birch Creeks) and four sloughs (Goose 2, Whitefish, Sunshine and Birch Creek Sloughs) located downstream of Talkeetna. Preliminary rating curves have been developed for Lower Goose Creek 2, Rabideux Creek, Sunshine Creek, Birch Creek and Birch Creek Slough. Insufficient data at the other sites prevented the development of rating curves. Goose 2 Slough and Sunshine Slough are 79 Table 41-3-4. Daily mean streamflow and surface water temperature record for Indian River, Alaska. -------------------------------------------------------SURFACE GAGE WATER HEIGHT DISCHARGE TEMPERATURE DATE (ft) (cfs) (C) ------------------------------------------------------- 820809 1.76 257 8.6 820810 1.73 244 8.4 820811 1.69 228 8.9 820812 1.59 195 8.9 820813 1.53 176 9.6 820814 1.51 169 9.0 820815 1.50 168 9.0 820816 1.46 156 9.4 820817 1.53 175 8.8 820818 1.53 177 8.4 820819 1.47 158 8.6 820820 1.42 145 9.4 820821 1.38 136 9.3 820822 1.36 131 9.3 820823 1.37 132 9.6 820824 1.35 130 9~7 820825 1.36 130 9.8 820826 1.36 131 9.7 820827 1.33 124 8.8 820828 1.33 123 8.6 820829 1.39 139 8.6 820830 1.80 275 8.0 820831 2.12 446 7.8 820901 1.99 367 7.9 820902 1.87 307 7.9 820903 1.90 322 7.6 820904 1.83 288 7.6 820905 1.77 259 7.5 820906 1.71 235 7.8 820907 1.72 240 8.1 820908 1.68 227 7.6 820909 1.67 220 7.4 820910 1.68 223 7 .1 820911 1.71 238 6.6 820912 1.72 240 6.2 820913 2.15 473 6.2 820914 2.48 762 6.6 820915 3.13 1815 7.1 820916 3.01 1557 6.7 820917 2.71 1041 5.8 820918 2.44 716 6.0 820919 2.63 931 6.2 ------------------------------------------------------- 80 Table 4I-3-4. Cont. DATE 820920 820921 820922 820923 820924 820925 820926 820927 820928 820929 820930 821001 821002 821003 821004 821005 821006 821007 821008 821009 821010 821011 821012 821013 821014 821015 821016 821017 821018 821019 821020 821021 821022 GAGE HEIGHT (ft) 2.87 2.59 2.42 2.24 2.11 2.01 1.96 2.10 1.95 1.95 1.92 1.86 1.80 1.75 1.70 1.67 1.61 1.60 1.58 1.56 1.53 1.50 1.53 1.53 1.47 1.42 1.42 1.43 1.40 1.40 1.37 1.31 1.32 81 DISCHARGE (cfs) 1291 879 693 539 444 378 352 434 347 345 330 277 252 233 215 202 183 182 174 170 161 154 162 160 146 132 134 136 130 129 123 110 111 SURFACE WATER TEMPERATURE (C) 6.1 5.9 5.7 4.7 4.2 4.6 5.0 5.0 4.0 4.9 5.1 4.6 4.5 4.3 3.3 2.7 2.2 2.4 2.4 2.6 2.6 2.1 2.0 1.7 1.3 .1 .6 1.6 .6 1.0 .6 0.0 0.0 Table 41-3-5. Daily mean streamflow and surface water temperature record for Portage Creek, Alaska. ------------------------------------------------------SURFACE GAGE WATER HEIGHT DISCHARGE TEMPERATURE DATE (ft) (cfs) (C) ··-------------------------------- 820809 2.17 602 8.0 820810 2.22 625 7.9 820811 2.16 594 8.7 820812 2.02 527 8.7 820813 1.94 489 9.7 820814 1.93 484 9.4 820815 1.96 495 9.3 820816 1.86 451 9.6 820817 1.89 464 8.6 820818 1.87 455 8.4 820819 1.79 418 8.6 820820 1.74 392 9.5 820821 1.70 376 9.4 820822 1.67 359 9.4 820823 1.69 369 9.8 820824 " 1.68 368 9.8 820825 1.69 371 10~0 820826 1.74 394 9.9 820827 1.67 362 8.7 820828 1.63 342 8.1 820829 1.72 385 8.4 820830 2.19 609 7.5 820831 2.50 766 7.3 820901 2.31 672 7.6 820902 2.19 612 7.5 820903 2.33 682 7.1 820904 2.28 658 7.1 820905 2.19 611 7.0 820906 2.13 579 7.5 820907 2.15 589 7.8 820908 2.09 563 7.0 820909 2.08 557 6.9 820910 2.15 592 6.8 820911 2.15 590 6.0 820912 2.16 595 5.7 820913 2.59 814 6.0 820914 3 .19 1088 6 .1 820915 4.06 1584 6.6 820916 4.21 1673 5.9 820917 3.73 1391 5.2 820918 3.41 1210 5.4 820919 3.58 1308 5.8 ------------------------------------------------------- 82 Table 41-3-5. Cont. ------------------------------------------------------SURFACE GAGE WATER HEIGHT DISCHARGE TEMPERATURE DATE (ft) (cfs) (C) ------------------------------------------------------- 820920 3.70 1375 5.5 820921 3.45 1229 5.5 820922 3.24 1114 5.3 820923 3.01 988 4.1 820924 2.83 891 3.6 820925 2.6 9 817 4.1 820926 2.59 765 4.6 820927 2.57 754 4.7 820928 2.45 691 3.5 820929 2.41 670 4.4 820930 2.39 660 4.6 821001 2.30 613 4.1 821002 2.22 578 4.0 821003 2.16 544 3.6 821004 2.09 512 2.6 821005 2.0"3 484 2.0 821006 1.96 449 1.5 821007 1.94 441 1 ~6 821008 1.91 428 1.5 821009 1.88 413 1.5 821010 1.84 394 1.7 821011 1.80 376 1.2 821012 1.79 371 1.7 821013 1.77 360 1.5 821014 1.72 340 1.0. 821015 1.61 290 o.o 821016 1.69 325 0.0 821017 1.69 324 .2 821018 1.62 292 0.0 821019 1.61 290 .1 821020 1.55 265 0.0 821021 1.42 210 0.0 821022 1.42 208 o.o ------------------------------------------------------- 83 -w lL. (.) -1.1.1 I 000 (,t) a:: <( ::1: (..) w Q 500 PORTAGE CREEK • t-----Q = 375 (GH)1·22 • 3001~--------~r-----r---~~--.--.-.-.~ 1000 -500 w u.. (..) - LLI (,t) a:: <( J: (..) w Q 1.0 5 GAGE HEIGHT IN FEET I NOlAN RIVER 10 100~--------~------~--~~--~~-.~ 1.0 5 GAGE HEIGHT IN FEET 10 Figure 41-3-25. Stage-discharge rating curves for Indian River and Portage Creek. 84 also referred to in the backwater area section of this report as Goose 2 side channel and Sunshine minor side channel, respectively. Stage readings were also obtained in the mainstem Susitna River at the Sunshine fishwheel station and mainstem Yentna River at the Yentna River fishwheel station. These data were compared to provisional USGS dis- charge data collected at Sunshine and Susitna Stations (for the Susitna River) and Yentna Station (for the Yentna River). In addition, mainstem Susitna River water surface elevation data was collected at the confluences of Goose 2 Slough mouth and head of Birch Creek, (Figure 41-2-2). A mainstem gradient map (Figure 41-3-26) shows a drop of 1.9 ft/mi from river mile 0 to R.M. 53.5 and 5.4 ft/mi from river mile 53.5 to 100.4. This data is presented in conjunction with the slough and tributary data. Cross sections were made from survey data collected by ADF&G personnel in 1982 for Rabideux Slough and Chum Channel (Appendix Figures 4-A-40 and 4-A-41). 3.1.1.4.1 Mainstem Sites Sunshine Fishwheel Station A summary of the Sunshine fishwheel station stage data as compared to provisional USGS discharge data (1982) for the Susitna River at the Parks Highway Bridge is presented in Table 41-3-6. Stage readings obtained nearly daily from July 1 to October 10, 1982 varied 5.60 ft. Discharge during this time varied from 19,900 to 91,300 cfs. 85 co (j) 600 +- Q) Q) 500 :!::: z 0 400 -I- <( 300 > w _J 200 w w 100 ~ 0::: I-0 0 I SUSITNA RIVER COOK INLET TO TALKEETNA G RADiENT: i.91t/mi REACH YENTNA RIVER ALEXANDER CREEK I 10 20 30 40 SUS I TNA RIVER Cook Inlet to Talkeetna L-J Distance from Slough Head to Mouth Relative to Susitna River Mile (Adopted from U.S.G.S Contour Mops, 1:63,360) CACHE CREEK SLOUGH WILLOW CREEK 50 RIVER MILE 60 GOOSE CREEK 2/ SLOUGH 70 80 90 I 0 Figure 41-3-26. Gradient of the Susitna River from Cook Inlet to Talkeetna. Table 41-3-6 A comparison of water surface elevation (WSEL) at Sunshine Fishwheel Camp (RM 79.2) to the mean daily Susitna River discharge r~corded at Sunshine (USGS gaging station 15292780). WSEL Sunshine Discharge Date Time (ft) (cfs) 821009 1030 239.06 19,900 821008 1030 239.17 20,400 821007 1120 239.25 21,400 821006 1700 239.34 22,300 821006 1000 239.47 22,300 821005 239.59 24,000 821005 1730 239.62 24,000 821005 239.71 24,000 821004 0915 239.88 25,800 821003 1500 240.08 27,800 821002 0900 240.34 29,700 821001 0900 240.50 31,500 820930 0900 240.60 33,400 820929 0800 240.66 33,900 820806 1900 241.84 34,700 820828 0910 242.14 35,600 820928 0900 240.90 35,900 820822 0715 240.79 37,600 820821 0715 240.84 37,600 820823 0700 240.89 38,000 820926 0900 241.10 38,000 820820 0800 240.89 38,200 820826 0930 240.54 38,400 820927 1000 241.12 38,500 820819 0945 240.89 40,700 820813 0945 241.19 42,000 820813 2345 241.24 42,000 820925 1010 241.42 42,200 820814 0615 241.39 42,800 820814 2400 241.44 42,800 820812 2300 241.19 44,000 820812 0715 241.39 44,000 820818 0645 240.84 44,400 820817 2000 240.89 46,500 820817 0945 241.49 46,500 820706 0800 240.69 46,600 820705 2215 240.79 47,100 820705 0830 240.99 47,100 820807 0815 241.89 47,700 820811 2355 241.49 47,900 820815 2200 241.64 47,900 aUSGS provisional data (1982). 87 Table 41-3-6 (Continued). WSEL Sunshine Discharge Date Time (ft) (cfs) 820811 0600 241.74 47,900 820808 0800 241.94 49,400 820704 2130 241.19 48,000 820704 1000 241.29 48,000 820708 1000 240.99 49,400 820708 2330 241.19 49,400 820805 241.93 50,400 820703 2100 241.49 51,300 820703 0930 241.69 51,300 820810 2315 241.79 51,600 820810 0845 241.99 51,600 820809 2200 241.94 52,500 820709 1200 241.34 55,400 820710 0800 241.39 56,100 820923 1810 242.26 56,600 820923 0900 242.62 56,600 820721 0815 241.39 57,800 820716 2300 241.19 58,200 820716 0900 241.34 58,200 820711 0815 241.44 58,400 820722 0845 241.69 59,000 820722 2340 242.19 59,000 820718 0945 241.54 59,800 820718 2300 241.79 59,800 820712 0800 241.54 60,100 820719 0830 241.69 61,500 820701 241.95 62,100 820714 2315 241.74 62,500 820713 0840 241.79 63,000 820922 0830 242.94 . 65 ,300 820922 0730 243.06 65,300 820919 0800 243.24 69,500 820920 0830 243.50 72,700 820920 0830 243.64 72,700 820918 0820 243.68 76,500 820917 2115 244.07 88,400 820917 0810 244.36 88,400 820916 0730 244.27 91,300 820916 1920 244.66 91,300 88 Yentna Fishwheel Station A summary of the Yentna River fishwheel station stage data as compared to provisional USGS discharge data (1982) for the Yentna River is presented in Table 41-3-7. The stage data at the Yentna River fishwheel station was relative to an arbitrary benchmark (elevation = 100.00 ft) and was not tied to project datum. Stage readings obtained periodically from June 30 to September 15, 1982, varied 3.61 feet. Discharges of the Yentna River varied from 30,000 to 61,000 cfs and within the Susitna River downstream of the Yentna River confluence from 71,000 to 142,000 cfs during the same period. 3.1.1.4.2 Tributaries Lower Goose Creek 2 Three discharge measurements were obtained on Lower Goose Creek 2 (Figure 41-3-27) ranging from 84.10 to 251.0 cfs over a corresponding change in water surface elevation of 0.92 feet. These data were used to develop a preliminary rating curve (Figure 41-3-28). Nine additional water surface elevations not collected in conjunction with discharge data showed a change in water surface elevation during the period June through October 1982, of 1.26 feet. Lower Goose Creek 2 was not direct- ly influenced by mainstem flows as determined from comparisons of change in the observed water surface elevations in the creek to the mainstem discharge (Appendix Table 4-A-6). 89 Table 41-3-7. A comparison of the relative water surface elevation (WSEL~ at the Yentna Fibhwheel Camp to the mean daily Yentna River and Susitna River discharge (cfs). WSEL (ft)c Yentna River Susitna River Date Time Discharge Discharge 820829 2000 86.55 30,000 71,000 820905 1730 86.68 31,000 75,000 820828 1740 86.72 31,500 74,000 820913 1920 87.36 32,000 90,000 820903 1740 87.26 32,000 82,000 820904 1850 87.35 32,000 72,000 820906 1800 87.49 33,000 74,000 820912 1950 88.00 33,000 77,000 820823 2200 87.19 33,100 78,000 820911 1920 88.03 34,000 77,000 820902 1930 87.67 34,000 87,000 820824 2130 87.43 34,200 80,000 820822 2350 87.28 34,200 78,000 820826 2300 87.11 34,400 80,000 820821 2350 87.51 34,800 79,600 820831 2100 90.16 35,000 92,000 820820 2100 87.50 35,200 81,600 820825 2200 87.48 35,500 82,000 820819 2200 87.60 36,800 86,700 820910 1815 87.66 37,000 80,000 820814 2030 87.83 37,400 88,100 820813 1000 88.01 39,200 91,800 820818 1930 88.07 40,300 93,300 820806 1450 88.28 41,500 104,000 820806 1945 88.33 41,500 104,000 820808 2150 88.42 41,900 109,000 820809 1830 88.33 42,100 107,000 820807 1945 88.33 42,300 103,000 820810 2000 88.48 42,600 107,000 820914 1930 88.96 43,000 140,000 820804 1645 88.48 43,900 112,000 820811 2100 88.71 44,500 104,000 820803 2045 88.88 47,100 120,000 820816 2030 88.95 48,300 103,000 820630 1630 90.15 61,600 142,000 aGaging station on the Yentna River near Su Station (USGS provisional data, 1982). bGaging station at Su Station (USGS provisional data, 1982). cWater surface elevations are relative to a temporary bench mark which was assigned an elevation of 100.00 feet. 90 073.1M3 JAM ADF8G ,. UPPER Q STATION ; 0 200 FEET (approx. scale) 6 STAFF GAGE Figure 41-3-27. Planimetric site map of Goose Creek 2/Slough, RM 73.1, GC S23N04W30.BCB. 91 -• -(,) -LLI (!) 0: <t :z: (,) en 0 300 200 100 GOOSE CREEK 2 ~0=10"3083 ( WSEL-210)3 .6539 5 WSEL-210(feet) Figure 4!-3-28. Stage-discharge rating curve for Goose Creek 2. 92 10 Rabideux Creek Discharge measurements were obtained at two gaging stations in Rabideux Creek (Figure 41-3-29); an upper site located 1.7 miles upstream from the mouth and a lower site approximately 0.25 miles upstream from the mouth. Three discharge measurements obtained at the upper gaging station ranged from 129.2 to 222.9 cfs over a corresponding change in water surface elevation of 0.40 feet. These data were used to develop a preliminary rating curve (Figure 41-3-30). Two additional water surface elevations not collected in conjunction with discharge data showed an overall change in water surface elevation of 1.65 feet (Appendix Table 4-A-6). Two discharge measurements obtained at the lower gaging site were 131.1 and 271.0 cfs over a corresponding change in water surface elevation of 0.78 ft. The mainstem flow during these two measurements was 29,700 and 36,400 cfs, respectively. Twelve additional water surface elevations not collected in conjunction with discharge data at this site showed a change in water surface elevation to be 6.37 ft overall, during which time the mainstem discharge varied from 24,000 to 88,400 cfs. From on site observations, the backwater area created during high mainstem discharges was substantial, extending upstream past the lower gaging station. Sunshine Creek Four discharge measurements were obtai ned 0. 7 miles upstream of the mouth in Sunshine Creek (Figure 41-3-31) ranging from 31.8 to 103.9 cfs over a corresponding range of water surface e 1 evati on of 1. 98 feet 93 0 500 FEET (approx. scale) U STAFF GAGE Figure 41-3-29. Planimetric site map of Rabideux Creek/Slough, RM 83.1, GC S24N05WT6ADC. 1.: ·' \~ it~ \' '· ,, ~ .. ,. I ~ ., -() -., -() LLJ (!) a:: <: :I: (.) CJ) -c 1000 500 200 100 80 60 40 RABIDEUX CREEK 5 10 WSEL-260 (feet) SUNSHINE CREEK Q = 10 -.e4oo( WSEL -260)2. i741 ~ 5 WSEL-260(feet) • 10 Figure 4!-3-30. Stage-discharge rating curves for Rabideux and Sunshine Creeks. 95 ... :. , ......... ..... ·:;· ...... • :·.· 't ·.=:'··:··:······: .. • :.:·:';.' .:·! '·. ·.: :.·. ';> ... .. 0 500 FEET (opprox. scale) 6 STAFF GAGE Figure 41-3-31. Planimetric site map of Sunshine Creek/Slough, RM 85.7, GC S24N05Wl4AAB. (Appendix Table 4-A-6). These data were used to develop a preliminary rating curve (Figure 41-3-30). Eleven additional water surface eleva- tions, not collected in conjunction with discharge measurements, showed the overall range in water surface elevation to be 4.14 ft at the gaging station. In addition, water surface elevation data was collected at the mouth of Sunshine Creek (which flows into Sunshine Creek Slough). This data had a range of 6.51 feet over a range of mainstem discharges of 21,400 to 91,300 cfs. Sunshine Creek, during periods of high mainstem flow, was found to exhibit an area of low velocity backwater originating at the creek mouth and extending upstream at least as far as the upstream gaging station (0.7 miles upstream). A comparison of the creek discharge obtained on October 4 (68.6 cfs) to the discharge obtained on September 1 (31.7 cfs) showed that water surface e 1 evati ons were higher for the 1 ower flow (267.20 feet) than for the higher flow (266.93 feet). This stage- discharge relationship is evidence that the discharge site was within a backwater area created during mainstem flows of 45,200 cfs or greater. Birch Creek Four discharge measurements were obtained 0.1 miles upstream of the mouth in Birch Creek (Figure 41-3-32) ranging from 62.4 to 114.1 cfs over a corresponding change in water surface elevation of 0.35 ft (Appendix Table 4-A-6). These data were used to develop a preliminary rating curve (Figure 41-3-33). Six additional water surface elevations, not collected in conjunction with discharge data, showed an overall 97 \.0 co ~ SUSITNA 6 STAFF GAGE 0 mile Figure 4!-3-32. Planimetric site map of Birch Creek/Slough, RM 88.4, GC S25N05W25DCC. 200 -en -0 l&J 100 <!) a:: <( 80 ~ (.) (I) c 60 40 200 --Q) Q) - l&J (!) a:: 100 <( ~ (.) (I) -c 50 BIRCH CREEK Q= I 0 ·&.s•Uit( WSEL -280)9 ·81!04 ~ I 5 10 WSEL-280 (feet) BIRCH CREEK SLOUGH (BELOW BIRCH CREEK) Q= 10'2454 ( WSEL-280) 2 ' 5776 --....____ 5 10 WSEL-280 (feet) Figure 4!-3-33. Stage-discharge rating curves for Birch Creek and Birch Creek Slough. 99 change in water surface elevation of 0.58 ft at the gaging station. In addition, twelve water surface elevations were collected at the mouth of Birch Creek varying 2.09 ft over a corresponding range of mainstem flows from 22,300 to 99,300 cfs. Backwater effects were observed to be present only in the immediate vicinity of the creek mouth, not extending up to the creek gaging station. 3.1.1.4.3 Sloughs Lower Goose 2 Slough (Side Channel) Lower Goose 2 Slough (Figure 41-3-27) is a relatively long slough (also referred to as a side channe 1), which head and mouth both confluence with the mainstem Susitna River. Two gaging stations were located in this s 1 ough, one above and one be 1 ow the confluence with Lower Goose Creek 2. Three discharge measurements, obtained at the upstream gaging station (upstream of the confluence with Lower Goose Creek 2), ranged from 1.8 to 458.0 cfs over a corresponding change in water surface elevation of 1.55 ft (Appendix Table 4-A-6). The overall range of water surface elevation is the same as found for the range of discharge measurements because only two staff gage readings were obtained, one during each of the discharge measurements for the 1.8 cfs flow and one for the 458.0 flow. Only one discharge measurement (101.0 cfs) was obtained at the lower gaging station (below the confluence with Lower Goose Creek 2) corresponding to a water surface elevation of 209.33 ft (Appendix Table 4-A-6). Fourteen additional water surface elevations, not collected in conjunction with discharge measurements at the lower 100 gaging station, showed water surface elevation to range 1.82 ft over a corresponding mainstem discharge from 31,500 to 68,700 cfs. Mainstem water surface elevations, collected adjacent to the mouth of Goose 2 Slough, had a range of 2.35 ft for mainstem flows of 31,500 to 68,700 cfs. A substantial backwater effect was observed to occur at the mouth of this slough during the range of mainstem flows from 31,500 to 68,700 cfs. Whitefish Slough Three discharge measurements were obtained at the mouth of Whitefish Slough (Figure 41-3-34) ranging from 6.6 to 24.2 cfs over a correspond- ing change in water surface elevation of 7.55 ft (Appendix Table 4-A-6). These data were used to develop a preliminary rating curve (Figure 41-3-35). Corresponding mainstem flows during the periods of discharge measurement varied from 29,700 to 91,300 cfs. Seven addition a 1 water surface elevations, not collected in conjunction with discharge measure- ments, showed the overall change in water surface elevation at the gaging station to be 8.94 ft. At most mainstem discharges observed this year, a backwater effect was present at the gaging station which, during high mainstem discharges, extended approximately 3/4 of a mile up Whitefish Slough. No staff gages were placed in the mainstem adjacent to this site. One discharge measurement (31.0 cfs) was obtained at a mainstem flow of 91,300 cfs in an unnamed tributary entering Whitefish Slough (Figure 4!-3-33). The slough discharge taken on the same day was found to be 101 -8 eaver Dam AD F 8 G a Q:: ~ :::.. ...... Q:: "'{ ~ ..... ,_. ...... 0 .. (/) N ~' ::::> (/) .. J • . .. . ; .. .. :.:: 0 1000 A OF S G ··.-.·.· a STATION .. ·:·,: ... , .. FEET .. ~ ··:·. ( opprox. scale) 6. STAFF GAGE Figure 4!-3-34. Planimetric site map of Whitefish Slough, RM 78.7, GC S23N05WOlBBC. en -0 LLI (!) a: c( :r: 0 (/) 60 40 20 10 0 8 6 WHITEFISH SLOUGH (mouth) Q= I0-·1488 (WSEL -230)1.46119 · ~ 5 WSEL-230 {feet) • 10 20 Figure 41-3-35. Stage-discharge rating curve for Whitefish Slough. 103 less than the flow from the tributary. This difference was attributed to the backwater, low velocity phenomenon created by mainstem flow occurring at the slough gaging station, lowering the slough discharge measurement. Sunshine Slough Sunshine Slough is a relatively short slough which head and mouth confluence a side channel of the mainstem Susitna River (Figure 4I-3- 31). Three discharge measurements were obtained in Sunshine Slough which ranged from 0.3 to 607.1 cfs over a corresponding change in water surface elevation of 4.19 ft (Appendix Table 4-A-6). Thirteen addi- tional water surface elevations, not collected in conjunction with discharge measurements, showed an overall change in water surface elevation at the gaging station of 6.25 ft. Corresponding mainstem flows during this period ranged from 25,800 to 91,300 cfs. Due to a lack of measured stream flows no rating curve was developed in this site. The slough was breached during the measured slough discharges of 85.8 and 607.1 cfs when corresponding mainstem flows were 47,200 and 76,500 cfs, respectively. By comparing ranges of water surface elevations measured at the slough gaging station to those measured at the Sunshine Creek mouth gaging station (6.25 ft and 6.51 ft, respectively) while the slough was breach- ed by the mainstem, it was apparent that backwater effects occurred at 104 least as far upstream as these gaging stations. At a mainstem flow of 91,300 cfs the slough water surface elevation at the slough gaging station was 270.80 feet whi 1 e at the gaging station at the mouth of Sunshine Creek it was 270.70 feet, and at the gaging station upstream on Sunshine Creek it was 270.81 feet. Birch Creek Slough Birch Creek Slough is a relatively long, meandering slough which head and mouth confluence with the mainstem Susitna River (Figure 41-3-32). Discharge measurements were obtained at two gaging stations in Birch Creek Slough; above the confluence with Birch Creek and below the confluence with Birch Creek. One discharge measurement (15.7 cfs) was obtained at the gaging station above the confluence with Birch Creek corresponding to a water surface elevation of 284.74 ft (Appendix Table 4-A-6). Eleven additional water surface elevations, not collected in conjunction with discharge measurements, showed an overall change in water surface elevation at the gaging station to be 2.05 ft. Four discharge measurements were obtained at the gaging station below the confluence with Birch Creek ranging from 75.4 to 131.8 cfs over a corresponding change in water surface elevation of 0.92 ft. These data were used to develop a preliminary rating curve (Figure 41-3-33). Five additional water surface elevations, not collected in conjunction with discharge, showed an overall change in water surface elevation at the gaging site of 1.01 ft. Corresponding mainstem flows during this time ranged from 22,300 to 69,500 cfs. 105 Stage data was also collected (not in conjunction with discharge) in Birch Creek Slough at the head, at the confluence with Birch Creek and at the mouth. At mainstem discharges of 42,000 to 69,500 cfs, flo~ was observed through the head of the slough with the water surface elevation varying 1.58 ft. Water surface elevations measured in the mainstem adjacent to the head of Birch Creek Slough had a range of 3.51 ft during corresponding mainstem flows of 27,800 to 69,500 cfs. The range of water surface elevations observed in Birch Creek Slough at the conflu- ence with Birch Creek was found to be 0.75 ft. Water surface elevations at the mouth of Birch Creek Slough were found to have a range of 3.78 ft during corresponding mainstem flows of 22,300 to 82,400 cfs. A signifi- cant area of backwater influence occurs in this slough during high mainstem flows. 3.1.1.5 Upstream of Devil Canyon Periodic discharge measurements were obtained in seven tributaries above Devil Canyon. Appendix Table 4-A-1 compares the discharge of the tribu- taries to that of the mainstem Susitna River at Vee Canyon. Refer to Volume 5 for the specific results and discussion of these discharge measurements. 3.1.2 Thalweg Profiles Streambed profiles for Sloughs 8A, 9, 11, and 21 are presented in Figures 41-3-36, 41-3-37, 41-3-38 and 41-3-39, respectively. Each figure contains a schematic drawing (upper left of Figure) showing gross 106 .,.. ~570 ,_. z C) 0 -....) ;:: ~ 56!5 ~ "' "' ::> ~060 ... ""' ~15t00 o•oo o•oo 10•00 Figure 41-3-36. ITUOY TMtcUCT lOCATIONI IAOI' a• MODILIIHI IT\IOY, IMt) 40•00 THALWEG PROFILE SLOUGH SA STREAMBED STATION (feel) Streambed profile for Slough 8A. SURFACE SUBSTRATE TYPES r:J SILT/SAND C:J ORAVE:L/RUSBLE ~ COBBLE I BOULDER ::r~bAtAE~E~E~~HICE, (SUSITNA RIVER REACH GRADIENT• 9.Sfl /"'I) uo•oo ~ 1-' z 0 0 co ~ > IIJ ...J IIJ IIJ :::> a: 1- 610 600 600 !19!1 !590 SLDUGH 9 STREAMBED !J PROFILE STUDY AREA 6 STREAMBED STATION ~ m ~ ~ 1 STUDY TRANSECT LOCATION THALWEG PROFILE SLOUGH 9 SURFACE SUBSTRATE TYPES C::=::J SILT I SAND I. :•. !; ;.} GRAVEL I RUBBLE ~ COBBLE I BOULDER (SUSITNA RIVER REACH GRADIENT:. aT ft /mi} ~+---------r--------,---------r---------r--------~----~IA_D_F_aTo __ Moo __ E_u_N_o_s_TrU-DY~,-19_e_z~l--~--------~--------r--------,---------r---------r--------,-------- -IO 00 0+00 10+00 liSt()() 20+00 21St00 31St()() 40+00 41St00 !50+00 !IIStOO 60+00 STREAMBED STATION (feet I Figure 4!-3-37. Streambed profile for Slough 9. -Q) Q) ,_. z 0 l.O 0 1-~ > w ...1 w w ::> 0: 1- 685 680 675 670 665 SLOUGH II STREAM BED E] PROFILE STUDY AREA .0. STREAMBED STATION THALWEG PROFILE SLOUGH II SURFACE SUBSTRATE TYPES D SILT I SAND I::::·:'·:·J GRAVEL I RUBBLE ~ COBBLE I BOULDER (SUSITNA RIVER REACH GRADIENT=I0.3 11/ml) 660~-------r-------,--------~-------r-------,--------~-------r-------.--------.-------,--------.--------.-- -IO+OO -5+00 OtOO 5+00 10+00 15i00 2o+oo STREAMBED STATION Figure 4!-3-38. Streambed profile for Slough 11. ~ • • ~ z 0 1-........ <( ........ > w 0 ...J w w :::> "' 1- 760 / ree no SLOUGH 21 COMPLEX 148 0 -PROFILE STUDY AREA IUOHT .6. -STREAMBED STATION . ... 740 738 730 j i S! ~ 780 > 7415 ... ;;l ... ::> .. 1- SIDE CHANNEL A -1+51•0 .. 00 THALWEG PROFILE SLOUGH 21 COMPLEX ~ i 0 SURFACE SUBSTRATE TYPES !i D SILT/SAND ED QUVEL/ RUBBLE m COBBLE/ BOULDER > ~ ... ... ::> 0: 1- (SUSJTNA RIVER REACH GRADIENT•I2.1fl/mi) 72~----.------r------,------,------,-----~.------r------~-----r----~,_--~~~~~~~~--.---LL-r------,------,------,---eoo 10+00 15 00 -50•00 STREAMBED STATION lfettl Figure 4!-3-39. Streambed profile for Slough 21 Complex. morphological features of the slough and mainstem Susitna River. In addition, each profile has been partitioned into discrete reaches defined by obvious changes in gradient. Corresponding gradients of the mainstem Susitna River are also provided below the key for surface substrate types. Also, study sites have been positioned on the profiles for Sloughs SA, 9, and 21 to provide a reasonably accurate representa- tion of the gross morphological features in each slough and the relative position of important features (e.g., study transects, beaver dams, etc). At some points, streambed elevations and/or water surface eleva- tions were estimated. The reader is advised to consult the methods section and data source (Appendix E) before extracting and applying information represented in the above figures. The following summary statements are primarily restricted to gross features of the streambed gradient. Slough SA Progressing upstream in Slough SA, the stream bed profile is comprised of a relatively gentle gradient near the mouth (7.S ft/mi), followed by a riffle area (gradient undetermined) ending at a beaver dam. The dam marks the downstream end of a short bench-like reach (4.0 ft/mi) fol- lowed by a steep incline (1S.O ft/mi) which terminates at another bench-like area (O.S ft/mi). Above the second bench, water depths were much reduced and gradient increased to 11.5 ft/mi. 111 Slough 9 The most notable characteristics of Slough 9 are the obvious differences in gradient between the upper and lower reaches of the slough (18.6 and 5.6 ft/mi' respectively)' and the 11 S11 shaped configuration of the channel (see schematic drawing in upper left corner of Figure 41-3-37). This sharp bend is near station 30+00, marking the area where the gradient changes and water levels decrease. Slough 11 The upper reach of Slough 11 is more steeply inclined (23.0 ft/mi) than its lower reach (15.4 ft/mi), however both are relatively steep compared to other sloughs. This slough is relatively short and the streambed is structured in distinct pool/riffle sequences up to station 30+00, fo 11 owed by a series of mounds near the head of the s 1 ough. These mounds may be the result of previous ice movement. It should be noted that since no water existed in this area and surveyors were selecting thalweg points on the basis of visual inspection, the mounds may mis- represent the true thalweg in this reach of the slough. Slough 21 Complex Morphology of the Slough 21 complex is more complicated than most sloughs since it is preceded by a long access channel which is longer than the slough itself. This access channel is connected to the main- stem Susitna River by several channels, two of which were observed 112 dewatered for most of the open-water season. Note that the mouth of this slough is located near station 52+00 ft, and not at station 0+00 as for sloughs 8A, 9, and 11. The slough (from stations 52+00 to 76+00) has a relatively steep, uniform gradient (19.4 ft/mi) and had very little water present immediately above station 55+00. At its upper end, this slough is forked, with the left fork head functioning as the hydraulic control point. 3.1.3 Other Hydrological Components 3.1.3.1 Backwater Areas Appendix Table 4-A-7 presents by two week intervals between June and September, 1982 the measurements of the area of the low velocity back- water which occurred behind the hydraulic barrier created by the main- stem Susitna River at Designated Fish Habitat locations. This backwater area is called the aggregate zone type II (H-II) and is defined in Section 2.2, Part II of this volume. Each H-II area is listed with the mean daily provisional discharge reported for the Gold Creek or Sunshine gaging station by the USGS for the corresponding date. Plots of the H-II surface areas measured at each site versus mainstem discharge are presented in Figures 4I-3-40 to 4I-3-53. The line connecting the surface area data presented on Figures 4I-3-40 to 4I-3-53 was carefully drawn to smooth the effect of scattered area measurements (mostly mapping errors) at closely related mainstem water surface elevations. In the case(s) where it was not obvious that a 113 specific distribution of area measurements was a result of data scatter (mapping errors), the data was not smoothed. Examples of both condi- tions occur in Figure 41-3-42 (Slough 19). The measurements indicating a total loss of H-II water area at discharges near 15,000 cfs are accurate, thus no smoothing of the data at this discharge was done. Measurements of H-II area at higher discharges however, were highly scattered as a result of mapping difficulties at this site, thus smooth- ing of the data was done. Smoothing of the data was also done for Sloughs 21 and 11 where measured areas (at related discharges) were interpreted as obvious scatter (map errors) based on our accumulated information on the site. Whiskers Creek and Sidechannel presented some unusual mapping difficulties at mainstem discharges of 25,000 cfs and above. Thus, no relationship was developed for discharges above 25,000 cfs (see Whiskers Creek section). Unless specifically noted, tributary discharges are not considered in the data presentations. A descriptive summary of the hydraulic conditions associated with the data and curves follows. Reference to photographs and additional site narratives of each habitat location in Appendix 4-F of Volume 4 is suggested for additional information. Summary By Habitat Location Slough 21 The head of Slough 21 becomes breached at mainstem discharges at Gold Creek greater than approximately 24,000 cfs. In addition, mainstem 114 lJ cr <l-wo u8 Lt-;< crt-:::>W (I)UJ u.. cr ww t-cr I--' <(<( I--' ~:::::> (jl 0 -(I) -- WN a.. >-J: t-<9 :::::> wg ~(I) (.!) wt- cr<l (.!) (.!) <( L • • • • • • / • 0 5 10 15 20 25 30 35 SUSITNA R. DISCHARGE (CFS x 1000) AT GOLD CREEK USGS PROVISIONAL DATA 1982 15292000 Figure 4I-3-40. Aggregate type II water surface areas at Slough 21 versus mainstem discharge at Gold Creek. water flows through a series of islands (Slough 21 complex) which at lowe_r discharges separate the slough's mouth from the mainstem. Main- stem flow through these islands at reference mouth #1 (see Appendix Plate 4-F-19) traverses directly across the mouth of the slough, forming a sort of "eddy" which creates the hydraulic barrier for water exiting the slough. As mainstem discharge decreased, the surface elevation at the eddy decreased and the area of H-I I backwater decreased. On July 11th (at 24,000 cfs), the head of the slough had recently closed and the elevation at the eddy was not sufficient to create an area of H-II water in the slough. During the August and September sampling trips when mainstem discharges were 17,000 cfs and below, the stage of the mainstem had dropped so that flow through the islands at the locations referred to above (identified as reference mouths #1 and #2) had ceased. During these discharges, water exiting the slough (e.g., ground water and surface runoff) joined the mainstem at reference mouth #3 (a lower island channel). The H-II water present during this time was found completely downstream of the mouth of the slough (as defined at the higher mainstem discharges). During October, Slough 21 was visited only briefly and no maps were drawn. However, the new confluence of slough water with the mainstem was about 5,000 ft downstream from the site of the mouth when the head of the slough was open. No appreciable H-II water was observed during this sampling trip when mainstem discharge was 8,220 cfs. 116 Slough 20 At a mainstem discharge of 33,250 cfs, the head of Slough 20 was obser- ved to be breached (refer to Table 41-3-2). At this time, an H-II area extended from the slough mouth upwards for about 360 ft. At observations during lower mainstem discharges, flow from Slough 20, originating from Waterfall Creek (which enters the slough approximately 1,250 feet above the mouth) and a smaller tributary near the head of the slough, freely entered the mainstem at the mouth of the slough. At mainstem discharges between 12,500 and 14,400 cfs, a small area of H-II water appeared directly above the hydraulic barrier created by the confluence with the mainstem. This area of H-II water appeared as a pool which could be related to the streambed thalweg elevation. Slough 19 Slough 19, considered an upland slough, confluences the mainstem only at its mouth. The head of Slough 19 consists of a small pool fed by ground water and surface runoff. In many respects, the hydraulic changes which occur with decreasing mainstem discharges are analogous to those described for Slough 21 above. At mainstem discharges of 16,600 cfs and above, the area of H-II type water surfaces was regulated by mainstem stage and the shape of the pool bed. 117 <! w,....... o::O <Co 0 W-;( Ot- Lt:w o::W :::>LJ_ CJ>w 0::0:: W<C t-:::> <eo !:CJ> ...... -...... =o co w C\1 CL:t: >-c:> t-:::> w:3 t-CJ) <( c:>t-W<C 0:: (!) (!) <( 20 10 0 ."' ··--·-·----·---· • ~-------T--------~--------r---~---T--------~--------r-------~ 0 5 10 15 20 25 30 SUSITNA R. DISCHARGE (CFSx 1000) AT GOLD CREEK USGS PROVISIONAL DATA 1982 15292000 35 Figure 4I-3-4l. Aggregate type II water surface areas at Slough 20 versus mainstem discharge at Gold Creek. <{ w 0:: <{ wO 30 uO <to LL>< o::._ 25 ::)w (/)UJ O::LL 20 ww t-o:: f-' <{<{ f-' 3::) \.0 15 _q -(I) ......... Wm 0..-10 >-:x: .... (,!) w::) 5 t-0 <{_J (,!)(/) w._ 0 0::<{ (,!) (,!) <t 0 • 5 10 15 20 25 SUSITNA R. DISCHARGE (CFS x 1000) AT GOLD CREEK USGS PROVISIONAL DATA 1982 15292000 30 Figure 41-3-42. Aggregate type II water surface areas at Slough 19 versus mainstem discharge at Gold Creek. At a mainstem discharge of 15,000 cfs, the mouth of the slough had moved down river approximately 350 ft due to dewatering of a small channel which cuts through a gravel island (reference mouth #1 on Appendix Plate 4-F-17). At this mainstem flow, the slough discharge was free-flowing to the new confluence with mainstem water, indicated as reference mouth #2. At a mainstem discharge of 13,300 cfs, continued dewatering of the gravel substrate caused the confluence of slough and mainstem water to move an addition a 1 300 ft downstream to reference mouth #3. At this time, an area of H-II water existed between the free-flowing portion of the slough and the new mouth. Slough 11 H-II water measured in Slough 11 during 1982 was confined to the back- water area present at the mouth of the slough. The H-II water appeared as a pool which was controlled by the mainstem stage and the cross-section and elevation relationships that describe the slough {pool) bed. The pool was very irregularly shaped making it difficult to precisely determine its area. The head of Slough 11 was never breached by the mainstem during the 1982 sampling period. Slough 9 The head of Slough 9 was breached by mainstem flows during the June and July samplings trips. During the highest observed mainstem discharges, the water in the slough above the mouth possessed appreciable velocity. 120 <( w cr <(,__ w8 oo <(-u.. )( cr._ ~w (f)w cru.. LLlw l-cr <(<( ....... 3~ N ....... -0 -(f) w- a..= >-.-:x: (.!) LLJ~ ..... g <((f) (.!) I.Lll-cr<r (!) (.!) <( 140 120 100 80 60 40 20 0 0 • • • • 5 10 15 20 25 30 35 SUS I TN A. R. DISCHARGE ( CFS x 1000) AT GOLD CREEK USGS PROVISIONAL DATA 1982 15292000 Figure 4I-3-43. Aggregate type II water surface area at Slough 11 versus mainstem discharge at Gold Creek. <( w a::: <(....-. 0 wo uo <!-LL>< a:::._ =>w (l)w a:::LL ww ..... a::: 1-' <(<( N N 3::::> -0 -(I) w-a..m >-:r: ..... (,!) w=> ._o <(_J (,!)(I) wr- O::<( (,!) (,!) <t 14 0 ·~ • •• • • 5 10 15 20 25 30 35 SUSITNA R. DISCHARGE (CFS x 1000) AT GOLD CREEK USGS PROVISIONAL DATA 1982 15292000 Figure 4!-3-44. Aggregate type II water surface area at Slough 9 versus mainstem discharge at Gold Creek. During visits at mainstem discharges of 19,400 and 16,700 cfs, the slough head was closed. At this time, a large area of H-II water (about 1000 feet 1 ong on August lOth) was found above the confluence of the slough and the mainstem. At the lower mainstem discharges sampled, the surface waters in the study area were not control~led by mainstem elevation (no appreciable area of H-II water existed) and the clear water exiting the slough was free-flowing to a mainstem confluence at a lower elevation. Slough 8A The area mapped in this study extended from the slough mouth to the first series of beaver dams which begin approximately 1350 ft above the mouth. Not mapped in this study is the very large area of calm water 1 ocated between these dams and the head of the s 1 ough. Within the mapped boundaries, the area of H-II water closely approached the total wetted surface area of the site. The head of the slough was breached during the June 8 visit at a mainstem discharge of 28,000 cfs, but the mainstem overflow into the slough was not large enough to significantly affect the velocity or size of the H-II area. The surface area of H-II water in the study area near the slough mouth was directly regulated by mainstem stage throughout the summer (Figure 41-3-45). 123 <! w 0:: <!,.... wO u8 <(_ I..Lx o::,_ ::::>w cnw O::Ll.. ww t-o:: <!c:t 3:::::> 0 =en -1-' N Wc:t ~ a..oo >-t-::r: (!) w::::> t-0 <(_J (!)(/) Wt- 0::<( (!) (!) <( 15 0 • • .,.- •• • 5 I 0 I 5 20 2 5 30 SUSITNA R. DISCHARGE (CFSx 1006) AT GOLD CREEK USGS PROVISIONAL DATA 1982 15292000 35 Figure 4I-3-45. Aggregate type II water surface area at Slough 8A versus mainstem discharge at Gold Creek. Lane Creek and Slough 8 The Lane Creek study site consists of a long and narrow (30ft wide), steep-sided trench (Slough 8) which, during the June and July trips, joined the outfall of Lane Creek and became a 70 ft wide eroded channel which entered the Susitna River approximately 300 ft further downstream (see Appendix Plate 4-F-10). The June 7 and June 19 trips to Lane Creek indicated Gold Creek discharges of 25,000 and 28,500 cfs, respectively. Observed water levels at Lane Creek and Slough 8 were lower on June 19 than on June 7 and the head of Slough 8 was open to the mainstem on June 7 but not on June 19. During both of these samplings, H-II type water covered the slough and channel from about 700 ft above Lane Creek to the mouth. At mainstem discharges of 22,400 and 18,100 cfs, the area of H-II water was limited (by mainstem stage) to the channel area between the outfall of Lane Creek and the mainstem. Between July 22 and August 8, Lane Creek formed a new mouth of two forks entering the Susitna River downstream from the erosion channel mentioned above. The area of H-II water in the August and September sampling trips (16,600 to 12,500 cfs) decreased as a function of Susitna River discharge and the shape of the channel between the Susitna River and the old outfall of Lane Creek. 125 c( LLI 0:: <t,_ 50 wO ~8 40 IJ.:)( o::,_ =>w (I)LLI o::LL LLI W 30 1-o:: <(<t :f:::> -0 -en -w. a. 0:: 20 >-u 1- LLI wz 1-<t <t...J (!) LLit- O::c;t (!) (!) <( 0 /. . ' /·---· • • ~· ~------~--------,---------~-------.--------,-------~ 0 5 10 15 20 25 SUSITNA R. DISCHARGE (CFS x IOOO)AT GOLD CREEK USGS PROVISIONAL DATA 1982 15292000 30 Figure 4I-3-46. Aggregate type II water surface area at Lane Creek versus mainstem discharge at Gold Creek. Slough 6A Slough 6A, considered an upland slough, is a steep walled erosion channe 1 which is connected to poo 1 s at its head through a series of thick sedge tussocks and a beaver dam. The area of H-II water within - the physical bounds of the slough represents the total wetted surface of the slough up to the beaver dam. The water surface area in the slough is controlled by the water surface elevation of the mainstem (Figure 4!-3-47). Whiskers Creek and Slough Whiskers Creek flows into Whiskers Creek Slough approximately 1100 ft above the mouth of the slough. When the head of the slough is breached, mainstem flows into the slough influence the extent of calm (H-II) water in the slough below. At lower mainstem discharges when the head of the slough is not breached, Whiskers Creek flows may also influence the area of H-II water in Whiskers Creek and Slough, depending on the discharge of the creek and the mainstem water surface elevation. During three visits when mainstem discharges were 25,000 cfs and above, the mainstem stage was sufficient to back water up the slough to an elevation similar to that of the water in Whiskers Creek. On each of these three occasions, the head of the slough was breached. Slough water (mixed with creek water), with varying velocity•s, separated the backwater area in the lower slough from a calm water area in the creek above. This velocity zone appeared to become more pronounced at higher 127 <( w a::_ :§ o-<()( u_t- a::W :::>w CJ)LL a::W wa:: t-<( <(::::> ~g f--' N co -<( ww a.J: >-t!) t-:::> wo 1-_J <((f) t!)l- w<t a:: t!) t!) <( 140 120 100 80 60 40 0 ··-·---·--.-. . --------· ~------~------------------~------~--------~--------r-------~ 0 5 10 15 20 25 30 SUS I TNA R. Dl SCHARGE ( CFS x 1000) AT GOLD CREEK USGS PROVISIONAL DATA 1982 15292000 35 Figure 4I-3-47. Aggregate type II water surface area at Slough 6A versus mainstem discharge at Gold Creek. g <(0 w>< 160 a:: I- <(LLJ LLJ wLL. 140 (.)LLJ <Co:: I.L.<( 0::::::> 120 :::>0 (f)(/) ......... o:::--1 100 ww 1-z <Cz ....... ~~ N 1.0 _(..) LLJ wo o..->-(/) ~--~ 0::: wo I-(f) <Co:: (.!)LLJ 20 LLJ::s:;: 0:::(1) (.!)- (.!)::r: 0 <(~ 1- <::( •I 1-UPPER LIMIT: SEE TEXT 2-LOWER Ll M ITS: SEE TEXT • 2• •2 • / ·-· 0 5 10 15 20 25 30 35 SUSITNA R. DISCHARGE (CFSxiOOO)AT GOLD CREEK USGS PROVISIONAL DATA 1982 15292000 Figure 41-3-48. Aggregate type II water surface area at Whiskers Creek/Sidechannel versus mainstem discharge at Gold Creek. 40 mainstem discharges and to increasingly separate the creek pool from the H-II area in the slough below. Based on observations, the velocity zone was deemed insignificant at a mainstem discharge of 25,000 cfs, and dominating at higher mainstem discharges (with respect to separating the two calm water areas). Thus, at a mainstem discharge of 25,000 cfs, the area of H-II water was measured from the slough mouth to 1200 ft up Whiskers Creek while at higher discharges it was measured only from the slough mouth to the beginning of high velocity zone near the mouth of Whiskers Creek. The area of H-II water measured at a mainstem discharge of 25,000 cfs is reported as a maximum va 1 ue whi 1 e the areas of H-I I water present at higher discharges are reported as minimum values. More observations are needed to better describe the relationship between these two calm water areas at high mainstem discharges. At a mainstem discharge.of 23,000 cfs, the slough head was barely breached and H-I I water was backed up 715 ft above the mouth of the slough. At a mainstem discharge of 16,600 cfs, the slough head was c 1 osed and water was backed up 550 ft above the mouth of the s 1 ough. During the mainstem discharges at and below these levels, the area of H-II water present near the mouth of the slough should vary as a function of mainstem stage and slough bed shape. That the water surface in this area is impacted by the discharge of Whiskers Creek was dramatically observed on September 28 when a rain swollen discharge of Whiskers Creek increased velocities near the mouth thereby eliminating the area of H-II water. The (zero area) data point measured at this time was not included in the H-II area versus mainstem discharge curve 130 as it was a function of tributary discharge and not of mainstem discharge. Birch Creek and Slough This study site encompassed the nearly mile long section of Birch Creek Slough between the Susitna River and its junction with Birch Creek, and the one-tenth mile reaches of slough and tributary above this junction. The zone of H-II water observed at this site at mainstem discharges between 58,400 to 99,300 cfs was nearly constant, covering almost the entire site but Birch Creek itself, except during the mainstem discharge of 99,300 cfs when a 160 ft section of the creek was a 1 so backed-up. The stream bed elevations at the uppermost H-II boundaries mentioned above visually appeared steep enough to limit the backwater observed. At a mainstem discharge of 52,500 cfs, the slough head remained breach- ed. At this time the zone of H-II water extended to only about 0.4 mile above the slough mouth. During trips at lower mainstem discharges (38,000 to 33,800 cfs), the head of the slough was observed to be closed and the zone of H-II water extended only 0.14 mile above the mouth of the slough. The boundary between the zone of H-II water and the higher velocity water upstream at these intermediate discharges was partly regulated by the volume of the slough and/or tributary water flowing into the zone of H-II water. Judging the precise location of this boundary was often quite difficult. 131 -<!o wo a:::o 400 <!- w )( or <!w LLw 0:::1.1.. ::>w 300 (/)a::: a:::<! w=> r-0 <!(/) ~-:I: 200 =(.!) 1-' w=> w a..g N )-(f) r-, wa::: r-o 100 <!:I: (.!)(.) wa::: a:::_ (.!)en (.!) <l:r <! 0 0 99,300 cfs~ • • + r • • ./ • 10 20 30 40 50 60 70 SUSITNA R. DISCHARGE (CFS x 1000) AT SUNSHINE USGS PROVISIONAL DATA 1982 15292780 Figure 4I-3-49. Aggregate type II water surface area at Birch Creek/Slough versus mainstem discharge at Sunshine. The mapping task at this site was also made somewhat imprecise by the extreme size of the wetted surface interface. During the limited time available for mapping, it was not possible to measure and record many slough width variations. The overall loss of H-II area with decreasing mainstem discharge is the significant result at this site. More observations and more accurate mapping are required to estab 1 ish more accurate surface area data at this very large habitat location. Sunshine Creek and Sidechannel This site was sampled from about 0.75 miles up Sunshine Creek to its confluence with a minor sidechannel, then downstream another 1000 ft to the confluence with the major sidechannel (see Appendix Plate 4-F-5). During the June and August sampling trips, mainstem discharges ranged from 82,400 to 60,100 cfs and the head of the minor sidechannel was open. The zone of H-I I water during these visits was determined to extend from the minor sidechannel-creek junction to about as far as 0.75 miles up the creek. The length of this backup zone was not easily determined nor relatable to mainstem discharges alone. This is apparent in the decreases in the areas of H-II water observed at mainstem dis- charges of 70,200 and 62,700 cfs, relative to the areas of H-II water observed at higher and lower mainstem discharges. It is possible that the zone of the H-II water in the creek was highly regulated by fluc- tuating creek discharges and not the result of errors in determining the exact location of the zone boundaries. 133 _250 0 <l:8 LLJ>< a::r- <l:LLI LLJ ~ 200 ow ~a:: a::<l: ::::>::::> C/)0 CJ) a::-150 w...J t-LLI <l:Z =:z <l: I-' _J: w -(.) +=> wLLJ 10 a.9 >-CJ) ........... LLJO:: ..... (.) <l:LLJ (!)Z 50 LLJ-a::::t: (!)(/) (!)Z <l::::l CJ) ..... <l: 0 0 1-A PORTION OF THE H-11 WATER AREA AT THIS DISCHARGE NOT MEASURED: SEE TEXT • \ 10 • / • 20 30 40 50 60 SUStTNA R. DISCHARGE {CFSx 1000) AT SUNSHINE USGS PROVISIONAL DATA 1982 15292780 ·-----. • 70 Figure 4I-3-50. Aggregate type II water surface area at Sunshine Creek/Sidechannel versus mainstem discharge at Sunshine. • 80 At a mainstem discharge of 51,600 cfs, the minor sidechannel 's head was closing. At this time the zone of H-II water extended from the minor sidechannel's confluence with the major sidechannel up into Sunshine Creek and into the closing minor sidechannel's head. Part of the area of H-II water in the minor sidechannel at this discharge extended above the study boundary and was not mapped. Between mainstem discharges of 38,700 and 33,400 cfs, the zone of H-II water was located entirely between the major and minor sidechannel confluence and the minor sidechannel-creek junction. Probably because water velocities are greater in the sidechannel environ- ment, the physical habitats in the reaches above and below the mouth of Sunshine Creek are notably dissimilar. An especially noticable feature is the lack of vegetative cover in reach below the mouth of the creek. The mapping at this site was subject to the same problems encountered at the Birch Creek site. Rabideux Creek and Slough Just below the old site of a bridge crossing (about 1 mile above its confluence with the Susitna River), Rabideux Creek widens into a pool- 'like area. A sandy bottom channel, about 700ft in length, connects the 1 ower end of the poo 1 to the upper end of a 0. 5 mi 1 e 1 ong bay (or widening) of the creek which forms the mouth of the creek. At high 135 -~§ a:: <(1- w w 1200 ()~ i'tw a: a: :::><( (!):::> 0 ll:(f) w- 1-:r: ~~ 600 0 -..J -(/) ~~ 400 >-o I-X 200 W:::> t-W <(0 0 (!)-wm • .--· ------· • a:<( 0 (!)lr 10 20 30 40 50 60 70 (!)I- <(<( SUSITNA R. DISCHARGE {CFSx 1000) AT SUNSHINE USGS PROVISIONAL DATE 1982 15292780 Figure 4I-3-51. Aggregate type II water surface area at Rabideux Creek/Slough versus mainstem discharge at Sunshine. mainstem discharges, the Susitna River breaches its banks. Under these conditions, sections of this widening bay-like area become slough-like. During every visit to this site, a large zone of H-II backwater existed. At the highest mainstem discharges (71,700 cfs),, the zone of H-II backwater extended to a point about 6,800 ft up from the confluence of the creek with the Susitna River. Backwater thus extended approximately 1500 ft up the creek above the old bridge site and enlarged the wetted surface area in the pool area below the bridge site. At mainstem discharges between 53,300 and 38,400 cfs, the boundary between the free flowing creek and the low velocity backwater occurred at locations in the pool area below the old bridge. At the lowest mainstem discharge sampled (33,400 cfs), the elevation of mainstem water had dropped sufficiently to expose a controlling stream- bed elevation in the sandy bottom connecting channel, reducing the zone of H-II backwater at this site to 41 percent of its previous observed area. The pool above the control point in the channel did not dewater; it simply became a geomorphological feature of the creek bed. Whitefish Slough The study area at this site was limited to a 900 ft long section of the slough nearest the mouth. The surface area measurements are thus only partial totals of the entire H-II area occurring in this long, channel- like slough. 137 90 ,..... <(0 wo 80 o::o <(- )( WI-70 uw Ltw o::LL. 60 =>w en a:: o::<r w=> 50 1-0 <(en ?it- 40 ,__. J: w -(!) co -::::> wO a.. _I 30 >-en I-:I: en w-20 I-LL <rw (!)I- WJ: 10 0:::3 (!) (!)I- <tc::t 0 0 NOTE: STUDY AREA LIMITED TO A 900' LONG REACH ADJOINING MOUTH OF SLOUGH. I • I 0 20 30 40 50 60 70 SUSITNA R. DISCHARGE {CFSxiOOO) AT SUNSHINE USGS PROVISIONAL DATA 1982 15292780 • Figure 4I-3-52. Aggregate type II water surface area at Whitefish Slough versus mainstem discharge at Sunshine. The entire wetted surface of this area was of H-II water during each sampling. Its area was entirely controlled by mainstem water surface elevation at the mouth of the slough (Figure 4I-3-52). Lower Goose Creek 2 and Sidechannel Lower Goose Creek 2 has two mouths. Its northernmost mouth empties into a sidechannel about 460ft above the sidechannel 's mouth. A log jam at the creek's mouth maintained the elevation of the water in the creek over any sidechannel water surface elevations observed during the 1982 sampling period, thereby eliminating this mouth from H-II water influ- ences. At all samplings between mainstem discharges of 38,700 and 64,200 cfs, the head of the sidechannel was open. The volume of water which breach- ed the head of the sidechannel significantly controlled the extent of H-II backwater in the lower (mouth) reach of the sidechannel though its effect on the velocity of these surfaces. At high flows over the head of the slough, the zone of H-II water was limited to a 600-ft reach nearest the mouth of the sidechannel. As the volume of breached water decreased, the zone of H-II water extended further up the sidechannel, until at a mainstem discharge of 38,700 cfs, the length of the zone of H-II water was nearly 1,500 ft long. During the September visits at mainstem discharges of 36,400 and 33,900 cfs, the head of the sidechannel was closed. Lower Goose Creek 2 water, 139 -125 0 0 <(0 w 0:: )( <( .... w ~ 100 (.)1.1.. ~w O::o:: :::><( (/):::> o::g 75 w-.... _. <tw 3:Z z ....., =<( +::- 0 w::r: 50 a_ c.> >-w .... e (/) w, ~(\J (.!) . 25 wo:: 0::(.) (.!)w (.!)(/) <to 0 (.!) 0 .... <( • ~ • • " ·~ • • ·-· I lb 0 2b 3b 4 1 0 5b 6 1 0 71o SUS ITNA R. DISCHARGE ( CFS x 1000) AT SUNSHINE USGS PROVISIONAL DATA 1982 15292780 Figure 4I-3-53. Aggregate type II water surface area at Goose Creek 2/ Sidechannel versus mainstem discharge at Sunshine. at this time, was free-flowing to the confluence of the sidechannel and the Susitna River. An area of water in the sidechannel above the outfall of Lower Goose Creek 2 was not influenced by mainstem stage at this time. The elevation of the water in this pool area was controlled by the streambed e 1 evati on and by a barrier presented by Lower Goose Creek 2 water. 3.1.3.2 Open Channels Depths, velocities, widths and water surface elevations used in the hydraulic simulations of segments of sloughs 8A, 9 and 21 and Rabideux Slough and Chum Channel are tabulated and summarized in Appendices A, B and E. This data has been entered into the computer·programs, however, the time of this report writing, the calibration procedure has yet to be completed. Thus, hydraulic parameters at unknown discharges cannot be extrapolated at this time. 3.2 Water Quality Investigations 3.2.1 Water Temperature Temperature measurements collected during 1982 included both instantan- eous and continuous measurements. Instantaneous temperature measure- ments were collected in conjunction with other water quality data and are compiled and presented in Appendix Table 4-D-5. Continuous tempera- ture data includes surface water and intragravel temperatures obtained with Peabody-Ryan thermographs, surface water and intragravel tempera- 141 tures obtained with (programmed as 2 channel temperature recorders) and associated thermistors and surface water temperatures obtained with datapods located at the stream gage stations in Indian River and Portage Creek. Appendix Table 4-C-1 lists the continuous recording temperature stations and period of record for those sites installed and monitored by the ADF&G during 1981 and 1982. Temperatures obtained with Peabody-Ryan thermographs are presented in Appendix Tables 4-C-2 to 4-C-25 and 4-C-66 to 4-C-76 as 6-hour minimum, mean and maximum temperatures calculated from corrected 2-hour point temperature readings. Daily and monthly means, calculated from the 2- hour readings, are also shown in each table. Weekly water temperature data presented as minimum, mean and maximum for 2 hour readings according to the USGS water year weeks and collected from Ryan thermographs are shown in Appendix Tables 4-C-26 to 4-C-49 and 4-C-77 to 4-C-87. Surface and intragravel water temperatures obtained with datapod are presented in Appendix Tables 4-C-50 to 4-C-57 as minimum, mean and maximum temperatures for time periods of 6 hours and 3 minutes duration. Six-hour, daily and monthly means calculated from these temperatures using a two part 1 inear equation interpolation method to 11 Correct" readings from actual 6 hour and 3 minute time intervals to 6-hour intervals are presented in Appendix Tables 4-C-58 to 4-C-65. Hourly and mean daily temperatures obtained with datapods located at the stream gage stations in Indian River and Portage Creek are presented in Appendix Tables 4-A-4 and 4-A-5, with a summary of daily mean temperatures for these sites in Tables 4I-3-4 and 5. 142 3.2.1.1 Mainstem Between Talkeetna and Devil Canyon 3.2.1.1.1 Surface Water Temperature Instantaneous Surface Water Temperature Instantaneous measurements of surface water temperatures of the mainstem Susitna River between Talkeetna and Devil Canyon were collected at various locations from May through October, 1982 (Appendix Table 4-D-5). Instantaneous surface water temperatures ranged from 5.0°C to 13.4°C, with the lowest temperature occurring at RM 138.9 on May 29 and the highest temperature occurring at RM 120.7 on July 7. In genera 1, instantaneous surface water temperatures of the mainstem Susitna River between Talkeetna and Devil Canyon increased from May to July and decreased from August to October, peaking in July and August. Continuous Surface Water Temperature Surface water temperature of the mainstem Susitna River between Talkeet- na and Devil Canyon was continuously monitored with Peabody-Ryan thermo- graphs at six locations (Figure 4I-2-4), from May through October, 1982. These mainstem temperature locations included the Talkeetna Fishwheel (RM 103.0), LRX 18 (RM 113.0), Curry Fishwheel (RM 120.7), LRX 29 (RM 126.1), LRX 35 (RM 130.8) and LRX 53 (RM 140.1). This data is presented in Appendix C, Tables 4-C-10 to 12 and Tables 4-C-14, 4-C-16 and 4-C-18. 143 Surface water temperature at these sites ranged from 0.0°C at LRX 18 in October to 15.7°C at LRX 29 in July. Generally, the mainstem surface water temperature increased during the period from May to July and decreased during the period from August to October usually peaking during July depending on location. 3.2.1.1.2 Intragravel Water Temperature Intragravel water temperature data was collected on an instantaneous basis only, at various mainstem Susitna River locations between Tal- keetna and Devil Canyon from May through October, 1982 in conjunction with the mainstem Adult Anadromous Fish Habitat Investigations (refer to Volume 4, Part II, section 3.1.1.1). 3.2.1.2 Sloughs Between Talkeetna and Devil Canyon 3.2.1.2.1 Surface Water Temperature Instantaneous Surface Water Temperature Instantaneous surface water temperatures of various sloughs situated between Ta 1 keetna and Devil Canyon were co 11 ected from May through October, 1982 (Appendix Table 4-D-5). Due to the large variability among slough habitats and the periodic nature of the instantaneous surface water temperature data, no summary statements concerning the above data have been made. 144 Continuous Surface Water Temperature The surface water temperature of six sloughs located between Talkeetna and Devil Canyon (Sloughs SA, 9, 11, 168, 19 and 21) was continually monitored with Peabody-Ryan thermographs or data pods during the open water field season from July to October 19S2 (Appendix 4-C). In addition, the surface water temperature of six sloughs located between Talkeetna and Devil Canyon (Whiskers Creek Slough and Sloughs 9, 98, 11, 19 and 21) was continually monitored during the 19S1-S2 ice covered season using Peabody-Ryan thermographs (Appendix Tables 4-C-66 to 4-C-72). Based on data from the open water season, the surface.water temperatures in the sloughs ranged from 0.2°C at mid-slough in Slough SA during October to 14.S°C in the mouth of Slough SA during August. The greatest variance in maximum surface water temperatures among the sampled sloughs between Talkeetna and Devil Canyon for any one week occurred during the first week in September when the maximum surface water temperature in Slough 9 was 11.0°C and the maximum in Slough 11 was 3.3°C. The greatest variance in weekly minimum surface water temperatures between sloughs for a given week was 4.4°C occurring in the last week of August when the minimum temperatures in the mouth of Slough SA and in Slough 11 were 7.S°C and 3.4°C, respectively. Surface water temperatures in the sloughs were notably warmer than surface water temperatures in the mainstem during the months of September and October. Comparing surface water temperatures in mid-slough SA (RM 126.1) with surface water temperatures in the mainstem adjacent to the slough (at LRX 29, RM 145 126.1) shows, for any given week, similar weekly maximum temperatures, but minimum weekly temperatures from 1° to 5.4°C colder in the slough than in the mainstem. Based on data from the winter season (Appendix Tables 4-C-66 to 4-C-72), the overall range of surface water temperatures in the sloughs studied between Talkeetna and Devil Canyon varied from 0.0°C in Whiskers Creek Slough in February to 10.3°C in Slough 98 in May. The greatest variance in maximum surface water temperatures among the sloughs occurred the first week of May when the surface water temperature reached 10.3°C in Slough 9B whereas the maximum in Whiskers Creek Slough was 2.0°C. Generally, winter surface temperatures in the sloughs increased gradually or remained stable through February and March and increased notably in April and the first week of May. 3.2.1.2.2 Intragravel Water Temperature Instantaneous Intragravel Water Temperature Instantaneous measurements of intragravel water temperature were obtain- ed at several sloughs located between Talkeetna and Devil Canyon to identify groundwater sources and to obtain intragravel water temperature data on FHU study transects (see Volume 4, Part II section 3.1.1.2.3) and also to characterize the intragravel water temperature regimes in locations of salmon redds (see Volume 4, Part II, section 3.1.2.2.4). Refer to the above sections for a summary of the results of this data. 146 Continuous Intragravel Water Temperature During the 1982 open-water field season, the intragravel water tempera- ture of five sloughs situated between Talkeetna and Devil Canyon (Sl- oughs 8A, 11, 168, 19 and 21) was continuously monitored using datapods from 1 ate August to October, 1982 (Appendix Tab 1 es 4-C-50 to 4-C-65). During the winter, the intragravel water temperature in four sloughs (Sloughs 9, 98, 19 and 21) was continuously monitored using Peabody-Ryan thermographs from February through the first week of May, 1982 (Appendix Tables 4-C-73 to 4-C-76). Based on data from the open water season, the intragravel water tempera- ture of the sloughs varied overall from 1.5°C at the mouth of Slough 21 during October to 7.6°C in Slough 168 during August. The overall range of intragravel water temperatures in the sloughs (1.5°C to 7 .6°C) was considerably less than the range of surface water temperatures observed in the sloughs (0.2°C to 14.8°C). In each slough studied, the minimum weekly intragravel water temperature was warmer than the corresponding surface water temperature from mid- September through October. Conversely, minimum intragravel water temperatures in the mouth of Slough 8A, upper Slough 8A, Sloughs 11 and 19 and upper Slough 21 were cooler than corresponding minimum surface water temperatures prior to September. The minimum intragravel tempera- tures in upper Slough 8A were consistently warmer than those in the other sloughs for this period. For August and September, the coolest intragravel temperatures in these sloughs were in Slough 19. The 147 difference between minimum intragravel temperatures in the mouth of Slough 8A and in Slough 19 for September was 3.0°C. Intragravel temperatures obtained during the winter season (February to April, 1982) showed considerable variation in intragravel temperatures existed between the sloughs while the intragravel temperature in the mouth of Slough 21 remained a steady 3.0°C from February through April, it varied from 0.2°C to 6.5°C in Slough 9 for the same time period. In Slough 19, the average intragravel water temperature was warmer than the corresponding surface water temperature from February to Apri 1. The same was true in the mouth of Slough 21 for February and March, but by mid-Apri 1 the average surface water temperature was warmer than the intragravel water temperature. In Sloughs 9 and 987 the surface water temperature was warmer than the intragravel water temperature from February through April. 3.2.1.3 Tributaries Between Talkeetna and Devil Canyon 3.2.1.3.1 Surface Water Temperature Instantaneous Surface Water Temperatures Instantaneous measurements of surface water temperatures in tributaries between Ta 1 keetna and Devil Canyon were collected from June through October, 1982 (Appendix Table 4-D-5). In general, surface water tem- perature increased from June to August and decreased from September to October, peaking in August. Instantaneous measurements of surface water 148 temperature ranged from 1. JOC in Portage Creek on June 7 to 12.0°C in Fourth of July Creek on August 22. Continuous Surface Water Temperature Surface water temperature was continuously monitored from June to October, 1982, in Indian River and Portage Creek. This data is presen- ted in Appendix Tables 4-A-4, 4-A-5, 4-C-17 and 4-C-20 as continuous hourly streamflow surface water temperatures and Tables 4I-3-4 and 4I-3-5 as daily mean stream flow and surface water temperatures. Based on the above data, the surface water temperature of Indian River varied from 0.0°C in late October to 12.5°C in mid-July. The surface water temperature of Portage Creek varied from 0.0°C in mid-October to 13.0°C in mid-August. Temperatures in both Indian River and Portage Creek generally increased from June to August and decreased in September and October, peaking in August. 3.2.1.3.2 Intragravel Water Temperature No intragravel water temperature data was collected from tributaries between Talkeetna and Devil Canyon during the 1982 open water field season. 149 Mainstem Sites 3.2.1.4 Mainstem , Sloughs and Tributaries Downstream of Talkeetna 3.2.1.4.1 Surface Water Temperature Instantaneous Surface Water Temperature Instantaneous measurements of surface water temperature of the mainstem Susitna River downstream of Talkeetna were collected from May through October, 1982 (Appendix Table 4-D-5). Instantaneous measurements of surface water temperature in the mainstem below Talkeetna ranged from 0.2°C at RM 77.0 on October 14 to 11.2°C at RM 18.2 on June 1. Because of the limited quantity of instantaneous surface water temperature data for the mainstem downstream of Talkeetna, no further summary statements on the above data are made. Continuous Surface Water Temperature Surface water temperature of the mainstem Susitna River downstream of Talkeetna was monitored on a continuous basis at three sites from May through October 1982. These sites include Susitna Station below the Yentna River confluence (RM 25.8), mainstem-west bank above the Yentna River confluence (R~1 29.5) and the Parks Highway Bridge (RM 83.4) (refer to Figure 4I-2-1). These data are presented in Appendix Tables 4-C-2 and 4-C-4 to 4-C-6. Temperature gaging stations were also located near the estuary and on LRX 1. No data was obtained from the estuary station 150 due to the instrument being lost during a flood and only two weeks of temperature data was obtained from LRX 1 due to instrument failure. The surface water temperature of the mainstem Susitna River downstream of Talkeetna ranged from o.ooc in October to 13.5°C in June and July. Both temperatures were recorded above the Yentna River confluence at RM 29.3. Generally, the surface water temperature of all mainstem sites downstream of Talkeetna increased during the period from May through August and decreased from September to October, peaking from mid-July to mid-August. The peak water temperature appeared to occur somewhat later in the mainstem downstream of Talkeetna (mid-July to mid-August) than in the mainstem above Talkeetna (July; see section 3.2.1.1.1). Slough Sites Instantaneous Surface Water Temperature Instantaneous measurements of surface water temperature of various sloughs downstream of Talkeetna were collected from June through Octo- ber, 1982 {Appendix Table 4-D-5). These temperature measurements ranged from 3.7°C in Lower Goose 2 Slough on October 1 to 14.2°C in Birch Creek Slough on July 11. Surface water temperature in the sloughs downstream of Talkeetna generally rose from June to July, peaking during July and August, and then decreased during September through October. 151 Continuous Surface Water Temperature No sloughs located below Talkeetna were continuously monitored for surface water temperature during 1982. Tributary Sites Instantaneous Surface Water Temperature Instantaneous measurements of surface water temperature in various tributaries downstream of Talkeetna were collected from June through October, 1982 (Appendix Table 4-D-5). Instantaneous measurements of surface water temperature in these various tributaries ranged from 17.4°C in Birch Creek on August 5 to 3.6°C in Sunshine Creek on October 4. Because of the limited quantity of instantaneous surface water temperature data for the tributaries downstream of Talkeetna, no further summary statements on the above data have been made. Continuous Surface Water Temperature Surface water temperature was continuously monitored in the three major tributaries downst~eam of Talkeetna (the Yentna, Talkeetna and Chulitna Rivers), from May through October, 1982 (Appendix Tables 4-C-3, 4-C-8 and 4-C-9). The surface water temperature of the Yentna River ranged from 0.0°C in early October to 13.0°C in late June. The surface water temperature in the Chulitna River ranged from 0.0°C in October to 8.5°C in September 152 (July and August temperatures not obtained). In the Talkeetna River, the surface water temperature ranged from 0.1°C in October to 11.5°C in August. From July to September, monthly mean mainstem Susitna River surface water temperatures obtai ned at the Ta 1 keetna fi shwheel camp located approximately 5 miles upstream from the confluence with the Chulitna and Talkeetna Rivers, were 1-2°C warmer than the monthly mean temperatures obtained in the Chulitna and Talkeetna rivers from July to September. In October, both the Chulitna and Talkeetna Rivers and the mainstem Susitna River averaged temperatures between 0.5°C and 1.0°C. Monthly mean surface water temperatures obtained in the mainstem Susitna River above the Yentna River were from 1.0°C to 2.5°C warmer than monthly mean surface water temperatures in the Yentna River. 3.2.1.4.2 Intragravel Water Temperature No intragravel water temperature data was collected downstream of Talkeetna during 1982. 3.2.1.5 Locations Upstream of Devil Canyon 3.2.1.5.1 Surface Water Temperature Instantaneous Surface Water Temperature Instantaneous measurements of surface water temperature were collected at various locations above Devil Canyon from May through October, 1982. These data are presented in Appendix Table 4-D-5 (refer to Volume 5 for further details on these results). 153 Continuous Surface Water Temperature Surface water temperatures were continuously monitored in five tribu- taries upstream of Devil Canyon (Tsusena, Watana, Kosina and Goose Creeks and the Oshetna River) from June to October, 1982. This data is presented in Appendix Tables 4-C-21 to 4-C-25. Refer to Volume 5 for further details on these results. 3.2.1.5.2 Intragravel Water Temperature No i ntragrave 1 water temperature data was co 11 ected upstream of De vi 1 Canyon during 1982. 3.2.2 Other Basic Field Parameters The basic field parameters of dissolved oxygen, pH, specific conductance and temperature were collected at various locations in the Susitna River basin from RM 5.0 to RM 233.4 during the 1982 open water field season. The basic field parameter temperature, as discussed in this section was collected on an instantaneous basis. In addition, turbidity was measured at various locations from RM 73.1 to RM 233.4. These data are compiled and presented in Appendix Table 4-D-5. The water quality data summarized in this section are provisional. The variety and large quantity of information presented in Appendix Table 4-D-5 limited sufficient review of this data. 154 The following water quality summaries do not include those zones that may include a dominant water source other than the site being summarized (i.e., sloughs and tributary sites with areas of mixing mainstem water were not included). 3.2.2.1 Mainstem and Side Channels Between Talkeetna and Devil Canyon The basic field parameters of dissolved oxygen, pH, specific conductance and temperature were collected at various mainstem and side channel sites situated between Talkeetna and Devil Canyon primarily in conjunc- tion with the electrofishing program (see section 3.1.1.1, Vol. 4, Part II). These data are presented in Appendix Table 4-D-5. From RM 114.4 to RM 148.2, the range of dissolved oxygen was 6.4 to 14.0 mg/1 over a corresponding range of surface water temperatures from 5.1° to 10.6°C. Measurements of pH were observed to range from 6.9 to 8.7 and specific conductance ranged from 33 to 132 umhos/cm. Turbidity in the mainstem Susitna River from RM 103.0 to RM 120.7 during the 1982 open water field season ranged from 2.4 to 288 NTU. 3.2.2.2 Sloughs Between Talkeetna and Devil Canyon The basic field parameters of dissolved oxygen, pH, specific conduc- tance, temperature and turbidity were measured at various upland and side sloughs situated between Talkeetna and Devil Canyon during the 1982 155 open water field season (refer to section 3.1.1.2 of Vol. 4, Part I for the definition of upland and side sloughs). This data is compiled and presented in Appendix Table 4-D-5. 3.2.2.2.1 Upland Sloughs Two upland sloughs (Sloughs 6A and 19) were monitored for the basic field parameters discussed above, primarily in conjunction with the FDS program, from June to October, 1982. The results are presented in Appendix Table 4-D-5. In Slough 6A, dissolved oxygen was found to range from 8. 9 to 13.9 mg/1 over a corresponding range of surface water temperatures from 4.3 to 15.0°C, while in Slough 19 the ranges for these parameters were 7.3 to 13.2 mg/1 and 3.3° to 13.-9°C, respectively. Measurements of pH and specific conductance in Slough 6A and 19 ranged from 4.3 to 7.8 and 41 to 135 umhos/cm and 6.0 to 7.7 and 52 to 147 umhos/cm, respectively. Turbidity in Slough 6A ranged from 3 to 150 NTUs while in Slough 19 it varied from less than 1 to 150 NTUs. Overall, dissolved oxygen in the upland sloughs situated between Tal- keetna and Devil Canyon was found to vary from 7.3 to 13.9 mg/1 over a corresponding range of surface water temperatures from 3.3° to 15.0°C, while measurements of pH and specific conductance varied from 4.3 to 7.8 and 41 to 147 umhos/cm, respectively. Turbidity in upland sloughs was observed to vary from less than 1 NTU to 150 NTUs. 156 3.2.2.2.2 Side Sloughs Twelve side sloughs situated between Talkeetna and Devil Canyon (Whis- kers Creek and Lane Creek Sloughs and Sloughs SA, 9, 9A, 98, 10, 11, 16, 20, 21 and 22) were monitored for dissolved oxygen, pH, specific conduc- tance, temperature and turbidity during the 1982 open water field season in conjunction with the FDS, FHU, and IFE programs. These data are compiled and presented in Appendix Table 4-D-4 and discussed below on a site by site basis. Overall, dissolved oxygen in the side sloughs situated between Talkeetna and Devil Canyon ranged from 5.9 to 14.5 mg/1 over a corresponding range of surface water temperatures from 2.4° to 16.3°C, while measurements of pH and specific conductance varied from 4.0 to 7.6 and 24 to 238 umhos/ em, respectively. Turbidity was found to vary from less than 1 NTU to 84 NTUs. Whiskers Creek Slough In Whiskers Creek Slough from June to October, 1982, dissolved oxygen was observed to vary from 8.3 to 13.3 mg/1 over a corresponding range of surface water temperatures from 3.3° to 12.4°C, while measurements of pH and specific conductance were found to range from 6.0 to 7.3 and 24 to 89 umhos/cm, respectively. Turbidity measurements obtained from June to September, 1982, ranged from 7 to 72 NTUs. 157 Lane Creek Slough In Lane Creek Slough from June to October, 1982, dissolved oxygen was found to vary from 8.9 to 14.5 mg/1 over a corresponding range of surface water temperatures from 4.6° to 7.2°C, while measurements of pH and specific conductance ranged from 5.5 to 7.1 and 26 to 80 umhos/cm, respectively. A single turbidity measurement of 1 NTU was obtained on June 7. Slough 8A In Slough 8A from June to October, 1982, dissolved oxygen was found to vary from 8.4 to 11.0 mg/1 over a corresponding range of surface water temperatures from 2.4 to 16.3°C, while measurements of pH and specific conductance ranged from 5.6 to 7.0 and 34 to 153 umhos/cm, respectively. A single turbidity measurement of 1 NTU was obtained on June 6. Slough 9 In Slough 9 from June to October, 1982, dissolved oxygen was observed to vary from 7.3 to 13.4 mg/1 over a corresponding range of surface water temperatures from 3.5° to 14.4°C, while measurements of pH and specific conductance were found to range from 6.4 to 7.5 and 53 to 183 umhosjcm, respectively. Turbidity measurements obtained from June to September, 1982, ranged 15 to 48 NTUs. 158 Slough 98 Measurements of the basic field parameters were measured once during the 1982 open water field season at Slough 98. On October 4, the dissolved oxygen was observed to be 9.2 mg/1 at a corresponding surface water temperature of 3.3°C, while measurements of pH and specific conductance were 6.6 and 163 umhos/cm, respectively. Slough 9A Measurements of the basic field parameters were measured once during the 1982 open-water field season at three locations in Slough 9A. On October 3, dissolved oxygen was observed to range from 10.2 to 11.3 mg/1 over a corresponding range of surface water temperatures from 3.6 to 5.0°C, while measurements of specific conductance varied from 121 to 161 umhos/cm. Measurements of pH was constant at 6.9 at all three loca- tions. Slough 10 Measurements of the basic field parameters were obtained twice in Slough 10 during the 1982 open-water field season. On June 8, measurements were made at two sites in Slough 10 while on October 4, measurements were obtained at four sites. At all measurement sites dissolved oxygen was observed to vary from 7.9 to 10.5 mg/1 over a corresp0nding range of surface water temperatures from 4.2 to 6.5°C, while measurements of pH 159 and specific conductance varied from 6.1 to 7.4 and 132 to 226 umhos/cm, respectively. Two turbidity samples, both obtained on June 8, showed turbidity to be less than 1 NTU at one site and 4 NTUs at another site. Slough 11 In Slough 11 from June to October, 1982, dissolved oxygen was observed to vary from 7.1 to 11.1 mg/1 over a corresponding range of surface water temperatures from 3. 0 to 11. 6°C, whi 1 e measurements of pH and specific conductance were found to range from 4.0 to 7.1 and 210 to 225 umhos/cm, respectively. No turbidity measurements were obtained at this site. Slough 168 In Slough 168, between June and October, 1982, dissolved oxygen levels were measured only on two occasions, and were found to be 11.1 and 11.8 mg/1. Surface water temperature in Slough 168 was found to vary from 4.3° to 7 .5°C, while pH and specific conductance were found to range from 6.2 to 6.6 and 34 to 70 umhos/cm. A single turbidity measurement of 3 NTU was obtained on June 4. Slough 20 In Slough 20 from July to October, 1982, dissolved oxygen was observed to vary from 10.3 to 14.3 mg/1 over a corresponding range of surface water temperatures from 3.0 to 9.3°C while measurements of pH and 160 specific conductance were found to range from 6.2 to 7.4 and 67 to 93 umhos/cm, respectively. Turbidity measurements obtained from July to October, 1982 ranged from 4 to 50 NTUs. Slough 21 In Slough 21 from June to September, 1982, dissolved oxygen was observed to vary from 5.9 to 12.7 mg/1 over a corresponding range of surface water temperatures from 3.4 to 10.0°C, while measurements of pH and specific conductance were found to range from 6.0 to 7.6 and 114 to 238 umhos/cm, respectively. Turbidity measurements obtained from June to September, 1982, ranged from 2 to 62 NTUs. Slough 22 In Slough 22 from June to September, 1982, dissolved oxygen was observed to vary from 9.3 to 13.2 mg/1 over a corresponding range of surface water temperatures from 4. 5 to 10. 6°C, while measurements of pH and specific conductance were found to range from 6.3 to 7.4 and 34 to 141 umhos/cm, respectively. Turbidity measurements obtained from June to September, 1982, ranged from 8 to 84 NTUs. 3.2.2.3 Tributaries Between Talkeetna and Devil Canyon The basic field parameters of dissolved oxygen, pH, specific conduc- tance, temperature and turbidity were collected at various tributaries 161 situated between Talkeetna and Devil Canyon during the 1982 open water field season. These data are presented in Appendix Table 4-D-5. Overall, dissolved oxygen in the tributaries sampled ranged from 7.9 to 14.5 mg/1 over a corresponding range of surface water temperatures from 1.7° to 12.2°C, while measurements of pH and specific conductance varied from 5.8 to 7.8 and 14 to 94 umhos/cm, respectively. Turbidity was found to vary from less than one NTU to 85 NTUs. These results are summarized below for each site. Whiskers Creek In Whiskers Creek from June to September 1982, dissolved oxygen was observed to vary from 7.9 to 13.0 mg/1 over a corresponding range of surface water temperature from 4.5° to 12.2°C, while measurements of pH and specific conductance were found to range from 5.8 to 7.4 and 14 to 31 umhos/cm, respectively. Turbidity measurements obtained from June to September, 1982 ranged from less than 1 to 40 NTUs. Gash Creek Measurements of the basic field parameters were measured three times during the 1982 open water field season at Gash Creek. Dissolved oxygen ranged from 10.5 to 14.4 mg/1 over a corresponding range of surface water temperatures from 5. 6° to 10. soc, whi 1 e measurements of pH and specific conductance ranged from 6.6 to 6.7 and 31 to 94 umhos/cm, 162 respectively. A single turbidity measurement of 2 NTUs was obtained in Gash Creek on June 6. Lane Creek In Lane Creek from June to September 1982, dissolved oxygen was observed to vary from 9.0 to 14.5 mg/1 over a corresponding range of surface water temperatures from 4.0° to 11.0°C, while measurements of specific conductance and pH were found to range from 26 to 68 umhos/cm and 6.6 to 7 .8, respectively. Turbidity values were observed to range from less than 1 NTU to 6 NTUs. Fourth of July Creek (mouth) In Fourth of July Creek from June to September, 1982, dissolved oxygen was observed to vary from 9.9 to 12.5 mg/1 over a corresponding range of surface water temperatures from 5.6° to 12.0°C, while measurements of pH and specific conductance were found to range from 6.2 to 7.3 and 21 to 26 umhos/cm, respectively. Turbidity measurements obtained from June to September, 1982, ranged from less than 1 NTU to 2 NTUs. Indian River In Indian River from June to September, 1982, dissolved oxygen was observed to vary from 10.3 to 14.2 mg/1 over a corresponding range of surface water temperatures from 2.6° to 11.7°C, while measurements of pH 163 and specific conductance were found to range from 5.8 to 7.2 and 29 to 46 umhos/cm, respectively. Turbidity measurements obtained from June to September, 1982, ranged from less than 1 NTU to 85 NTUs. Portage Creek In Portage Creek from June to October, 1982, dissolved oxygen was ob- served to vary from 10.7 to 12.7 mg/1 over a corresponding range of surface water temperatures from 1.7° to 9.7°C, while measurements of pH and specific conductance were found to range from 6.2 to 7.5 and 36 to 66 umhos/cm, respectively. Turbidity measurements obtained from June to October, 1982 ranged from less than 1 NTU to 9 NTUs. 3.2.2.4 Mainstem and Side Channels Downstream of Talkeetna The basic field parameters of dissolved oxygen, pH, specific conductance and temperature were collected at various mainstem Susitna River and side channel sites below Talkeetna during the 1982 open water field season primarily in conjunction with the electrofishing program (refer to Section 3.1.1.1, Vol. 4, Part II). These data are presented in Appendix Table 4-D-5. Overall, from RM 5.0 to RM 88.4, the range of dissolved oxygen varied from 6. 4 to 13.8 mg/1 over a corresponding range of surface water temperatures from 0.2° to 12.5°C. Measurements of pH were observed to 164 vary from 5.2 to 7.6 while specific conductance ranged from 46 to 131 umhos/cm. Turbidity was sampled from RM 73.1 to RM 88.4 and ranged from 4 NTU to 160 NTUs. 3.2.2.5 Sloughs Downstream of Talkeetna The basic field parameters of dissolved oxygen, pH, specific conduc- tance, temperature and turbidity were collected at various sloughs below Talkeetna during the 1982 open-water field season primarily in conjunc- tion with the FDS, FHU and IFE programs. These data are compiled and presented in Appendix Table 4-D-5. Overall, dissolved oxygen ranged from 8.7 to 12.8 mg/1 over a corre- sponding range of surface water temperatures from 5.3° to 16.4°C. Measurements of pH and specific conductance were observed to vary from 6.1 to 7.7 and 19 to 204 umhos/cm, respectively. Turbidity ranged from 2 to 120 NTUs. These results are summarized below for each site. Lower Goose 2 Slough In Lower Goose 2 Slough from June to October, 1982, dissolved oxygen was observed to vary from 8.7 to 11.2 mg/1 over a corresponding range of surface water temperature from 5.3° to 12.8°C, while measurements of pH and specific conductance were found to range from 6.7 to 7.7 and 33 to 204 umhos/ em, respectively. Turbidity measurements obtai ned from June to September, 1982, ranged from 5 to 120 NTUs. 165 Whitefish Slough In Whitefish Slough from June to October, 1982, dissolved oxygen was observed to vary from 8.3 to 10.7 mg/1 over a corresponding range of surface water temperature from 10.2° to 16.4°C, while measurements of pH and specific conductance were found to range from 6.1 to 7.3 and 19 to 121 umhos/cm, respectively. Turbidity measurements obtained from July to September, 1982, ranged from 18 to 46 NTUs. Rabideux Creek Slough In Rabideux Creek Slough on July 7, 1982, dissolved oxygen was observed to be 9.1 with a surface water temperature of 13.0°C·while measurements of pH was found to be 6.4. Specific conductance was not measured due to equipment malfunction. Turbidity measurement obtained was found to be 10 NTUs. Sunshine Slough In Sunshine Slough from May to October, 1982, dissolved oxygen was observed to vary from 10.6 to 11.4 mg/1 over a corresponding range of surface water temperatures from 6.4° to 11.3°C while measurements of pH and specific conductance were found to range from 7.1 to 7.1 and 54 to 93 umhos/cm, respectively. A single turbidity measurement obtained July 12 was found to be 100 NTUs. 166 Birch Creek Slough In Birch Creek Slough from June to October, 1982, dissolved oxygen was observed to vary from 9. 9 to 12.8 mg/1 over a corresponding range of surface water temperatures from 5.3° to 15.4°C, while measurement of pH and specific conductance were found to range from 6.4 to 7.7 and 70 to 165 umhos/cm, respectively. Turbidity measurements obtained from June to September, 1982, ranged from 2 to 76 NTUs. 3.2.2.6 Tributaries Downstream of Talkeetna The basic field parameters of dissolved oxygen, pH, specific conduc- tance, temperature and turbidity were collected at various tributaries below Talkeetna during the 1982 open water field season primarily in conjunction with the FDS, FHU and IFE programs. These data are compiled and presented in Appendix Table 4-D-4. Overall, dissolved oxygen varied from 8.5 to 13.4 mg/1 over a corre- sponding range of surface water temperatures from 3.6° to 17.4°C. Measurements of pH and specific conductance were observed to vary from 5.6 to 7.4 and 14 to 111 umhos/cm, respectively. Measurements of turbidity obtained in tributaries below Talkeetna during 1982 ranged from less than 1 NTU to 38 NTUs. These data are summarized below for each site. 167 Lower Goose Creek 2 In Lower Goose Creek 2 from June -September, 1982, dissolved oxygen was observed to vary from 10.6 to 11.0 mg/1 over a corresponding range of surface water temperature of 3.7° to 11.6°C, while measurements of pH and specific conductances were found to range from 6.8 to 7.4 and 27 to 40 umhos, respectively. Turbidity measurements obtained from June to September, 1982, ranged from less than 1 NTU to 18 NTUs. Whitefish Slough Tributary A single measurement of the basic field parameters was obtained on September 16 from a tributary entering Whitefish Slough. Due to a meter malfunction, only surface water temperature (9.3°C) and specific conduc- tance (14 umhos/cm) were obtained. Rabideux Creek In Rabideux Creek from September to October, 1983, dissolved oxygen was observed to vary from 8. 9 to 12.0 mg/1 over a corresponding range of surface water temperature 5.2° to 17.2°C, while measurements of pH and specific conductance were found to range from 5.8 to 7.2 and 27 to 69 umhos/cm, respectively. Turbidity measurements, obtained from June to September, 1982 ranged from 2 to 9 NTUs. 168 Sunshine Creek In Sunshine Creek from August to October, 1982, dissolved oxygen was observed to vary from 9. 5 to 13.4 mg/1 over a corresponding range of surface water temperature from 3.6° to 16.4°C, while measurements of pH and specific conductance were found to range from 5.6 to 7.3 and 27 to 111 umhos/cm, respectively. Turbidity measurements obtained from June to September, 1982, ranged from 1 to 9 NTUs. Birch Creek In Birch Creek from June to October, 1982, dissolved oxygen was observed to vary from 8.5 to 13.4 mg/l over a corresponding range of surface water temperature from 5.2° to 17 .4°C while measurements of pH and specific conductance were found to range from 5. 5 to 7. 4 and 50 to 94 umhos/cm, respectively. Turbidity measurements obtained from June to September, 1982, ranged from 1 NTU to 38 NTUs. 3.2.2.7 Locations Upstream of Devil Canyon The basic field parameters of dissolved oxygen, pH, specific conduc- tance, temperature and turbidity were collected at various locations in the Susitna River basin above Devil Canyon during the 1982 open-water field season. These data are compiled and presented in Appendix Table 4-D-5. 169 Overall, dissolved oxygen in the tributaries above Devil Canyon ranged from 6.6 to 14.3 mg/1 over a corresponding range of surface water temperatures from 0.1° to 14.8°C, while measurements of pH and specific conductance ranged from 6.7 to 8.1 and 22 to 212 umhos/cm, respectively. Turbidity in the tributaries ranged from less than 1 NTU to 42 NTUs. In the mainstem above Devil Canyon, dissolved oxygen ranged from 9.0 to 13.5 mg/1 over a corresponding range of surface water temperatures from 0.1° to 13.9°C, while measurements of pH and specific conductance ranged from 6.6 to 8.1 and 10 to 146 umhos/cm, respectively. Turbidity in the mainstem above Devil Canyon was found to vary from 14 to 150 NTUs. In the one slough studied above Devil Canyon, dissolved oxygen ranged from 4.8 to 9.9 mg/1 over a corresponding range of surface water temperatures from 6.6 to 13.6°C while measurements of pH and specific conductance were found to range from 6.8 to 7.1 and 396 to 452 umhos/cm, respectively. Turbidity measurements obtained from May to September, 1982 ranged from 1 to 7 NTUs. Refer to Volume 5 for a site by site presentation of these results. 3.2.3 Total Dissolved Gases All basic field dissolved gas data collected during 1981 and 1982 is compiled and presented in Appendix Table 4-D-1. The 1981 data has been previously reported in separate techni ca 1 reports conducted by Teraes- trial Environmental Specialists (1981, 1982), however some minor correc- tions in calculations were made in these data and are incorporated in 170 120 c: 110 0 109 +-._. 0 108 L.. -......! :J ._. +-107 0 (/) 106 c: 105 Q) u L.. <I> 104 0... 103 102 N= 14 -b= .033 r 2 = .98 r N=6 -b= .054 r2 = .96 -b= .038 r 2 = .95 L=7 -b =. 082 r 2 = .97 5 10 15 20 25 30 35 miles below Devil Canyon Figure 41-3-54. Percent concentration of total dissolved gas versus distance below the Devil Canyon proposed dam site. this report as corrected. In addition, a residual analysis of the multiple regression examination of decay data is included in Appendix Table 4-D-3. Although temperature was examined initially, one discharge (at Gold Creek) and distance (number of miles) below the proposed Devil Canyon dam site were examined as predictor variables. Temperature was found not to have any significant contribution to the variability in the concentrations of dissolved gas recorded. The decay of the supersatura- tion that began in the canyon near the dam site is plotted in Figure 41-3-54 for four different sampling periods. The decay of the super- saturated gas follows a reasonable log decay function and the regression coefficients are indicated, but the s·l opes of the decay curves vary from sampling period to sampling period. The concentrations of dissolved gas immediately above and below the rapids of the canyon were measured on two separate trips during June and August of 1981. During the June, 1981 trip, the dissolved oxygen was also recorded (Figure 41-3-55). The continuous record of dissolved gas concentrations and temperature at the site immediately below Devil Canyon are listed in Appendix 4-D-4. The relationship of the dissolved gas concentrations to discharge is plotted in Figure 41-3-56. 172 ....... -......j w 120 (/) w (/) <( 115 (.!) 0 w > ..J 0 (/) (/) 110 0 IJ... 0 z 0 1- <( 105 0:: ::> 1- <( (/) 1-z w 100 u 0:: w a. Gold Creek Discharge=32.3 ......-\ \ \ ........ ,, \ \ \ · .. / \ \ \'. \ \ \ \\ ..... ·" \_/ ,.,..·.,... -·-.. _ /·------ Gold Creek Discharge= 14.8 ·-. --·- ..... ·-·-·-·-------·--.. -;-· ----- 95~----~~LL~~~L----r----.-----.---~~~~~~TL---.c---~~~~{~L---,---~ 0 2 3 4 5 6 7 8 9 10 II 12 13 Total gas saturation - --and ...... . MILES ABOVE MOUTH OF PORTAGE CREEK Nitrogen saturation -·-·-· Oxygen saturation *Hashmarks indicate areas of rapids. Figure 41-3-55. Concentrations of dissolved gases in Devil Canyon rapids complex. 14 1-' '--I ..p. 850 r 2 = 0.711 linear 840 1/1 r 2 =0.713 Q) log :I 0 > .?:-830 0 0 c: 0 Q) :::E 820 1/1 0 (!) 0 -810 0 1- II >- '-;::) u ~ 800 :::E ._ 0 E E 790 780+-----~------~-----T------~----~------T------T------T-----~-- IO,OOO 12,500 15,000 17,500 20,000 22,500 25,000 27,500 30,000 32,500 Mean Daily Discharge at Gold Creek { CFS) Figure 41-3-56. Mean daily discharge versus saturometer readings below Devil Canyon. 4. DISCUSSION 4.1 Hydrological Investigations 4.1.1 Stage and Discharge Talkeetna to Devil Canyon Mainstem water surface elevations were monitored at 31 staff gage sites located between Talkeetna and Devil Canyon. Mainstem water surface elevations were compared to the mean daily mainstem discharge at the USGS Gold Creek gaging station. Changes in the mainstem water surface elevation were found to generally range between 3 to 5 feet over a range of mainstem discharge from 8,000 to 32,000 cfs. Review of 1949-1975 streamflow records (USGS 1978), indicate the mean monthly Susitna River discharge determined at Gold Creek for the months of June -October can range from a 1 ow of 3,124 cfs (October 1970) to a high of 50,850 cfs (June 1964). The stage-discharge relationship for the mainstem Susitna River from Talkeetna to Devil Canyon, as determined from 1982 observations, is well defined for flows ranging from approximately 8,000 to 30,000 cfs at Gold Creek. Additional data need to be obtained to further define the range of flows not adequately defined during the 1982 open water season (below 8,000 cfs and above 30,000 cfs). 175 Mainstem discharge was found to influence the water surface elevation at the slough mouths studied to varying degrees (also see section 4.1.3.1). Backwater areas were still present at the mouths of Whiskers Creek Slough and Slough 6A as mainstem discharges at Gold Creek dropped to 8,500 cfs. A backwater area was present at the mouth of Slough 11 at mainstem discharge of 11,700 cfs; whereas mainstem discharges of 18,000 to 22,000 cfs were necessary before backwater areas even began to form at the mouths of Sloughs 168, 20 and 22. The effects of mai nstem discharge on backwater area and access to sloughs 8A, 9 and 21 has been discussed partially in this report and will be discussed further in the Fisheries-Habitat Report due in June, 1983. Except when breached at their head by mainstem water, side slough discharges (sloughflows) are generally quite small unless substantial flow is contributed by a tributary. Of the nine sloughs (omitting Slough 9, refer to the June report) studied between Talkeetna and Devil Canyon, only Whiskers Creek Slough and Slough 20 had substantia 1 flow from tributaries contributing to the sloughflow. The other seven s 1 oughs were dependent so 1 ely on ground water and surface runoff for flow during unbreached conditions. During the 1982 open water field season, sloughflows during unbreached conditions ranged from 0.2 cfs at Whiskers Creek Slough to 11.6 cfs at Slough 20 (Table 41-3-1). Once the side sloughs became breached, sloughflow generally increased by an order of magnitude. Measurements of sloughflow during 1982 during breached conditions ranged from 16.5 to 257 cfs (Table 41-3-1). The 1982 sloughflow measurements are considerably less than the 500 cfs measured at Slough 168 during breached conditions in 1981 (ADF&G 1981c). This is 176 primarily attributable to the abnormally low mainstem discharges which occurred during the late summer of 1982. Mainstem discharges were relatively high during 1981, however, the average daily discharges (based on past records) on the dates that sloughflow measurements were made in 1981 were not excessively large. Most side sloughs between Ta 1 keetna and Devil Canyon were found to breach as mainstem discharge at Gold Creek passed from 20,000 cfs to 26,000 cfs. Some error is associated with these discharge values because breaching observations are referenced to the average daily discharge at Gold Creek rather than a site specific discharge measure- ment. The error is believed to be slight, however, mounting to approxi- mately ±15%. Periodic discharge measurements were obtained at seven tributaries entering the Susitna River between Talkeetna and Devil Canyon. These measurements were made to determine the genera 1 flow contributed by these tributaries to the mainstream during the 1982 open water field season. The discharge measurements obtained from these tributaries were found to range from 0.2 to 142.5 cfs. Sufficient data was not collect- ed, however, to establish the overall ranges of flows or seasonal patterns of flows for each tributary. ~lhiskers Creek and a small unnamed tributary near the head of Slough 20 were the only tributaries studied in this reach of river that contri- buted flow to a slough. Whiskers Creek provided a substantial contribu- tion to the total sloughflow of Whiskers Creek Slough while the unnamed 177 tributary provided only a minimal contribution to the total sloughflow of Slough 20. All other tributaries studied emptied into the mainstem. Continuous streamflow records were obtained for Indian River and Portage Creek from August 9 through October 22, 1982. These flow data were obtained to determine the general magnitude and variability of seasonal streamflows from these tributaries and to provide a basis for estimating their effect on the mainstem discharge at Gold Creek. Discharges estimated from Indian River and Portage Creek were found to be re 1 a- tively stable with flows in August averaging approximately 180 cfs for Indian River and 465 cfs for Portage Creek. During most of September, flows increased to an average of 316 cfs for Indian River and 648 cfs for Portage Creek. Mid-September was a period of high discharge for both Indian River and Portage Creek with a peak flow of 1 ,815 cfs for Indian River and 1673 cfs for Portage Creek. These high flows were the result of a storm which occurred around September 14 or 15. Flows in both tributaries were found to recede in the month of October to 111 cfs in Indian River and 208 cfs in Portage Creek. Overall, the 1982 flows in Indian River and Portage Creek were relatively stable with a peak occurring in mid-September and flow decreasing in October. Below Talkeetna Mainstem water surface elevations were only measured adjacent to two slough study areas (Birch Creek Slough and Goose Creek 2 Slough) below Talkeetna in order to determine the influence that the mainstem has on these sloughs at various discharges. These data are discussed below in conjunction with the sloughs. Mainstem discharge was found to 178 influence, to a varying degree, the water surface elevation at the mouths of the sloughs and tributaries studied downstream of Talkeetna (also see section 4.1.3.1). Backwater areas were present at the mouth of Whitefish Slough with mainstem flows of at least 34,000 cfs (as determined from the USGS Sunshine gaging station). Backwater areas were also present at the mouth of Lower Goose 2 Slough at mainstem flows of 32,000 cfs, Sunshine Creek Slough at mainstem flows of 58,000 cfs and Birch Creek Slough at 23,000 cfs. Except when breached at their heads by mainstem water, sloughflow within Lower Goose 2 Slough, Sunshine Slough and Birch Creek Slough was gener- ally provided by tributaries flowing into the slough. Upstream of the slough/creek interface, discharge was quite small· during unbreached conditions consisting primarily of surface water runoff and pondage within the slough. Whitefish Slough was the only upland slough studied below Talkeetna. The 1982 discharge measurements for Lower Goose 2 Slough, Sunshine Creek Slough and Birch Creek Slough ranged from 0.3 to 607.1 cfs upstream of the slough/creek confluence and from 86.5 to 711.0 cfs downstream of the slough/creek confluence. Periodic discharge measurements were also obtained at five tributaries located downstream of Talkeetna. These flow measurements were made to determine the general magnitude of flow contributed by these tributaries during the open water season of 1982. The discharge measurements obtained from these tributaries were found to range from 31 to 251 cfs. Of the five tributaries studied, only Rabideux Creek did not contribute flow into an adjoining slough. Lower Goose Creek 2, the unnamed tribu- 179 tary on Whitefish Slough, Sunshine Creek and Birch Creek emptie.d into adjoining sloughs. These tributaries, during unbreached conditions, provided the majority of flow passing through the mouth of the slough. From site observations, Birch Creek provided at least 50% of the flow of Birch Creek Slough at the mouth during unbreached conditions. 4.1.2 Thalweg Profiles Thalweg profiles are valuable for assessing the effects of discharge and channel morphology on fish migration and access; thus they are discussed in Part I I. 4.1.3 Other Hydrological Components 4.1.3.1 Backwater Areas Calm backwater areas which are largely regulated by the stage of the mainstem Susitna River, occur in the lower reaches of sloughs and at the mouths of some low gradient streams and side channels. The surfaces of these backwater areas have been designated as H-II zones and consist of aggregates of nine broadly defined hydraulic conditions, as defined in Volume 4, Part II, Section 2.2 of this report. These low velocity areas respond in a complex manner to changes in discharge of the mainstem and to changes in discharges of associated tributaries. The proportion of the total wetted surface areas available as fisheries habitat, that these areas compose, often vary in an unusual but predictive manner in response to changes in discharge of the mainstem Susitna River. These 180 areas have been traditionally recognized as unique ecological areas in riverine systems. The total area of H-II zones within the boundaries of the upper and lower Susitna River study sites is shown in Tables 41-4-1 and 41-4-2 and Figures 41-4-1 and 41-4-2. These values were obtained by determining the areas indicated at 2,500 and 5,000 cfs discharge intervals from Figures 41-3-30 to 41-3-43. These curves represent the best available data of the overall availability of this specific hydraulic zone as a function of mainstem discharge. Generally the number of observations used to generate Figures 41-4-1 and 41-4-2 are much higher for the upper river summary than for the lower river (n=9 vs n=5, respectively). The upper river data indicate a rather marked inflection in the relationship of areas to Gold Creek discharges above and below 17,500 cfs. The lower river curves indicate that a change in the relationship of areas to Sunshine discharge occurs near 40,000 cfs. The surface area curves presented here and in results requires cautious interpretation. These data should not be misinterpreted as broader concepts of overall wetted surface area or of available habitat. They represent only the surface area of low velocity backwater reaches (H-11 zones) that are caused by Susitna River stage. For instance, at several locations it is noted that the area of H-11 water begins to increase with decreasing Susitna River stage. At Slough 19 for example, above a mainstem discharge of 16,000 cfs, it was observed that the H-11 wetted surface area approached the total wetted surface area while at lower discharges, new H-11 areas developed downstream as the mainstem receded. 181 ....... 00 N Table 41-4-1 Total surface areas gf Type I I hydraulic zones within the boundaries of nine study areas on the upper Susitna River vs. Cold Creek discharge , June through September, 1982. Habitat Location 12,500 Slough 21 52. Slough 20 1. 8 Slough 19 4.2c Slough 11 22. Slough 9 1 o. Slough SA 155.8 Lane Creek/Slough 8 6.1 Slough 6A 127.7 Whiskers Creek/Sidechannel 29. Total by Discharge 408.6 auscs Provisional data at Cold Creek, 1982, Surface Areasb (Square Feet x 1000) at Habitat Location Discharge (cfs)a 15,000 17,500 20,000 22,500 63.8 69. 42.3 16.5 0.4 0 0 0 0 9.4 11.3 13.7 32. 46. 73. 105. 84. 128. 109. 77. 164.4 173.1 181.7 190.4 9. 13.8 14.5 16.2 129.2 130.7 132.3 133.8 37.5 52. 66. 80.5 520.3 622. 630.1 633.1 15292000. boata compiled from figures 41-3-40 through 41-3-48. cArea measured at 13,300 cfs. dArea measured at 24,900 cfs. eArea measured at 23,000 cfs. fArea measured at 23,000 cfs. 25,000 27,500 3.9 12.2 0 1.9 26.d 26.d 109. 110. 44. 11. 199. 207.7 45. 47. 135.4 136.9 83.9e 83.9f 646.2 636.6 Table 41-4-2 Total surface areas of Typ~ II hydraulic zones within the boundaries of five study areas on the Lower Susitna River vs. Sunshine station discharge , June through September, 1982. Surface Areasb (Sguare Feet x 1000) at Habitat Location Habitat Location 35,000 40,000 45,000 50,000 55,000 60,000 65,000 70,000 Birch Creek 84. 147. 150. 153. 225. 365. 378. 385. Sunshine Creek/Sidechannel 25. 55. 86. 118. 148. 178. 128. 121. Rabideux Creek/Slough 496. 826. 880. 933. 987. 1040. 1090. 1150. Whitefish Slough 21. 37. 51. 61. 67. 72. 77. 80. Goose Creek/Sidechannel o. 58. 117. 109. 103. 93.5 85.5 77.5 Total by Discharge 626. 1123. 1284. 1374. 1530. 1749. 1759. 1814. 1-' a uses Provisional data at Sunshine, 1982, 15292780. 00 boata compiled from figures 41-3-49 through 41-3-53. w 8 0 )( t- IJJ IJJ LJ... ww ~a:: (.!)<( IJJ:::J ere (!)en (.!)- <ten IJJ u..t-o-en ........ <ti co ..j:::. IJJ(.) a::<( <tiJJ a:: IJJ ua:: <(W u..O... a::O... :::::>=' ent- <:( ..Ja:: <(LI.J t-t- 0<( t-3 LI.J 0... >-t- 0 SUSITNA R. USGS I DISCHARGE ( CFS x 1000) AT GOLD CREEK PROVISIONAL DATA 1982 152 9 2000 Figure 41-4-1. Total surface area of aggregate type II water within the study boundaries of nine upper reach sites versus Susitna River discharge at Gold Creek (USGS Provisional Data). 0 0 0 )( 1-w ww I-LL <Cw <.!)cr: w<C cr:::> <.!)0 <.!) (/) <(--- LL C/) 0~ <((/) W::r: cru 1-' <(<( (X) (J1 w wcr ucr ltw cr3 :::>0 (/)..J _JI- <(<( t-cr ow 1-t- <( ~ w a.. >-1- 2000 1500 1000 50 0 10 20 0 SUSITNA R. DISCHARGE (CFS x 1000) AT SUNSHINE USGS PROVISIONAL DATA 1982 15292780 Figure 4I-4-2. Total surface area of aggregate type II water within the study boundaries of five lower reach sites versus Susitna River discharge at Sunshine (USGS Provisional Data). Appendix Figure 4-F-4 demonstrates the same trend at Slough 21. These new H-II areas often had very different depths, substrate conditions and rearing potential for juvenile fish because of unstable geomorphological conditions. These conditions were not a factor in this analysis. Similarly, in Rabideux Creek, the sudden loss of H-II area requires interpretation. The pool area which is connected with the mainstem backup at high mainstem flows, disconnects as the mainstem recedes, thus reflecting a sudden decrease in H-II surface area; what remained was a morphological pool that provided similar habitat. This pool however, is apparently maintained by geological processes that are influenced by mainstem stage. 4.1.3.2 Open Channels The open channel studies are comprised of the hydraulic model, used for simulation of hydraulic conditions under various flow regimes. These models are in the preliminary stages of calibration and are discussed in Part I I. 4.2 Water Quality Investigations 4.2.1 Temperature The continued monitoring of surface water temperatures through the 1982 fie 1 d season provided background data concerning the therma 1 regime of the Susitna River. 186 Continuous surface water temperatures of the mainstem Susitna River were obtained at twelve locations during the 1982 open water season. Since the most notable effects in the thermal regime of the river during dam construction and operation will probably occur between Talkeetna and Devil Canyon, efforts were concentrated in this reach. Generally, monthly mean surface water temperatures were relatively constant in the reach from Talkeetna to Devil Canyon, varying at most about 2°C. Maximum daily temperatures recorded in the mainstem during 1982 peaked at 13-15°C in July and August and dropped down to ooc by late October. To better understand the intragravel/surface water temperature relation- ship in side sloughs, temperature recorders which continuously monitor simultaneously both intragravel and surface water temperatures were installed in six side sloughs between Talkeetna and Devil Canyon. Except during periods when the mainstem breaches the head of a side slough, surface water temperatures in side sloughs are independent of surface water temperatures in the mainstem. When a side slough is not breached, surface water temperatures are largely affected by local runoff and solar radiation and, to a lesser degree, by groundwater percolation and air temperature. In Sloughs 21 and 8A, temperature recorders were installed at 2 sites (near the head and near the mouth) and a thermograph monitoring surface water temperature was installed mid-slough. Data, to date (August-October, 1982), shows significantly more fluctuation in surface water temperatures than in intragravel water. temperatures on both a daily and seasonal basis. Surface water tempera- tures in the mouth of Slough 8A varied as much as 6.8°C in one day (late August) from a high of 14.6°C to a low of 7.8°C. Overall, surface water 187 temperatures ranged from 14.8° to 0.2°C in the period August -October. In comparison, intragravel water temperatures at this site varied at most 0.2°C in one day, always remaining within the range of S to 7°C. Surface water temperatures obtained in the mouth of Slough 8A were markedly warmer than surface water temperatures obtained in the other sloughs monitored. Generally, intragravel water temperatures were in the range from 3 to soc from August to October and surface water tem- peratures ranged from 8 to goc in August down to 1 to 3°C in October. Slough surface water temperatures remained warmer than intragravel water temperatures until mid to late September, when the surface water temper- atures had dropped to the 3 to soc range. As surface water temperatures continued to decrease into October, the i ntragrave l water temperature dropped at a slower rate and remained warmer than the corresponding surface water temperature. Continuous surface water temperatures were also obtained during the 1982 open water season in ten tributaries in the Susitna River between RM 27.7 (Yentna River) and RM 206.8 (Kosina Creek). Generally, surface water in the tributaries was 1 to 2°C cooler than adjacent (i.e., to the nearest mainstem temperature monitoring station) mainstem surface water. In the first couple weeks of October, however, when the mainstem dropped rapidly from 3 to 4°C for a couple weeks, the surface water temperature of the tributaries dropped to 0°C. 188 4.2.2 Other Basic Field Parameters The basic field parameters of specific conductance, pH, dissolved oxygen, water temperature and turbidity were collected in conjunction with various sub-projects of the ADF&G Su Hydro Aquatic Studies Team. The parameters were collected at various locations in the Susitna River basin from RM 5.0 to RM 258.0 during the 1982 open water field season. Portions of these data, as they relate to the respective sub-project involved in its collection, are discussed in Part II of this volume and Volume 5. The discussion of water quality in this section includes an overview of the water quality data collected in the main.stem (entire river), the sloughs and tributaries between Talkeetna and Devil Canyon and the sloughs and tributaries downstream of Talkeetna. Mainstem (entire river) Adequate water quality measurements were not collected in the mainstem Susitna River during the 1982 open water field season to quantify the overall ranges of water quality present in the mainstem throughout the ice-free season. From the limited data collected, however several trends are apparent. The water quality of the mainstem Susitna River appeared to be relatively homogenous throughout the areas sampled (RM 5.0 -RM 233.4) with no apparent relation to mainstem discharge, loca- tion or date of collection. A comparison of the mainstem water quality in the three reaches (upstream of Devil Canyon, Talkeetna to Devil Canyon and downstream of Ta 1 keetna) showed no si gni fi cant differences between these reaches of the river. 189 Primarily, the basic field parameters gathered in the mainstem Susitna River during the 1982 open water field season were collected in conjunc- tion with the electrofishing sub-program to characterize the water quality present at habitats utilized for spawning by adult anadromous and resident fish. Refer to Part II of this Volume for a further discussion of these results. Sloughs Between Talkeetna and Devil Canyon Water quality data were collected on a regular basis in various upland and side sloughs located between Talkeetna and Devil Canyon during the 1982 open water field season. In several of these sloughs, water quality was collected during both breaching and non-breaching mainstem flows. It is expected that water quality in a slough will vary depend- ing on whether or not it is breached by the mainstem. During breaching conditions, the water quality present in a slough is expected to be directly tied to the mainstem while under non-breaching conditions it is expected to be more closely tied to the characteristics of the slough. Thus a comparison of the water quality in a slough under breaching and non-breaching conditions can be used to determine the effect the main- stem has on the overall water quality present in the slough. Two upland sloughs (Sloughs 6A and 19) were monitored for their water quality during the 1982 open water field season. Upland sloughs are defined as sloughs having no connection to the mainstem other than at their mouths (see Section 3.1.1.2). Thus it is expected that these 190 sloughs will not exhibit any significant changes in water quality, other than within the zone of backwater influence, that can be related direct- ly to mainstem discharge. A comparison of the upland slough water quality to mainstem discharge revealed that for mainstem flows ranging from 12,400 to 28,000 cfs for Slough 19 and 11,700 to 28,000 cfs for Slough 6A, the parameters of dissolved oxygen and pH remained constant. This indicates that the water quality in the upland sloughs is not related to mainstem discharge. Both these sloughs were observed to have large backwater areas during relatively high mainstem discharges. At Slough 19, the conductivity values were determined to be slightly higher in the areas of the slough removed from mainstem influence while the inverse of this was found for turbidity levels. In addition, nine side sloughs were monitored for their water quality during the 1982 open water field season. Side sloughs are defined as those sloughs connected to the mainstem at their mouth and, during periods of high mainstem flow, at their heads (see section 3.1.1.2). Thus these sloughs may exhibit a significant change in their water quality during breaching and non-breaching conditions. Whiskers Creek Slough Surprisingly, the water quality in Whiskers Creek Slough was similar during periods of both breaching and non-breaching mainstem flows. Ranges of surface water temperature, dissolved oxygen, pH and specific 191 conductance were very similar during periods of both breaching and non-breaching mainstem flows. Even ranges for turbidity, which would be expected to increase during periods of breaching mainstem flows, were similar. The high turbidity levels obtained in the slough during periods of non-breaching mainstem flows are most likely attributable to the turbid flow from Whiskers Creek during periods of high creek dis- charge. During periods of non-breaching mainstem flow, the major source of flow into Whiskers Creek Slough is from Whiskers Creek. A comparison of the slough water quality to that of the creek during unbreached conditions showed tha~ overall the water quality in the creek was similar to that in the slough except that the ranges of surface water temperature, dissolved oxygen and specific conductance were slightly greater in the slough. These data indicates that the major influence on the water quality in Whiskers Creek Slough during periods of both non-breaching and breaching mainstem flows is from Whiskers Creek. Lane Creek Slough (Slough 8) During periods of breaching mainstem flows, the water quality in Lane Creek Slough appears to be primarily influenced by the mainstem. A comparison of the ranges of dissolved oxygen, pH and specific conduc- tance during periods of breaching and non-breaching mainstem flows shows that the ranges of these parameters were slightly less during periods of breaching mainstem flows than during periods of non-breaching mainstem flows. Due to a lack of turbidity samples collected during the 1982 open water field season, ranges of turbidity during periods of breaching 192 and non-breaching mainstem flows could not, unfortunately, be determined for Lane Creek Slough. During periods of non-breaching mainstem flows, the water quality in Lane Creek Slough appeared to be primarily influenced by groundwater and surface water. This is indicated in that the ranges of specific conductance and surface water temperature were slightly higher in the slough than in the mainstem during periods of non-breac;:hing mainstem flows. Sloughs SA All water quality data obtained in Slough SA during the 19S2 open water field season were gathered during non-breaching mainstem flow conditions. Consequently, the water quality data cannot, at this time, be referenced to breaching or non-breached mai nstem flow conditions. The water quality data obtained in Slough SA is within the range observed in other studied side sloughs and does not appear to be a limiting factor to fish. Sloughs 9 Except for surface water temperatures, water quality in Slough 9 did not differ significantly during periods of breaching and non-breaching mainstem flows. The range of surface water temperatures observed during breaching mainstem flows was less than observed during non-breaching mainstem flows. This would be expected, as solar radiation and air 193 temperature would be expected to affect the slough's surface water temperature to a greater extent during periods of non-breaching than breaching mainstem flows. The water quality of Slou.gh 9 does not appear to be a limiting factor to fish. Slough 11 Slough 11 was never breached by the mainstem Susitna River during the 1982 open water field season. The relatively high levels of specific conductance observed in the slough during this summer (133-230 umhos/cm) indicate that the primary source of water in the slough is groundwater, except during periods of high precipitation when surface water influence becomes important. The parameters of dissolved oxygen, pH and turbidity did not appear to be a limiting factor to fish in Slough 11. Slough 168 Water quality data was collected twice in Slough 168 during the 1982 open water fie 1 d season; once during breaching and once during non- breaching mainstem flows. Based on this limited data, the water quality in the slough during periods of breaching mainstem flows appeared to be dependent on the mainstem while, during periods of non-breaching main- stem flows appeared to be dependent on groundwater and surface water runoff. This is indicated in that the surface water temperature and specific conductance were lower in the slough during breached conditions than during non-breached conditions. From the 1981 data, the water 194 quality in the slough during non-breaching mainstem flows appears to be influenced by Indian River (ADF&G 1981c). Slough 20 During periods of breaching mainstem flows, the water quality in Slough 20 appeared to be primarily influenced by the mainstem. This is shown in a comparison of the ranges of surface water temperature and turbidity in the slough during periods of breaching and non-breaching mainstem flows. Surface water temperatures were generally 1 ower and turbidity levels generally higher in the slough during periods of breaching mainstem flows. Ranges of dissolved oxygen, pH and specific conductance were very similar within the slough during both the breached and un- breached condition. During periods of non-breaching mainstem flows, the water quality in Slough 20 appeared to be primarily influenced by Waterfall Creek. Ranges of pH, specific conductance and turbidity were similar in the slough and Waterfall Creek during unbreached conditions. Slough 21 During periods of breaching mainstem flows, the water quality in Slough 21 appeared to be primarily influenced by the mainstem. This is shown in a comparison of the ranges of surface water temperature and turbidity in the slough during periods of breaching and non-breaching mainstem flows. Surfaces water temperature were generally 1 ower and turbidity 195 levels generally higher in the slough during periods of breaching mainstem flows. During periods of non-breaching mainstem flows, the water quality in Slough 21 appeared to be primarily influenced by groundwater and surface water runoff from a small tributary located near the head of the slough. Slough 22 During periods of breaching mainstem flows, the water quality in Slough 22 appeared to be primarily influenced by the mainstem. This is shown in a comparison of the ranges of surface water temperature and turbidity during breaching and non-breaching mainstem flows. Surface water temperatures were generally lower and turbidity levels generally higher in the slough during periods of breaching mainstem flows. In addition, ranges of dissQlved oxygen, pH and specific conductance were higher in the slough during periods of breaching mainstem flows. The main influ- ences on the water quality in Slough 22 during periods of non-breaching mainstem flows appeared to be from surface water runoff. Groundwater did not appear to have a major influence on the water quality of this slough during unbreached conditions. Sloughs and Tributaries Downstream of Talkeetna All sloughs studied downstream of Talkeetna during the 1982 open water field season had tributary influences. Water quality data was collected in these sloughs during both breached and unbreached conditions, in the associ a ted tributaries and the adjacent mainstem. The rna i nstem flows 196 necessary to breach the heads of the studied sloughs downstream of Talkeetna are not currently 9efined. Consequently, the water quality data cannot, at this time, be referenced to mainstem flow conditions. Based on a preliminary overview of the water quality data obtained in the sloughs and their associated tributaries downstream of Talkeetna, several relationships are apparent. Comparisons of the water quality in the slough to that in the adjacent tributary reveals that the ranges of specific conductance, turbidity, surface water temperature and pH were higher in the sloughs than in the adjacent tributaries. Only the range of dissolved oxygen was lower in the sloughs than the associated tribu- taries. Of the four sloughs studied downstream of Talkeetna, all were relatively similar in their water quality characteristics. 4.2.3 Total Dissolved Gases The formation of supersaturated water below the lower Devil Canyon rapids pro vi des an unusua 1 phenomenon. Most often, rapids are associated with dissipation of dissolved gas above 100% of saturation, rather than entrainment of gas at supersaturated levels. Higher dissolved gas concentrations were recorded at this location than at any other in the ten mile reach of Devil Canyon. The continuous monitor installed during the summer of 1982 provided an extensive collection of baseline conditions and provided an accurate portrayal of the response of gas supersaturation to the volume of water passing through the 197 canyon. This increased supersaturation depicted in Figure 4I-3-56 as a function of discharge is probably associated with increased depths of the plunge pools and the amount of air trapped as water passes through this precipitous set of rapids. Fish collected in the area of highest concentrations have not exhibited any embolisms associ a ted with gas bubble disease. The concentrations of dissolved gases are sufficiently high to create gas bubble disease at high water periods for sensitive species if exposure is for a sufficient period of time. These high water conditions did not occur during the low flow year experienced in 1982. The formation of dissolved gas supersaturation appears to be a purely physical process, probably caused by plunge pools· below the rapids within Devil Canyon. Figure 4I-3-55 depicts the changes in gas concen- trations through the canyon during two separate sampling trips. This relationship suggests that both rapid formation and dissipation occur in the river through the canyon. Dissolved oxygen levels paralleled total dissolved gas suggesting a 1 so that the supersaturated conditions were caused by a physical process. Dissolved gas saturation above the canyon was consistently near 100% as were the waters in Gold Creek, a clear water tributary that was sampled occasionally as a control. This suggests that the supersaturated conditions found in the vicinity of Devil Canyon are apparently unique to the mainstem river. The data presented does not provide any direct support as to the fate of man caused supersaturated gas entering the canyon above the Devil Creek rapids. Examination of data collected in a similar situation near 198 Kootenai Falls below Libby dam in Montana suggests that elevated gas concentrations entering an area of entrainment may dissipate only partially when the concentrations initially entering the falls are above the natural level of supersaturation (USACOE, 1981). Therefore, major reductions in dissolved gas entering the lower Devil Canyon rapids, may not occur if high concentrations enter the rapids. Initial examination of the decay data below Devil Canyon during the 1981 field season suggested a predictable response of the decay of gas supersaturated in water. The concentrations of dissolved gas appear to be a linear function of discharge, with the initial concentrations pre- dictably increasing with increases in mainstem discharge. The supersat- urated condition of the water decreased, downstream as would be expected since supersaturated water tends to become equilibrated with the atmos- phere at 100% of satonation. It also appeared, from this limited data base, that the rate of decay was also dependent on mainstem discharge through Devil Canyon(Figure 4I-4-3). Further supporting this relation- ship was the data collected below Libby dam by the USACOE (1981). This information suggested decay of dissolved gas was dependent on discharge. However, data collected during the summer of 1982 on the Susitna did not support this re 1 ati onshi p and suggested other factors may affect the decay of dissolved gas. The effects of the variables discharge, temperature, and distance downstream on the concentrations of dissolved gas were examined in depth by use of multiple regression analysis techniques. The computer print- outs from this analysis are included in Appendix Table 4-D-3. 199 r--7 z .100 0 I i= <( I 0::: SUSITNA RIVER • f- .090 1981 DATA z I w SUSITNA RIVER 1982 DATA ... ---8 (.) • I z KOOTENAI RIVER DATA • 0 .080 I (.) ~--9 _J <( L-10 i= .070 z I - 1-I lL. z cno w .060 ~--12 W>-(_) I _J<( LL • • I -(.) ~w LL ~--14 0 w .050 0 I a:::~ (_) wo • I 2:~ I'V ... ~--18 a::: a:: 0 >-.040 0 <( I 0 (_) ... lL. w I 0 0 .030 • r--22 w • 0::: I :::::> 0 • I w .020 r--26 0::: ~--28 w I (.) z .010 <( f-en -• 0 . 000 0 10,000 20,000 30,000 40,000 50,000 DISCHARGE (CFS) Figure 41-4-3. Dissolved gas decay rates versus Gold Creek discharge with dissolved gas data below Libby Dam, Kootenai River, Montana, provided as a comparison (Source U.S. Army Corps of Engineers, T. Bonde, Seattle, WA). The main conclusion from these analyses is that a high degree of pre- dictability of dissolved gas concentrations can be established using discharge and distance downstream as two variables for the first 11.8 miles of the river below the Devil Canyon dam site. Regardless of the initial concentration, decay of gas supersaturation occurs at a predict- able rate of approximately a 50% decrease in the initial concentration for approximately every 20 miles of downstream movement. Below this location, the predictability becomes less reliable and the gas satura- tion levels decay at a faster rate. Factot·s which may contribute to the latter effect include: 1) changes in the lower reach of the river where the channel is more braided; 2) mean depths less than that present in the up river streches; and 3) dilution of the dissolved gas concentrations by the addition of water from Indian River and Gold Creek. These changes could provide condi- tions for more rapid equilibration of the supersaturated water to stable conditions (_100% of saturation). However, one other major factor may have affected the data valves recorded. During the 1981 summer period, instrument prob 1 ems occurred frequently. The high degree of autocorrelation observed when the data was ordered by time period suggest possible effects of the analytical procedure used in the field. When using only the data collected during the summer of 1982, this problem did not occur, suggesting instrument problems in 1981. The data points collected in the lower river were almost all collected during the 1981 field season. Further sampling of 201 the lower river decay rates of dissolved gases is planned for the 1983 open water season to determine what the dissipation rate of dissolved gas is for this reach. The results of this study can easily be applied to determining the relative hazard of supersaturated gas to downstream fish populations. The State of Alaska standard for maximum allowable dissolved gas super- saturation is 110%. conditions below Devil This value is clearly exceeded under natural Canyon (Figure 4I-3-45). Concentrations of dissolved gases produce increased mortalities in fish hatchery environ- ments at levels between 105% and 110% (Weitkamp and Katz, 1980). Fish have no method of escaping the elevated gas conditions by sounding in hatchery holding areas. In natural systems, the threshold for increases in natural mortality caused by elevated gas supersaturation usually are documented to occur between 115 and 120% (IBID). These conditions are approached only under the highest discharge conditions that occur in the Susitna River, thus suggesting that the natural hazard to fish is very minimal. The data presented suggests that the decay rate of dissolved gas is sufficiently low so that any mencaused elevation of supersaturation above the peak levels associated with the natural conditions could potentially create problems for the salmon stocks associated with Portage Creek and would probably affect the Indian River stocks as well. These systems are major producers of salmon in addition to resident species in the system. 202 PART I I FISH HABITAT INVESTIGATIONS 1. OBJECTIVES 1.1 Adult Anadromous Fish Habitat Investigations Adult anadromous fish habitat studies were designed to meet the follow- ing objectives: 1) Identify the presence of spawning at specific locations within mainstem, side channel and slough habitats. 2) Identify the ranges of physical and chemical conditions present at locations utilized for spawning and passage. 3) Support the analysis of the availability of spawning habitat within sloughs at a variety of flows of the mainstem Susitna River. 4) Support an evaluation of the accessibility of slough habitats to adult salmon at a variety of flows of the mainstem Susitna River. 5) Support an evaluation of whether to initiate detailed salmon spawning habitat investigations in the Susitna River between Cook Inlet and Talkeetna in 1983. 203 1.1.1 Salmon Habitat 1.1.1.1 Mainstem Adult anadromous salmon have been reported to utilize the mainstem Susitna River for spawning (ADF&G 1981b). Sampling conducted from August 1 to September 15, 1982, included the following tasks: 1) Determine the extent, timing and number of chum, pink, sockeye and coho salmon spawning in the mainstem Susitna River. 2) Evaluate the physical and chemical characteristics of mainstem habitats utilized for spawning. 3) Identify the relationship between changes in mainstem dis- charge and temperature to the extent, timing and number of salmon present in the mainstem. Results of the first task are summarized in Volume 2 of this report. Results of the second task are summarized in Section 3.1.1.1 of this vo 1 ume. Resu 1 ts of the third task are to be summarized in the Draft Fisheries Habitat Relationship Report due in June, 1983. 1.1.1. 2 Slough This portion of the study focused on the evaluation of adult salmon spawning habitat (primarily chum salmon) in selected side sloughs. It 204 is integrally related to objectives stated in Volume 2 and Volume 4, Part I, but expands them a step further and evaluates the habitat actually available to and utilized by fish. Specific tasks were as fallows: 1) Identify the types and ranges of hydraulic, morphologic and water quality variables (e.g., discharge, water velocity and depth, substrate composition, presence of upwelling, surface and intragravel water temperatures) present in slough and side channel habitats during the adult salmon spawning period. 2) Identify the types and ranges of the above variables which are utilized by adult salmon for spawning in sloughs. 3) Model and quantify the availability of spawning habitat in sloughs at a variety of flows of the mainstem Susitna River. 4) Collect data supporting an evaluation of the accessibility of slough and tributary habitats to adult salmon at a variety of flows of the mainstem Susitna River. 1.1.2 Eulachon Habitat Eulachon (Thaleichthys pacificus [Richardson]), an anadromous member of the smelt family, has been previously reported to spawn in the lower 205 Sus itna River (Morrow 1980, Lee et a 1. 1980) Samp 1 i ng conducted from May 16 (ice-out) to June 12, 1982, included the following tasks. 1) Determine the extent, timing and numbers of the spawning runs of eulachon in the Susitna River. 2) Evaluate the physical and chemical characteristics of habitats utilized for spawning by eulachon. 3) Identify the relationship between changes in mainstem discharge and temperature to the extent, timing and number of eulachon present. Results of the first task are summarized in Volume 2 of this report. Results of the second and third tasks are summarized in Part II, Section 3.1.6 of this volume. 1.1.3 Bering Cisco Habitat Bering cisco ( Coregonus 1 aurettae Bean), an anadromous member of the whitefish family, were first discovered to utilize the Susitna River basin for spawning in 1981 (ADF&G 1982b). A total of 747 fish were sampled during 1981 using fishwheels, gillnets, and electroshocking gear. Habitat eva 1 uati on surveys were a 1 so conducted at three major spawning areas located between RM 75 and 80 during 1981. Tasks pursued during the 1982 open-water field season were as follows: 206 1) Determine the extent, timing and number of the spawning runs of Bering cisco in the Susitna River. 2) Evaluate the physical and chemical characteristics of habitats utilized for spawning by Bering cisco. 3) Identify the relationship between changes in mainstem discharge and temperature to the extent, timing and number of Bering cisco present. The results of the first task are summarized in Volume 2 of this report. Results of the second and third tasks are summarized in Part II, Section 3.1.7 of this volume. 1.2 Juvenile Anadromous Fish Habitat Investigations A portion of the juvenile anadromous fish studies included measurements of a variety of physical and chemical habitat variables at 17 sites (Appendix 4-F) between Goose Creek and Portage Creek during the ice-free season of 1982. Details of the program and sampling sites are contained in Section 2.3 of Volume 3. These studies were designed to determine how fluctuations in mainstream discharge affected habitat parameters at sampling sites and how those changing habitat parameters affected fish distribution and relative abundance. Specific objectives were as follows: 1) Define the ranges of various habitat parameters at sampling sites. 207 2) Characterize the seasonal habitat requirements of selected species. 3) Determine how spatial and temporal differences in habitat parameters affect fish distribution and relative abundance. 4) Determine the relative importance of the habitat parameters which influence fish distribution and relative abundance. 5) Determine if changes in mainstem discharge has an effect on the distribution and relative abundance of selected species at the sampling sites. 6) Determine the ranges of habitat parameters within specific hydraulic zones, determine the preference of selected species for particular hydraulic zones, and estimate the comparative value of habitats utilized by each species. 1.3 Resident Fish Habitat Investigations Objectives of the resident fish habitat investigations during 1982 included those listed in Section 1.2 as well as the following: 1) Determine characteristics of habitats utilized for spawning by adult resident fish. 208 2) Determine movement and migrational patterns of adult resident fish. 3) Determine characteristics of overwintering habitats utilized by adult resident fish. 209 2. METHODS 2.1 Adult Anadromous Fish Habitat Investigations 2.1.1 General Mainstem and Lower River Studies 2.1.1.1 Mainstem Salmon Boat-mounted (Plate 4II-2-1) and backpack electrofishing gear (for methods and design see ADF&G 1982a), drift nets, and foot surveys were utilized to identify spawning sites in the mainstem Susitna River below Devil Canyon (RM 152.0) from August 1 to September 15, 1982. The 11 mainstem 11 in this study is defined to include the main channel and its associated side channels. It does not include tributary-mainstem confluence zones or slough habitats (as defined in ADF&G 1982b). The mainstem Susitna River was sampled for spawning salmon five days each week throughout the survey period. The sampling area (Figure B) extended from the estuary (RM 0.0) to Devil Canyon (RM 151.0) and was sampled by three separate crews as follows: 1) Yentna crew-estuary (RM 0.0) to Kashwitna River (RM 61.0), 2) Sunshine crew -Kashwitna River (RM 61.0) to Talkeetna (RM 97 .0), and 210 Plate 411-2-1 Electroshocking on the mainstem Susitna River. 211 3) Gold Creek crew -Talkeetna (RM 97.0) to Devil Canyon (RM 151.0). Salmon were not assumed to be spawning at a catch site unless all of the following criteria were met (AFD&G 1982a): 1) Fish exhibited spawning maturation colors and morphology. 2) Fish expelled eggs or milt when slight pressure was exerted on the abdomen. 3) Fish were in vigorous condition, with 25 percent or more of the eggs or milt remaining in the body cavity. 4) Additional sampling efforts produced fish that met criteria one through three above. When a mainstem spawning site was identified, the habitat of the site was also evaluated. This was a first attempt at evaluating habitat characteristics of mainstem salmon spawning areas and the study design, procedures and methods of study were modified in the field as necessary. The following procedures were utilized: 1) River mile, geographic code (GC) and time of sampling were determined and recorded. 212 2) A qualitative description of general habitat characteristics of the site and sampling methods and gear were recorded. 3) The overall substrate composition of the site was determined using methods described in the Procedures Manual (ADF&G 1982a) and recorded. 4) Representative measurements of the following variables were collected at each site using techniques described in the Procedures Manual (ADF&G 1982b): air temperature, surface and intragravel water temperatures, pH, dissolved oxygen, specific conductance, turbidity and water depth and velocity. 5) A map of the area was drawn indicating salmon spawning sites and areas of data collection. 6) Representative photographs of the site were taken. (A com- plete set of photographs are on file at the ADF&G Su Hydro Office, 2207 Spenard Road, Anchorage, Alaska 99503.) 2.1.1.2 Eulachon The Susitna River was sampled for spawning eulachon every day from May 15 (ice out) to June 16, 1982, by a three-person cre~t/ stationed at Susitna Station (RM 25.5). Set and dip nets and boat-mounted electrofishing gear (for methods and design see ADF&G 1981a Procedures 213 Manual) were utilized to define eulachon spawning sites and the upstream limits of their migration. Eulachon sampled by the above gear were not assumed spawning at a catch site unless all of the following criteria were met: 1) Fish freely expelled eggs or milt. 2) Fish were in a vigorous free-swimming condition. 3) Twenty or more fish, with a mixture of both sexes, were caught in the initial or subsequent site sampling efforts which met criteria 1 and 2 above. It was difficult to distinguish between migrational, milling and spawn- ing areas using the above criteria. Eulachon are known to be broadcast spawners and thus do not fan a nest (Morrow 1980), making it difficult to observe the exact location and timing of spawning. Attempts were made to identify deposited eggs in substrate samples by direct observa- tions. This proved largely unsuccessful, because the eggs are quite small and opaque white (Morrow 1980). When a eulachon spawning site was identified, the habitat at the site was also evaluated. Because this was a first attempt at evaluating the habitat characteristics of eulachon spawning areas, procedures and methods of study had to be designed and modified in the field. Due to the similarity between eulachon and Bering cisco spawning behavior, 214 techniques similar to those used in the Bering cisco study were employed in this study (ADF&G 1982b). The following procedures were utilized: 1) The site was assigned a name and the river mile, geographic code, and time of sampling were determined and recorded. 2) A qualitative description of the general habitat characteris- tics of the site, the sampling methods, and gear used were recorded. 3) The overall substrate composition of the site was determined, using methods described in the Procedures Manual (ADF&G 1982a), and recorded. 4) Representative measurements of the following water qua 1 ity variables were collected at each site, using techniques described in the Procedures Manual (ADF&G 1982a), and record- ed: water and air temperature, pH, dissolved oxygen, specific conductance and turbidity. 5) A map of the area was drawn and a sampling grid for the collection of depth and water velocity data was developed based on procedures developed by Bovee and Cochnauer (1977). 6) Depth and water velocity data were collected and recorded. 215 7) Representative photographs of each site were taken. (A complete set of photographs are on fi 1 e at the ADF&G Su Hydro Office, 2207 Spenard Road, Anchorage, Alaska 99503.) Two Peabody-Ryan model J-90 thermographs were placed in the Susitna River to continuously monitor water temperature. These data were used to determine surface water temperatures at the time of the eulachon spawning runs. Thermographs were placed along the east bank of the Susitna River (Figure 41-2-4) at RM 5.5 (at the east bank gill net site) and RM 25.5 (at Susitna Station). The thermograph at RM 5.5 and its recorded data were lost during an attempt to recover it. The thermograph at ~M · 25.5 was recovered and daily mean temperatures were calculated as the mean of four, 6-hour, point readings. 2.1.1.3 Bering Cisco Sampling was conducted from September 1 to October 15 (freeze-up), 1982, in the mainstem Susitna River and its associated side channels and sloughs to ascertain the degree of spawning by Bering cisco. In addi- tion, tributary mouths were occasionally sampled. Sampling was con- ducted utilizing fishwheels and standard boat-mounted electrofishing gear (for design and procedures see ADF&G 1982a). Bering cisco are believed to be broadcast spawners (Morrow 1980). This makes it difficult to determine the exact timing and location of 216 spawning. Bering cisco captured by the above gear were not considered to be spawning at a catch site unless all of the following criteria were met: 1) Fish freely expelled eggs or milt. 2) Approximately 20 or more fish, with a mixture of both sexes, were captured at a catch site. 3) Ripe or spent fish were present at the same site 24 hours after the initial sampling effort. When a catch site was determined to have Bering cisco spawning, the habitat of the site was also evaluated. To assure consistency of data, procedures similar to those employed during the 1981 study of Bering cisco spawning grounds (ADF&G 1982b) were employed during this year. The following procedures were utilized: 1) The site was assigned a name and the river mile, geographic code and time of sampling were determined. 2) A qualitative description of the general habitat characteris- tics of the site, sampling methods and gear used were record- ed. 217 3) The overall substrate composition of the site was determined, using methods described in the Procedures Manual (ADF&G 1982a), and recorded. 4) Representative measurements of the following water quality measurements were collected at each site, using methods described in the Procedures Manual (ADF&G 1982a) and recorded: air temperature, surface and intragravel water temperatures, pH, dissolved oxygen, specific conductance and turbidity. 5) A map of the area was drawn and a sampling grid for the collection of depth and water velocity data was developed (based on procedures in Bovee and Gochnauer 1977). 6) Depth and water velocity data were collected and recorded. 7) Representative photographs of each site were taken. 2.1.2 General Slough and Tributary Studies Thirteen sloughs were selected for general slough studies during the 1982 open-water field season including Whiskers Creek and Lane Creek sloughs and sloughs 6A, 8A, 9, 9A, 10, 11, 168, 19, 20, 21 and 22. These sloughs were selected for study based on their relative importance to the fishery. 218 Each of the sloughs were surveyed one time during early October. This was during a low flow period which enabled easy access and visibility of substrates and areas of upwelling. A foot survey was conducted at each slough, visually assessing substrate and upwelling areas and recording these characteristics on scaled (1"-50 1 ) maps obtained by aerial photo- graphy. Representative water quality measurements (pH, DO, specific conductance and temperature) were also obtained. Spawning areas were recorded by Adult Anadromous stream survey personnel who had monitored these sloughs throughout the spawning season. Ice-free areas were mapped once in November 1982 and once in February 1983 from a heli- copter. 2.1.3 Specific Slough Studies Shortages of time and manpower limited the number of sloughs that could be intensively studied during the 1982 open-water season. Thus, four sloughs (8A, 9, 11 and 21), each located within the Talkeetna to Devil Canyon reach of the Susitna River, were selected for intensive studies. These sloughs were selected based on their relative importance to the fishery (based on observed numbers of spawning salmon in previous years) and the comparatively large fisheries data base available from previous fish and game studies. The hydraulic data required for modeling Slough 11 was not collected due to time and personnel limitations. The intensive slough studies were comprised of two components: hydrau- lic modeling and fish spawning habitat availability and utilization. There was a significant overlap in data types required to fulfill 219 objectives for the hydraulic modeling and fish spawning habitat avail- ability and utilization components of the study. Both required dis- charge data collected across several transects at a variety of different flows. Within each slough, specific sites and transect locations were se 1 ected to represent the range of hydraulic and other habitat con- ditions in the slough. These transects were numbered sequentially, proceeding in an upstream direction, and used for both components of the study. 2.1.3.1 Modeling Data collection for the hydraulic portion of the model involved measure- ment of water surface elevation, depth, velocities and substrate along several transects within a site chosen to be representative of the reach being modeled. These transects were tied together with respect to elevation and horizontal distances. The specific field procedures followed are outlined in Procedures Manuals (ADF&G 1981a, 1982a). In addition to the hydraulic portion of the model, a habitat simulation portion will eventually be added to determine the amount of habitat usable by the appropriate life stage of the species being considered. The field data collection methods are discussed in Section 2.1.3.2.2. The programming and analysis procedures are discussed by Milhouse et al. (1981). 220 2.1.3.2 Habitat Availability and Utilization This portion of the study was designed to address two tasks. 1. Determine the ranges of several physical habitat characteris- tics (water depth and velocity and substrate composition) of study sloughs available to selected fish species and life stages at different mainstem discharges (AVAILABILITY). 2. Determine the characteristics of the habitat actually utilized by the fish species and 1 ife phases observed in the study sloughs at different mainstem discharges (UTILIZATION). The primary species studied was chum salmon; however, limited data were also obtained for sockeye and pink salmon. 2.1.3.2.1 Availability Data were collected to describe the habitat available to fish for spawning. Water depth and velocity and streambed substrate types were measured at regular intervals along transects within each study site. The transects included those used for the modeling portion of the study and additional transects located in areas of fish activity which occurred outside of the modeling site. These additional transects were labeled alphabetically, proceeding in an upstream direction. Substrate analysis was conducted following procedures outlined in the 1982 Procedures Manual (ADF&G 1982a). 221 2.1.3.2.2 Utilization Data were collected to describe the specific habitat that was actually used by fish for spawning. When it was determined that a fish had established a redd, water depth and velocity, substrate composition, and intragravel water temperatures were measured at the same time the fish were in the process of spawning. The criteria used for confirming a spawning fish are described in the 1981 Procedures Manual (ADF&G 1981a) and Estes et al. (1981). Utilization data collected at redds at a particular water stage was supplemented with a set of water surface elevations, depths and velocities collected along the availability transects. If the stage changed significantly and more utilization data were collected, additional availability data were also collected at transects. Although the adult salmon spawning utilization data in slough habitats are primarily limited to adult chum salmon in this report, other species and life stages will be analyzed as more data are compiled in future studies. 2.1.3.2.3 Water Quality Basic water quality parameters were measured in each study slough to determine the differences in water quality within the slough, to help identify water sources, and to document the quality of the water available to and utilized by the fish (when present). The majority of these data are discussed in Part I of this volume. 222 Interim analysis of intragravel temperatures collected at salmon redds raised several questions concerning the source and importance of intra- gravel water. The following study was developed to address these questions. In each s 1 ough, temperature ( i ntragrave 1 , substrate/water interface, and surface) measurements were obtained along study tran- sects. In addition, i ntragravel and surface water temperatures and conductivity measurements were obtained at a variety of specified locations (Appendix Figures 4-F-1 to 4-F-3) generally selected for specific comparative purposes (e.g., ground water vents vs. no vent areas). These data were used to determine the sources and importance of intragravel water to available spawning habitat. 2.2 Juvenile Anadromous Fish Habitat Investigations Rationale Different methods were developed to sample the distribution and abundance of j uveni 1 e anadromous fish with respect to habitat at a particular site during the 1982 field season than were used during the 1981 field season. This was necessitated by the relatively low density of juveniles observed at most of the habitat sites during 1981 sampling efforts (ADF&G 1981d). Observations during 1981 showed that concentrations of juveniles often changed markedly between sampling peri ads, i ndi cati ng that juvenile fish in the upper river were often transient during their summer rearing period. This likely reflected outmigration and behavioral responses to changing habitat conditions. 223 Fish, through behavioral responses to changing environmental conditions, are able to select between different micro-habitats at a site. Thus, fish distribution data can provide an indication of the behavioral preference for the variable conditions that existed at the sites. Based on 1981 data (ADF&G 1981d), the numbers of fish collected were not expected to be sufficient to allow a true multi-variate analysis of environmental parameters at a given site if point measurements were made at each fish capture location. Variability within sample sites would preclude collection of sufficient data. Also, a quantitative description of the amount of habitat that would be available for the fish to select from, as is typically done in the development of prefer- ence or selectivity curves, would not be possible because of the extensive field work required to document the full range of environmental parameters available at each sampling site. Therefore, habitat areas were stratified to cover a wide range of conditions during 1982. These areas were designated as habitat zones (Table 411-2-1, Figure 411-2-1) and were classified on the basis of surface water velocity and water source in nine zones. The distribution of zones at a hypothetical site at three different levels of mainstem discharge is depicted in Figure 4II-2-1. The relative importance of these different habitat zones for each species will be reflected in their preference for different zones. The proportion of catch per unit effort for each species or age class at a particular time will provide an index to the importance of the zones. It will then be possible to deduce the overall response of juvenile 224 Table 4II-2-1. Description of habitat zones sampled at Designated Fish Habitat sites: June through September, 1982. Zone Code Description 1 Areas with a tributary or ground water source which are not influenced by mginstem stage and which usually have a significant surface water velocity. 2 Areas with a t~ibutary or ground water source which have no appreciable surface water velocity as a result of a hydraulic barrier created at the mouth of a tributary or slough by mainstem stage. 3 Areas of significant surface water velocities, primarily influenced by the mainstem, where tributary or slough water mixes with the mainstem water. 4 Areas of significant water surface velocities which are located in a slough or side channel above a tributary confluence (or in a slough where no tributary is present) when the slough head is open. 5 Areas of significant water surface vel oci ties which are located in a slough or side channel below a tributary confluence when the slough head is open. 6 Backwater areas with no appreciable surface water veloci- ties which result from a hydraulic barrier created by mainstem stage which occur in a slough or side channel above a tributary confluence (or in a slough or side channel where no tributary is present), when the head of the slough is open. 7 Backwater areas with no appreciable surface water velo- cities which result from a hydraulic barrier created by mainstem stage which occur in a slough or side channel below a tributary confluence, when the head of the slough is open. 8 Backwater areas consisting of mainstem eddies. 9 A pool with no appreciable surface water surface veloci- ties which is created by a geomorphological feature of a free-flowing zone or from a hydraulic barrier created by a tributary; not created as a result of mainstem stage. a 11 Significant" and "appreciable" surface water velocities mean a velocity of at least 0.5 ft/sec. However, there are site-specific exceptions to this, based on local morphology. 225 Tributary Mouth ""-s Iough -OlliE-MAINSTEM -- HJGH MAINSTEM DISCHARGE ---~Slough Head (Open) MEDIUM MAINSTEM DISCHARGE ·.:: ., ..... ~ ·:... ··:~ .. , ....... .--3 Mouth ---~Slough _._.MAINSTEM --Head (Open) Tributary . Mouth ~ .( .. , . •• <-\:::::<<~: < ...... . • ~1' .,~ • ~Slough .-3 Mouth ..,.._MAINSTEM- 0 MAINSTEM BACKWATER AREA ~FREE-FLOWING WATER LOW MAINSTEM DISCHARGE ·!·~ .. ~' .. - -... :.~i~·"·.;.··;··:;?.-.."::·. --~Slough Head (Closed) Figure 4!!-2-1. Hypothetical slough, with associated tributary, showing hydraulic zones present at three dif- ferent levels of mainstem discharge. 226 habitat to the variable mainstem discharge. This requires the assump- tion that reductions in wetted surface area reflect loss of habitat for a particular species or age class. The size and occurrence of these habitat zones responded, often dramatically, to changes in mai nstem discharge. Fish collection efforts were designed to provide represen- tative catch per unit effort within each of these designated zones at various levels of mainstem discharge. The response of the zones to mainstem discharge was characterized primarily by measuring changes in wetted surface area or in the linear extent of each zone at various mainstem discharges. Further analysis, using 1982 staff gage data and discharge measurements within the habitats, will evaluate changes in depth and possibly velocity of these zones with mainstem discharge. Ultimately, effects of tributary or ground water inflow on depth, surface area, and velocity, as well as the effects on temperature and turbidity will be examined. Long-term effects on cover and geomorphological changes have not been quantified, but observations by field biologists of the changes associated with flood or icing events on these parameters will be described in narrative form. Methods The sampling design, methods, and sampling sites of the biological data collection effort are described in Volume 3, Section 2.1.3. The loca- tion of the 17 tributary mouth and slough sampling sites of this study, called Designated Fish Habitat (DFH) sites, are shown in Figure 411-2-2. 227 '---LANE CREEK AND SLOUGH 8 SLOUGH 6A AND SLOUGH CREEK AND SLOUGH Sunshine Cr. 21 20 19 SUNSHINE CREEK AND SIDE CHANNEL t.l.---WH ITEFISH SLOUGH 0 MILES 10 Figure 411-2-2. Location of Designated Fish Habitat sites on the Susitna River, Goose Creek 2 to Portage Creek. 228 A general description and an aerial photo of each site are contained in Appendix 4-F. A description of the techniques used in measuring the surface area of the sampling zones backed up by the mainstem is contained in Part I, Section 2.1.3.1 of this volume. All of the sampling sites responded hydraulically to changes in mainstem discharge, some more than others. The prevailing hydraulic conditions at each site were evaluated each sampling trip prior to the deployment of any gear. Each site was classified into habitat zones (Table 4II-2-1) using the following criteria: 1) presence or absence of a backed-up area resulting from a hydraulic barrier created by the mainstem at the mouth of the site; 2) slough head breached or unbreached (for slough sites), and 3) source of water (tributary and/or ground water versus mainstem water). Water velocity and turbidity were used to he 1 p determine zone boundaries. In some cases where the gradient was very low, the decrease in surface water velocity at the point where a free-flowing stream or s 1 ough started to respond to the effect of a backed-up area was imperceptible to the observer. At those sites, a series of mean column water velocities was taken and a zone boundary drawn where the velocity of the backed-up area was at least 0.2 ft/sec less than the velocity of the free-flowing area. The extent of mainstem backwater zones was determined by surface water velocity, by locating a 11 COntrol 11 (a riffle area above the backwater zone), and by considering whether or not extremely low mainstem discharges could effect the surface area, velocity, or water depth of the area being examined. 229 Water temperature, dissolved oxygen, pH, specific conductance, turbidity and water velocity were collected twice a month from each DFH sampling site, for each zone where fish distribution data was collected. One to three measurements of each parameter were made in each zone in that part of the zone which was actually sampled by the fishing gear and the average reading recorded. Fluorescein dye was used initially in minnow traps to determine the location of the scent plume from the minnow trap. Measurements recorded were representative of the part of the zone which was sampled by the fish collection gear; they are not necessarily representative of the entire zone, although in most cases there is little difference. Field observations on the dominant substrate type and amount and quality of cover in each zone were also recorded. The equipment and techniques used to measure the different habitat parameters are described in Part I of this volume (Section 2.2) and in the Procedures Manual (ADF&G 1982a). Staff gages were installed at most of the DFH sites so that water surface elevations could be obtained for each zone. The methods are described in Part I of this volume (Section 2.1.1). Staff gages were read twice a month concurrently with the collection of biological and habitat data. The habitat zones (Table 4II-2-1) were aggregated in various ways to aid in analysis of the data. Aggregate zones using hydraulic conditions as a criterion are as follows. 230 Aggregate Zone H-I H-II H-I II Habitat Zones Included 1, 4, 5, 9 2, 6, 7, 8 3 Definition not backed up by mainstem backed up by mainstem mainstem Zone 9, a pool created by morphological features, can occur within a zone 1, zone 4, or zone 5, so these three zones, which normally have medium to high water flow, may include slackwater areas. The criterion is that the slackwater areas in aggregate zone H-I are not caused by mainstem backup. Aggregate zones using water source as the criterion are as follows. Aggregate Habitat Zone Zones Included Definition W-I 1' 2 tributary water and/or ground water only W-I I 4, 6, 8, mainstem water only sometimes 3 W-III 5' 7' mixed water sources sometimes 3 The zones can also be aggregated using the open/closed status of the s 1 ough head as a criterion. The presence of any one of the numeri ca 1 zones 4, 5, 6, or 7, indicates that the slough head is open. If none of these zones are present, the slough head is closed. In this case, for 231 those sloughs that are associated with a tributary, the zone 1 and zone 2 extend into the slough channel. 2.3 Resident Fish Habitat Investigations 2.3.1 Mainstem 2.3.1.1 Radio Telemetry Studies From October 5 through October 14, 1981, five burbot and five rainbow trout captured in the Susitna River between RM 76.3 and 84.7 were tagged with surgically implanted radio transmitters to determine: 1) the movement and/or migrational patterns of these species, and 2) the location and characteristics of overwintering habitats utilized by these species. These fish were tracked using aerial, boat and snowmachine surveys from the dates of implantation and release until transmitter failure occurred or until early April 1982. Preliminary evaluations of the overwintering habitats of these fish were attempted. These evaluations included measurement of water temperature, pH, specific conductance, dissolved oxygen, substrate, and water depth and velocity at overwintering sites. Findings by species of these studies are presented in Part II, Sections 3.3.1 and 3.3.2. 232 2.3.1.2 Miscellaneous Spawning Fish Conditions associated with habitat utilized by any resident fish observed spawning in the Susitna River basin were recorded during 1982. Habitat conditions assessed included measurement of water temperature, pH, specific conductance, dissolved oxygen, substrate and water depth and velocity at observed spawning sites. 2.3.2 Slough and Tributary Methods used for resident fish studies at Designated Fish Habitat sites, except for the fish collection gear, are the same as the methods out- lined in Section 2.2 of this volume. For the methods of resident fish studies at Selected Fish Habitat sites, refer to Sections 2.1.1 and 2.1.2 of Volume 3. Selected Fish Habitat sites are areas ranging from Cook Inlet to Devil Canyon which were primarily sampled by boat electro- fishing. 233 3. RESULTS 3.1 Adult Anadromous Fish Habitat Investigations 3.1.1 Chum Salmon 3.1.1.1 Mainstem During 1982, mainstem spawning sites were not located for any of the salmon species except chum salmon. Mainstem chum salmon spawning sites were not found downstream of Lane Creek (RM 113.6). Eight mainstem chum salmon spawning sites (Figure 411-3-1), located between Lane Creek (RM 113.6) and Devil Canyon (RM 152.0), were surveyed with respect to habitat; these included: River Mile Site Number Geograehic Code 114.4 1 S28N04W06CAB 128.6 6 S30N03W16BCA 129.8 8 S30N02W09DAB 131.1 7 S30N03W03DAD 136.0 2 S31N02W19AD 137.4 5 S31N02W17DBB 138.9 4 S31N02W09DBD 148.2 3 S32N01W26DCA Planimetric maps, identifying the spawning areas within each of the identified spawning sites, are presented in Appendix Figures 4-F-4 to 234 N w (.)1 MAP AREA I 0 10 MILES ®MAIN STEM SPAWNING SITE IDENTIFICATION NUMBER Figure 411-3-1. Location of the mainstem chum salmon spawning sites on the upper Susitna River: September 4-15, 1982. 4-F-11. Representative chum salmon spawning areas are shown in Plates 411-3-1 and 411-3-2. Water quality data for each spawning site are summarized in Table 411-3-1. Water depth and velocity and substrate composition data for each spawning site are summarized in Table 411-3-2. 3.1.1.2 Slough The analysis of chum salmon spawning in sloughs included: computer modeling, summarization of important spawning habitat variables (Appendix Figures 4-F-12 to 4-F-69), comparison of water quality from surface and ground water sources, and comparison of available water depths and velocities with those utilized for chum salmon redds. Other salmon species are not analyzed due to insufficient data. 3.1.1.2.1 Modelina Water depths and velocities and substrate composition were recorded along transects at various flows at the Chum Channel, Rabideux Slough, and Slough 8A, Slough 9 and Slough 21 study locations (Appendix Figures 4-F-12, 4-F-13, 4-F-24. 4-F-30 and 4-F-59). Cross sections along these transects are in Appendix 4-A. Before the hydraulic and habitat models can be combined, the hydraulic model must be calibrated (Milhous et al. 1981). This task is currently in progress. 236 . I Plate 411-3-1 Chum salmon spawning area on the Susitna River at RM 114.4 (GC S28N04W06CAB): September 9, 1982. Plate 411-3-2 Chum salmon spawning area on the Susitna River at RM 128.6 (GC S30N03Wl6BCA): September 7, 1982. Table 411-3-1. Water quality at chum salmon spawning sites on the Susitna River, September 4-14, 1982. Temeerature (oc) Specific Dissolved Site River Sample Intra-Conductance Oxygen Number Mile Number gravel Water Air (umhos/cm) (mg/1) 1 114.4 1 7.6 10.6 13.4 85 13.4 2 7.6 10.5 14.0 79 14.0 2 136.0 1 5.6 5.8 12.2 79 7.1 2 5.8 6.1 12.2 80 8.0 3 3.7 7.5 12.2 108 10.6 3 148.2 3 a 7.5 13.0 96 9.9 4 138.9 1 3.3 5.1 12.2 58 9.0 5 136.9 1 3.3 7.7 12.2 91 10.4 6 128.6 1 4.5 8.8 12.0 106 12.3 2 4.7 8.8 12.0 104 12.3 3 4.7 9.1 12.0 112 12.1 4 4.7 8.8 12.0 116 11.8 7 131.3 1 5.4 10.2 13.0 74 12.8 2 5.2 10.2 13.0 74 12.8 3 4.2 9.5 11.8 92 13.9 4 3.8 8.6 11.8 124 12.9 5 4.1 8.5 11.8 132 12.5 6 7.0 9.3 11.8 33 13.1 8 129.8 1 4.1 7.2 7.6 113 6.4 a Meter malfunction, no reading taken. 239 .P.!:!. 7.5 6.9 7.3 7.6 7.8 8.1 7.1 7.3 7.1 7.4 7.7 7.7 8.7 8.7 7.0 7.9 7.9 8.0 7.4 Table 411-3-2. Water depths, velocities and substrates at chum salmon spawning sites on the Susitna River: September 4-14, 1982. Site River Sample Depth Velocity Number Mile Number (ft) (ft/sec) Substrate Embededness Notes 114.4 0 -4.0a 0 -1.0b 30% silty sand Yes (50%) Turbid water 30% rubble 20% cobble 10% gravel 2 1.5 0 (same as sample 1 ) redd 2 136.0 1 .5 0 25% cobble Yes (80%) redd 20% rubble clearwater 15% gravel 2 0.5 0 25% cobble Yes (80%) redd, 5% gravel clearwater 70% silt 3 0.5 0 (same as sample 2) redd 3 148.2 1 1 .5 0 60% boulder Yes Turbid water 2 2.1 0.2 20% silt 3 1.3 o. 1 10% cobble N 4 1. 9 0 10% rubble +:> 5 2.0 0 0 4 138.9 0 -2.0a 0 -0.2b 30% gravel Yes clearwater 20% cobble 20% rubble 25% silt 5% boulders 5 136.9 0 -2.5a 0 -0.3b 90% silt Yes clearwater 10% boulders 6 128.6 0.7 0 30% gravel Yes redd, 30% cobble clearwater 30% rubble 10% silt 2 0.9 0 30% gravel Yes redd, 30% cobble clearwater 30% rubble 10% silt 3 0.8 0 50% gravel Yes redd, 30% rubble clearwater 20% silty sand a Range of depths in spawning area. b Range of velocities in spawning area. Table 411-3-2 (Continued). Site River Sample Depth Velocity Number Mile Number (ft) (ft/sec) Substrate Embededness Notes 4 0.9 0 50% gravel Yes redd, 20% cobble clearwater 20% boulder 10% silt 7 131.3 0.7 0.2 70% cobble Yes (30%) redd, 10% gravel clearwater 20% silt 2 0.9 0 70% cobble Yes (SO%) redd, 10% gravel clearwater 20% silt 3 0.8 0.2 40% gravel Yes (40%) redd, 30% rubble clearwater 20% sand 10% sand N .j:::. 4 0.9 0 40% gravel Yes (30%) redd, 1---' 30% cobble clearwater 15% rubble 15% sand 5 1 • 1 0 40% gravel Yes (30%) redd, 30% cobble clearwater 15% rubble 15% sand 6 1. 2 0 30% gravel Yes (40%) redd, 30% rubble turbid water 30% cobble 10% sand 8 129.8 1.0-2.Sa 0 -0.2b 40% cobble Yes redd, 40% rubble clearwater 20% silt a Range of depths in spawning area. b Range of velocities in spawning area. 3.1.1.2.2 Habitat Summaries A qualitative description of the general habitat characteristics of the four intensively studied slough (8A, 9, 11 and 21) is presented below. Additional information covering sloughs 11 and 21 can be found in Part I, Section 3.1.1.2.1. Maps including information on the location of sampling sites, substrate composition, upwelling areas, ice-free areas, spawning areas and location of redds were also developed for each study slough (Appendix Figures 4-F-14 to 4-F-69). These maps show relationships of upwelling and substrates to selected spawning sites in each slough. These relationships will be discussed in detail in the 1983 Fisheries and Habitat Relationship Report. Slough 8A Slough 8A is relatively long (1.8 miles) and narrow, possessing two side branches and four major "heads" that provide surface water connections to the mainstem Susitna River during medium and high flows. At periods of low mainstem flow, the upper half of the slough was characterized by very low discharges (less than 5.0 cfs). During these periods, slough water is apparently comprised of surface runoff (from the right bank) and ground water upwelling and seepage. Beaver dams in the lower 0.5 mile section of the slough restricted the majority of chum salmon spawning sites to the area below the dams. Rubble-cobble was the most commonly used substrate for spawning. Only 242 one site of upwelling was observed in this area. Dense concentrations of fish were found immediately below the dams, probably not because of a preference for .this habitat but due to lack of access to upper slough areas. After the high flow period in September 1982, when the beaver dams were overtopped, several salmon were observed spawning in upper slough areas. These fish also appeared to show a preference for rubble-cobble sub- strate. Several spawning sites occurred in areas of upwelling or seepage. Slough 9 Slough 9 is a relatively short (1.2 miles) slough containing two small tributaries along its right bank. Its non-vegetated channel is relatively wide and is maintained by periodic high flows of mainstem water breaching the head. The extent of the backwater zone is highly variable, depending on mainstem stage. In general, it varies from a small, relatively confined pool at very low mainstem discharges to an extensive backwater zone, over 600 feet long, at high mainstem discharges (see also ADF&G 1981c, 1982b, Trihey 1982). During periods when the head is not breached by mainstem water, most of the slough flow is contributed by surface runoff and ground water, with ground water sources apparently being of lesser magnitude. During these times, flows are generally less than 10 cfs. When mainstem discharge at 243 Gold Creek was 12,500 cfs on August 24 (USGS 1982b), flow in Slough 9 was 3 cfs. This posed significant access problems for spawning salmon. Chum salmon spawning areas were found to be on both gravel-rubble and rubble-cobble substrates. However, it should be noted that when spawn- ing areas occurred on gravel-rubble substrates there was extensive seepage and ground water influences also observed in the area. This was the case in the primary chum spawning area for this slough. Salmon spawning activity was limited to the lower half of the slough unti 1 high water on September 15, 1982, a 11 owed access to the upper slough. During that period, salmon were observed as far up as the mouth of Slough 98. Slough 11 Slough 11 is a relatively short slough (approximately 1.0 mile) that is essentially linear in shape and oriented almost parallel to the mainstem Susitna River. Unlike most sloughs, the head of this slough was never breached after spring breakup in 1982. The channel bed is primarily devoid of silt (likely a result of infre- quent breaching) and is arranged in an alternate pool/riffle sequence. Because it has no obvious tributaries, its flow is comprised almost entirely of ground water. However, since there is little or no silt on the slough bottom, upwelling areas are difficult to observe. 244 High concentrations of salmon were observed spawning in this slough. Chum sqlmon were observed most often on rubble-cobble substrates. Several upwe 11 i ngs were a 1 so observed in these areas. The man-made channel noted in Appendix Figure 4-F-43 was apparently formed by shifting large rocks and dragging a boot heel through loose substrate for about 50 feet in a steep riffle connecting two pools. This 11 Channelized 11 the previously meandering and more dispersed flow so that sockeye salmon, blocked from further upstream movement by low water in the riffle area, were able to swim up a narrow stream of 4-to 6-i nch-deep water. It is unknown who formed this channe 1 and when it was formed. Without this alteration, salmon could not have spawned above the riffle. Refer to Part I, Section 3.1.1.2 for additional information on this slough. Slough 21 Complex In this report, Slough 21 has been defined to include the slough, as described in the Aquatic Habitat and Instream Flow Phase I Final Draft (ADF&G 1981c), and the extended access channel oriented parallel to the mainstem Susitna River (see Appendix Figure 4-F-63). During periods in 1982 when the head of Slough 21 was not breached, the relatively small discharge in the slough was primarily composed of water from a single small tributary (entering the right fork) and from ground water. Ground water appeared to originate from localized seepages and upwellings along both banks below the mouth up to the fork (Plates 4II-3-3 and 4II-3-4). 245 Plate 411-3-3 Seepage of ground water sources into Slough 21. Plate 4II-3-4 Upwelling ground water in silted area of Slough 21. Prior to the high water period on September 15, 1982, salmon spawning in the slough complex was limited to the channel immediately below the mouth of the slough. Observations of spawning fish were difficult in much of the Slough 21 access channel due to the presence turbid water. Chum salmon were the most abundant species observed spawning at this site. Most of the redds were located in rubble-cobble substrates. Extensive upwelling and seepage were also observed in these areas. After high flows occurred, chum sa 1 mon were observed to have moved to locations above the mouth. Several chum salmon redds were observed in areas of silt-sand substrate where upwelling occurred. Refer to Part I, Section 3.1.1.2 for additional information on this slough. 3.1.1.2.3 Water Quality Data collected to describe the general water quality characteristics of the sloughs are presented in Part I, Section 3.2. One important use of water quality data is to trace water sources in sloughs. Two water quality parameters useful in this respect are intragravel water temperature and specific conductance. Water Temperature Intragravel water temperatures were obtained along study transects. These data provided a basis for comparison to data collected at 248 specified locations including salmon redds. In addition, these data provided a means of evaluating variability in intragravel water temperatures within transects of a particular slough and between study sites (data pooled for all transects within a study site) of different sloughs. These data (at study transects as well as at specific locations) are intended to supplement the continuous thermograph data (Appendix 4-C) by providing a more detailed description of variability in intragravel temperatures in sloughs during October 1982. This period was selected because mainstem flows and flows in sloughs were very low, allowing sources of ground water to be more easily observed. A summary of mean intragravel temperatures collected at transects within study sloughs 8A, 9, 21 and at specified locations within sloughs 9B and 11 are presented in Table 411-3-3. Surface water temperatures in early October (Table 411-3-4) were generally very cold. Mean surface water temperatures for all locations (excluding tributaries and side channels) in sloughs 8A, 9, and 9B ranged between 1.4° and 4.2°C, while surface water temperatures in Slough 11 were generally 1-2°C higher. Surface temperatures were not obtained in Slough 21. Mean temperatures obtained at the substrate/water interface (Table 411-3-5) generally ranged between intragravel and surface water tempera- tures. The degree to which they resembled surface or intragravel temperatures appeared to be a function of depth and/or velocity. Thus substrate/water temperatures could not be used as reliable predictors of ground water upwelling. 249 Table 411-3-3. Data summary of intragravel temperatures obtained at 1982 ADF&G study transects (sloughs 8A, 9, 21) and specified locations (sloughs 9B and 11) from September 30 to October 5, 1982. Mean Standard SamEle Size Location (x) Deviation Range (n) Slough 8A 3.3 0.92 1.5 -4.7 20 Slough 9 3.0 0.58 1.9 -4.2 17 Slough 21 3.3 0.37 2.9 -4.2 72 Slough 9B 3.8 0.18 3.6 -4.3 16 Slough 11 4.6 0.65 3.7 -5.7 18 250 Table 4II-3-4. Data summary for surface water temperatu.res (°C) at specified locations in sloughs SA, 9, 98, and 11 collected during October 1-5, 19S2 (raw data in Appendix D). Slough Locationa X so Range SA Left fork (mouth) 3.2 3.1-3.4 SA Spawning A 3.0 2.5-3.4 SA Spawning B 2.4 2.1-2.6 SA Spawning C 2.S 2.7-2.9 9 Pool A 3.2 0.59 2.7-3.9 9 Upwelling A 3.1 0.94 l.S-4. 7 9 Transect (1-2)L 3.1 o.os 3.0-3.2 9 .Transects (5-6)L l.S 0.1S 1.5-2.2 9 Transects (5-6)M 1.6 0.00 1.6-1.6 9 Transects (5-6)R 1.4 0.11 1.2-1.5 9 Mid-slough 3.2 9 Tributary B 2.2 9 Tributary s• 2.3 9 Tributary B11 l.S 9 Pool C 2.9 2.4-3.2 98 Mouth 2.5 O.S1 1.5-3.2 98 Mid-slough 2.9 0.25 2.5-3.2 98 Upwelling B 4.2 0.20 3.9-4.4 11 Left bank (LB) 5.3 0.32 4.7-5.6 11 Mid-slough (M) 5.2 0.30 4.7-5.6 11 Right bank (RB) 5.0 0.53 4.2-5.6 11 Upper pool 5.2 0.11 5.0-5.3 a Sampling locations in sloughs SA and 9 are diagrammed in Appendix Figures 4-F-2, 4-F-3, and 4-F-29. 251 N 2 2 3 3 6 10 6 10 10 10 1 1 1 1 4 5 5 7 6 6 6 5 Table 411-3-5. Data summary for substrate/water interface temperatures (°C) collected at specified locations in sloughs 8A, 9, 98, 11 and 21 during October 1-5, 1982 (raw data in Appendix D). Slough Locationa X -so Range N 8A Transects {1-11)L 3.3 0.56 2.4-4.2 11 8A Transects {1-11 )M 2.6 0.37 2.1-3.4 11 8A Transects {1-11)R 3.0 0.21 2.7-3.3 11 8A Pool (L,M,R) 4.2 4.1-4.4 3 8A Channel (L,M,R) 2.4 2.2-2.6 3 9 Transect {1-2)L 3.0 0.20 2.6-3.2 6 9 Transect {1-2)L I 3.5 0.36 2.9-3.9 6 98 Mouth 3.8 0.20 3.6-4.0 5 98 Mid-slough 3.9 0.32 3.6-4.4 5 98 Upwelling 8 3.8 0.12 3.7-4.0 6 11 Left bank (L8) 4.9 0.79 3.8-5.8 6 11 Mid-slough (M) 4.7 0.50 4.2-5.5 6 11 Right bank (R) 5.0 0.64 4.1-5.6 6 11 Upper pool 4.4 0.11 4.2-4.5 5 a Sampling locations in sloughs 8A and 9 are diagrammed in Appendix Figures 4-F-1 and 4-F-3. 252 In general, sloughs 8A and 9 exhibited the widest ranges in mean intra- gravel temperatures (Table 4II-3-6). Means within sloughs 98, 11 and 21 ranged less than 1°C (0.2, 0.7 and 0.3°C, respectively). In Slough 8A, intragravel water temperatures from the Spawning 8 1 ocation were 1 owest, probably reflecting surface water temperatures. This spawning area had more rapidly flowing water than either of the other locations, and water may have inundated the substrate to a greater degree. In Slough 9, mean intragravel water temperatures were also quite vari- able between locations. Pool A and Upwelling A temperatures were approximately 1 oc warmer than either of Transects (l-2)L or Transects (1-2)L' with the warmest and coldest mean intragravel water temperatures at Pool A and Transects (l-2)L, respectively. Intragravel water tem- perature at Slough 98 were very uniform. Mean temperatures at three locations (Table 4II-3-6) were within 0.2°C. Since all values at Upwelling 8 were obtained in upwelling vents, the uniformity in temperatures (and standard deviations) suggests that upwelling may be occurring in the other areas as well. However, this conclusion does not correspond with observations made at the mid-slough location. Although this area was overlain with several inches of silt, no obvious upwelling vents were observed. More data would be required to determine whether or not upwelling was present at other areas in Slough 9B. 253 Table 4II-3-6. Data summary for intragravel temperatures (°C) collected at specified locations in sloughs 8A, 98, 11 and 21 during October 1-5, 1982 (raw data in Appendix D). Slough Locationa X so Range N 8A Spawning A 4.0 3.9-4.1 2 8A Spawning B 2.6 2.1-3.1 3 8A Spawning C 4.6 4.4-4.9 3 9 Pool A 4.2 0.33 3.8-4.6 6 9 Upwelling A 4.0 0.32 3.6-4.7 10 9 Transects (1-2)L 2.8 0.24 2.7-3.2 9 Transects (1-2)L I 3.1 0.32 2.8-3.6 9B Mouth 3.7 0.19 3.4-3.9 9B ~1i d-s 1 ough 3.9 0.27 3.6-4.3 9B Upwelling B 3.8 0.14 3.6-4.0 11 Left bank (LB) 4.8 0.87 3.7-5.9 11 Left bank (M) 4.7 0.50 4.2-5.5 11 Left bank (RB) 5.0 0.64 4.3-5.6 11 Upper pool 4.3 0.10 4.2-4.4 21 Transects (4-5)L 3.4 0.15 3.3-3.6 21 Transects (4-5)R 3.1 0.05 3.0-3.1 a Sampling locations in sloughs 8A and 9 are diagrammed in Appendix Figures 4-F-2, 4-F-3, and 4-F-29. 254 6 6 5 5 7 6 6 6 5 6 6 Mean intragravel water temperatures in Slough 11 were generally warmer than those in other sloughs (Table. 4II-3-6). Mean surface water temperatures were typically lower than mean intragravel water tempera- tures in all sloughs except Slough 11. Specific Conductance Specific conductance is another indicator of the sources of water (tributaries or prominent seepage) in sloughs. The contribution of different water sources to water quality in sloughs 8A and 9 was evaluated by measuring specific conductance at several locations, including locations downstream of tributary confluences. Surface Water Sources In Slough 8A values of specific conductance varied in a consistent pattern (Table 4II-3-7). The mean value for the left side of the channel [Transects (1-11)L] was highest, the mid-channel [Transects (1-ll)M] mean was intermediate and the right side [Transects (1-ll)R] mean was lowest. Specific conductance along the right side was probably due to surface water draining from beaver ponds along the bank (values as low as 44 umhos/cm occurred in this area). It is likely that water from a side channel entering the left side of the slough immediately above the spawning location elevated the specific conductance in downstream locations. 255 Table 411-3-7. Data summary for specific conductance (umhos/cm), collected at specified locations in sloughs 8A and 9 during October 3~5, 1982 (raw data in Appendix D). Slough Locationa X -so Range N 8A Transects (1-11)L 118 16.60 98-147 11 8A Transects ( 1-11 )M 89 6. 71 84-108 11 8A Transects (1-11)R 74 16.16 44-90 11 8A Pool (L,M,R) 139 132-152 3 8A Channel (L,M,R) 86 84-88 3 8A Left fork (mouth) 166 115-218 2 8A Spawning A 128 123-133 2 8A Spawning B 111 110-112 3 8A Spawning c 114 111-117 3 9 Pool A 215 17.77 194-233 6 9 Transect (1-2)L 115 2.58 111-118 6 9 Transect (1-2)L 1 102 3.58 98-108 6 9 Transect (5-6)L 132 6.29 121-140 10 9 Transects (5-6)M 92 3.92 89-102 10 9 Transects (5-6)R 89 1.10 87-90 10 9 Transects (6-10)L 132 5.79 122-142 8 9 Mid-slough 153 1 9 Tributary B 70 1 9 Tributary B • 69 1 256 Table 4II-3-7 (Continued). Slough Locationa X so Range 9 Tributary B11 39 9 Pool C 125 119-137 9 Transects (81-85) 94 9.73 78-103 9 Transects (A1-A5) 104 28.01 72-149 9 Transects (C1-C5) 72 4.'82 65-76 9 Transects (C1'-C5') 82 3.42 78-87 a Sampling locations in slough 8A and 9 are diagrammed in Appendix Figures 4-F-1, 4-F-2, 4-F-3 and 4-F-29. 257 N 1 4 5 5 5 5 A similar pattern occurred in Slough 9. Low specific conductance found on the right side of the slough was undoubtedly the effect of a plume extending downstream from the confluence of the Tributary B, s•, 8 11 complex (Table 4II-3-7). Specific conductance immediately above the tributary complex (153 umhos/cm) was higher than the left, mid, or right bank specific conductance between Transects 5 and 6. These data indicate that tributary water remained partially unmixed as far downstream as Transect 5 and resulted in a downstream reduction in specific conductance values. Surface water from the tributary was also evidenced along two parallel transects located below Tributary A. Specific conductance values along the right bank Transects (Cl-C5) were lower than those in the slough ~hannel, suggesting a 11 plume effect•• due to water entering from Tributary A (values in Tributary A were not obtained). Ground Water Sources In Slough 9 relatively high specific conductance was detected in Pool A, Transects (1-2)L and Pool C. Specific conductance in Pool A was the highest encountered. Water was apparently originating from seepage - through a dry channel bed connecting the slough with the mainstem Susitna River. At Transects {1-2)L the specific conductance along the bank was significantly higher (Mann-Whitney U test, P=0.05) than along a parallel transect, six feet into the slough channel. 258 3.1.1.2.4 Available and Utilized Habitats To quantify available and utilized spawning habitats, water depths and velocities were sampled across selected hydraulic features (including riffles, runs and pools) of Chum Channel, Rabideux Slough and sloughs 8A, 9 and 21 (Figures 41 I-3-2 to 41 I-3-6 and Appendix 4-B). At 1 ow discharges, transects with a narrow range of depths and wide range of velocities indicate presence of a riffle while transects with a wide range of depths and a narrow range of velocities indicate presence of a pool. At higher discharges this relationship becomes obscured because the ranges of depths and velocities can both be wide. The range and weighted mean of depth and velocity for low discharge in sloughs 8A, 9 and 21 (Figures 4II-3-4 to 411-3-6) were compared with the ranges and means of the depths and ve 1 ociti es at chum sa 1 mon redds during low flows (3 to 8 cfs) in August and September (Figure 4II-3-7 and Appendix 4-B). The means of available and utilized water depths and velocities were approximately the same. However, chum salmon redds (N = 118) were located in the shallower depths, less than 2.6 feet. More samples will be required to identify water depth and velocity at redds during higher discharges. Insufficient data are available to indicate similar patterns for sockeye and pink salmon which also spawn in these sloughs (Appendix Table 4-B-19). Because chum salmon are the primary spawners in side slough habitats above Talkeetna, most intragravel temperatures were obtained at chum salmon redds. Temperatures at pink salmon redds were only collected at 259 CHUM CHANNEL Q =0.4 cfs AUG.29, 1982 Q = 7 cfs AUG. II, 1982 Q= 90 cfs SEPT.I4,1982 Figure 4!!-3-2. Depth 5 4 ....,3 <U <U -2 0 t t + I • 1 2 345678 Transect Depth 5 4 _3 <U Q) -2 j 1 t t 0 • ' t t • 1 2 3 4 5 6 7 8 Transect Depth 5 4 -3 Q) Q) -2 0 1 t t t t t 1 2 3 4 5 6 7 8 Transect 1-8 1-8 1-8 4 ~ 3 "' , .. ::: 2 4 <..> 3 a> "' ' 2 -- 0 4 (.) 3 Q) (II" ' 2 -- 0 Velocity 1 2 3 4' 5 6 7 8 1-6 Transect Velocity 1 2 3 4 5 6 7 8 1-8 Transect Velocity t 1 2 345678 1-8 Transect Water depths and velocities (mean and range) of Chum Channel transects at three discharges in 1982. 260 RABIDEUX SLOUGH Q =0.3 cfs AUG. 10, 1982 Q= 281 cfs SEPT. 17, 1982 Figure 4II-3-3. 9 a 7 6 5 -Cl> ~4 -Cl> 3 2 0 9 a 7 6 5 ~4 3 2 Depth I t t + 1 • 0 1 2 3 4-5 6 7 0-7 Transect Depth I 0 1 2 3 4 5 a-7 0-7 Transect 4 ~ 3 t/)_ ....... -2 .... 0 4- ~ 3 "' ~ 2· .... 1· Velocity 0 t 2 3 4 5 6 7 0-7 Tronse'}t Velocity I I l 0 1 2 3 4 5 6 7 0-7 Transect Water depths and velocities (mean and-range) of Rabideux Slough transects at two discharges in 1982. 261 SLOUGH SA e 5 4 -Q=4cfs Q) AUG. 22,1982 .! 3 "'2 0 e 5 4 Q= 7 cfs Q; Q) 3 SEPT. 7, 1982 2 0 e 5 4 Q= 20 cfs : 3 SEPT. 19,1982 2 0 Figure 4II-3-4. Depth t t t 1 2 3 4 5 e 1 e 9 10 11 Transect Depth \I \ I 1 2 3 4 5 e 7 8 9 1011 Transect Depth j l d t~lltl 1 2 3 4 5 8 7 8 9 10 11 Transect 1-11 ~ 3 "' = 2 1-11 4 0 3 Q) "' ::: 2 - 0 1-11 Velocity 1 2 3 4 5 e 1 8 9 10 11 1-11 Transect Ve I ocity 1 2 3 4 5 e 1 8 e 10 11 1-11 Transect Velocity 1 2 3 4 5 8 7 8 9 10 11 1-11 Transect Water depths and velocities (mean and range) of Slough SA transects at three discharges in 1982. 262 SLOUGH 9 Q = 3 cfs AUG. 25, 1982 Q = 8 cfs SEPT. 4 , 1982 Figure 4II-3-5. 5 Depth Velocity 4 4 -: 3 u 3 .... Cl) . I t \ ... 2 ...... 2 -.... 0 0 1 2 4 8 7 8 9 10 1-10 1 2 4 6 1 a 9 10 Transect Transect 8 Depth Velocity 4 .. -; 3 3 Cll \ t \ l u .... Cl) 2 <h 2 ...... -.... 0 t t 0 1 2 4 6 1 a a 10 1-10 1 2 4 e 1 a s 10 Transect Transect Water depths and velocities (mean and range) of Slough 9 transects at four discharges in 1982. 263 1-10 1-10 SLOUGH 9 Depth 5 .. 3 Q = 145 cfs -Q) SEPT. 20, 1982 Q) -2 1 0 1 2 .. 8 7 8 9 10 Transect Depth 5 .. -3 Q = 232 cfs Q) SEPT. 18, 1982 Q) Ill 1 - 2 1. 0 T 1 2 .. 8 7 8 9 10 Transect Figure 4!!-3-5 (Continued). 264 u Q) ... ...... -- 1-10 u Q) U) ...... -- 1-10 ... 3 2 0 .. 3 2 1 0 Velocity t 1 2 .. 8 7 8 9 10 1-10 ·Transect Velocity t l 1 2 .. 8 7 8 9 10 1-10 Transect SLOUGH 21 Q = 5 cfs SEPT. 2,1982 Q=IO cfs SEPT. 19,1982 0= 157 cfs SEPT. 17, 1982 Figure 4II-3-6. Depth Velocity 5 4 4 -; 3 ~ 3 CD "' 2 ~ \, l ~2 t - t t 0 I 2345678 1-8 I 2 3 4 5 6 1 8 Transect Transect Deeth Velocit~ 5 4 4 ; 3 u 3 CD CD (}) 2 ::::2 0 0 I 2 3 4 5 6 7 8 1-8 I 2 3 4 5 6 1 8 Transect Transect Depth Velocity 5 4 4 - 3 .:.,3 Q) l l CD I CD fff (}) ._ 2 '-2 = t t ("\ 0 I 2 3 4 5 6 7 1-7 I 2 3 4 5 6 7 Transect Transect Water depths and velocities (mean and range) of Slough 21 transects at three discharges in 1982. 265 1-8 l 1-8 1-7 SLOUGH 8A Q1 =4 cfs AUG.22,1982 Q2 =7 cfs SEPT. 7,1982 SLOUGH 9 Q1 =3 cfs AUG.25,1982 Q2 =8cfs SEPT. 4,1982 SLOUGH 21 a 2 = 5 cfs Sept.2, 1982 Depth 5 "' -3 Q) Q) -2 f 1 t 0 A U A U Q1 Q2 Depth 5 4 -3 Q) Q) I -2 j 0 A U A U Q1 Q2 Depth 5 ~ : II 0"'----+-....--- "' u 3 Q) en ....... 2 --1 0 "' t) 3 Q) ~ 2 --1 0 u 3 Q) en ........ 2 --1 Velocity ~ \ A U A U Q1 Q2 Velocity A U A U Q1 02 Velocity Figure 4!1-3-7. Water depths and velocities (mean and range) available (A) and utilized (U) for chum salmon redds in three sloughs during August 25-26 (Ql) and September 2-7 (Q2), 1982. 266 two redds in Slough 9 and data collected at sockeye salmon redds were primarily limited to Slough 11. Intragravel temperatures collected at chum salmon redds in sloughs 8A, 9, 11, and 21 (N = 94) ranged from 3.1-11.4°C, with most temperatures between 4.0 and 4.9°C (Appendix Tables 4-C-50 to 4-C-53). 3.1.2.2.5 General Slough Water qua 1 ity data for Whiskers Creek Slough, Slough 6A, Lane Creek Slough, sloughs 9A, 10, 168, 19, 20 and 22 are found in Appendix 4-D. Maps including information on the location of sampling sites, distribu- tion of substrates, upwelling areas, and ice-free areas are presented in Appendix 4-F. These maps will be discussed in detail in the 1983 Fishery and Habitat Relationships Report. 3.1.2 Sockeye Salmon Limited numbers of sockeye salmon were observed spawning in the specific study sloughs. In Slough 11 (Appendix Figures 4-F-44, 4-F-45, 4-F-47, and 4-F-48) sockeye salmon were observed most often on gravel-rubble substrates in areas of suspected or known ground water seepage. It should be noted that access to the upper slough area was facilitated by a man-made channel in this slough, as discussed in Part II, Section 3.1.1.2.2 (see also Appendix Figure 4-F-47). Prior to high flows, sockeye salmon redds in Slough 21 were found among chum redds in rubble-cobble substrates, below the mouth of the slough. After high flows, they were also located on silt-sand substrates in areas above the mouth where upwelling occurred. 267 3.1.3 Pink Salmon Limited numbers of pink salmon were observed spawning in sloughs 9, 11 and 21 (Appendix 4-F). Gravel-rubb 1 e substrates were most commonly chosen. In Slough 9, both areas where pink salmon spawning occurred contained upwelling. Upwellings also were present in several areas where pink salmon were found in Slough 11. 3.1.4 Coho Salmon Slough 8A is the only specific study slough where coho salmon were observed spawning. Most of the spawning activity occurred in areas where rubble-cobble substrate and ground water seepage were present (Appendix Figures 4-F-25, 4-F-26, 4-F-28, 4-F-29). 3.1.5 Chinook Salmon Adult chinook salmon spawning occurred exclusively in tributaries and thus were not addressed in this study. 268 3.1.6 Eulachon Twenty sites (Figure 411-3-8) were surveyed for eulachon spawning habitat. These include: River Mile Site Number Geographic Code 8.5 18 S14N07W22ACA 11.0 19 S15N07W10DCC 15.0 14 S16N07W35BDD 16.5 8 S16N07W22DCD 18.2 7 S16N07W15CDB 18.3 20 S16N07W15CDB 21.4 6 S16N07W04CAC 22.8 16 S16N07W04BBA 25.5 4 S17N02W22CAA 25.8 5 S17N07W22DCD 25.9 2 S17W07W22DDA 26.0 1 S17N07W22DAA 26.3 3 S17N07W23CAB 28.0 11 S17N07W13DBB 31.1 12 S17N06W18BAA 31.8 13 S17N06W05ABA 35.5 15 S18N06W15CCC 41.3 10 S19N06W25CCD 43.3 17 S19N06W24ACC 44.0 9 S19N05W20CAC 269 INLET @SPAWNING SITE IDENTIFICATION NUMBER Figure 4!!-3-8. Eulachon spawning sites surveyed for habitat characteristics on the Susitna River: May 24 - June 7, 1982. 270 Planimetric maps wer_e developed to show spawning areas at each of the above spawning sites (Appendix Figures 4-F-70 to 4-F-89). Measurements of water quality, mean spawning depths, mean spawning velocities and substrates taken at each site are tabulated and presented in Table 411-3-8 and Figures 411-3-9 and 411-3-10. Water quality measurements were taken at 12 other sites where it could not be determined whether eulachon were milling, migrating or spawning, using criteria outlined in the methods section. These sites include: River Mile Site Number Geograehic Code 5.0 Misc. 4 S14NOYW05DDB 5.0 Misc. 5 S14N07W05DDB 5.5 Misc. 6 S14N07W05ADB 16.5 Misc. 7 S16N07W22DCD 19.5 Misc. 1 S16N07W09DDD 24.8 Misc. 8 S17N07W28ADD 36.7 Misc. 9 S18N06W15BDB 41.1 Misc. 2 42.7 Misc. 10 S19N06W25AAB 47.0 Misc. 3 49.0 Misc. 11 S20N05W34CCD 49.2 Misc. 12 S20N05W34BDD Water quality measurements obtained at these sites are tabulated and summarized in Table 411-3-9. 271 Table 411-3-8. Eulachon spawning site evaluations on the Susitna River: May 24-June 7, 1982. Dissolved Mean S~awnin9 Water Conductance Oxygen Depth Standardelocity Standard Site Date Tern~ (°C) .e.':! (umhos/cm) (m!:j/1) (ft) Deviation (ft/sec) Deviation Substrate 820531 8.5 7.1 96 11. 1 1. 4 0.5 a 1. 5 0.3 Silty sand (n=15) interspersed with 10% gravel. 2 820531 9.3 6.7 73 10.8 1. 9 0.5 1.1 0.6 Silty sand inter- (n=18)a spersed with 20% gravel and cobble. 3 820531 8.8 7.1 66 10.9 2.1 0.4 0.8 0.3 Silty sand inter- (n=16)a spersed with 10% gravel. 4 820531 11. 1 7.1 95 1 o. 3 3.1 0.8 0.8 0.3 Silty sand with (n-10)a 30-50% gravel and cobble present. N 10. 1. 8 30% silty sand -.....1 5 820601 9.3 7,0 72 1 o. 7 2.7 0.5 N (n=12)a 30% gravel 30% rubble 10% cobble 6 820601 10.2 6.7 72 8.2 2.2 0.7 1.3 0.4 Silty sand (n=24)a i nte rmi xed with 40% gravel and 20% rubble. 7 820601 11.2 6.8 100 7.5 1. 8 0.7 1.2 0.7 Silty sand mixed (n=33)a with 40% gravel and 20% rubble. 8 820601 11.2 6.7 102 6.4 1. 2 0.4 (n=16)a 1. 9 0.4 100% silt 9 820603 8.3 7.5 41 12.4 1. 9 0.5 1.7 0.5 Silty sand (n=27)a interspersed with 30% rubble. 10 820604 8.3 7.1 46 10.8 2.0 0.6 (n=16)a 0.7 0.5 100% silt 11 820605 7.9 7.2 63 11.0 1. 9 0.8 (n=24)a 0.7 0.5 100% silt a Sample size. Table 411-3-8 (Continued). Dissolved Mean S~awning Water Conductance Oxygen Depth Standard elocity Standard Site Date Tem2 (°C) £!:! (umhos/cm) (mg/1) (ft) Deviation (ft/sec) Deviation Substrate 12 820605 7.9 7.2 64 11.5 1 • 1 0.5 1.4 0.9 50% gravel (n=18)a 30% rubble 10% cobble 10% silt 13 820605 8.2 7.2 67 10.6 1. 9 0.6 (n=14)a 0.9 0.4 100% silt 14 820606 7.6 7.1 69 10.2 1.2 0.6 a 1.6 0.8 30% silty sand (n=29) 50% gravel 20% cobble 15 820607 7.1 7.0 51 12.3 1. 7 0.6 1. 8 0.8 30% gravel (n=21)a 40% rubble 20% cobble N 10% silty sand -....! w 16 820530 6.3 7.0 64 12.2 1. 9 0.8 0.9 0.6 Sand intermixed (n=17)a with 20% gravel. 17 820524 (hydrolab malfunction) 1.7 0.9 0.7 0.3 Sand intermixed (n=10)a with 10% silt and gravel. 18 820526 6.2 6.6 70 11.9 1. 8 0.8 0.9 0.5 Sand inter- (n=6)a spersed with 5% gravel. 19 820526 6.3 6.3 71 11.3 2.3 0.5 0.6 0.2 Sand inter- (n=6)a spersed with 10% gravel. 20 820526 6.9 6.8 82 10.9 2.0 1.0 0.9 0.5 80% gravel (n=3)a i nte rmi xed with 70% sand. a Sample size. 12 (.) 0 10 UJ 0:: :::> 1-8 <( 0:: UJ a. :::!: 6 UJ 1- 0:: UJ 4 1- <( 3 2 0 erzo 0 -..... 0 .c EIOO ..:! UJ (.) z <( 1- (.) :::> 0 z 0 (.) u 40 ;:;:: 0 UJ 20 a. (/) 0 • • • • • • • • mean • • • • • • • • c .2 -() c :I !:: 0 e ... Gl -Gl e I 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 17 18 19 20 10 8 6 a. 4 c .2 -0 c :I -0 e I 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 17 18 19 20 14-r-120 • • • • • • mean • • • • • • • c .2 • -• () c :I -0 e ... .! .. e 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 17 18 19 20 SITE NUMBER 12 ~10 e % ~a- >-X 0 6- 0 UJ > c5 4 (/) (/) 0 2- 0 • 0 • • • • • • 1--...::•:.._• __ ...:•:_ ___ --tlr•---....:•:__.,_-;;-mean ----t Ll 6 6 ~-~--6~6~-~--6~-mean--~6~6~-6-~A--------~-~6-n~ 6 Ll • 6 • 6 • 6 e DISSOLVED OXYGEN (mg/1) 6 DISSOLVED OXYGEN SATURATION (%) I ~ ~ 4 5 6 ~ J 9 1 1 0 11 12 13 14 SITE NUMBER 15 ~ I 16 c 0 .... 0 c :I -0 e ... Gl .... Q) E I 17 18 19 20 Figure 4II-3-9. Surface water temperature, pH, specific conductance and dissolved oxygen at 20 eulachon spawning areas on the Susitna River: May 24-June 7, 1982. 110 cf!. z 100~ ~ a:: 80 :::> ~ Ul 60 z UJ (!) >-X 40 0 0 UJ ::J 20 0 Ul Ul 0 0 5 -4 - :t: 1- 0... 3 w 0 a:: w 2 1-<t ~ t,) Q) Ul 5- :::-4-- >- t: 3- (.) g w > ·z.- a:: w ~ 1- 3 t 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 17 18 19 20 SAMPLING SITE IDENTIFICATION NUMBER t t t r 1 l t If f oL-~.~--~--~--.-I--,1--~I--~---,I,--,I----~--r-l--r-1--,-1--ll---,l--~lr-~r---r-.--r-,--.-.-l l 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 17 18 19 20 SAMPLING SITE IDENTIFICATION NUMBER Figure 411-3-10. Water depths and velocities (mean and range) at 20 eulachon spawning sites on the Susitna River: May 24-June 7, 1982. Table 411-3-9. Miscellaneous eulachon spawning site habitat evaluations on the Susitna River: May 16-June 12, 1982. Specific River Water Conductance Dissolved Site Mile Date Teme (°C) E!:! (umhos/cm) Ox;tgen (mg/1) Notes Misc. 19.5 820601 10.0 6.7 72 7.9 Misc. 2 41.1 820603 6.8 7.2 40 10.4 I Misc. 3 47.0 820602 9.2 7.2 61 11.5 Misc. 4 5.0 820605 8.7 7.1 77 9.5 West Bank gi 11 net site Misc. 5 5.0 820538 6.1 6.8 78 11.9 West Bank gi 11 net site Misc. 6 5.5 820528 6.3 6.8 73 12.0 East Bank gi 11 net site Misc. 7 16.5 820528 6.8 6.9 81 11.3 Spawning site #8 N Misc. 8 24.8 820530 6.1 6.9 70 12.0 "-... CJ) Misc. 9 36.7 820529 6.4 6.8 66 12.0 Misc. 10 42.7 820529 6.1 6.9 65 12.2 Misc. 11 49.0 820529 6.1 6.8 65 12.1 Misc. 12 49.2 820529 5.0 6.9 46 12.0 Mouth of Willow Creek To carrel ate the water--temperature a'ssoci a ted with the movement patterns and timing of spawning of eulachon, surface water temperature was continuously collected for the Susitna River at Susitna Station (RM 25.5). These data were converted into daily means calculated as the mean of 12, 2-hour, point temperature readings and graphed and presented in Figure 411-3-11. These water temperature data were also plotted with provisional discharge data (USGS 1982b) for the Susitna River at Susitna Station (RM 25.5) and catch per unit effort (catch per minute per net) ca 1 cul a ted for the gi 11 net sets at high tide May 17 through June 9, 1982. These data are presented in Figure 411-3-12. 3.1.7 Bering Cisco A total of 730 Bering cisco were sampled by fishwheel (212/730, 29 percent) and electroshocking gear (518/730, 71 percent) from August 7 to freeze-up on October 15 (Volume 2). Only one site was determined to have spawning Bering cisco. This site, located along a gravel bar in the mainstem channel of the Susitna River opposite Montana Creek (Appendix Figures 4-F-90 and 4-F-91; RM 76.8-77.6), was also a documented spawning site during the 1981 Bering cisco study (ADF&G 1982b). Fish were present at the site beginning in early September although none were in spawning condition until October 13, 1982. It is not known whether the fish present in early September were migrating through the site, milling or preparing to spawn at the site, because tagging studies were not initiated in 1982. Based on 1981 preliminary studies which included a limited tagging effort, however, it appears as 277 w a:: :::> 6 ~ a:: 4 w a.. :E 2 w 18 19 20 21 22 23 24 25 MAY ~ 0~---.-----.----.-----.------.-----.-----.------.-----~- -to u 0 -8 w a:: :::> 6 ~ ~ 4 w a.. :E 2 w 26 27 28 29 30 MAY 31 2 JUNE 3 ~ 0~---.----~------.-----~----~----r-----~----~ 4 5 Figure 411-3-11. 6 7 8 9 10 II JUNE Water temperatures for the Susitna River at Susitna Station (RM 25.5): May 16-June 10, 1982. 278 N -......! \..0 140 CPUE~ 130 9 18 TEMPERATURE -----DISCHARGE o-o 120 8 16 110 7 +- II> Cll 't 100 t) 6 ~12 0 N 0 w (.!) 0::: <( J: t) (/) 0 Q) -w ::J 0::: .!: 90 ::> 5 1- <( .c: 0::: (.) w -0 80 a. 4 ~8 ::!!: ~ Ill w 1-::> a. 70 3 t)6 60 50 A/ J 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 2 3 4 5 MAY 1982 JUNE Figure 411-3-12. Provisional discharge (USGS l982b) and daily mean water temperatures for the Susitna River at Susitna Station (RM 25.5) compared with CPUE (catch/minute/net) for the gill net set at RM 5.0: May 17 -June 10, 1982. though a portion of the fish which arrive early at a site remain and spawn at a latter date when river conditions facilitate spawning. The site located at RM 76.8-77.6 was surveyed for spawning habitat (Table 4II-3-10) utilizing procedures described in the methods section. Water temperatures and discharge data of the mainstem Susitna River at time of spawning for the 1981 and 1982 Bering cisco spawning sites are also compared (Table 4II-3-11). Another catch site, 1 ocated at RM 81.2, was suspected to have Bering cisco spawning; however, spawning could not be confirmed. No habitat surveys were performed at this catch site. To compare surface water temperatures associated with the movement patterns and timing of spawning of Bering cisco, surface water temperature was continuously collected for the Susitna River at Sunshine (Parks Highway Bridge, RM 84.0). This data was converted into daily means calculated from 12, 2-hour, point temperature readings. Daily mean water temperatures and provisional discharge data (USGS 1982b) for the Susitna River at Sunshine (RM 84.0) are plotted with fishwheel catch per day at Sunshine for the period September 1-30, 1982 (Figure 4II-3-13). A similar graph of 1981 Bering cisco data (ADF&G 1982b) is included for comparison (Figure 4II-3-14). 280 Table 411-3-10. Bering cisco spawning site habitat evaluations for RM 76.8 -77.6 on the Susitna River: October 14, 1982. Dissolved Mean S~awnin9 River Water Conductance Oxygen Depth Standard elocity Standard Site Mile Teme (°C) E!:! (umhos/cm) l.!!!.9ill (ft) Deviation (ft/sec) Deviation Substrate Upper 1. 80a Montana 77.3-77.6 0.4 7.6 126 2.3 0.97 b 1. 9 0.84 Onshore (n=39) 50% gravel 50% rubble Offshore 20% cobble 60% rubble 20% gravel Lower Montana 76.8 -77.3 0.2 7.6 131 17. sa 2.4 0.99 b 2.7 1.06 Onshore N (n=35) 50% gravel 00 50% rubble I-' Offshore 20% cobble 60% rubble 20% gravel a These figures are probably inaccurate due to a meter malfunction. b Sample size. Table 4II-3-11. Water temperatures (°C) and discharges at Bering cisco spawning sites: 1981 and 1982. Water Dischargea Site River Mile Date Temperature (cfs) 1981 Sunshine 78.0 -79.0 811013 3.8 17,000 Montana 1 77 .o -77.5 811015 3.0 19,000 Montana 2 76.0-77.0 811015 3.3 19,000 Mainstem-West Bank 75.0 811013 3.1 17,000 1982 Montana (Upper) 77.3-77.6 821014 0.4 17,900 Montana (Lower) 76.8-77.3 821014 0.2 17,900 a USGS provisional data collected at Sunshine (Parks Highway Bridge). 282 10 9 8 (.) 0 -7 w 0::: :::> 1-6 <( 0::: N ~ 5 co w ::E w 1-4 3 2 0 100 ~ WATER TEMPERATURE .__... DISCHARGE 90 0--0 CATCH -;;;-80 ..... u 6 I') 0 70 >-<( 0 w 0:::50 <.9 60 w 0::. 0... <( I 50 u (/) 0 40 30 20 10 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 SEPTEMBER, 1982 Figure 4II-3-13. Bering cisco catch per day at the Sunshine fishwheel compared with daily mean surface water temperatures of the Susitna River at Sunshine (RM 84.0) and provisional discharge at Sunshine (USGS 1982b): September 1982. 10 9 8 (.) 7 ~ w 0:: ::l 6 1- <{ 0:: 5 Ill 11.. N ~ co w 4 ..J:::> 1- 3 2 0 100 80 90 70 80 60 ~70 u >- I') <{ 0 oro .::.so 0:: w w 11.. C> 0:: 50 ::t:40 <{ (.) ::t: 1- (.) <{ ~ 40 (.) 0 30 20 10 0 0 o---D 24 26 28 30 AUGUST 1981 15 17 19 21 SEPTEMBER 6---t:~ WATER TEMPERATURE _ _. DISCHARGE 0--1] CATCH Figure 4II-3-14. Bering cisco catch per day at the Sunshine fishwheel compared with daily mean surface water temperature of the Susitna River above Montana Creek (RM 77.5) and provisional discharge (USGS 1982a) at Sunshine (RM 84.0): August 25- September 30, 1981. 3.2 Juvenile Anadromous Fish Habitat Investigations Catch and catch per unit effort (CPUE) data for all juvenile salmon species at Designated Fish Habitat (DFH) sites are presented in Volume 3 (Section 3.1.2). Catch and CPUE data by specific site are contained in Appendices 4-G and 4-H of this volume (boat electrofishing data are not included in these tables). Habitat data for the DFH sites are contained in Appendix 4-I and hydraulic conditions and discharge data are presented in Part I of this volume (Section 3.1.3.1). Summaries of the hydraulic conditions, habitat data, and biological data for each DFH site are presented in Appendix 4-F. 3.3 Resident Fish Habitat Investigations Resident fish catch and CPUE data at DFH sites are presented with the juvenile anadromous data (Section 3.2). Resident fish catch and CPUE data at Selected Fish Habitat (SFH) sites are contained in Volume 3 (Appendix 3-A and Section 3.1.1). 3.3.1 Rainbow Trout Seasonal rainbow trout movement based on the 1981-82 winter radio telemetry studies are presented in Figure 4II-3-15. Table 4II-3-12 summarizes water depths, water velocities, water quality and substrate composition at overwintering areas. 285 N CX> (j) 100 80 w 60 _J ~ a: w > 40 a: 20 . . . ..__. '-- .... :1:-lt e I I .--------~ -770-2 ·-·--~ ...... _ __ ..... ______ 6 _ -------... 740 2 ..., _____ -:-_ ... ,_";"' ______ 760-3_______ -------·-----· - -:::--:-ii ----:----:, • • • ' - \ "'-• • • 770-1 \ \ \ \ \ \ \ \ \ \ \ \ ., \ \ \ ....... ______ ,....------760-1 ---.... ., 0+----------~---------~---------~---------~r----------~---------~---------~----------, SEPT OCT NOV DEC JAN 1981 FEB MAR 1982 APR MAY Figure 411-3-15. Movement of five radio-tagged rainbow trout in the Susitna River: October 1981 through April 1982. N co -.....J Table 411-3-12. Water quality and quantity and substrate data at overwintering areas utilized by radio tagged-rainbow trout during 1981. Water Dissolved Specific Water Water River Geographic Temp. Oxygen Conductance Depth Velocity Mile Code Date Time L£L £!:!__ (m9/l) (umho/cm) J.!!.L (ft/sec) ' Substrate 67.5 S22N05W240AC 820304 1230 0.0 7.1 11.2 162 . o.s 30% sand 30% cobble 30% gravel 53.5 S20NOSW14BCA 820221 1330 0.3 5.7 7.9 134 1.0 . 100% gravel 53.5 S20NOSW14BCA 820221 1330 0.4 5.9 11.0 212 1.2 . 80% gravel 20% sand 61.0 S21NOSW13BBA 820304 1200 o.o 7.3 11.6 243 5.8 0.1 61.0 S21NOSW13BBA 820221 1630 -0.1 6.1 11.4 147 2.5 . 20% cobble 50% gravel 20% sand 3.3.2 Burbot Seasonal burbot movements based on the 1981-82 winter radio telemetry studies are presented in Figure 4II-3-16. Table 4II-3-13 summarizes water depths, water velocities, water quality and substrate composition at overwintering areas. 3.3.3 Other Two longnose sucker spawning areas and one Arctic lamprey spawning area were located in 1982. Preliminary evaluations of these spawning habitats were attempted. The results of these preliminary evaluations are presented in Table 4II-3-14. 288 w _J 90 80 70 ~ 60 0::: w > 0::: 50 40 ·--• .... ,, ..... ... --·----·------, \ \ I I I \ .{750-1 \ -·-·-· ....... ·-·-·-·~ \ '·,_ \ --·--·----· 760-2 ' '· \ ------}.---·--_':.:::.-',-----------'·,) ·~ '•---·---· 750 2 ------. --... ---------· - 0+-------.--------.-------,-------,-------~------~--------------~ SEPT OCT NOV DEC JAN 1981 FEB MAR 1982 APR MAY Figure 4II-3-16. Movement of five radio-tagged burbot in the Susitna River: October 1981 through April 1982. N l.O 0 Table 411-3-13. Water quality and quantity data at overwintering areas utilized by radio-tagged burbot during 1981. Water Dissolved Specific Water River Geographic Temp. Oxygen Conductance Depth Mile Code Date Time .Lf.L .e!!_ (m2/l) (umho/cm) .ill.L 68.5 S22N05W14ADD 820305 1300 +0.6 7.1 12.8 225 6.2 68.5 S22N05W14ADD 820305 1300 +0.5 6.7 13.2 223 7.0 82.0 S24N05W22DAC 820308 1600 o.o 7.1 13.4 216 7.5 84,0 S24N05W10DCC 820305 1200 +0.1 6.6 9.7 119 . Water Velocity (ft/sec) . . . . Table 411-3-14. Spawning site habitat evaluations for longnose sucker and Arctic lamprey: 1982. Range of Range of Specific Dissolved Spawning Spawning Site Water Conductance Oxygen Depths Velocity Species (River Mile) Date Temp (0 C) E!:! (umhos/cm) ~ (feet) feet/second Substrate Embedded Sucker Sunshine Slough 820525 6.4 7.1 54 11.4 1.5-~.7 0.9-i!·7 60% cobble Yes (RM 85.7) (n=5) (n=5) 20% gravel 20% silt Sucker Trapper Creek 820605 10.0 -a -a -a 2.2 -6·8 0.5-1.1 · 60% cobble Yes mouth (n=5) (n=5)a 20% gravel (RM 91.5) 20% silt Arctic Birch Creek 820624 15.3 6.8 50 10.0 0.9b 1.4b 100% gravel No Lamprey mouth (n=1) (n=1) (RM 89,2) a Data not available. N <..0 b ....... Sample size. 4. DISCUSSION 4.1 Adult Anadromous Fish Habitat Investigations 4.1.1 Salmon Species 4.1.1.1 Mainstem Adult anadromous fish distribution data collected during the 1981 (ADF&G 1981b) and 1982 (Volume 2) open-water field seasons indicate that adult salmon spawning activity in the mainstem Susitna River is limited. The sampling procedure used is considered sufficient to accurately determine spawning activity with respect to habitats sampled and species considered. Preliminary data indicate that the substrate in the majority of the mainstem is cemented, making these areas unsuitable for adult salmon spawning. Chum salmon appear to be the only salmon species which utilize portions of the mainstem Susitna River for spawning. Coho, pink, sockeye and chinook salmon were not found to spawn in the mainstem Susitna River during the 1982 open-water field season. Based on an evaluation of the data presented in Tables 4II-3-1 and 4II-3-2 and Appendix Figures 4-F-4 through 4-F-11, the majority of the mainstem chum salmon spawning sites surveyed were located in clear backwater habitats situated in side channels which were cut off from mainstem water influence at their heads. Only one surveyed spawning site (located at RM 148.2, study site 292 number 3) was located in the main channel (Figure 4II-3-1 and Appendix Figure 4-F-6). Mean water depths and water column velocities measured at chum salmon spawning sites ranged from 0.1-4.0 feet and 0.0-1.0 feet/second, respec- tively. Substrate utilized for spawning ranged from silty sand to boulders with gravel, rubble and cobble substrate being the most commonly utilized substrates. The substrate was most often 1 oose ly embedded with silty sand which was cleared during redd formation. Water temperatures, taken at a depth of approximately 1 to 2 feet below the surface, ranged from 3.3 to 7.0°C. Each chum salmon spawning site, except site number 3 (at RM 148.2), had clear water zones i ndi cati ng the surveyed spawning areas were either entirely or partially isolated from mainstem surface water influence. The presence of clear water at these spawning sites can be attributed to subsurface percolation, since very little surface drainage was observed in the study areas. Intragravel water temperatures ranged from 0.2 to 5.3°C cooler than surface water temperatures. The tributary-mainstem confluence zone, which includes the area of the mainstem influenced either directly (i.e., the delta area and the downstream mixing zone) or indirectly (i.e., the tributary ground water influence zones) by the tributary, was not investigated in 1982. Observations, however, suggest that these zones may provide a sub- stantial amount of spawning and juvenile rearing habitat for chum, pink 293 and coho salmon, as well as rearing habitat for selected resident fish. Because these confluence zones will be directly impacted by the proposed project, studies are planned to investigate the habitat of these zones during 1983. Because this year was the first attempt at describing the habitat characteristics of mainstem salmon spawning areas, data and evaluations presented should be considered preliminary. Continuation of these studies are planned in 1983. 4.1.1.2 Slough Slough habitats are used to varying extents for spawning by four of the five species of salmon. Chum salmon extensively utilize the sloughs for spawning while sockeye and pink salmon spawn less frequently in sloughs. Coho salmon rarely spawned in sloughs and chinook salmon were never observed to spawn in sloughs. Chum salmon were found in most sloughs upstream of Susitna RM 107 (sloughs 5, 6A, 80, 8C, 8A, B, 9, 8B, Moose Slough, sloughs 9B, 9A, 10, 11, 15, 17, 19, 20, 21). Sloughs 8A, 9, 11, and 21 had the highest number of spawning chum salmon. 4.1.1.2.1 Spawning Site Selection Chum salmon were generally found to use gravel, rubble and/or cobble substrates in areas of the slough where depths were over 0.2 feet, 294 averaging about 1.1 feet, and velocities ranged from 0.0 to 1.5 ft/sec, averaging about 0. 3 ft/ sec. During the 1982 spawning season, chum salmon were observed using areas with significant amounts of silt overlaying gravel and rubble substrates (Plate 411-4-1). In Slough 21, one redd was observed where nearly 18 inches of silt had been fanned away. Survival of eggs deposited in silt this deep is questionable. Upwe 11 i ng or i ntragrave 1 ground water observed in si 1 t-covered areas, however, may allow survival of eggs and alevin in this type of substrate by providing a continuous flow of sufficiently oxygenated water. The utilization of areas of heavy silt was likely a result of the salmon being forced to use less than optional areas due to low flow conditions which restricted access to more desirable substrates. Chum salmon did appear to prefer areas with upwelling present. 4.1.1.2.2 Timing of Spawning Much of the following discussion was derived from data in Volume 2. Information has been arranged here to faci 1 itate comparisons between sloughs that were most intensively studied by Fish Habitat Utilization personne 1 • Numbers of 1 i ve chum, pink and sockeye sa 1 mon observed in side sloughs during the spawning season are presented in Figure 4II-4-I. Data for sloughs SA, 9, 11 and 21 are presented individually; all other sloughs sampled were combined and presented collectively. The other sloughs sampled include: 1, 2, 3A, 38, 4, 5, 6, 6A, 7, 8, 88, 8C, 80, A, 9A, 98, 10, 12, 13, 14, 15, 168, 17, 18, 19, and 20. Because coho salmon were only present in limited numbers, they have not been included in the figures; 295 Plate 411-4-1 Chum salmon spawning in silted area of Slough 21. Note: fish have fanned silt from spawning area. OTHER SLOUGHS SAMPLED SLOUGH 8A ~3.0 0 -:c (/') ti: 2.0 w > _J IJ.. 1.0 0 0 z 0.0 I 5 ~ 3.0 0 -:c ~ 2.0 IJ.. w > _J 1.0 IJ.. 0 0 z 0.0 I 5 /·\ /\ \ 1 \ CHUM i . ....-PINK I \/ • \ I \ I I \ • I \ \ I . A I \ \...~ ', //SOCKEYE\ / .. , 'v/ I ' "" -,./ . ' / ' --'\/ ' 10 15 20 25 30 5 10 15 20 25 30 AUGUST SEPTEMBER , ............ I ............ I \ _/CHUM I ,_........ I ', I '\ I \ I \ I \ I \ I \ I \ I ' / /SOCKEYE ', // PINK ', / ·-·< 10 15 20 25 30 5 10 15 20 25 30 AUGUST SEPTEMBER Figure 4II-4-l. Numbers of live salmon counted in August and September, 1982 in sloughs 8A, 9, 11, 21 and others (1, 2, 3A, 3B, 4, 5, 6, 6A, 7, 8, 88, 8C, 80, A, 9A, 98, 10, 12, 13, 14, 15, 16, 17, 18, 19, 20). ?07 SLOUGH 9 SLOUGH II N'" 3.0 0 -J: (/) -~o 1.1.. - w > ..J 1.0 1.1.. 0 0 z 0.0 I 5.0 --4.0 "' 0 -J: (/) LL.. 3.0 LLl > ..J LL.. 2.0 0 0 z 1.0 0.0 I .r / \ // \ r \ I \ I \ CHUM~ 1 \ I \ I \ I \ I \ 1 SOCKEYE \\ .................. PINK I \ -~ ;:::..::-; ~ • • --L. I 5 10 15 20 25 30 5 10 15 20 25 30 AUGUST SEPTEMBER SOCKEYE~ ~', I \ I \ I \ I \ I \ I \ I \ I \ CHUM I \ / I \/ I \ I \ I \ j•--..!._ \ \ • 1• PINK \ I I "'· / \ • I "'-._ ', ' / I • ' . ............ " ' .../'_...... . ....... ,_ -. --I I 5 10 15 20 25 30 5 10 15 20 25 30 AUGUST SEPTEMBER Figure 4II-4-l (Continued). 298 SLOUGH 21 -C\l 0 -:r: en IJ... w > ...J IJ... 0 d z I 5 10 15 20 25 30 5 10 15 20 25 30 AUGUST SEPTEMBER Figure 4II-4-l (Continued). 299 Sloughs 8A, 9, 11, and 21 each contained more fish than the other sloughs combined (Figure 4II-4-1). With the exception of Slough 11, where sockeye salmon outnumbered chum salmon, chum salmon were numerically dominant almost every day (refer to Volume 2 for specific numbers). The timing of peak numbers of fish and their duration of residence within sloughs generally followed consistent patterns. In general, pink salmon numbers peaked earlier than chum salmon in all sloughs. With the exception of Slough 11, pink salmon entered sloughs in early to mid-August, peaked in mid-August and were completely absent by September 1. Chum salmon typically entered sloughs by August 10, peaked sometime between August 20 and September 1, declined rapidly in mid-September and were completely absent by the end of September. In contrast to the pattern for pink and chum salmon, numbers of sockeye salmon generally 1 acked definite peaks, were much 1 ess abundant than chum sa 1 man and persisted in 1 ow numbers during 1 ate September ( s 1 oughs 8A, 9, 21). The obvious exception to the above generalizations occurred in Slough 11 where sockeye salmon numbers exhibited a bimodal peak at August 30 and September 13 and persisted in the slough until mid-October. In spite of the unique characteristics of Slough 11, it is obvious that of all sloughs sampled, sloughs 8A, 9, 11 and 21 contained the largest numbers of live salmon observed in 1982. In addition, there was a tempera 1 segregation in usage pattern between species. This was most evident between pink and chum salmon, with numbers of pink salmon 300 consistently peaking before chum salmon. The pattern for sockeye salmon _was less distinct, but generally indicated that sockeye salmon spawned in sloughs during the period of, or later than, chum salmon spawning. 4.1.1.2.3 Access Access to spawning areas may prohibit spawning in otherwise suitable habitats. When access is denied to a slough or tributary it eliminates consideration of all other factors influencing spawning (Figure 4II-4-2) within the habitat. Of critical concern are the potential impacts resulting from construction and operation of hydroelectric dams. If proposed Susitna hydroelectric dams are constructed, existing discharge levels, rates of sediment transport and seasonal thermal regimes are expected to change. Changes in these habitat characteristics are expected to alter existing quantity and/or quality of fish habitat (Acres 1982). It is anticipated that routine operations of the hydroelectric dams will reduce summer flows and elevate winter flows. Changes in flow-dependent habitat characteristics will be greatest between Talkeetna and Devil Canyon. In addition, it is suspected that reductions in mainstem discharge levels may seriously inhibit fish access to traditional spawning habitats. Water surface elevations at the downstream entrance to side sloughs are generally lower than the water surface elevation in the adjoining rna i nstem channe 1 • Thus, the stage of the rna i nstem causes a hydraulic 301 POTENTIAL Ll M ITATIONS TO SALMON SPAWNING IN SLOUGHS I NO • Available Habitat Limiting? YES-(depth, velocity, substrate, water qua I ity, cover, etc.) I NO ~ Competition, Predation, Disease, etc. Limiting? I NO ~ Optima I Spawning Habitat Figure 4!!-4-2. Factors limiting salmon spawning in sloughs. 302 plug which impedes the flow of clear water from the mouth of the slough, causing a clear back'11ater zone to form in the vicinity of the slough mouth that may extend several hundred feet upstream into the slough. As the mainstem discharge increases, the depth and surface area of the backwater zone at the mouth of the slough continues to increase. At some point, the water surface in the mainstem river reaches a critical level, allowing flow from the mainstem to enter the slough at its upstream end. Once breached, flows within the sloughs often increase rapidly from 1 ess than 10 cfs to more than 500 cfs (ADF&G 1982b, R&M 1982). Although limited spawning in the mainstem was documented (Section 4.1.1.1), the most intensively used spawning areas for salmon between Talkeetna and Devil Canyon were located in tributary streams and side sloughs (ADF&G 1981b). It is hypothesized that decreases in mainstem flows will limit access of salmon into tributaries and side sloughs. The most complete information regarding access pertains to side sloughs. Because sloughs 8A, 9, 11 and 21 contained the greatest numbers of spawning fish, they were investigated in greater detail and are the primary focus of the remaining discussion regarding fish access problems in side sloughs. Discharge levels in the mainstem Susitna River principally influence side slough habitats in two ways: 1) intermediate discharges cause a backwater effect at the mouth of the slough which facilitates access of fish into the slough (ADF&G 1981c and 1982b); and 2) high flows breach 303 the upstream end of the slough and may pro vi de a temporary access corridor to upper reaches of sloughs· that would otherwise have been inaccessible (refer to Part I, Section 3.1.1.2 for summary of mainstem discharges at which sloughs breach). The interaction of mainstem and slough discharges, the extent of backwater zone and the characteristics of streambed gradient largely define access conditions to a slough. Although high velocities can block the upstream migration of spawning fish, entrance conditions and associated backwater effects in the lower portions of the side sloughs of the Susitna River in the Ta 1 keetna to De vi 1 Canyon reach 1 imit formation of velocity barriers at these locations. Thus, the ease at which adult salmon can enter the side sloughs from the mainstem Susitna appears to be primarily a function of water depth. Slough 9 was selected for discussion of access-related problems because it is the first slough with sufficient preliminary analysis of data to be completed and it also represents an intermediate level of access difficulty: easier than sloughs 168 or 19, more difficult than Whiskers Creek Slough or Slough 8A, and comparable to sloughs 20 and 21 (Trihey 1982). The thalweg and water surface profiles which defined entrance conditions for Slough 9 on August 24, 1982 are presented in Figure 41-3-37. The mainstem discharge at Gold Creek was 12,500 cfs and flow in Slough 9 was 3 cfs. Data obtained during the 1981 and 1982 field seasons indicate that the flow from Slough 9 is quite small unless it is breached (Table 411-4-1). 304 Table 4II-4-1. Comparison of Slough 9 discharge with the average daily mainstem discharge at Gold £reek. Streamflow Date (cfs) 810624 2.9a 810721 714.0a 810930 1.5a 811014 1.2a 820623 182.0b 820715 108.0b 820720 28.5b 820825 3.4a 820904 8.4a 820904 3.0b 820918 232.0a 820920 145.0a ~ ADF&G 1981c and 1982b. R&M Consultants 1982. 305 Mainstem ( cfs) 16,600 40,800 8,000 7,290 No Record 25,600 22,900 13,400 14,400 13,400 26,800 24,000 On the basis of these data, 3 cfs was selected as being typical of the mid-summer clearwater base flow from Slough 9. Note that only rough comparisons of Slough 9 flow and the average daily mainstem discharge at Gold Creek (Table 4II-4-1) are possible for reasons discussed in Part I, Section 2.1.1.1.2. An ADF&G staff gage station (129.2W1) was established at the downstream entrance to Slough 9 to determine the relatinship of mainstem discharge to water surface elevations in the slough and to evaluate fish access conditions at various mainstem discharges (Figure 4II-4-3). Staff gage W1B was placed in the deepest part of a cross section at the staff gage statin to insure that the gage site would not dewater prior to the reach of slough it represented. As a result, gage height readings were estimated to be 0.3 feet greater than the average depth within this cross section. Water surface elevations were determined for each staff gage reading and compared to the average daily mainstem discharge at Gold Creek (Table 4II-4-2). A plot of these data (Figure 4II-4-4) indicates a well-defined relationship existed between mainstem discharge and the water surface elevation in the mouth of Slough 9 for mainstem flows ranging from 11,700 to 32,500 cfs. Mainstem flows less than 11,700 cfs did not appear to influence the water surface elevation within this reach of the slough mouth. The 0.3 foot stage indicated on Figure 4II-4-4 was maintained by the slough baseflow of 3 cfs. At this time, mainstem flows were less than 11,700 cfs. Under these conditions, the backwater effect of the mainstem river at this cross section was eliminated. 306 594 593 .-. .... Q) Q) 592 .... w z 0 0 591 -....J ~ > liJ 590 -I liJ liJ 589 ::::> 0::: ~ 588 587 AOF 8G Ga9es .129.2 WIA and~ WIB ... Pono9e Reach B -5+00 0+00 5+00 10+00 THALWEG STATION (feet) Figure 4II-4-3. Backwater profiles at the entrance to Slough 9 for selected mainstem streamflows at Gold Creek. Table 4!1-4-2. Comparison of water surface elevations (WSEL) at the entrance to Slough 9 and the average daily mainstem discharge at Gold Creek, 1982. Gold Creek Gold Creek WSELa Discharge WSEL Discharge Date (ft) (cfs) Date (ft) (cfs) 820824 590.03 12,500 820905 590.16 13,600 820825 590.19 13,400 820906 589.91 12.,200 820826 590.24 13,600 820907 589.84 11 '700 820827 590.04 12,900 820916 594.09 32,500 820828 589.98 12,400 820917 593.71 32,000 820829 589.91 12,200 820918 592.86 26,800 820902 590.82 16,000 820919 592.37 24,100 820903 590.51 14,600 820920 592.36 24,000 820904 590.42 14,400 820929 589.98 12,400 a ADF&G gages 129.2 W1A and W1B. 308 --z 0 ~ > I.LJ ...1 I.LJ I.LJ ~ a::: :::> en a::: I.LJ ~ == 594.0 593.0 592.0 591.0 590.0 589.5 • 4.5 4.0 3.5 3.0 2.5 2.0 _A_ Q = 10,000 to 11,700 cfs Depth of slough flow maintained by base flow in slough. 1.5 Depth (feet) = 0.3 B Q = 11,700 to 17,200 cfs Depth of Slough flow controlled by mai nstem di scha r'ge. 1.0 Depth (feet) = .00023 Q -2.745 c Q = 17,200 to 32,500 cfs Depth of slough flow controlled by 0.0 mainstem discharge. Depth (feet)= .00019 Q-2.132 -o.3 10 15 20 25 30 35 40 MAINSTEM DISCHARGE Q) GOLD CREEK(IO~fs) Figure 411-4-4. Water surface elevation and depths of Slough 9 (Figure 411-4-3) versus main- stem discharge (Provisional USGS 1982b) at Gold Creek. 309 z 0 1-u I.LJ en en en 0 a::: u I.LJ (!) <t (!) l.l.. l.l.. <t 1-en 1-<t --- J: 1-a. I.LJ 0 I.LJ > 1-<t 1-z I.LJ en I.LJ a::: a. I.LJ a::: Two potential problem areas existed· during 1982 for adult salmon entering Slough 9: a 125-foot reach (Reach A) approximately 400 feet downstream from the mouth of the slough, and a 280-foot reach (Reach B) from 620 to 900 feet upstream from the mouth (Figure 4II-4-3). The approximate length and average depth within the two critical passage reaches were determined for each backwater profile (Table 4II-4-3.). Based on data in Table 4II-4-3 and Figure 4II-4-4 and field observations by ADF&G personnel, upstream passage into Slough 9 by adult chum salmon does not appear restrictive at either passage reach A or B when mainstem discharges are 18,000 cfs or higher. At this discharge, passage reach A is no longer an obstacle, having an estimated depth of 1.75 feet (Table 4II-4-3); passage reach B increased slightly in depth (from 0.20 to 0.30 feet) and decreased greatly in length (from 280 feet to 80 feet). However, access becomes increasingly more difficult as rna i nstem discharge decreases, with acute access problem existing at mainstem flows of 12,000 cfs or less. On August 24, 1982, when mainstem discharge at Gold Creek was 12,500 cfs and no appreciable backwater zone was observed at the entrance of the slough, several chum salmon were observed grounded in shallow water near the entrance to the slough (passage reach A) as well as at passage reach B (Plate 4 I I -4-2). Depths were measured at numerous points where fish were grounded. Although a few isolated depths of 0.5 feet were measured, the most representative depth restricting access at the entrance to the slough was found to be 0.2 feet. 310 Table 411-4-3 Entrance conditions at the mouth of Slough 9 at various mainstem discharges at Gold Creek when slough discharge was 3 cfs. Mainstem Discharge (cfs) 10,000 12,000 14,000 16,000 18,000 20,000 22,000 Slough 9 vJSEL (ft) 589.50 589.90 590.35 590.85 591.25 591.60 591.90 Passage Reach A Average Reach Depth (ft) Length (ft) 0.10 0.40 0.85 1.35 1. 75 2.10 2.40 125 125 125 125 125 125 125 Passage Reach B Average Reach Depth (ft) Length (ft) 0.20 0.20 0.20 0.25 0.30 0.50 0.60 280 240 200 140 80 30 10 Mainstem conditions ranged between 12,200 and 13,300 cfs during the five days preceding these observations (USGS 1982b). The limited number of chum salmon (20 total) observed above passage reach B indicate that even during poor access conditions blockage was not complete. Additional evidence concerning access difficulty in sloughs involves observed changes in distributions of spawning salmon before and after heads of sloughs 8A, 9, and 21 were breached in mid-September (because the head of Slough 11 was not breached, access into this slough was relatively unchanged). The breaching event in mid-September occurred as numbers of live chum salmon were sharply declining (Figure 411-4-1) thereby limiting numbers of fish available to move upstream. Because this figure represents only live fish, and the natural mortality rates 311 Plate 411-4-2 Chum salmon stranded in riffle during low flow conditions in Slough 9, inhibiting access to spawning areas. at this time were very high, it is likely that· many live fish on September 15 were in poor condition and not able to migrate upslough. However, it is believed that if this high water event had occurred earlier in the year, when the numbers of live fish were greatest (late August-early September), considerable spawning may have occurred in upper reaches of sloughs 8A, 9 and 21. These observations suggest that if the timing of a peak mainstem flow (resulting in temporary breaching) more closely coincided with peak numbers of 1 ive spawners, access to upper reaches of sloughs may be facilitated. Such an event, if properly timed would probably reduce many access problems near the slough mouth. In this discussion, the quantification of flow-related access problems for spawning salmon has only been attempted for Slough 9. A similar analysis is possible for sloughs 8A, 11 and 21, and will be presented in the Fishery and Habitat Relationships report. 4.1.1.2.4 Modeling Discharge of the sloughs cannot be correlated with discharges in the mainstem at this time because 1982 discharges were so low that data were not representative of the normal range of flow conditions. The ranges of the various aquatic habitat types utilized by salmon species are also still under investigation. A computer model is being employed that will predict the surface area suitable for a species and/or specific life stage by weighing the utilized depth, velocity and 313 substrate variables against those that were available (Milhous et al. 1981). Some data have been co 11 ected at chum sa 1 mon redds. However, these variables have been measured at only a few pink and sockeye salmon. Data from other studies cannot be used to model sloughs in the Susitna River because fish habitat suitability data may not be com- parab 1 e between stream systems (Estes et a 1. 1981, AEIDC 1981). For these reasons, the surface area utilized for salmon redds cannot be de- termined at this time. The Final Draft Fishery and Habitat Relationships report will include the following discussions: 1) A comparison of observed water surface elevations, depths, velocities, and discharges for selected transects in Chum Channel and sloughs 8A, 9, and 21 with values calculated during calibration of the computer program.· 2) A comparison of surface areas of calculated depths and velocities at 0.2 feet and 0.2 ft/sec intervals, respectively, with depths and velocities observed at chum salmon redds. 3) Whenever possible, conditions in sloughs will be compared with mainstem discharges. The vulnerability of salmon redds in sloughs is an important consid- eration in regulating mainstem flows during the critical spawning 314 season. It is essential that the data base which predicts usable spawning area be reliable under a variety of hydraulic conditions. FY 84 objectives of this study include: developing habitat utilization curves for each salmon species and life phases using the sloughs and side channels of the Susitna River, determining a better understanding of relationships between the discharge (in mainstem and sloughs) and usable spawning area and determining mainstem discharges that would minimize impact to the fishery. 4.1.2 Eulachon Based on 1982 catch data (Volume 2), eulachon began their spawning migration into the Susitna River during May. The earliest capture of a eulachon was in a gillnet at RM 5.0 on May 16, 1982. Eulachon (Plate 4II-4-3) were observed from the mouth of the Susitna River (RM 0) to a point upstream of the Susitna River near Willow Creek (RM 49.5). The Yentna River was not surveyed upstream of Kroto Slough mouth where eulachon were observed; however, historical accounts of past runs show an upstream limit of the run on the Yentna River to Big Bend with isolated accounts of fish presence to Skwentna. Eulachon appeared to utilize the majority of the mainstem Susitna River and its associated side channels for passage and spawning. Eulachon did not, however, appear to utilize the clear water tributaries upstream of the confluence zones. In general, eulachon spawning runs occurred during periods of general increases in both mainstem discharge and surface water temperature (Figures 4II-3-12). 315 Plate 4II-4-3 Male and female eulachon taken from the Susitna River at RM 21.4: June 1, 1982. Eulachon appeared to key on water velocity for upstream orientation during their spawning migration run. Eulachon were seldom observed in areas of low water velocity (less than 0.3 ft/sec) or backwater or eddy habitat zones. They appear to bypass these areas in favor of areas with moderate downstream velocities. The majority of the upstream eulachon migration appeared to occur along banks with water velocities from 0.3 to 3.0 ft/sec. At times, the upstream movement of fish was so dense as to create a visible surface wave (Plates 411-4-4 and 411-4-5). The habitat requirements necessary for eul a chon spawning appear quite broad (Tables 411-3-8 and 411-3-9; Appendix Figures 4-F-70 to 4-F-91). Thus, a significant portion of the lower Susitna River is available as spawning habitat. Spawning occurred throughout the mainstem Susitna River and its associ- ated side channels, but bar and riffle zones with moderate water velocities were most commonly utilized. One riffle zone (spawning site #14) had approximately 10,000 fish milling in what appeared to be spawning behavior (Plates 411-4-6 and 411-4-7). In addition, over 10,000 fish were observed dead a 1 ong the banks, with most fish being spawned out (Plates 411-4-8). Deposited eggs were found in substrate samples at this site. Eulachon have been reported to spawn over course sand and pea-sized gravel in water up to 7.6 feet deep (Morrow 1980). The mean water depth measured at surveyed spawning sites ranged from 1.1 -3.1 feet with the range of depths varying at all survey sites from 0.3 -4.3 feet. The 317 Plate 4!!-4-4 Upstream movement of eulachon along the west bank of the Susitna River at RM 16.5: June 1, 1982. 318 Plate 4II-4-5 Upstream movement of eulachon creating a visible surface wave along the east bank of the Susitna River at RM 15.0: June 6, 1982. Plate 411-4-6 Milling fish in what appeared to be spawning behavior 1 along the east bank of the Susitna River at RM 15.0: June 6, 1982. Plate 411-4-7 Milling fish in what appeared to be spawning behavior along the east bank of the Susitna River at RM 15.0: June 6, 1982. Plate 4II-4-8 Accumulation of dead eulachon along the east bank of the Susitna River at RM 15.0: June 6, 1982. mean water column velocity measured at surveyed spawning sites ranged from 0.6 to 1.9 ft/sec with the range of velocities varying at all survey sites from 0.0 to 3.2 ft/sec. Substrate used for spawning varied from 100 percent silt to silt and sand intermixed with gravel, rubble and cobble. The substrate most commonly used ranged from silt to sand intermixed with gravel. Water temperatures at surveyed spawning sites ranged from 6.2° to 11. 2°C. These va 1 ues are somewhat higher than the water temperatures recorded at Susitna Station (RM 25.5) which range from 1.0° -9.0°C (Figure 4II-3-11). Local variability may be in part responsible for these deviations in values. Water temperature at time of spawning ranged from 3.0° -9.5°C while during the peak of the run (as seen by an increased CPUE) varied from 6.0° -9.0°C (Figure 4II-3-12). These observed water temperatures are somewhat higher than previously reported, preferred spawning temperatures of 4.4° -7.8°C (Morrow 1980). It should be noted that because this was a first attempt at describing the habitat characteristics of eulachon spawning areas and the data and evaluations presented should be considered preliminary. Continuation of these studies are planned in 1983. 4.1.3 Bering Cisco Based on 1982 fishwheel and electrofishing catch data (Volume 2), Bering cisco began their spawning migration into the Susitna River during early August. The earliest capture of a Bering cisco was in a fishwheel at 323 Susitna Station (RM 25.5) on August 7. The upstream limit of migration in the Susitna River appears to be RM 101.9. This compares to 1981 findings (ADF&G 1981b), which showed the upstream limit of migration to beRM 100.5. The Yentna, Chulitna and Talkeetna rivers were not sampled above their confluence; however, it is probab 1 e that a portion of the spawning run utilizes these drainages. Bering cisco have been captured at the ADF&G fishwheel site 6 miles upstream on the Yentna River. In general, Bering cisco spawning runs occurred during periods of general decreases in both surface water temperature and discharge (Figures 4II-3-13 and 4II-3-14). In addition, increases in discharge seem to discourage movement. For example, during 1982 a high discharge event which occurred on September 13 (90 ,000 cfs) corresponded to a reduced catch at the Sunshine fishwheel. Further, during this period the electrofishing catch was low. As discharge dropped after September 15, catch rates increased. Bering cisco appear to utilize the mainstem channels of the Susitna River for spawnings and passage. They do not appear to utilize sloughs or clear water tributary confluence zones. They were most often distributed individually or in small aggregates along gravel bars in the mainstem channel. These findings generally concur with 1981 findings. Bering cisco were not present in the east channel of the Susitna River between RM 62 and RM 70.0 during either 1981 or 1982, although habitats in this reach of the river are similar to those in other reaches utilized by Bering cisco. There were no discharge or velocity 324 measurements taken in the east channel. However, the discharge and overall velocity regime of the east channel is less than that in the main west channel, which may be partly responsible for these observations. In addition, the east channel has several clear water tributaries which empty into it, which may create less favorable conditions of turbidity or temperature. Bering cisco have never been observed in the vicinity of clear water tributaries in the Susitna River basin. Only one spawning site for Bering cisco was found in 1982. This site, which was a documented spawning site in 1981 (ADF&G 1981b) was located along a mainstem gravel bar opposite Montana Creek (RM 76.8 -77.6). The site was divided into two study areas and surveyed for its spawning habitat and the substrate composition ranged from gravel to cobble, with gravel being predominant. The smaller substrate types were located in zones with low to medium velocities (less than 3.5 ft/sec) and shallow depths (less than 2.5 feet). Spawning site water column velocities and depths ranged from 0.0 to 5.0 ft/sec and 1.0 to 4.0 feet, respectively. The mean spawning site water column velocity and depth were 2.3 ft/sec and 2.4 feet, respectively. These habitat characteristics generally concur with 1981 findings at this site (ADF&G 1981b). Water temperatures was recorded at the time of spawning, however, were different. Water temperatures in 1981 at the time of spawning ranged from 3.0° -3.8°C, while 1982 water temperatures ranged from 0.2° - 0.4°C (Table 4II-3-11). Discharge at the time of spawning during both 1981 and 1982 ranged from 15,000 -20,000 cfs. 325 Fewer spawning sites were located in 1982 than in 1981. One reason for this may be that in 1982 Bering cisco appeared to have begun spawning later. No ripe fish were found in 1982 until October 13, while in 1981 ripe fish were found earlier in October. Due to an early freeze up, sampling was discontinued after October 14, 1982, when spawning sites could no longer be located and studied. It is likely that Bering cisco utilized other areas for spawning after October 14, 1982. Because of the limited data base for Bering cisco spawning sites during 1981 and 1982, the data and evaluations presented should be considered preliminary. Continuation of these studies are planned in 1983. 4.2 Juvenile Anadromous Fish Habitat Investigations These investigations were based on the assumption that fish have a choice of habitat types at each sampling location and will be found in the highest concentration in those zones which have the most desirable habitat conditions. This assumption holds well for chinook and coho salmon juveniles which remain in the system for one or two years and have the capability of moving upstream in tributaries and sloughs. The assumption may not hold as well for chum and pink salmon juveniles which do not overwinter in the system and may be outmigrating from the spawning areas. In other words, juvenile chum and pink salmon may not have the opportunity to select the various zones with an equal probability. Sockeye salmon juveniles probably exhibit both types of behavior. Chum juveniles rear in the Susitna system, holding in some of the slough and tributary areas exhibiting growth (see Volume 3, Section 326 3.2); however, they probably would not migrate from a slough up into a tributary. Chum salmon adults spawn in tributaries and both chum and sockeye salmon spawn in the free-flowing area (zone 1) of sloughs such as Slough 21, Slough 11, and Slough 8A. In these sloughs, juveniles can remain in the zone 1 areas or migrate, either down to the mainstem backwater area or into the mainstem itself. At the time of spawning by chum and sockeye salmon in 1981 and 1982, the zone 1 areas of sloughs 8A, 11 and 21 were located in the slough channel, fed by springs or by very small tributaries. Birch Creek and associated slough is an example of an area where the juvenile salmon catch was strongly segregated by habitat zone (see Section 2.2 for definitions). During June and July, the slough was backed up by the mainstem to a point about 600 feet above the confluence of Birch Creek, creating a zone 6 (turbid, backwater) in the slough above the creek, a zone 7 (turbid backwater with tributary input) in the slough below the creek, and a zone 1 (clear, free-flowing) in the creek itself. Sixty percent of the chinook salmon juveniles captured were in zone 7, the rest were evenly distributed between zone 1 and zone 6. Chums were evenly distributed between zone 6 and zone 7 with none captured in zone 1. Eighty-eight percent of all coho salmon captured were from zone 1. These three species were clearly exhibiting a preference for a particular habitat type. No sockeye or pink salmon were captured at this site. An attempt will be made in the Fishery and Habitat Relationships report to correlate these kinds of habitat preferences with measured habitat variables such as temperature, turbidity, and the amount of cover available. 327 In the following discussion the number of juvenile salmon of each species captured in the mainstem backwater zone as a percentage of the total juveniles of that species captured in all zones sampled is presented to provide an indication of the relative habitat importance of the backwater zone to that species. Because the surface area of the backwater zone is a function of mainstem discharge, this analysis provides an indication of how varying mainstem discharges might be related to those juvenile salmon that demonstrate use of these areas. Chum and sockeye salmon juveniles were captured mainly in the backwater zone, whereas cohos and chinook salmon juveniles were captured mainly in other zones. Coho sa 1 mon were the 1 east 1 ike ly to be captured in the backwater zone. Pink salmon juveniles are not discussed because very few were captured. Our present hypothesis is that low discharges which lead to the closure of slough heads and the corresponding decline in surface area of mai nstem backwater zones have the most serious reper- cussions for chum and sockeye salmon juveniles; a lesser impact on chinook and coho juveniles is expected. The nature of habitat conditions that make the mainstem backwater zone a desirable habitat for juvenile salmon will be analyzed more thoroughly in the Fishery and Habitat Relationships report. Habitat conditions in sloughs can undergo radical changes when the slough head opens or closes because of the change in water source and water velocity. The backwater zone may buffer this phenomenon, as well as fluctuations due to rainwater runoff, and may provide a more stable set of habitat conditions than the zones above and be 1 ow this area. Backwater zones are generally conducive to vegetative growth, which provides ~over. 328 Water velocities are low, thus providing a good holding area. Backwater zones may provide juvenile salmon with an "edge" effect; a variety of habitat conditions are available in a usually short distance. Also, - tributaries of various sizes are often near the backup zones, providing a source of food. A further analysis of the effect of slough heads opening and closing on fish distribution in sloughs will be presented in the next report. This phenomenon causes changes in slough habitat conditions and fish respond to these changes. The opening or closing of a slough head is not an abrupt event, relative to the time it takes for fish to respond by moving to areas of more favorable habitat if the new conditions are not desirable. 4.2.1 Chum Salmon Of the five species of Pacific salmon which spawn in the Susitna River basin, chum salmon, Oncorhynchus keta (Walbaum), is the only one which spawns extensively in both tributaries and sloughs. Consequently, the population of chum salmon fry is exposed to a wider variety of habitat conditions than other species from the time of emergence to the time of outmigration from the system. The number of chum salmon juveniles captured steadily declined from the beginning of sampling in early June to mid-Aug_ust, when the last chum salmon juvenile was caught. Generally, juvenile chum salmon 329 distribution and relative abundance appeared to be influenced by the location of spawning the previous fall and by seasonal outmigration. Definite conclusions regarding chum salmon preference for a certain range of any particular habitat parameter are difficult to make because of the relatively short time chum juveniles rear in the system and the relatively small numbers of fish collected. A general idea of the ranges of values for varying habitat parameters can be obtained by extracting from Appendix 4-G those sites where chum salmon juveniles were abundant and from Appendix 4-I from the habitat data for those sites. Juvenile chum salmon were generally captured in areas of low water velocity. The chum salmon juveniles present in Indian River (zone 1) during June were observed in small backwaters created by gravel bars and by deadfall. They also seemed to prefer areas with cover provided by turbidity contributed by the mainstem. The different temperature regime in tributary redds versus slough redds should affect emergence timing. The chum salmon eggs in sloughs, which have warmer intragravel temperature resulting from upwelling ground water, would be expected to have a shorter incubation time than chum salmon eggs in tributaries. Data are needed on intragravel temperatures at spawning areas in tributaries. Interpretation of the relative importance of different habitat con- ditions is difficult because of the problem in determining if the fish collected were rearing (feeding) or simply migrating through the area where they were collected. Juvenile chum salmon were captured mainly in zones backed up by the mainstem except for areas where adult chum salmon 330 spawn in tributaries (for example, Indian River and Goose Creek). Slough areas with slack water caused by mainstem backwater and with at least moderate turbidity were evidently an important habitat type which chum salmon used as holding/rearing areas during outmigration. An example of such an area is Slough 6A. Very few adult chum salmon spawn in this slough, but juvenile chum salmon were abundant during June. Taking the percentage of chum salmon caught in the zones influenced by mainstem backwater (zone 2, zone 6, zone 7) as a percentage of chum salmon caught in all zones at each sampling site (only for those sampling periods and sites where there was beach seine or electrofishing sampling effort in both kinds of areas) and summing all sites shows that 59 percent of all chum salmon juveniles captured in early June, 85 percent in late June, and 94 percentin early July were captured in a mainstem backwater zone. The lower percentages earlier in the season reflects chum salmon captured in zone 1 during outmigration from stream spawning areas. The relationship of the total surface area of the aggregate type H-II backwater zone habitat type to mainstem discharge is shown in Figures 41-4-1 and 41-4-2. The availability (surface area) of this type of habitat at the sampling site generally declined with a decrease in mainstem discharge over the range of mainstem discharges observed. Although chum salmon juveniles were caught in this kind of habitat more than in other zones, the relationship of juvenile chum salmon catch to the availability of this type of habitat cannot be adequately analyzed because there were only three sampling periods. A more definitive analysis is presented for chinook and coho salmon juveniles, which are 331 present in the system all year and were caught in larger numbers than juvenile chum salmon. A more intensive sampling effort for juvenile chum salmon will have to be conducted in late spring and early summer next season to understand the dependency of this species on rna i nstem discharge conditions. The closure of slough heads during low mainstem flows in the early part of the summer may create conditions that are undesirable to rearing juvenile chum salmon. About 1,800 chum salmon fry were visually observed in Slough 8 (adjacent to Lane Creek) in late June in a mainstem backwater zone. The head of this slough had recently closed and the backwater zone was undergoing significant changes in habitat conditions, including increasing water temperature and reduced turbidity. Fourteen days later no chum salmon were observed in this area. It cannot be concluded at this time whether the absence of juvenile chum salmon at the later date is a function of undesirable habitat caused by closure of the slough head or simply a result of seasonal migration out of this slough. This problem points out difficulties in establishing cause-effect relationships when behavior of juveniles correlates with natural changes in habitat conditions. An examination of behavioral differences between sites may ultimately provide better insight into the importance of the stimulus associated with mainstem discharge changes. The closure of slough heads can also cause stranding of juvenile salmon in isolated pools. Shortly after the head of Slough 8 closed, ten juvenile chum salmon were observed in an isolated pool in the slough 332 just below the head. This condition has been noted in other.areas of the river. 4.2.2 Sockeye Salmon Surveys conducted to date indicate that adult sockeye salmon, Oncorhynchus nerka (Walbaum), which spawn above Curry (RM 130.7) in the Susitna River do so almost entirely in sloughs. The majority of the few thousand sockeye sa 1 mon adults which migrate upstream past Curry have spent as juveniles one additional winter in the freshwater system after emergence. However, the scanty evidence collected so far on juvenile sockeye salmon indicates that there may not be much overwintering occurring above Curry (see discussion in Volume 3, Section 4.1.2.4). The farthest upstream that an age 1+ or 2+ sockeye salmon juvenile has been collected is Slough 6A (RM 112.3). This however does not mean that sockeye salmon juveniles do not overwinter above this point. The methods used in 1981 did not effectively collect sockeye salmon juveniles, and effective techniques (electrofishing and beach seining) used in 1982 were not as intensive in early June as they were later in the year. The sockeye salmon smolts may have moved downstream before these methods were fully deployed in the upriver areas. Sockeye salmon juveniles are found in sloughs where adults spawn and also in the mainstem backwater zone of other sloughs. The seasonal average of the number of sockeye salmon juveniles captured in the mainstem backwater zone (zone 2, zone 6, zone 7) as a percentage of the total sockeye salmon juveniles captured in all zones (only for those 333 sampling periods and sites where there was sampling effort in both kinds of areas) was high (greater than 72 percent) for all sites in the lower reach (Goose Creek to Chulitna confluence). Except for Slough 8A, Slough 11, and Slough 21, this percentage was also high (greater than 71 percent) for all sites in the upper reach (Chulitna confluence to Portage Creek). The free-flowing areas (zone 1) of Slough 8A, Slough 11, and Slough 21 have a low gradient with many small pools which sockeye salmon juveniles seemed to prefer. Also, the adult sockeye salmon normally spawn in zone 1 (when zone 1 is in the slough channel) at these sloughs, which contributes to the broader distribution of the juveniles. The availability of mainstem backwater zone habitat as a function of mainstem discharge is shown in Figures 41-4-1 and 41-4-2. The surface area of this habitat type generally declines with a decrease in mainstem discharge over the range of mainstem discharges observed. Dewatering of these areas could have deleterious effects for this species which was found in such high proportions in this habitat type. A more intensive sampling effort at sloughs during the period immediately after ice-out will be necessary to collect more definitive data on this species. 4.2.3 Coho Salmon Adult coho salmon, Onchorhynchus kisutch (Walbaum), in the Susitna River system spawn primarily in tributaries. Coho salmon juveniles were captured in the tributaries and sloughs of the Susitna River between Goose Creek 2 (RM 73.1) and Slough 21 (RM 142.0) from June to September. 334 Juvenile coho salmon were found in all major habitat types in the system including tributaries, sloughs, side channels and the mainstem, but were observed with a greater frequency at tributary sites, including sloughs associated with tributaries. Adult coho salmon spawn in the tributaries upstream of all the sampling sites where the largest numbers of coho salmon juveniles were captured (Rabideux Creek, Sunshine Creek, Birch Creek). Juvenile coho salmon exhibited a seasonal movement between the major habitat types with a preference for tributaries and sloughs that have an abundance of cover. They were captured in larger numbers and with greater frequency in areas with emergent or aquatic vegetation and/or overhanging and deadfall cover. Fewer juvenile coho salmon were observed at many of the sites above the Chulitna than observed at similar habitat types in the reach below the Chulitna confluence. These sites above and below the Chulitna confluence were quite different in amount of available cover. Several sites above the Chulitna confluence were lacking in the amount and quality of cover as compared to some sites below the Chulitna confluence. Juvenile coho salmon were general- ly captured in areas of low water velocity with moderate turbidity and abundant aquatic or emergent vegetation. Some of these areas of low velocity and emergent cover were created by the backwater effects of the mainstem water surface elevation at the mouths of tributaries and sloughs. The mainstem backwater zones at sites below the Chulitna confluence inundated considerable amounts of emergent vegetation creat- 335 ing suitable rearing habitat with sufficient cover for coho salmon juveniles. Mainstem backwater areas at sites above the Chulitna con- fluence were typically smaller in area than sites below Chulitna, primarily because side sloughs and tributaries have steeper gradients and the Susitna River floodplain is much narrower upstream of the Chulitna River confluence. Coho salmon juveniles were often captured. in the mainstem backwater zone, but were also frequently captured in tributaries above the influence of the mainstem backwater. They were not captured in the mainstem mixing area below the mainstem backwater zone nearly as often as were juvenile chinook salmon. The following table indicates the number of coho salmon juveniles captured in the mainstem backwater zones (zone 2, zone 6, and zone 7) as a percentage of the number of coho salmon juveniles captured in all zones sampled at the site, summed for all 17 Designated Fish Habitat sites (only for those sampling periods and sites where there was minnow trapping effort in both kinds of areas). The data are from minnow traps only and are weighted by the effort (number of traps) deployed in each zone. Sampling period June 1-15 June 16-30 July 1-15 July 16-31 August 1-15 August 16-31 September 1-15 September 16-30 336 Percent cohos captured in mainstem backwater zones 23 32 31 15 20 20 23 23 One-third or less of the coho salmon juveniles captured at all sites were captured in the mainstem backwater zone. This percentage is lower than that of any other salmon species. Specific sites did show higher percentages. Goose Creek and Side Channel, Whitefish Slough, and Slough 6A were all greater than 50 percent. However, in general, coho salmon juveniles appear to use the mainstem backwater zone less than other salmon species. Furthermore, compared to the other salmon species, the percent use of the mainstem backwater zone by coho salmon juveniles is relatively constant from June to September, thus indicating less season a 1 dependence on this type of habitat than there may be with chinook salmon juveniles. The availability (surface area) of the type of habitat as a function of mainstem discharge is shown in Figures 41-4-1 and 41-4-2 for the range of mainstem discharge observed. 4.2.4 Chinook Salmon Adult chinook salmon, Oncorhynchus tshawytscha (Walbaum), spawn pri- marily in tributaries of the Susitna River in the reach covered by the juvenile anadromous fish studies. However, juvenile chinook salmon are found in all major habitat types in the system, including large and small tributaries, sloughs, sidechannels, and the mainstem. The juvenile chinook salmon exhibit seasonal movement back and forth among these areas, but present data do not allow a definite conclusion with regard to the seasonal importance of each of these major habitat types. The majority of adult chinook salmon migrating upstream past Talkeetna camp have spent as juveni 1 es an addition a 1 winter in the freshwater system after emergence. 337 Juvenile chinook salmon were often captured in the area of the sampling sites which was backed up due to mainstem stage, but were also frequently captured in tributary mouths (zone 1) and in the mixing zone (zone 3) below the mouth of a slough or tributary. The following table shows the number of chinook salmon juveniles captured in the mainstem backwater zone (zone 2, zone 6 and zone 7) as a percentage of the total number of chinook salmon juveniles captured in all zones sampled at the site, summed for all 17 DFH sites (only for those sites and sampling periods when there was minnow trapping effort in both kinds of areas). The catch data are from minnow traps only and are weighted by the effort (number of traps) deployed in each zone. Sampling period June I June II July I July II Aug I Aug II Sept I Sept II Percent chinooks captured in mainstem backup zones 60 68 33 33 22 35 41 4 The majority of chinook salmon juveniles captured in June were in the mainstem backwater zone. The percentage in this zone decreased by one-half in July and remained below 50 percent the rest of the season. It is difficult to determine why the percentage was high in June, but it is probably a result of chinook salmon juveniles migrating out of tributary systems at that time of year and the fact that the greatest amount of this type of habitat was present in June when mainstem dis- charge was highest. The availability (total surface area) of the 338 mainstem backwater zone habitat type as a function of mainstem discharge is shown in Figures 41-4-1 and 41-4-2. The aggregate mainstem backwater zone in sloughs includes zone 6 in sloughs above the confluence of tributaries and zone 7 in sloughs below tributaries. Chinook salmon juveniles exhibited a preference for zone 7 over zone 6, evidently attracted by tributary effluents. Chinook salmon juveniles were also often found in zone 3, which is the mixing zone of tributary/slough effluent with mainstem water. The desirability of these types of habitats is probably related to a supply of food drifting out of tributaries and the availability of cover provided by the turbidity of mainstem water. 4.3 Resident Fish Habitat Investigations Similar habitat conditions may attract different species of ·resident fish with comparable habitat requirements. These fish may be in association at a site and may compete with each other for food, space, or other biological needs. While interspecies associations need not be competitive, it is unlikely that such associations would be beneficial. The mixing zones (zone 3) of Lane Creek, 4th of July Creek, Indian River, Slough 20, and Portage Creek are all very similar and the species composition of resident fish inhabiting them is also similar. Mixing zones at these sites typically have moderate water velocities and temperatures and the substrate is normally gravel or sand with rocks 339 ranging up to several feet in diameter with cover provided by the turbid water flow of the Susitna River. Resident fish associated with these mixing zones normally include round whitefish, Arctic grayling, and rainbow trout. Large longnose suckers also may congregate in these zones, especially in August and September. Skull Creek and Jack Long Creek, two selected fish habitat sites, also have similar mixing zones and resident fish populations. During June and July, the associated species of rainbow trout, Arctic grayling, and round whitefish may compete for food. Food habits of these species are very similar and food items generally include immature stages of various insects (TES 1981, Morrow 1980). Competition might be reduced, however, by time or place of feeding. Arctic grayling are primarily surface or mid-depth feeders (TES 1981) while round whitefish feed on the bottom (Hale 1981). It is also possible that the various species partition the space within a mixing zone; for instance, Arctic grayling might feed in areas with higher water velocities than round whitefish do. Rainbow trout, being larger in size, would probably be more able to compete for available cover in the form of large rocks or submerged brush piles. In August and September, resident fish presumably feed almost entirely on salmon eggs of which there is an abundant supply. Stomachs of sampling mortalities examined during this period were almost always full of eggs. Large longnose suckers may gather at the mixing zones at this time to take advantage of this food source. Food waul d probably not 340 limit resident numbers and competition for space may become more important. At designated fish habjtat sites such as Goose Creek 2 and Side Channel, Sunshine Creek and Side Channel, and Whiskers Creek and Slough, mixing zones typically have lower water velocities, higher turbidities and finer materials for substrates than in many of the upper sites. Species associated here are adult and juvenile longnose suckers, juvenile round whitefish, slimy sculpins, and sometimes juvenile Arctic grayling. With the exception of Arctic grayling, all of these fish are bottom feeders. Spatial separation of habitat within a zone could be important in limiting competition. Sloughs not associated with tributaries, such as Whitefish Slough and sloughs 6A, 8A, 11, 19, and 21 typically had fewer resident fish present. Often these sloughs were used by rearing juvenile round whitefish, Arctic grayling, longnose suckers, and slimy sculpins. Adult rainbow trout and burbot also made some use of these sloughs and probably preyed on these juveniles at times. Sometimes adult longnose suckers, round whitefish, and humpback whitefish were also found in mixing zones and backed up zones where the turbidity was moderate. 4.3.1 Rainbow Trout Rainbow trout (Salmo gairdneri Richardson) are generally recognized as spring spawners (Morrow 1980, Scott and Crossman 1973). Susitna River rainbow trout generally begin their spawning migration to the clear 341 water tributaries from the mainstem and its various side channels during May to late June (Volume 3). Trotline catches of rainbow trout at designated fish habitat sites were comparatively high in June in mixing zones of slough or tributary water and mainstem water (aggregate zone W-I II) and then dropped in July as the rainbow trout moved from these zones farther up into the tributaries to spawn (Figure 4II-4-5). Electrofishing catch rates at mainstem and tributary or slough sites also dropped in July indicating a spawning migration during June (Figure 3-4-1). Actual spawning of rainbow trout has not been observed in the Susitna River basin and therefore their traditional spawning areas, exact periods of spawning and the habitat conditions associated with successful spawning in the Susitna River are not known. However, other investigations indicate that rainbow trout spawning occurs over a bed of fine gravels in a riffle zone above a pool (Morrow 1980). The female fans a redd, drops her eggs which are simultaneously fertilized by the male during a courtship ritual, then re-covers the redd. Several redds may be used, with 800-1,000 eggs deposited per redd. The eggs hatch in 4-7 weeks with alevin development lasting 3-7 weeks. The young emerge from the redds during June-September, depending on temperature (Morrow 1980, Scott and Crossman 1973). After spawning, rainbow trout move into their summer rearing habitat. Rainbow trout were captured with trotlines at designated fish habitat sites in zones with a tributary or slough water source (aggregate zone W-I) consistently during July and August (Figure 4II-4-5). Trotline 342 >- <t 0 w z w .....1 +:> I-w 0 0:: I- 0:: w 0... I 0 I- <t 0 0.5 0.4 0.3 0.2 0. I ~ I Zone W-I (Tributary or Slough ) Zone W-II(Mainstem) Zone w-m(Mixing) I I 0 0 I I I I 0 0 I I o.o+-L-~~~~~~J-~3-,_~J__B~~_L_L ____ _,~-L~~--~~-----,.-~L-~~.-~~~~.-- 16-31 1-15 16-31 1-15 16-30 JUNE JULY AUGUST SEPTEMBER Figure 4II-4-5. Rainbow trout catch per unit of trotline effort by aggregate water source zones at Designated Fish Habitat (DFH) sites on the Susitna River between Goose Creek 2 and Portage Creek: June through September, 1982. catches of rainbow trout in mixing zones (aggregate zone W-III) and rna i nstem water zones (aggregate zone W-I I), on the other hand, were comparatively lower during this time period. In addition, boat electrofishing catch rates were also very low in W-II and W-III zones during July and August (Figure 3-4-1). These data suggest that the preferred summer rearing habitat for rainbow trout in the Susitna River basin are the clear water tributaries and sloughs upstream from their confluence zones. Juvenile rainbow trout in particular are very rarely captured near confluence zones of tributaries or sloughs during the summer. Since very little study has been conducted in these upstream areas, little is known of the habitat characteristics associated with summer rearing habitats of rainbow trout in the Susitna River basin. Trotline catch rates of rainbow trout in mixing zones (aggregate zone W-III) of slough or tributary water with mainstem water rose in Septem- ber (Figure 4II-4-5) as did boat electrofishing catch rates at both tributary and mainstem sites (Figure 3-4-1). These results indicate that rainbow trout move out of the tributaries into the mainstem and its various side channels for overwintering during mid-August to late September. The movement out of the tributaries is likely cued to water temperature, with decreasing water temperatures in the tributaries during fall, initiating outmigration. Based on 1981-82 catches and radio telemetry studies (Volume 3), the preferred habitats for overwintering are the sloughs and side channel habitats exhibiting slow to moderate water velocities (0.2 to 3.0 ft/sec) free of under-ice slush (Table 4II-3-12). Fish are generally 344 not observed or caught in areas of open leads, suggesting that ice may be used as cover or else velocities are too high. The preferred substrate is gravel, rubble, and cobble rather than silt and sand, although fish are present in areas of silt and sand. Rainbow trout are most often observed in areas of higher specific conductance (above 200 umhos/cm) and water temperatures (above 0,5°C), indicating areas of upward percolation of water. Food sources during the winter period are unknown, since studies on food habits were not initiated in 1982. Preliminary observations indicated however, that benthic invertebrates may make up a significant portion of the winter diet of rainbow trout. The movement patterns of rainbow trout from the time they leave the tributaries in the fall to when they re-enter the tributaries in the spring has been largely unknown. Radio telemetry studies (Figure 3-3-3) show that between the period of freeze-up and the time the fish move into their overwintering habitat, the fish move in a general downstream pattern, probably searching for suitable overwintering habitat. Once in their overwintering habitats, they appear to remain fairly sedentary until they begin their movement into the tributaries after breakup. 4.3.2 Arctic Grayling Arctic graying (Thymallus arcticus Pallas) are generally recognized as spring spawners, with spawning occurring immediately after breakup (Morrow 1980, Scott and Crossman 1973). Arctic grayling in the Susitna River begin their spawning migration from their overwintering habitats into clear water tributaries in May (Volume 3). Although Arctic 345 grayling spawning has not been observed in the Susitna River basin it is presumed to occur only in the clear water tributaries during May to mid June. Arctic grayling sampled in late June were found to be spawned out. Male and female Arctic grayling have been reported to engage in a courtship ritual, during which time spawning takes place (Morrow 1980). No particular substrate is reportedly preferred for spawning, but sandy gravel substrate is reported to be most often used. Development to hatching requires 11 to 21 days, depending on temperature. No data is currently available on the habitat requirements of Arctic grayling spawning in the Susitna River. After spawning, Arctic grayling move into their summer rearing habitats. Boat electrofishing catch rates (see Volume 3, Section 3.1.1.2) show that the preferred summer rearing habitat for adult Arctic grayling appears to be the clear water tributaries, especially those above the Chulitna River confluence, rather than the mainstem. Adult Arctic grayling were captured most often during the summer in mixing zones (zone 3) at the mouths of large tributaries such as Lane Creek, Indian River, and Portage Creek (see Volume 3, Section 3.1.1.2). Arctic grayling greater than 300-mm fork 1 ength comprised only a very sma 11 portion of the catch during July and August (Figure 3-4-3). These large fish are probably able to set up feeding territories in desirable pools in upstream areas of the tributaries and displace small fish which then move down to the 1 ess des i rab 1 e habitat at the confluence and in the mainstem. Summer habitat for adult Arctic grayling in the mainstem Susitna River below Devil Canyon is therefore limited. 346 Juvenile (fork length under 200mm) Arctic grayling during the summer were found mostly in the mixing zone (zone 3) of tributaries in the reach of river between the Chulitna River confluence and Devil Canyon. These tributaries, such as Lane Creek, Skull Creek, Indian River, and Jack Long Creek, seasonally discharge clear and cold water. The juveniles appeared to rear in areas of slow to moderate water velocities (under 1.5 ft/sec) and with moderate to high turbidities (over 20 NTUs) at the mouths of these tributaries. Although Arctic grayling juveniles were most prevalent at tributary mouths, they were also found in relatively large numbers at mainstem sftes above the confluence of the Chulitna River, notably after August. At these sites, juveniles were found rearing in areas with similar water velocities and turbidities to that found at tributary sites. With the decrease in water discharge at the tri but aries and the decrease in turbidity in the mainstem during fall, it is probable that these fish were migrating to overwintering areas, or were at their overwintering habitat. Adult Arctic grayling begin to move out of their summer rearing habitats into their overwintering habitats in late August to early September (Volume 3, Section 4.1.1.2). Due to very low catches of Arctic grayling during the winter, the locations and habitat characteristics of Arctic grayling overwintering habitats in the Susitna River are currently unknown. It is presumed that Arctic grayling overwinter in the mainstem and its associated side channels. 347 4.3.3 Burbot Burbot (Lota lota) are generally recognized as under-ice winter spawners (Morrow 1980, Scott and Crossman 1973). Due to the timing of burbot spawning actual spawning of burbot in the Susitna River has not been observed. Because of this, the exact period of burbot spawning in the Susitna River is currently unknown. In the lower reaches of the Susitna River, the gonads of burbot begin to enlarge in late August, but spawning does not appear to take place until sometime in mid-winter. Burbot have been shown to congregate in late September in what appears to be preparation for spawning. Actual spawning is assumed to take place in late January to February in such areas as the mouth of the Deshka River (RM 40.6) (Volume 3). The habitat characteristics neces- sary for successful spawning of burbot to occur in the Susitna River basin are unknown. Burbot have been shown to congregate in moderately shallow water under the ice over a substrate ranging from sand to coarse gravel (Morrow 1980). During spawning, males and females form a 11 globular mass of fish" during which spawning takes place (Morrow 1980). Preliminary investigations of habitat conducted in areas of burbot milling during the 1982-83 winter (Table 4II-3-13) reveal that burbot appear to mill in preparation for spawning in areas with an ice cover having low to medium (0.1-4.0 ft/sec) water column velocities. In areas of milling, moderately high specific conductances (70-150 umhos/cm) have been observed, suggesting that upwelling may be occurring. Development of eggs takes 30-70 days, depending on temperature (Morrow 1980). 348 After spawning, burbot appear to use the mainstem and to a lesser extent the associated side channels and sloughs for overwintering habitats. (Volume 3). Areas of relatively deep water (2-10-ft) under the ice in the mainstem seem to be preferred (Table 4II-3-13). Burbot are rarely observed or captured in areas of open leads, which may be due to their strong negative phototrophism (Morrow 1980). Burbot have been observed utilizing areas of both gravel, rubble and cobble and silt and sand substrate during the winter, but seem to prefer a substrate composed of silt and sand. Burbot are most often found in lower velocity backwater areas (0.0-1.0 ft/sec), but have been observed in areas of higher veloc- ities. Since burbot are bottom dwellers, they do not seem to be ham- pered by under ice slush so long as at least six inches of water is present. Based on radio telemetry studies, most burbot overwinter in mainstem areas having relatively high specific conductances (above 200 umhos/cm) and water temperatures (above 0.5°C) indicating areas with an upward percolation of flow. For summer rearing habitat adult burbot appear to prefer relatively deep eddies in the mainstem (Appendix 4-G). Trotline catch rates at designated fish habitat sites (Figure 4II-4-6) were highest in mainstem water (aggregate zone W-II) and in mixing zones (aggregate zone W-III). Tributary or slough water (aggregate zone W-I) was utilized by relatively few adult burbot as indicated by very low catch rates. Burbot may avoid this clear water due to their negative phototrophism. After water temperatures in sloughs, side channels, and tributaries drop below l0°C, adult burbot have been observed to move into shallow water at night to feed. Trotline catches suggest this may happen in early September (Figure 4II-4-6). Prior to this time, burbot remain in the 349 2.0 I .6 >-<{ 0 w z I .2 -w ..J U1 1-0 0 0::: 1- 0::: 0.8 w a.. :c 0 1-0.4 <{ 0 i . . Zone w-r (Tributary or Slough) Zone W-IT (Mainstem) Zone w-m (Mixing) JULY Figure 4II-4-6. Burbot catch per unit of trotline effort by aggregate water source zones at Designated Fish Habitat (DFH) sites on the Susitna River between Goose Creek 2 and Portage Creek: June through September, 1982. mainstem in deep holes or in mixing. zones. Scott and Crossman (1973) report the optimal temperature for burbot ranges from 15.6° to 18.3°C. Catches of juvenile burbot (Appendix 4-G) at designated fish habitat sites were small but they were most often captured in mixing zones (zone 3) and in backed up zones or pools (zones 2, 6, 7 and 8). The movement patterns of burbot are largely unknown (Morrow 1980). Based on radio telemetry studies (Volume 3), burbot in the Susitna River are -~sually sedentary, but they are capable of long distance movements (Volume 3). One radio-tagged burbot, for instance, moved downstream a distance of approximately 60 miles in the winter and then held its new position. 4.3.4 Round Whitefish Round whitefish (Prosopium cylindraceum Pallas) are recognized as fall spawners with spawning taking place from late September to early Novem- ber (Morrow 1980). Because round whitefish spawn during freeze-up, actual spawning of round whitefish in the Susitna River has not been observed; although ripe fish have been captured in the mainstem during late summer to early fall (ADF&G 1981d). Thus, the exact period of round whitefish spawning in the Susitna River is unknown. In the upper reaches of the Susitna River, the gonads of round whitefish appear to enlarge in late June, but spawning does not appear to take place until at least late September or early October. Spawning has been reported to be annual, with spawning beds located along gravelly shallows of rivers 351 (Morrow 1980). In the Susitna River, round whitefish may utilize both the clear water tributaries and the mainstem for spawning (Volume 3). No nest is dug during spawning, with eggs being broadcast over the substrate. Egg development has been reported to take about 140 days depending on temperature (Morrow 1980). After spawning, round whitefish move into their overwintering habitats. Due to very low catches of round whitefish during the winter, the 1 ocations and habitat characteristics of round whitefish overwintering in the Susitna River are unknown. It is presumed round whitefish overwinter in the mainstem and its associated side channels. Round whitefish appear to move out of their overwintering habitats into their summer rearing habitats from May to June (Figure 3-4-4). Large concentrations of round whitefish were observed at tributary mouths in June. Preferred summer rearing habitat for adult round whitefish appears to be the clear water tributaries upstream of their confluences. However, round whitefish also appear to utilize, to a lesser extent, the mainstem for summer rearing habitat. Small numbers of adult round whitefish were electroshocked along mouths of sloughs and tributaries and along bars in the mainstem throughout the summer (Figure 3-4-4). Adult round whitefish were usually captured in mixing zones with a moderate current (zone 3) or in backed up zones (zone 2 or zone 7) at the designated fish habitat sites studied. In late August or early September, round whitefish apparently begin to move into overwintering habitat or to spawning areas (Volume 3). 352 Juvenile round whitefish (fork length less than 200mm) were found at all of the designated fish habitat sites studied (Appendix 4-G). Juvenile round whitefish were most often found rearing in clear water sloughs such as Slough 6A, Slough 8A, Slough 9, and Slough 21 in the reach of river between the Chulitna River confluence and Devil Canyon. The hydraulic zone in the sloughs which recorded the highest catch was the mixing zone (zone 3). Most of the catch at tributary sites was also in the mixing zones (zones 2 and 3). Juveniles, however, were also present in areas at sloughs and tributaries that contained mainstem water. The only areas where juveniles were captured in clear tributary or slough water were Whitefish Slough, Slough 6A and Slough 8A. Most of the zones with juvenile round whitefish present were characterized by low water , velocities or pools. Turbidity, at least under 120 NTUs, does not appear to exclude juvenile round whitefish from a rearing area. Juveniles were captured at a variety of sites with the turbidities ranging to 120 NTUs. However, no mainstem sites were consistently sampled by effective juvenile capture methods. Very high turbidities may exclude juvenile round whitefish from rearing in an area. Little is currently known of the specific habitat requirements for summer rearing of juvenile or adult round whitefish in the Susitna River. 353 4.3.5 Humpback Whitefish The taxonomy of the humpback whitefish (Coregonus spp.) is unclear. Morrow ( 1980) states that the humpback whitefish appears to be truly anadromous, while McPhail and Lindsey (1970) state that humpback whitefish typically occur in lakes and large rivers, with a portion of the population in rivers being anadromous. In the Susitna River, the humpback whitefish population appears to be divided into both an anadromous and resident population. The species of humpback whitefish inhabiting the Susitna River below Devil Canyon is believed to be Coregonus pidschian (Volume 3). Anadromous populations of humpback whitefish in Alaska have been report- ed to spawn during the fall, with their spawning runs beginning in June and lasting through October (Morrow 1980). In the Susitna River, the anadromous portion of the humpback whitefish population begin their spawning runs in early August in the lower reaches of the river, reach- ing the upper reaches by mid-September (Volume 3). Although actual spawning of humpback whitefish has not been observed in the Susitna River, it is presumed that spawning occurs in the fall prior to freeze-up. Little is known of the spawning behavior or spawning habitat of this species , but it is assumed to be similar to the Alaska whitefish (C. nelsoni) (Morrow 1980). Following the completion of spawning, humpback whitefish are reported to move back downstream, with small 354 numbers remaining in deep pools to overwinter (Morrow 1980). The timing of their return migration in the Susitna River is also not known. Young of the year have been reported to hatch in the 1 ate winter to early spring and subsequently move downstream. Due to the limited catch of juvenile humpback whitefish in the Susitna River, little is known of their timing of outmigration and the characteristics of preferred rearing habitat in the Susitna River. Catches of juvenile humpback whitefish at a downstream migrant trap in the mainstem (RM 102.0) peaked in August (Volume 3) suggesting a juvenile outmigration during August. A resident population of humpback whitefish appear to inhabit a number of clear water sloughs and tributaries of the Susitna River especially those above the Chulitna River confluence such as Slough 1, Slough 6A, Slough 17, Slough 19 and Portage Creek (Volume 3). Many of the catches were made in backed up zones (zones 2 or 7), or in areas where the water from a tributary or clear water slough mixed with mainstem water in a low velocity mixing zone or pool (zone 3). Few habitat measurements were taken during 1981 and 1982; thus, little is known of the charac- teristics of summer rearing habitats used by humpback whitefish in the Susitna River. The timing of resident humpback whitefish spawning is expected to be very similar to that of any anadromous populations present although it is possible that resident humpback whitefish spawn at a different time than anadromous fish. Spawning migrations, of course, would be shorter in length than those of anadromous populations. It is not known if the 355 distribution of wintering fish is similar to that of fish rearing during the summer. No juvenile humpback whitefish (fork length less than 200mm) have been captured above RM 102.0 (Volume 3). 4.3.6 Longnose Sucker Longnose suckers ( Catostomus catostomus Forster) are generally recog- nized as spring spawners, with spawning occurring as early as May and as late as July (Morrow 1980). In the lower Susitna River, longnose suckers have been observed spawning in 1 ate May to early June (Tab 1 e 4II-3-14). Spawning occurs most commonly over a gravel substrate in shallow water (0.3-2.0 ft) with a current ranging from 1.0 to 1.5 ft/sec (Morrow 1980). Water temperature at time of spawning is reported to be between 5.0 to 10.0°C. The limited data collected on longnose sucker spawning habitat in the Susitna River basin concur fairly well with published data. The data, however, suggest that longnose suckers utilize a wider range of depths and water velocities for spawning than previously reported. In the Susitna River, longnose suckers have also been captured in ripe condi- tion during the fall. Males, upon slight abdominal pressure, discharged milt and females, upon necropsy, showed well developed, separated eggs. Longnose suckers have not been previously reported to spawn in the fall. It is possible that the fish overwinter in this ripe condition. After spawning, longnose suckers move into their summer rearing habi- tats. In the Susitna River, longnose suckers appear to prefer tributary 356 and clear water slough mouths for summer rearing over mainstem sites (Volume 3). Longnose suckers, however, have been observed to utilize deep back eddy zones in the mainstem as summer rearing habitat. Schools of longnose suckers were present in Rabideux Creek Slough in a backed up zone (zone 2) during July and August in 2-5 feet of water. Often these fish were in submerged brush piles or near overhanging riparian vegetation. Adult 1 ongnose suckers were associ a ted with this type of habitat at a number of other sites electrofished. Data collected at Designated Fish Habitat sites allow a basic description of rearing areas used by juvenile longnose suckers (Appendix 4-F) to be formulated. Juvenile longnose suckers (less than 200mm fork length) were most often found in association with clear water slough sites where water velocities were less than 1 ft/sec. Catches at tribu- tary mouths were also typically in backed up zones (zones 2, 6, 7, and 9) where flow was insignificant. Turbidity in these backed up zones varied greatly and juveni 1 e 1 ongnose suckers were often found in very turbid water. At Goose Creek 2 and side channel, for example, longnose sucker juveniles were captured in zones 4 and 6 during June and July when the turbidity in these zones was very high. In Slough 9, longnose sucker juveniles were also captured in turbid water in zones 4 and 6 in late June and early July. On the other hand, young of the year longnose suckers were captured in Slough 8A during early September in clear water in zone 1. Slough 6A also provided a clear water rearing area for age class 1+ longnose suckers in zone 2 during late June and early July. Mainstem sites may also provide suitable rearing area for longnose 357 sucker juveniles, but these sites have not been extensively sampled with beach seines. Based on 1982 electrofishing observations, adult longnose suckers appear to begin to move out of their summer rearing habitats into their overwintering habitats during August. Due to very low catches of longnose suckers during the winter, the locations and habitat charac- teristics of longnose sucker overwintering habitats in the Susitna River are currently unknown. It is pres~med that 1 ongnose suckers overwinter in the mainstem and its associated side channels. Morrow (1980) states that 11 except for movement to and from spawning grounds, the 1 ongnose sucker apparently does not undertake any definite migrations... No major migrations have been observed for longnose suckers in the Susitna River to date. 4.3.7 Other Species 4.3.7.1 Dolly Varden Dolly Varden (Salvelinus malma Walbaum) were infrequently caught at the sites sampled in the Susitna River below Devil Canyon. When found, they were most frequently associated with large, cold, fast flowing tribu- taries such as the Kashwitna River, Lane Creek, Indian River, and Portage Creek. Dolly Varden are generally recognized as fall spawners (Morrow 1980). Adult catches at these sites and other sites are typically highest in June and September. The high catches in June are believed to be due to fish moving into the tributaries for summer 358 rearing from the mainstem and the high catches in September are due to movements back into the mainstem or to spawning streams (ADF&G 198ld). Dolly Varden occupied the designated fish habitat sites studied only during spring or fall migrations. No more than a few scattered fish were thought to occupy any of the hydraulic zones studied on a consis- tent basis during the ice-free season (Appendix 4-G). Dolly Varden captured are mostly likely transients passing through the zone. Because of low catch rates, little specific information is currently known about the summer rearing or fall spawning habitat requirements of Dolly Varden in the Susitna River. 4.3.7.2 Threespine Stickleback Threespine stickleback (Gasterosteus aculeatus Linnaeus) usually inhabit shallow water areas associated with aquatic plants (Morrow 1980) and this appears to be the case in the Susitna River. In the Susitna River, threespine stickleback are found in shallow warm-water sloughs or slow flowing tributaries, especially those with emergent vegetation such as Rolly Creek, Caswell Creek, Whitefish Slough, Sunshine Creek and Side Channel, and Birch Creek and Slough. Substrate at sites preferred by threespine stickleback was often silt or sand. Populations at these sites may fluctuate greatly from year to year (Volume 3). Distribution may also vary from year to year but populations generally decrease upstream of the Chulitna River confluence (RM 98.5). Three- spine stickleback are only rarely present at the mouths of cold, fast 359 flowing tributaries like Lane Creek and Slough, 4th of July Creek, Indian River, or Portage Creek. Sloughs well above the Chulitna con- fluence such as Slough 10 have very few threespine stickleback even though they may have abundant emergent vegetation. Abundance and dis- tribution above the Chulitna confluence may be limited by water tempera- tures or velocities or a combination of these factors. 4.3.7.3 Slimy Sculpin The slimy sculpin (Cottus cognatus Richardson) is an often abundant species which inhabits lakes and streams across northern North America. It prefers streams with a rocky substrate and fairly high water veloc- ities (Morrow 1980). Spawning occurs in the spring soon after breakup. In the Susitna River, the slimy sculpin is a widely distributed species. It has been sampled in moderate numbers during the summer at most locations sampled with relatively high numbers being observed along rocky banks of the mainstem and its associated side channels, tribu- taries and sloughs (Volume 3). At a given designated fish habitat site, slimy sculpins were found to inhabit almost all zones present (Appendix 4-G). Generally the highest numbers of slimy sculpins were found in zones 1, 2, and 3. Often slimy sculpins were associated with substrates where some rocks were present. Rocks are used by slimy sculpins as escape cover and as spawning nest sites (Morrow 1980). Since winter catch data on slimy sculpins are limited, little is currently known about the overwintering habitat of this species although catches have often been made in the same areas where they were found in the summer. 360 4.3.7.4 Arctic Lamprey Arctic lamprey (Lampetra japonica Martens) are generally recognized as spring spawners (Morrow 1980). In the Susitna River basin, Arctic lamprey have been observed spawning in late June in isolated locations (Table 411-3-14). During spawning, male and female engage in a nest building ritual in an area of gravel substrate in water depths ranging from a few inches to 3. 0 feet deep in a current of 0. 5 to 1. 0 ft/ sec (Morrow 1980). Based on preliminary habitat evaluation data, Arctic lamprey spawning habitat at Birch Creek and Slough (RM 88.3) concur fairly well with the published data. Since very few Arctic lamprey have been captured, little is known about their summer rearing or overwinter- ing habitats. 361 5. LITERATURE CITED Acres American, Inc. 1982. Susitna Hydroelectric Project: FERC lic.ense application. Exhibit E. Volume 1, Chapter 2 (Draft Report). Prepared for Alaska Power Authority, Alaska Department of Commerce and Economic Development, Anchorage, Alaska. Alaska Department of Fish and Game (ADF&G). 1981a. Aquatic studies procedures manual. Phase I Final Draft. Subtask 7 .10. Prepared for Acres American, Incorporated, by the Alaska Department of Fish and Game/Su Hydro. Anchorage, Alaska. 1981b. Adult anadromous fisheries project. Phase I Final Draft. Subtask 7 .10. Prepared for Acres American, Incorporated, by the Alaska Department of Fish and Game/Su Hydro. Anchorage, Alaska. 1981c. Aquatic habitat and instream flow project. Phase I Final Draft. Subtask 7.10. Prepared for Acres American, Incorporated, by the Alaska Department of Fish and Game/Su-Hydro. Anchorage, Alaska. 1981d. Resident fish investigation on the lower Susitna River. Phase I Final Draft. Subtask 7 .10. Prepared for Acres American, Incorporated by Alaska Department of Fish and Game/Su Hydro. Anchorage, Alaska. 362 1982a. Aquatic studies procedures manual. Phase II. Prepared for Acres American, Incorporated, by the Alaska Department of Fish and Game/Su Hydro. Anchorage, Alaska. 1982b. Aquatic studies program. Phase II Final Draft. Subtask 7.10. Prepared for Acres American, Incorporated, by the Alaska Department of Fish and Game/Su Hydro. Anchorage, Alaska. Arctic Environmental Information and Data Center (AEIDC). 1981. An assessment of environmental effects of construction and operation of the proposed Terror Lake hydroelectric facility, Kodiak, Alaska. Instream Flow Studies final report. Univ. Alaska, Anchorage. 419 pp. 1982. Illustration of Susitna River habitats. Unpub 1 i shed file. Anchorage, Alaska. Arnette, J.J. 1975. Nomenclature for instream flow assessments. Western Water Allocation Office of Biological Services, U.S. Fish and Wildlife Service. 7 pp. Bouck, G.R. 1982. 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Willow and Deception Creeks instream flow demonstration study. Prepared for the USDA-SCS by ADF&G, Habitat Protection and Sport Fish Divisions. Anchorage, Alaska. Hale, S.S. 1981. Freshwater habitat relationships: round whitefish Prosopium cylindraceum). ADF&G Habitat Division, Resource Assessment Branch. Anchorage, Alaska. 364 Lee, D.S., C.R. Gilbert, C.H. Hocutt, R.E. Jenkins, D.E. McAllister, and J.R. Stauffer, Jr. 1980. Atlas of North American freshwater fishes. Publication #1980-12. North Carolina State Museum of Natural History. 854 pp. McPhail, J.D. and C.C. Lindsey. northwestern Canada and Alaska. 381 pp. 1970. Freshwater fishes Fish. Res. Bd. Canada Bull. of 173. Milhous, R.T., D.L. Wegner, and T. Waddle. 1981. Users• guide to the Physical Habitat Simulation System. Cooperative Instream Flow Service Group. USFWS/OBS-81/43. Washington, D.C. Morrow, J.E. 1980. The freshwater fishes of Alaska. Alaska Northwest Publishing Co., Anchorage, Alaska. 248 pp. R&M Consultants, Inc. 1982. Susitna Hydroelectric Project: hydraul"ic and ice studies. Prepared for Acres American, Inc., Anchorage, Alaska. Scott, W.B. and E.J. Crossman. 1973. Freshwater fishes of Canada. Fish. Res. Bd. Canada Bull. 184. Ottawa. 966 pp. Scully, D.R., L.S. Leveen, and R.S. George. 1978. Surface water records of Cook Inlet Basin, Alaska, through September 1975. USGS. Open file report 78-498. Anchorage, Alaska. 1978. 365 Terrestrial Environmental Specialists (TES). 1981. A preliminary assessment of natura 1 supersaturation of Devil Canyon. Subtas k 7.10-Fish Ecology. June 1981. Prepared for Acres American, Inc. Buffalo, New York. Unpublished technical report. 1982. Appendix A. Summary of significant findings from the 1981 dissolved gas investigations of the Susitna River in the Devil Canyon vicinity. pp. A-1 to A-8. In: Task 7, Environmental Studies, Subtask 7.10. Fish Ecology. Phase I Supporting Documentation, May Buffalo, New York. 1982. Prepared for Acres Unpublished technical report. American, Inc. Trihey, E. W. 1982. Preliminary assessment of access by spawning salmon to side slough habitat above Talkeetna. Draft Report. Prepared for Acres American, Inc., Anchorage, Alaska. U.S. Army Corps of Engineers. 1981. Unpublished data file on the dissolved gas below Libby Dam on the Kootenai River, Montana. From: Thomas Bonde, USACOE, Seattle, Washington. U.S. Geological Survey (USGS). 1977. Water resources data for Alaska: Water year 1976. USGS Water-Data Report AK-76-1. Anchorage, Alaska. 366 1978a. Water resources data for Alaska: Hater year 1977. USGS Water Data Report AK-77-1. Anchorage, Alaska. 1978b. See Scully, et al. 1979. Water resources data for Alaska: Water year 1978. USGS Water-Data Report AK-78-1. Anchorage, Alaska. 1980. Water resources data for Alaska: Water year 1979. USGS Water-Data Report AK-79-1. Anchorage, Alaska. 1981. Water resources data for Alaska: Water year 1980. USGS Water-Data Report AK-80-1. Anchorage, Alaska. 1982a. Water resources data for A 1 ask a: Water year 1981. USGS Water-Data Report AK-81-1. Anchorage, Alaska. 1982b. Provisional summary of 1982 water resources data for Alaska. Weitkamp, D.E. and M. Katz. 1980. A review of dissolved gas supersaturation literature. Trans. Am. Fish. Soc. 109:659-702. 367