The URL can be used to link to this page

Home My WebLink AboutSUS591ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT FEDERAL ENERGY il.EGULATORY COMMISSION PROJECT NO. 7114 DRAFT lNSTREAM FLOW RELATIONSHIPS REPORT TECHNICAL REPORT N0 .3 A LIMNOLOGICAL PERSPECTIVE OF POTENTIAL WATER QUALITY CHANGES OCTOBER 1985 PREPARED BY HARZA-EBASCO SUSITNA JOINT VENTURE TABLE OF CONT!tJTS Section/Ti::le Preface Ac knowledgements Exe c utive Summary 1.0 INTRODUCTION 1.1 Objectives 1.2 Brief Summary of Information Sources 2.0 TH! SUSITRA RIV!l VAT!ISB!D - A LIKMOLOGICAL BAC~GIOUWD 2 .1 The Pr o posed Project 2.2 The Project Setting 2.2 .1 Susitna River Watershed 2.2.2 The Geological Setting 2 .2 .3 Soils and Vegetation 2.2.4 Mineral Resources and Human Influence3 2.2.5 Bas ic Watershed Climate 2.2.6 Nutrient Limitations of Terrestrial Vegetatio n 2 .2.7 Basic Hydrol o gic Regime 3.0 GENERALIZED PROJECT D!SCIIPTIOIS : MORPHOLOGY AND PUWCTIOR 3.1 Dams, Reservoirs and Basic Considerat i ons 3.1 .1 Watana Reservoir-Stage I 3 .1 .2 Devil Canyon Reservoir-S tage II 3.1 .3 Watana Reservoir-Stage Ill l l l l V 1-1 1-1 1-1 2-1 2-l 2 -1 2-1 2 -3 2-6 2-11 2-11 2-12 2-12 3-1 j -1 3-1 3-3 3-6 3 .2 Generalized Reservoir Operatio ns and Do wnst r eam Fl ows 3-7 3.2.1 Watana Stage I Operation-Alone 3-8 3.2.2 Operation of Either Watana Stage I o r S tage I II 3-13 with Devil Canyon Stage II 4. 0 BASEL IN! WATER QUALITY .urD ESTIMATED WATER QUALITY CHANGES 4.1 Baseline Water Quality and Limnological Characteristics -The Middle Ri ver Reach 4.2 Expected Water Quality Changes -Generalized 4.3 Selected Water Quality Issues 5. 0 SUSP!IDID S!DDI!ITS AND TUUIDITY 5.1 An Altered Suspended Sediment and Turbidit y Regime 5.2 Suspended Sediments and Turbidit y Relationsh i ps 5 .3 The DYRESM Model and Its Use for Estimating the 425832 /TOC 8511 1 1 With-Pro jec t Sediment Regime Change i 4-1 4 -1 4 -4 4 -4 5-l 5-I 5-3 5-24 TABLE ov CONTENTS (C ont'd ) Section/Title 5.4 Studies of the Existing Turbidity Regimes in the 5-49 Susitna River Middle Reach , in Eklutna Lake, and Estimates of the With-Project Turbidity Regime 5.5 Relationship Between Tu rbidit y and Light Transmissio n 5-65 5.6 Estimated Fisheries Impa c ts of An Altered Sediment 5-67 and Turbidity Regime in the Middle Reach 6.0 HYDIOG!H ION COHC!RTRATIOJ AND ALIALIHITY 7. 0 G!H!RALIZED INPOIMATIOI REGAIDIJC PIOJECT !FF!CTS OM HEAVY METALS 7.1 Introduction 7.2 Mercury 7. 3 Cadmium 7.4 Copper 7.5 Zinc 7.6 Manganese 7 .7 Iron 7.8 Aluminum , Lea1, Nickel and Bismuth 7.9 Conclusions and Recommendations 7.10 Appendix-Correlation Analyses o f Metals and other Aquatic Habitat Ch aracteristi c s 8. 0 T9.! POT!ITUL FOI GAS SUP!ISATUIATIOH RELATED TO TH! PROJECT 9 .0 AQUATIC MACROIUTIIEMT CBAHGES RELATED TO TK! PROJECT 10.0 DISSOLVED OXYG!J, OIGAIIC CAIJOI AND PROJECT EFFECTS 11.0 BRIEF SUMMARY OF PROJECTED WATER QUALITY CIIAUCT!RIS- TICS IN I!LATIOJ TO TROPHIC STATUS AND COMPOSITION OF TH! AQUATIC COMliUWITY 11 .1 Reservoir Biot ic Co mmunities and Trophic Status 11.2 Middle River Biology and Project ed Trophic Status 11 .3 Summary Thoughts Regarding Potential Project Induced Water Quality Changes 12. 0 R!F!I!JC!S 425832 /TOC 85 llll Ll 6-1 7-1 7-1 7-4 7-1 2 7-13 7-l 5 7-17 7-19 7-22 7-25 7-27 8-1 9-1 10 -1 11 -1 I 1-1 11-2 1 1-11 LIST OF TABLES Number/Title 2.1 APPROXIMATE MINERALOGY OF SUSITNA RIVER SUSPENDED SEDIMENTS 2-7 2.2 ELEMENT COMPOSITION OF MINERALS COMPOSING COHMONI.Y ANALYZED 2-8 SUSPENDED SEDIMENT PARTICLES FROM THE SUSITNA AND OTHER NEARBY GLACIAL RIVERS 2.3 TYPE AND ACREAGE OF VEGETATION TO BE !~UNDATED BY EACH IMPOUNDMENT OF THE SUSITNA HYDROELECTRIC PROJECT 3.1 MORPHOLOGICAL AND HYDROLOGICAL FEATURES-WATANA RESERVOIR : STAGES I AND III 3.2 MORPHOLOGICAL AND HYDROLOGICAL FEATURES -DEVIL CANYON RESERVOIR : STAGE II 2-10 3-2 3-4 4.1 APPROXIMATE WATER QUALITY CHARACTERISTICS OF THE SUSITNA 4-3 RIVER AT GOLD CREEK DURING HAY-OCTOBER VS. NOVEMBER-APRIL 4.2 ESTIMATED APPROXIMATE WATER QUALITY CHARACTERISTICS OF THE 4-6 PROJECT'S SURFICIAL RESERVOIR WATERS AND WATERS DISCHARGED DOWNSTREAM 5.1 AVERAGE TOTAL SUSPENDED SOLIDS AND TURBIDITY VALUES SETTLING 5-12 COLUMN TESTS 5.2 SETTLING COLUMN RUN NO. 1 -TOTAL SUSPENDED ~OLIOS AND 5-13 TURBIDITY 5.3 SETTLING COLUMN RUN NO. 2 -TOTAL SUSPENDED SOLIDS AND TURBIDITY 5.4 NATURAL AND ESTIMATED MEAN MONTHLY SUSPENDED SEDIMENT CONCENTRATIONS AND MINIMAL TURBIDITY VALUES EXPECTED TO EXIT WATANA RESERVOIR DURING STAGE I OPERATION 5.5 NATURAL AND ESTIMATED MEAN MONTHLY SUSPENDED SEDIMENT CONCENTRATIONS AND MINIMAL TURBIDITY VALUES EXPECTED TO EXIT DEVIL CANYON RESERVOIR DURING STAGE II OPERATION 5 .6 NATURAL AND ESTIMATED MEAN MONTHLY SUSPENDED SEDIMENT CONCENTRATIONS AND MINIMAL TURBIDITY VALUES EXPECTED TO EXIT DEVIL CANYON RESERVOIR DURING STAGE III OPERATION 425832 /TOC 851111 iii 5-14 5-61 5-61 5-63 LIST OF TABLES (Cont'd ) Number /Title 5.7 APPROXIMATE ANNUAL RANGE AND MEAN VALUES OF TSS AND TURBIDITY IN SELECTED REACHES OF TWO SOUTH CENTRAL ALASKAN GLACIAL RIVERS COMPARED TO WITH-PROJECT ESTIMATES FOR THE SUSITNA PROJECT DISCHARGE VALUES 7.1 SUSITNA HYDROELECTRIC PROJECT: AVAILABLE USGS DATA -METAL ANALYSES 5-70 7-5 9.1 GENERAL RANGES OF TOTAL PHOSPHORUS AND TOTAL NITROGEN 9-5 WHICH ARE RELATIVELY CHARACTERISTIC OF DIFFERENT TROPHIC CATEGORIES IN RELATIVELY CLEAR LAKES AND RESERVOIRS 9.2 PHOSPHORUS IN SUSITNA RIVER SAMPLES 9-12 11.1 TROPHIC STATUS AND RATES AT ANNUAL PRIMARY PRODUCTIVITY 11-2 OBSERVED IN VARIOUS LAKES, LAKE-RESERVOIRS AND RESER-thru VOIRS IN TEMPERATE, SUBARCTIC AND ARCTIC REGIONS OF 11-3 THE NORTHERN HEMISPHERE 425832 /TOC 851111 iv LIST OF FIGUUS Number /ritle 2.1 PROPOSED PROJECT LOCATION 2.2 SUS I TNA RIVER WATERSHED INCLUDING MAJOR TRIBUTARIE S AND GLACIERS 2.3 GRADIENT OF THE SUSITNA RIVER FROM TALKEETNA TO PORTAGE CREEK 2.4 REPRESENTATIVE ANNUAL HYDROGRAPHS OF THE WATANA DAM SITE AND THE GOLD CREEK GAGING STATION FOR TWO WET YEARS WITH SPRING (1964) AND FALL (1967 ) FLOODS AND FOR ONE DRY YEAR (1970) 3.1 SUSITNA RIVER STREAHFLOWS EXCEEDED SO% OF THE TIME AT GOLD CREEK -STAGE I -1996 ENERGY DEMAND 3.2 SUSITNA RIVER STREAHFLOWS EXCEEDED 50% OF THE TIME AT GOLD CREEK -STAGE II -2007 ENERGY DEMAND 3.3 SUSITNA RIVER STREAHFLOWS EXCEEDED SO% OF THE TIME AT GOLD CREEK -STAGE III -2008 ENERGY DEMAND 3.4 SUSITNA RIVER STREAHFLOWS EXCEEDED 50% OF THE TIME AT GOLD CREEK -STAGE III -2020 ENERGY DEMAND S.1 TURBIDITY VS. SUSPENDED SEDIMENT CONCENTRATION- SUS ITNA RIVER 5.2 TURBIDITY VS. SUSPENDED SEDIMENT CONCENTRATION IN SEVERAL ALASKAN RIVERS S.3 1984 EAST FORK DATA : TURBIDITY VS. TOTAL SUSPENDED SOLIDS FOR LOTIC INFLUENTS TO EKLUTNA LAKE S.4 1984 GLACIER FORK DATA ; TURBIDITY VS. TOTAL SUSPENDED SOLIDS FOR LOTIC INFLUENTS TO EKLUTNA LAKE S.S EMPERICAL RELATIONSHIP OF TURBIDITY VERSUS SUSPENDED SEDIMENT CONCENTRATION FOR PLACER-MINED AND NEIGHBORING UNHINED STREAMS IN INTERIOR ALASKA, SAMPLED DURING SUMMER, 1983-1984. 5.6 PLOT OF TURBIDITY AND SUSPENDED SEDIMENT CONCENTRATION FOR CERTAIN PLACER-MINED STREAMS IN ALASKA 42S832 /TOC 851111 v 2-2 2-4 2-14 2-16 3-9 3-10 3-11 3-12 5-S S-6 S-7 S-8 5-9 5-10 LIST OF FIGURES (Cont'd) Number /Title 5.7 RELATIONSHIP BETWEEN TURBIDITY AND TOTAL SUSPENDED SOLIDS 5-15 5.8 TURBIDITY VS. SUSPENDED SOLIDS FROM SETTLING COLUMN RUN 5-16 NO. 1 AND NO. 2 -SUSITNA RIVER SAMPLES 5 .9 COMBINED TURBIDITY VS. SUSPENDED SOLIDS FROM SETTLING 5-17 COLUMNS NO. 1 AND NO. 2 -SUSITNA RIVER SAMPLES 5.10 SETTLING COLUMN: TURBIDITY VS. TIME-SUSITNA RIVER SAMPLES 5.11 SETTLING COLUMN RUN: TOTAL SUSPENDED SOLIDS VS. TIME - SUS ITNA RIVER SAMPLES 5-18 5-19 5.12 EKLUTNA LAKE DATA: TURBIDITY VS. TOTAL SUSPENDED SOLIDS 5-21 5.13 1984 EKLUTNA LAKE TAILRACE DATA: TURBIDITY VS. TOTAL SUSPENDED SOLIDS 5.14 EMPIRICAL RELATIONSHIPS OF TURBIDITY VERSUS SUSPENDED SEDIMENT CONCENTRATION FOR RIVERS AND LAKES IN ALASKA 5.15 SUSPENDED SEDIMENT SIZE DISTRIBUTION SUS ITNA RIVER NEAR CANTWELL 5.16 SUSPENDED SEDIMENT RATING CURVE AT U.S.G.S. GAGING STATION -SUSITNA RIVER NEAR CANTWELL 5-22 5-23 5-37 5-38 5.17 WATANA RESERVOIR OUTFLOW (0-10 MICRONS) SUSPENDED SOLIDS -5-40 MINIMUM INFLOW YEAR (1970) -STAGE I 2001 ENERGY DEMAND 5.18 WATANA RESERVOIR OUTFLOW (0-10 MICRONS) SUSPENDED SOLIDS-5-41 MAXIMUM INFLOW YEAR (1981) -STGAE I 2001 ENERGY DEMAND 5.19 WATANA RESERVOIR OUTFLOW (0-10 MICRONS) SUSPENDED SOLIDS -5-42 AVERAGE INFLOW YEAR (1982) -STAGE I 2001 ENERGY DEMAND 5.20 WATANA RESERVOIR OUTFLOW (0-10 MICRONS) SUSPENDED SOLIDS -5-43 AVERAGE INFLOW YEAR (1982) -STAGE II 2002 ENERGY DEMAND 5.21 DEVIL CANYON RESERVOIR OUTFLOW (0-10 MICRONS) SUSPENDED SOLIDS -AVERAGE INFLOW YEAR (1982) -STAGE II 2002 ENERGY DEMAND 'j-44 5.22 WATANA RESERVOIR OUTFLOW (0-10 MICRONS) SUSPENDED SOLIDS -5-46 AVERAGE INFLOW YEAR (1982) -STAGE III -2020 ENERGY DEMAND 425832/TOC 851111 vi LIST OF FIGURES (Cont'd ) Number /Tit 1e 5.23 DEVIL CANYON RESERVOIR OUTFLOW (0-10 MICRONS ) SUSPENDED SOLIDS-AVERAGE INFLOW YEAR (1982)-STAGE III- 2020 ENERGY DEMAND 5-4 7 5.24 ESTIMATED MEAN MONTHLY SUSPENDED SEDIMENT CONCENTRATIONS 5-48 FOR PROJECT DISCHARGES 5.25 MAINSTEM DISCHARGE, WATER TEMPERATURE, AND TURBIDITY 5-51 RECORDED AT THE GOLD CREEK STATION, SUSITNA RIVER -1983 5.26 TURBIDITY, WATER TEMPERATURE, AND SUSITNA RIVER DIS-5-52 CHARGE VERSUS TIME AT THE TALKEETNA FISHWEEL CAMP, SUSITNA RIVER -1983 5.27 MAINSTEM DISCHARGE, WATER TEMPERATURE , AND TURBIDITY IN 5-53 THE MIDDLE REACH OF THE SUSITNA RIVER , 1984 5.28 TURBIDITY DATA SUMMARY SHOWING RANGE, 25TH, 50TH (MEDIAN) 5-54 AND 75TH PERCENTILE FOR MAINSTEM AND TRIBUTARY STUDY SITES 5 .29 ISO-TURBIDITY VS. TIME, EKLUTNA LAKE AT STATION 9, 1982 5-57 5.30 ISD-TURBIDITY VS. TIME, EKLUTNA LAKE AT STATION 9, 1983 5-58 5.31 ISO-TURBIDITY VS. TIME, EKLUTNA LAKE AT STATION 9 , 1984 5-59 5.32 MINIMAL MEAN MONTHLY TURBIDITY VALUES FOR PROJECT 5-64 DISCHARGES (BASED ON NTU • 2X TSS) 5.33 AN EMPIRICALLY DERIVED, GENERALIZED RELATIONSHIP BETWEEN 5-67 TURBIDITY AND MAXIMUM EUPHOTIC ZONE DEPTH (1.0% P .A.R.) 6.1 pH DATA SUMMARY SHOWING RANGE, 25TH, 50TH (MEDIAN), AND 6-2 75 PERCENTILE FOR MAINSTEM AND TRIBUTARY WATER QUALITY STUDY SITES 6.2 SUMMARY, BY STUDY, OF THE INTRAGRAVEL pH DATA PERIODICALLY MEASURED WITKIN STANDPIPES DURING THE 1983-1984 WINTER PERIOD IN THE MIDDLE SUSITNA RIVER 6.3 SUMMARY, BY HABITAT TYPE, OF THE INTRAGRAVEL pH DATA PERIODICALLY MEASURED WITKIN STANDPIPES DURING THE 1983-1984 WINTER PERIOD IN THE MIDDLE SUSITNA RIVER 425832 /TOC 85llll Vll 6-4 6-5 LIST OF FIGOI!S (Cont'd) Nu111ber /Title 8.1 TOTAL DISSOLVED GAS (PERCENT SATURATION) VS. DISCHARGE 9.1 DATA SUMMARY-TOTAL PHOSPHORUS 9.2 DATA SUMMARY-TOTAL NITROGEN 10.1 DATA SUMMARY -DISSOLVED OXYGEN 10 .2 DATA SUMMARY -DISSOLVED OXYGEN% SATURATION 10.3 DISSOLVED OXYGEN DATA SUMMARY 10.4 DISSOLVED OXYGEN DATA SUMMARY 425832/TOC 851111 viii 8-3 9-6 9-7 10-2 10-3 10-4 10-5 PREFACE This text constitutes the third technical report of t he Instream Fl o w Relationship Series (IFRS). Its primary purpose ts to pr ovide a limnologically oriented perspective for reviewing some i mportant wat e r quality issues associated with the Susitna Hydroelec t ri c Pro ject . This report will dis c uss certain c haracteristics of the reservotr innundat ion zones and the Sus itna River "middle" reach which will affect their With-project aquatic biol o gy. Qualitative and quantitative estimates of project-induced changes to selected water quality charac teristic s are discussed . Estimates of the With-project water quality and trophic status in the proposed reservoirs and the downstream Susitna River middle reach are included, particularly as they relate to fisheries biology . The technical report series at tempts to consolidate data presented tn a variety of previously written reports by a variety of private, state an d federal agencies and organizations. While the IFRS report series ts not intended to be an impact assessment, it presents estimates of dif fe rences bet ·o~een the natural and regulated river which may be useful fo r project impact assessment. Technical Report No.1. Fish Resources and Habitats of the Susitna Basin. This report consolidates information on the fish resources and habitats in the Talkeetna-to-Devil Canyon reach of the Susitna River available through January 1985 . Technical Report No.2. Physical Processes Report. This report desc ribes such physical processes as reservoir sedimentation, channel morphology and stability and groundwater upwelling. Technical Report No .3. Water Quality/Limnology Report. Thi s report consolidates much existing i nformation on water quality in the Susitna Ba s in. It addresses the potential for with-project leaching of h eavy metal s 425832 i 851111 from the reservoirs inundat ion zones and their possible interactions wi th higher biologic al tr o phi c levels; expected influences of the project o n nitrogen gas supe r satu ra tion; expected pr oj ect e ffects on hyd r ogen ton co nc ent rat ion and alkalinity; project-induced ch anges to plant macronutrients and the ir pote n tial for influencing the t r ophic status of both of the pr o ject reservoirs and of the Middle river reach downstream of the reservoir s; and c hanges i n the suspended s ediment and turbidity regimes togethe::-with some potential biological effects related to these changes. This report will also discuss the estimated trophic s tatus characteristics of the project reservoir( s ) and the r1vert n e habitats immediatel y downstream. Technical Report No . 4. Instream Temperature. Thi s report c onsist s of three principal components: l) instream temperature modeling; 2) development of temperature criteria for Susitna River fish stocks by species and life stage; and 3) evaluation of the influences of with-project stream temperatures on existing fish habitats and natural ice processes. A fi nal report describing downstream temperatures associated with var ious reservoi r operating scenar i os and an evaluation of the effects of t he these s tream temperatures on fish was prepared 1n October 1984. A draft re port addressing the influence of anticipated with-pr ojec t stream temperatures on ice processes was prepared in November 1984 . Technical Report No .5. Aquatic Habitat Report. This report describes the availab i lity of various types of aquatic habitats in the Talkeetna-to-Devil Canyon river reach as a function of mainstem discharge. Tee hn ica l Report No. 6. Ice Processes Report . This report will descrir~ naturally occurring ice proces ses in the middle ri~er , anticipated changes in those processes due to project construction and operation , and it will dis c us s the effects of naturall y occurring and with-pr oj ect ice t:o nditions on fish habitat. 425832 851111 ii (To be written ) t..25832 85 1111 Aknowlegements i i i Executive Su.mary Several water qual i t y characterist i cs have been i d e n tified as pot e n t ia l environmental LSsues. Water quality characteristic s for the pro po sed impoundment zones and the Sus i tna River "middle" reach have been exam i ned and estimates of project-induced effects on some of the more important water quality issues are emphasized herein. A moderate amount of water quality information has been collected, examined and narrowed to six sets of issues which may affect salmon and resident fish habitats and populations downstream of the proposed project . The six water quality issues discussed here are : 1) suspended sediments and turbidity, 2) pH, 3) heavy metals, 4) gas supersaturation, 5) plant macronutrients, and 6) dissolved oxygen and carbon c oncentrations . Suspended Sediment and Turbidity Suspended sediment and turbidity regimes have been examined with respect to project-induced alterations in their naturally c y clic regime. At present, estimates of project effects on the reservoir and river habitats and their biological inhabitants appear to be complex and mostly detrimental because of expected alterations to natural suspended sediment and turbidity regimes. Important fisheries habitats will be affected and mitigation presentl y appears to be necessary to balance some potential l y detrimental effects . I t is apparent that Alaska state water quality criteria regarding turbidity and suspended sediment wi 11 be exceeded during some temporal periods due to project c onstruction and operations. 4 25832 85Llll i v pH and Buffering System Hydrogen Lon concentrations and the buffering capacity of the aquatic ecosystem have been examined with respect to potential project effects. At present it is believed that the project effects on pH and buffering capacity will be minimal and biologically unimportar.t with respect to Susitna River fisheries ecology. No mitigation plans are proposed regarding this topic. Heavy Metals The potential for heavy metal leaching, downstream transport of toxic metals, and mobilization of toxic metals into the biological food chain has been investigated. Results from current literature researc h indicate that the project will substantially reduce the absolute quantities of most metals transported through the project to downstream areas. Literature research also indicates that the greatest potential for a problem regarding heavy metals will likely be the potential for biomagnification of mercury concentrations in organisms belonging to higher trophic levels in the reservoir and riverine aquatic ecosystems. Potentially useful mitigation measures have been briefly described. Other heavy metals besides mercury appear unlikely to cause biological problems. Pre-project and With-project monitoring of potentially toxic heavy metals have been proposed for both water and aquatic organisms. Dissolved Gas Concentrations Total dissolved gas concentrations, especially dissolved nitrogen, have been examined in the existing natural state. Analysis of the extant dissolved gas situations indicates that gas supersaturation conditions are naturally created by high volume flows through Devil Canyon rapids. Ana 1ys is of proposed project designs and operations and the watershed's hydrology result 425832 851111 v tn conclusions that the project will mtnlmlZe the chances for c reating biologica lly harmful concentrations of supersaturated gases tn aquati c habitats downstream of the project. Extensive mitigation measures are presently included in preliminary plans for design and operations o f the Susitna Hydroelectric Project 1n order to m1n1mtze the potential f e r detrimental gas supersaturation and its effects on the aquatic ecosystem. Macronutrients for Lower Trophic Level Organisms Analysis of phosphorus and nitrogen concentrations found tn the natural r1ver1ne habitat, together with estimates of the reservoir water quality conditions, indicates that both the proposed reservoirs and the Sus i tna River "middle" reach will be chronically light limited with respect to autochthanous primary productivity. Although the net downstream transport of both phosphorus and nitrogen will be substantially reduced by the project impoundments, both macronutrients should exist at concentrations tn excess of their demand by photosynthetic microbial COIIIIIIUnities tn both the reservoirs and the downstream r1ver1ne habitats directly affected by mainstem flows. Minimal rates and quantities of aquatic pr1mary productivity are to be expected ln the chronically turbid reservoir and mainstem r1ver1ne environments affected by project flows. Nutrient limitation of aquatic primary productivity LS not expected to occur under with-project conditions. ~issolved Oxygen, Organic Carbon and Project Effects Concentrations of dissolved oxygen in the natur3l riverine habitat have been found to be moderately high to very high during all seasons. Chemical oxygen demands are naturally low to moderate and are expected to remain so. Limnological conditions in both project reservoirs are expected to minimize biological oxygen demands and to m1n1m1Ze format ion of oxygen deficient waters at most depths . No detrimental environmental effects are expected Ln either the project reservoirs or 1n riverine habitats downstream due to project induced changes of dissolved oxygen concentration. 425832 851111 vi Dissolved and particulate organic carbon presentl y exi s ts in low to moderatel y high concentrations in the Susitna Ri v er. Most o f the o rganic carbon compound s are assumed to be of allochthonous origin , relat i vel y refractory, and of low food quality. The project reservoirs will 1 i k el y cause a short term increase in downstream organic carbon transrort duri n g each stage of filling, but as the reservoirs age this effect will decrease. In the long term, the project will cause a decrease in allochthono us c arbon input into and transport through the Susitna River middle reach. Microbial processing of dissolved and particulate organic carbon with i n the reservoirs may enhance its food quality with regard to microbial and invertebrate organic carbon processors located downstream. Reservoir and Riverine Productivity and Trophic Status The productivity both project reservoirs is expected to be light limited and primarily dependent on microbial processing of allochthonously derived detritus. Both reservoirs are expected to have sparse populations of most organisms, including fish. Both reservoirs are expected to be c lassi f iable as ultra-oligotrophic throughout their life expectancies. The biological productivity of the middle reach rivecine habitats whic h remain chronically turbid is expected to decrease with re3pect t o the present conditions. More peripherial riverine habitats whi c h are shallow, clear or intermittently turbid are expected to maintain or increase their biological productivity . some middle reach habitats. 425832 851111 Streambed substrate improvement lS expected 1n vii 1 • 0 IRTIODOCTIOI l . 1 OBJECTIVES The objectives of this report are mu1tifold. One primary objective i !l to describe selected water quality characteristics of the unregulated middle reach of the Sus itna River. A second objective is to estimate potential riverine water quality changes which may result from construction and op.eration of the proposed project. A third objective is to qualitatively and quantitatively describe selected aspects of the morphology and operation of the proposed project, especially with regard to potential project-induced water quality effects in both the reservoirs and the 52 mile river reach immediately downstream from the project. In this report, most limnological discussion will pertain to a fairly limited riverine reach primarily composed of the impoundment zone, located from river mile (RH) 240 downstream to RM 152, and to the "middle" river reach downstream of the project (i.e . RM 152 to RH 98.5 at the confluence of the Susitna and Chulitna Rivers). An additional report objective is to generically describe the trophic status of the ;Jnregulated Susitna River "middle" reach as it now exists, and to provide discussion regarding the approximate trophic status and water quality characteristics of the project reservoirs and downstream riverine habitats especially as they relate to riverine fisheries. 1.2 BRIEF SUMMARY OF INFORMATION SOURCES Information summarized or referenced in this report is derived in part from an assortment of published and unpublished reports produced by private organizations, and by agencies of the State of Alaska and the U.S. federal government. Many referenced documents were produced by private or public organizations under contract to the State of Alaska via the state's power development agency, the Alaska Power Authority . Additional sources of in format ion are the project's official License Application to the Federal 425832 851111 1-1 Eneray Reaulatory C~ission (FERC), the Draft Environaental Impact Stateaent produced by the FERC, published doc:uaents 1n peer reviewed scientific: journals, and articles in popular publications available in the open literature. In addition, personnal comaunications with aquatic bioloaists and other professionals havina personal experience within the Sus itna River eco•ystea as well as other siailar and dissi~ailar riverine systeas have been useful. Conceptualizations have been made about structural and functional relationships between abiotic and biotic entities which presently exist in Susitna River. Atte.pts have been ~Dade to describe trophic status chana•• which aay result froa an altered water quality regime associated with construction and operation of the proposed project. 425832 851111 l-2 2.0 'lBE SUSITNA RIVER WATERSHED - A LIMNOLOGICAL BAC~GROUND 2 .1 THE PROPOSED PROJECT Applic ation f or a major hydr o e l ectric projec t to be l o cated o n the Susit n a River has been submit ted b y the State of Alaska. Primaril y consisting of two re s ervoirs and electrical generating plants , the project will be located approximately 140 miles (220 km.) north-northeast of Anchorage, !!nd 110 miles (180 km.) south -southeast of Fairbanks (Figure 2.1 ). The pro posed system will consist of two dam s, each with long, narrow and deep res e r vo ir s, and underground powerhouses designed for a total c ombined generat i ng c apacity of 1,620 megawatts (HW). An annual average of approximatel y 6,5 70 gigawatt hours (Gwh) could potentially be produced by the system. The projec t is being proposed in order to supply the electrical power needs of customers in the south-central Alaska area known as the Railbelt . The projec t will non-comsumptively (except for small evaporation losses ) utilize waters of the Susitna River for hydroelectri c power production. All water will be reutrned directly to ~he r1ver bed v1a powerplant tailrac es, controlled releases v1a fixed-cone valves and , during rare high r unoff events in the watershed, by spillway ov e rflows (APA 1983 a,b ). 2 .2 THE PROJECT SETTING 2 .2.1 Susitna River Watershed The Susitna River watershed is the sixth largest r1ver basin in Alaska wi t h a total drainage area of 19,400 square miles (50,250 km2), and is not ranked amongst the principal 50 rivers in the United States in terms of length (Todd 1970). The Susitna and its tributaries are free flow i ng rivers fr om the i r headwaters in the glacier s o f the Alaska and Tal k eetna mounta in rang e s to the river's mouth (Figure 2 .2). 42 58 32 85 1111 2-1 I i I ,, I ..r l I I • • I ~ ; I ·-.... 2 -2 z I S I ~ -I s : 1-Cl: (.) -~ : 0 ~ a: 0.. 0 w en 0 0.. 0 a: c.. The Susitna River watershed is bounded by the Alaska Range of mountain s t o the north, west and southwest . To the east-southeast the river basi n t s bounded by the Talkeetna Mountains, while to the east -northeast the basi n lS bounded by the northern Talkeetna plateau and the Gul k ana uplands. Elevations within the drainage basin range from 20,320 feet (6,194 meters ) MSL at the south peak summit of Mt . McKinley , North America's highest peak, to sea level at the river's mouth in Cook Inlet, 320 miles downstream (AEIDC 1984. 1985 ) . Detailed r1ver1ne watershed and morphological descriptions are plentiful in several project documents (AEIDC 1985b, APA 1983a, FERC 1984, R&M Consultants, Inc. 1982) and need not be reiterated here in great detail. However, the fundamental climate, geology, morphology, hydrology, soils and vegetation will largely determine the water quality 1n the proposed reservo1rs and the downstream "middle" river reach. Therefore, they merit some description and discussion in this report since they will limit and modify the ecosystem's limnological responses to the project. This document briefly discusses selected watershed features and aspects of the water quality expected in the project reservoirs and the 52 mile nver reach immediately downstream of the proposed project, especially as the criteria relate to salmonid fishes. Limited discussion of lower river (downstream of the Sus itna-Chul itna-Talkeetna confluence) water quality wi 11 be presented when appropriate . 2.2.2. The Geological Setting Lithic materials from upper Paleozoic strata appear to be the oldest rocks known to be exposed in the watershed. They may be approximatel y 250 to 30 0 111illion years old, and appear to consist of sequences of volcanic flows which frequently contain interbedded limeston~s. Overlying the oldest rock sequence is another layer of volcanic and sedimentary rocks which consist of metabasalt flows interbedded with chert, argillite, marble, sandstone and s hale of Triassic age (200-250 m. yr. ag o ). 425832 851111 2-3 (j) a: UJ (..) < ~ " c z < (j) UJ a: < 1- QJ a: 1- a: 0 ~ < ~ " z c ::> ...J (..) z c UJ ~ (j) a: UJ 1- < 3: a: UJ > a: < z 1- (j) ::> (j) C\1 C\1 UJ a: ::> " ~ 2 -4 During the Jurassic period the older mor e surficial rocks were intruded by diorite plutons. Subsequent uplift and erosion of the former strata was followed by mar1ne deposition of a thick sequence of lower Cretaceous argillites and graywackes (Csejtey 1978). The aforementioned rock strata were subsequently faulted and folded during the late Cretaceous period (65-100 m.y. ago ). During the early Tertiary (40-65 m.y. ago) the area was again intruded by plutons of granitic and /or diorite composition and one of these diorite plutons lies under the Watana dam site. During these latter intrusions and following them, volcanic flows were extruded over the local area. At least three major periods of tectonic deformation important to the project area have taken place. The first during the Jurassic ( 160-210 m.y.ago), the second during the late Cretaceous (65-110 m.y. ago), and the third which ocurred 1n the middle to late Tertiary (40 m.y. ago). [ntrusions of plutons, crustal uplift, regional metamorphism, complex folding and faulting, and finally extensive uplift and erosion occurred during these three periods. Widespread eros1on has removed much the volcanic and sedimentary rock which was thrust over this area 65-100 m.y. ago. Durin~ the last few million years repeated glaciations have modified the Alaska and Talkeetna mountains and surrounding terrain into the basic topography which is apparent today. Glacial erosion has removed much of the soil at higher elevations, while the lower valleys and plains are covered by glacial drift of various thicknesses. At the Watana dam site bedrock is o overlain by up to 450 feet of glacial and fluvial deposits. Downstream, at the proposed Devil Canyon damsite, a thin layer of glacial drift c overs the graywacke and argillite rocks which form the canyon's V-shaped, 600 foot high, sheer valley walls through which the Susitna River flows. 425832 851111 2-5 Ground up, eroded, pulverized, glaciated and o therwise weac hered r o ck fragments from all of the forgoing lithic materials, soils and vegetati o n are the source of most o f the mileau o f water quality entities, both suspended and dissolved , which are found tn the ground waters and surfa c e waters of the Susitna River drainage. S uspended in o rganic particulat e s sampled from the Sus itna River ar r! fr om weathering of watershed geo logica 1 entities . Their generalized mineral ogy has been analyzed by polarized li ght microscopy (R&M Consultants, Inc . 1984c, and 1982d) and are present e d i n Table 2.1. Petrographic analyses of these rock fragments ts probably the simplest and best method for getting a representative sample of the fundamental mineralogy of the river's entire watershed and fo r assessing the potential of many minerals to influence and /or be a part of the Susitna River's water qual i ty milieu. Analyses of these particulates (Table 2 .2) indicates the mineral and elemental groups which will influence or be a part of the river's water qualit y . The geological landscape of barren mountain peaks, glacial til l co vered plains, exposed bedrock cliffs, and steep, bedrock walled stream canyons with gravel beds , has characteristically poor soi l development. Th e soils are typical of those developing in subarctic deposits of glacial till and outwash material. cold, wet c limates o n recent Spodzolic soils with a thin organic layer over a predominantly mineralized horizon are present in the majority of the proposed project drainage areas. 1'he soil types include acidic often saturated, peaty soils of poorly drained areas ; the a cid i c, relatively infertile forest soils; and the virtually inorganic gravels and sands along the river banks. Portions of the upper basin, including some limited areas around Watana Reservoir are underlain by la y ers of discontlnuous permafrost. Permafrost has been pr i marily iden ti fied tn localized pockets of fine grained glaciolacustrine and glacial ti ll deposits (APA 1983a,e). 425832 851111 2-6 TAaLE 2 .1 SUSITNA HYDROELECTRIC PROJECT APPROXIMATE MINERALOGY OF SUSITNA RIVER SUSPENDE D ~~DIMENTS (MODIFIED FROM R&M CONSULTANTS, INC. 1982 d , 1984b ) Mineral Quartz Feldspars (mixed) Pyr ~xenes Magnetite Limonite Clays Colloidal S i 1 ica Calcite Mica (Biotite Zircon Pyrite (FeS2) Augite 42 5832 /2 /TBL 851111 & Muscov i te ) Percent Composition 15-40 15-30 10-15 10-15 5-10 >5 >5 >2 5-20 >1 >5 5-10 2-7 TABU: ~.2 SUSIT~A YYDROELECTRIC ?ROJECT ELE !iE NT CO MP OSITION OF ~I ~ERAL S COMPARI~G CO ~O N LY .-\.'lAL YZED SUSPENDED SEDI !iE NT PARTICLES FRO ~ THE SCSIT~A ~'lD OTH ER 'lEARSY GLA CI AL RIVER D ~A I~AGES Pyo te s (FeSz l Alka l; feldspar (KA1 Si.)08 a nd Na Alz Si3 08) Pl ag ioc a se f e lds par (Na Al S t ) 08 an d Ca Alz Si208 ) Py r o xenes (Ca [~g . Fe ] Si2 06) Ir on and titan ium o x i des ~agnet i te (Fe 304) Hemat i te (Fez 0 4 ) Il menite (Fe Ti OJ ) Li monite (Z Fe z 0)•3 HzO ) Bi ot ite mica (c omp l ex K, ~g . Fe Al and Ti hyd r ox y fluo silicate ) Apa ti te [c a s (O H, F' Cl ) ( P04 ) 3 I Ol i v i ne [Fe, 1-ig ]2 S t 04 ~uso vite (comp l ex K, Al hy dr o x y fluo Cl a ys Il lite (~ A l 4 [S iz -xAl x02oJ OH4 ) Kaoli n t t e (Al4 [Si40tol (OH)8) ~o ntmor illo n i te slltc at e ) (Na,K )x+y (Al 2 -xMg x )2 [(Sil -yA l v )8 0 2o l OH4 C h 1 o r i t e ( Mg , A l) 1 z [ ( S i , A l) 8 0 2 0 ) ( 0 H 1 6 ) Ca lcit e (Ca CCJ) 425832 /2/TBL 851111 Z-8 El ements Fe , s Si, 0 Na , Ca , Al , S t , 0 Na , Ca , Al, s l. 0 Ca , ~g . Fe, 5 i' 0 Fe, 0 Fe, 0 Fe, T i , 0 Fe , 0 K, ~g' Fe, Al, s l. Ca , t' c 1. P, 0 .. Fe , :-lg, s i. 0 !<, A 1, St, 0, F K ' A 1, s i. 0 , H Al, s i' 0 Na , K, Al, ~g . s l • nHzO ~g . AI , Si, 0 Ca , c, 0 0 , F 0 Within the proposed Watana Reservoir irlUndation zone (i.e. 36,135 acres), more than 75 percent of the vegetated area is forested while most of the r~maining area is shrubland (Table 2.3). The pr~dominant forest types ar~ black spruce and mixed conifer-deciduous forest c ontaining black and white spruce, paper birch, trembling aspen, and balsam poplar. Most borrow sites are classified as shrubland or various forest types (APA 1983a,b ). Bog-like areas with the proposed impoundment zones occupy less than one percent of the area. Practically all of the area to be inundated by the Devil Canyon impoundment (i.e. 7,550 acres) 19 forested, and over 50 percent of that is of mixed conifer-deciduous type (Table 2.3). These forests and shrubland types are growing on fairly well drai~ed and sometimes relatively warm south or southwest facing soils. Forests and shrubland are also present in areas of shallow peat, glacial till deposits, lowlands, and north facing slopes. The organic soil layer beneath them is often well developed, but generally not as extensive as in the Watana inundation zone (APA l983a,b). In the upper Susitna Basin a myriad of wet or poorly drained soils elCists which are classified as wetlands. The wetlands on the upland plateaus include riparian zones, ponds and lakes which support sedge-grass tundra, low shrubland, and black spruce forest. These areas commonly consist of muskeg-bogs with thick mats of mosses, sedges, 1 ichens and dwarfed shrubs, occassional black spr<1ce, cotton grass tussocks, rushes, willows, labrador tea, Dwarf Arctic birch, blueberries, cranberries, bearberries, crowberries, bluejoint grass and polar grass . The underlying organic peat la y er is of ten thick, slightly acidic and waterlogged (APA 1983a,f,g). The riparian areas along the middle reach of the Susitna below the proposed dam sites (i.e. RM 150 downstream to RM 98) are characterized by pioneering communities of herbaceous and shrub species which are initially replaced by alder and then by balsam poplar and black cottonwood. The oldest and most stable areas are covered by mixed conifer-deciduous (white spruce and paper birch) fares t. 425832 851111 However, physical disturbances such as lce jams, 2 -Q TABLE 2.3 SUSITNA HYDROELECTRIC PROJECT TYPE AND ACREAGE OF VEGETATION TO BE IN UN DATED BY EACH IMPOUNDMENT OF THE SUSITNA HYDROELECTRIC PROJECT Vegetation Type Acreage for Each Impoundment Watana I Devil Canyon Conifer Forest 6,639 1, 048 Breadleaf Forest 720 393 Mixed Forest 5. 741 3,996 Ow art Tree Sc rub 1 1 719 101 Tall Shrub 63 59 Low Shrub 308 9 Dwarf Shrub 0 0 Graminoid Herbaceous 25 0 Sparse Vegetation 14 0 Barren Ground 68 0 Water 4,146 1 '944 Total Ac reage 19,443 7,550 Source: APA 1985 Draft License Amendment (T able E.3.83) 425832/2/TBL 851111 2-10 II Watana 8. 523 332 4,493 1,258 214 1,308 0 225 21 2 586 16,692 III flooding events, bank eroSLon and sediment deposition have c aused climax vegetation stages to be replaced by earlier seral stages along most middle reach riverine habitats (R&M Consultants, Inc. 1984a). Plant and animal materials present 1.n the drainage yield an additional spectrum of minerals and elements necessary for life. Thus, between ab io tic (geological) and biotic sources of minerals and elements contributed to t he Susitna River from its watershed, all the elements necessary for aquatic life exist in atleast moderate concentrations. The biological productivity of the Susitna River, howeve~, appears to be somewhat limited. Some of the environmental variables which apparently retard r1.ver1.ne biological productivity and biomass produc :: ion may include : low temperatures, light limitations by suspended particulates and/or ice and snow cover, high flow variability, high water velocity, particulate scour, unstable streambed substrate, and high concentrations of fine inorganic partic ulates within the str~ambed substrate interstitial spaces. 2.2.4. Mineral Resources and Human Influences Few economically important mineral resources are currently known to exist in the immediate vicinity of the reservoirs or other proposed project features. Only a limited number of placer mines which are generally characterized b y intermittent activity are known to exist in the drainage (FERC 1984). 2.2.5. Basic Watershed Climate Alaska is divided into four major climatic zones on the basis of temperature and precipitation : arctic, continental, transitional and maritime. The upper Susitna River basin (including the proposed project reservoir zones) 1.s predominantly in the continental zone , while the lower river basin extends into the more coastal, transition zone. Alaskan continental climate is characterized by extreme daily and seasonal temperature fluctuations and relativel y low precipitation. Winds at the Watana dam site are predominantl y from the southwest or northeast at approximately 20 mph (10m. 425832 8511 d 2-11 per second) or less. The approximate range of temperatur~s within the reservoir impound zones 1s between -58°F and 95°F (-50 °C to 35°) (APA l983a ). The lower river basin whi ch i.s closer to the coastline i s better buffured against extreme temperature fluctuations by the proxirni.ty of Cook Inlet marine waters, and also receives more precipitation than the r~s~rvoir zones withi n the upper river basin (APA 1983a). 2.2.6. Nutrient Limitation of Vegetation 1n Alaskan Soils Terrestrial plant production in subarctic ecosystems like the Susitna River basin appears to be nutr1ent limited. Adequate nitrogen, phosphorus, potassium and micronutrients appear to be present i.n Alaskan soils for plant growth. However, the slow rate of recycling (rather than the total quantity) of nutrients in subarctic plant communities is currently thought to limit the availability of plant nutrients. The lac k of available nitrogen is thought to be of primary importance 1n limiting terrest:i.al subarct i.e productivity. Nitrogen 1s present 1n adequate amounts in the ecosyst~m but appears to be strongly bound in the surficial organic soil layer and apparently under goes very slow recycling. Phosphoru ~ utilization by subarctic tundra plants is thought to be limited by the turnover rate and supply of available nitrog~n (Kubanis 1982; Laughlin 1973; ~cKendrick 1978; <:hapin and Van Cleve 1978; Haag 1974). lt may be reasonable to assume that more ~han adequate supplies of most plant nutrients will enter the reservo1rs a~d downstream riverine habitats especially when the expected microbial demand f 0 r them is expected to be limited by other prevailing physical conditions (high . ·.-bidity, low temperatures, etc). 2.2.7. Basic Hydrologic Regime The northernmost Susitna River headwaters originate at glaci~rs i.n the north eastern Alaska Range. The glaciers feed shallow, braided tributari~s which are heavily laden with sand, silt and clay-sized v utwash particulates. These tributaries f low southward for approximately 18 miles, converging just 425832 851111 2 -12 north of the Denali Highway bridge, and th~re join to fol"tll a shall....,, single mainstem channel. The 950 square mile drainage abo ve the Denali gauging station approaches maximal flows during the warmest da y s of the y ear which usually occur i1 l July and August, and mi nimal winter flows during January and February of approximately 100-200 cfs. Mean annual discharge at Denali is approximately 2700 cfs. Between the Denali stream gauge and Vee Cany o n the Susitna receives the glacial tributary MacLaren River (R.H. 259.8), the non-glacial, but hUDic acid stained Tyone River (R.H. 246.5), and the glacial river Oshetna (R.H . 233.4). The Susitna at Vee Canyon (R.H. 223 ) conveys a mean annual flow of approximately 6,404 cfs o f water and approximately 6.5 million tons of suspended sediment (predominately during the periods Hay-September). From Vee Canyon, the Susitna flows westerly in a deep, narrow valley towards the Watana dam site while losing altitude from approximately 2000 feet HSL to 1, 456 MSL . At the Watana dam site (IU'I 184.4) the Susitna drains an area of 5,180 sq. m1. and has a mean annual disct-arge of approximately 7986 cfs. From the Watana dam site through the upstream portion of Devil Canyon the Susitna River drops in altitude from 1,456 ~:.::c HSL to approximately 900 HSL at the Devil Canyon dam site (R.~. 152.2). The Susitna River's mean annual discharge at the Devil Canyon dam site is approximately 9084 cfs, and it drains a total area of 5810 square miles. The river drops precipitously through one-tvo miles of the lower Devil Canyon gorge to approximately 850 feet ~SL at RH 150, and then flows more southerly to the Alaska Railroad bridge and the USGS gauging station near Gold Creek (RM 136.4). The total river drainage area at Gold Creek is approximately 6,160 sq. mi. and the mean annual discharge at the Gold Creek bridge is 9703 cfs. The "middle" Susitna reach (RM 152 downstream t o RM 98 .5 ) extends from the downstream mouth of Oevil Canyon to the confluence of the Susitna and Chulitna Rivers. The stream gradient of the middle reach is approximately 8-12 feet per linear mile (Figure 2.3) or approximately 500 feet tn 52 miles. 4 25832 851111 2 -13 >14 -" li ... u a:., UJOI >o --a:-~ cto z- t=o cnc: ~-cnl .ae -~ 0 ]. -0 ::l 0 :.tl The majority (approximately 90%) of the upper and middle Susitna River flow usually occurs during the May-September periods of each year (Figure 2.4). Peak flows at the Gold Creek monitoring station have varied from 20-50 x 103 cfs in fairly average years (Figure 2.4, 1970 hydrograph) to more than 85,000 cfs during maximal flood peaks corresponding to maximal freshet discharge composed of snoW'IIIelt and rainfall (Figure 2.4 , 1964 hydrograph ). Glacial melting, which usually reaches maxima i n July and August, c an contribute to high riverine discharges when combined with relatively large precipitation events in middle or late S!Dmer (Figure 2.4, 1967 hydrograph ). Glaciers located on the south slopes of the Alaska Range oc c upy approximately 290 square miles of the Susitna River drainage basin. During drought years, such as 1969, it has been estimated that glacial melt waters may contribute approximately 30 to 50 percent of the Susitna's discharge at the Gold Creek gauging station (FERC 1984). 425832 851111 2 -1 5 II ao ~ ~ '2 ,_ , ... o l ; .. ;:... · • •• 41r&f &N& 'lOW §:~ -.:.00..0 Clll([c ·~o• ~ ·•[ ~ lZ i5 2 4 l •• ,.. ~ • ~ 0 •• 10 72 •M7 ••• 1 .# •• ~ ~ ~· -.. ~ J: i5 Z4 Figure 2 .4 Representat ;ave annual hydrographS at the watana d~ s1te and the Gold Creek gaging station for two wet years with spring (1964) and fall (1967) floods and for one dry year ( 1970). So urce : FERC 1984 ')-l"' 3.0 GEREIALIZED PROJECT DESCRIPTIONS: MORPHOLOGY AND FUNCTION 3.1 DAMS, RESERVOIRS AND BASIC CONSIDERATIONS The basic development scheme for the project invo lves three s eparate construction and operation phases: 3.1.1 Watana Stage I Watana Stage I LS the initial project. It will have a nonnal o perati ng level at el. 2,000 ft. MSL. At this level the reservoir will be approximately 39 miles long, with a maximum width of approximatel y three miles. the total volume will be 4.25 million acre-feet, and the surface area will be approximately 19,900 acres (Table 3.1). The max1mum drawdown will be 150 feet, resulting in a minimum operating level of 1,850 ft. MSL. Watana Stage I provides 2.37 million acre-feet of active storage which corresponds to roughly 40 percent o f the mean annual flow at the damsite, and while functioning alone, it will operate as a base load power plant. The Watana Stage I power house wi 11 have four generators served by five multi-level intakes spaced between el. 1,800 and el. 1,980. In general, the uppermost intake level which 1s available for usage would be operated. Turbine tailrace waters will be discharged through two 34 foot diameter, concrete 1 ined tunnels, each d is charging beneath the surface of the river tailrace at the downstream toe of th~ dam. Water for controlled spills will be withdrawn from the reservoir at el. 1, 930 and discharged through any of six, 78 inch fixed-cone valves. These fixed-cone valves compose the terminal point of the o utlet works and wa ter discharged from these valves will form a spray while falling approximately 105 feet to the downstream tailwater elevati o n at I ,455 ft. HSL. Fix ed-cone valves will be designed to dissipate the energ y of the falling waters by c reating spray o ver a relativel y large su rface area. Spray discharges are de si red 1n order to avoid plunging and the po tential for producing gas 425832 851111 3-1 Tab l e 3.1 SUSITNA HYD ROE LECT RIC PR OJEC T MORPHOLOGICAL AND HYD ROLOG IC AL FEAT URES -WATA NA RESERV OI R Elevation (maximum surcharge l evel ) (n ormal maximum l evel ) (minimum operating Level ) Max i mu.m Dr awdown Live Storage Maximum Surface Area Maximum Length Maximum Width Maximum Depth Mean Depth Gross Storage (total volume ) Shorl ine Length Mean Hydraulic Residence Time Drainage Basin Mean River Inflow Peak Flood Inflows PMF 10 ,000 yr. SO yr. 25 yr. Tailwater Elevation Area of Innundation -Stage I water and barren ground vege tation Area of Innundation -Stage III water and barren ground vegetation Total Aref 1of Innundation- S tagc II I- Watana Stage III 2,201 MSL (671 m) 2,185 MSL (666 m) 2,065 MSL (630 m) Watan a 2,014 2,000 1 , a so 150 Sta!5 e I ~S L ~S L MSL reec 120 feet ()6 .6 m) 3.7 X 106m ) tcre-ft. (4.6 X 109 mJ) 38,000 acres (60mi 2) 2 .37x1 0 6 acr-e-ft approx. 48 miles (77 km ) approx. 8 miles (12.8 km ) 735ft . (2 23m ) 250 ft. (7 6 m) 9.5 x 106 acre-ft . (11.7 X 109m3) 183 miles (295 ~) 1.65 years 5,180 mi2 (1 3,416 km) 7,990 CFS (226 !!l3s-1 ) 326,000 CFS 19,900 ac r es approx . 39 mi.. approx . 3 mi . 550 ft. ~.2S x 10 6 acre-ft 5, 180 2 mi. 7 ,990 CFS SAME (9,226 m3s-1) 156,000 CFS (4,415 m3s-1) 87,000 CFS (2,~26 76,000 CFS (2,151 SAME m3s-1 )SA..'iE m3:~-1 )sAME 1,455 ft. MSL (443.5 m) 1,455 MSL 16,692 acres addit iona l 586 acres additional 16,106 acres additional 36,135 acres 19,~4 3 acres 4, 14 6 acres 15,2 9 7 acres l / Area appr oximated from topographic maps, not utrapo l ated to estimate of a c tual i nundated surface area. 425 832 851111 3-2 supersaturation. Spillway usage is only expected t o o ccur when riverine inflows exceeding the one in 50-year flood o ccur together with c ertain rare ci rcums tances when the normal and surcharge storage c apacit ~ o f the r ~servoir ma y be exceeded (APA l983c,d). The outlet works capacity at Watana Stage I Ls 24,000 cfs, while the powerhouse capacity is about 14,000 cfs. In the event that a flood could not. be passed through the combined powerhouse and outlet works, because of energy demand and hydraulic capacity limitations , the reservoir wi 11 be allowed to surcharge to a maximum elevation of 2,014 ft. MSL. tn order to avoid spillway usage . 3.1.2 Devil Canyon Stage II Dev ;.l Canyon Stage II wi 11 be constructed next. It wi 11 have a Mnnal operating level of 1 ,455 feet l'ISL., and a maxL.mum planned drawdown of SO feet. It will impound a reservoir approximately 26 miles long with a maxtmum surface area of 7,800 acres. Total volume impounded will be 1.1 millio n a cr e-feet while pr ovi~ions are made for an active storage of 350,000 acre-fe et (APA 1983c,d). Devil Canyon Stage I I wi 11 be constructed i n a l o ng narrow gorge and will have little active s torage. Its main function will bt:. to develop hig r. head to r effic ient power generation per unit of water discharge, and it will be used extensively to generat e base load p o wer and to rereg ula t e peak water discharges released from Watana Stages I and Ill (Table 3.2 ). During construction of Devil Canyon dam the rtver wil l be diverted int o a 35.5 foot diameter concrete-lined tunnel located on the south rLver bank. The tunnel is designed to pass flood flows up to the 1 :25-ye ar summer flood r o uted through Watana Stage I. River diversion will .::llow dewatering of a?proximately 1,100 feet o f the Susitna River be tween u p s tream and downstream cofferdams. Devil Canyon dam will be a t hin arch concrete structure co nstruc ted at lt.'i 152 , and wi 11 s pan a narrow port ion of the gorge f o rming a downstream p o rt ion o f Devil Can yon . The dam's crest el e vatio n will be 1,463 f t . (446m) 4 25832 3-3 851111 Table 3 .2 SUSITNA HYDROELECTRIC PROJECT ~ORPHOLOGICAL AND HYDROLOGICAL FEAT URES DEVIL CANYON RESERV OIR -STAGE II El~v ation (maximum surcharge level) (normal maximum level ) (Minimum operating level) Maximum Drawdown Live Storage Maximum Surface Area Maximum Len~th Maximum Width Maximum Depth Mean Depth Gross Storage (total volume) Shoreline Length ~ean Hydraulic Residence Time Drainage Basin ~ean Ri v er Infl ow Peak Flood Inflows PMF 10,000 yr. SO yr. 25 yr. Tailwater Elevation Area of Innundation-Stage Irl/ Water and Barren Ground Vegetation 1,466 MSL (446 .8 m) 1 , 4 5 5 MS L ( 44 3 . 5 m ) l , 4 0 5 MS L ( 4 2 8 • 2 m ) 50 ft. (15.2 m) 350,000 a c re-ft. (432 x1 06m 3 ) 7,800 acres (12 mi.2 ) 26 mi. (42 len) approximatel y L ~ile (1.6km) 56~ ft. (1 71 m) 140 ft. (42 ;n ) 1 .1x106 acre -f t.(l.4x l 0 9m3 ) 76 mi. (123 km ) appr ox. 60 days 5,8 10 mi.2 (15 ,048 km 2 ) 9,0 80 CFS (2 56m3 s -1) 34 5 .0 00 CFS (w/Watana ) 165,000 CFS (w/Watana ) 39.00 0 CFS (w/Watana) 37,800 CFS (w /Watana) 850 ft. ~SL 7 ,550 acres to tal I, 944 a cres 5,606 a c r~s l / Area appr oximated f rom t o pographi c mdps, not extrapolated t o est imate of a c tual i nundated surface area. 4258 32 851111 3-4 MSL with an actual height of 646 ft.(197m) above its fou ndatio n. Large concrete thrust blocks o n each valley wall abutment will help support the s tructure. The dam itself will be composed of app-:-oximatel y 1.3 million cubic yards of concrete (APA 1983c,d). Four 20 foot diameter concrete-lined intake s tructures on the north end of the dam will draw water from two near surface depths between el. 1,455 and el. 1 ,405 MSL into C.Jncrete-lined penstock tunnels. These tunnel s will conduct water to the underground powerhouse where four 150 MW turbine generators will be ~ocated. Each turbine will be rifted fo r a maxtmum discharge of 3,680 CFS (i.e. 14,700 CFS total potential discharge from all four turbines combined). Tailrace waters exiting the turbines will be routed downstream approximately 6,800 feet through a single 38 foot diameter concrete-lined tunnel. Thus tailrace waters from Devil Canyon turbines will be discharged under the river surface and downstream of nearly all the violent lower Devil Canyon rapids (APA l983c,d). This long tailrace tunnel discharge will help dilute any flows still discharged through Devil Canyon outletwork3 and /o r spillways and will thereby help avoid any downstream gas supersaturation conditions. Auxiliary outlet facilities of Devil Canyon Dam will consist of seven fixed-cone valves l o cated 1n the lower portion of the dam. The seven fixed-cone valves will have a combined maximal discharge capacity or appr o ximately 42,000 CFS when the reservotr pool level is at el. 1,455. Four 102 inch, and three 90 inch d1ameter valve s will be i nstalled at d am elevati o ns of 1,050 ft. MSL and 9JO ft. MSL respectivel y. The fixed-cone valves at Devil Canyon dam, opposed to those at Watana dam, will not draw water from the reservoir surface. Instead, the cone valves at Devil Canyon dam will draw water from deep with in the reservoir's hypolimnion at depths of 405 ft. (123m) and 525 ft. (160m) (APA 1983 c,d). Controlled releases from Devil Canyon dam's fi xed-cone valves, as at Watana, will be in the form of a spray from the downstream face of the dam. Sprays from the mo re s hallow valve s will be discharged from an elevation o f 170 425832 851111 3-5 feet above tailwaters, while sprays from then deeper valves will be discharged approximately 50 feet above downstr e am tailwater s . The tailwater s urface el evat ion down st ream of Devil Can yon dam will be appr oximatel y 9 00 teet ~SL, and f r om there , di scharged wat e rs will enter the remaining one to two mile stretch of Devil Canyon rapids bef o re mixing with tailrace discharges and then passtng down s tream thro ugh the middle rea c h (A PA 1983c,d). 3.1.3 Watana Stage III Watana Stage III involves raising the Stage I structure b y 180 feet t o its original planned height. Watana ~tage III will have a normal o perating level at el. 2,185 and a planned maximum drawdown of 120 feet. At el. 2,185 the reservoir would cover 38,000 surface a c res, be approx1matel y 48 miles long and have a live storage 3.7xl06 acre-feet (APA 1983c,d) (Table 3.1). In the final planned configuration Watana Stage III would be utilized as peaking power plant with the mo re downstream Devil Can yon Reservoi r used t o reregulate its downstream dis c harge s . In general, neither reservoir will have an extensive li ttoral zone stnce the topography within each impoundment zone t s characterized by relativel y steep valley walls. Average hydraulic residence time will be relatively sho rt fo r Watana and very short for Devil Canyon Reservoir . Both reserv oirs will be relatively deep and cold, and both will have re la t ively great maximum and mean depths. Both reservoirs will have relatively small surfac e area t o water volume ratios and will have very shallow e uphotic zones. Each reservo tr ts expected to remain relativel y unproductive (b iol og i ca ll y speaking) based on the morphologi ca l and hydr o l ogic al c harac tertst1cs al o ne (We tzel 1975). During construction of Watana Stage III, the dam wou ld be rai s ed and t wo additi o nal power unit s added to the f o ur previously e xi sting ones . The se two additional units would hav e water intakes at four level s between el . 2,000 and e l. 2,170. Fo ur additi o nal intakes fo r wi::hdrawals betweer. e l . 2,0 00 and el . 2 ,1 70 will also be added to the exi s ting intakes fo r the four 425832 851111 3-6 generators o riginal !)' install e d dur i ng Watana Stage l. Thus Watana S tage III wi ll have six gete rat o rs, four of which may be abie to d raw wa te r f r o m a s many as nine depths between el. 1 ,800 and el . 2,170 . Watana Stage III p o werh o us e hydraulic capacities total appr o ximatel y 22,000 cfs with an additional out let wo r ks total c apac ity of approximatel y 30,000 cfs. 3.2 GENERALIZED RESERVOIR OPERATIONS AND DOWNSTREAM FL OWS Re s ervoir operation simulations have been co nduct e d in o rde r t o o pt imi ze the projec t benefits with respect to power production, while simultaneous ly conf o rming t o environmental co nstra i nts s pect fi ed fo r pr o tec t t on of c~rtain habitat features downstream. Ke y constraints o n the res ervoi r o perat ion simulations are the operating guide and the minimum and maxunum in stream flow requirement s at Gold Creek whi c h mu s t be s ati sfied each week. The system operating guide g overns the releas e for power while t h e total powerhouse releases are restri c ted b y the discharges required t o meet the system power demand. An y addi t i o na l flow requi red to meet downstreaw environmental flow requirement is released through the o ut Let work s of t he appropriate dam(s). Flood releases to maintain dam safety requiremen t s are first made t hr o ugh the o ut le t wo rk s and, addttio nal ly tf necessary, th r o u gh the approprtate spillway(s ). Case E-VI is the Appli c ant's s elec ted best f low c a se fo r o ptimi ztng power generation and downstream environme~tal habttat pr otection. Detailed di scussion of E-VI and other f low regime co nsiderations are co n t a ined tn another proj ect document ( Harza-Ebasco 1984f). Ba sic a lly, Case E-VI f l o w requi rem e nt s matntain summ e r mtnimum disch ar ges (a t Go ld Creek) of !3 -9,000 cfs, while allowing summer ma ximum dtscha r ges of no more than 35,000 cfs ( ~xce pt during the rare event o f large flood ing with a re turn period o f g reater th an L i n 50 ye ar s). Winter time flows wil l be cons t r ai n ed between 3 ,000 a nd 16 ,000 cfs and wtl l be a llowe d t o v ar y withi n ce rtat n bounds in 425832 851111 3-7 order to satisfy certain water qualit y constraints while still me~ting the system power demand. Approximate streamfl:1ws simul ated t o be ~x c ~eded 50 per c ent of the time for the staged hydroelectric project Ln 1996 (Stage r>, 2007 (Stage II), 2008 (Stage III), 20'!0 (Stage III) have been displayed in Figures 3 .1, 3.2, 3.3, and 3.4 respectively. 3.2.1 Watana Stage I Operation Alone A mtnimum instream flow requirement ts prescribed at Gold Creek to ensure that the project will release flows for environmental purpo s es. The historical intervening flow between Watana and Gold Creek ts assum~d to be available t0 supplement the project releases to meet the mtntmum flow requirement. If the flow prescribed by the operating guide does not meet the environmental requirement, the operation program will attempt t o release more water through the powerhouse in order to meet the requirement. If the release required to meet environmental 1 low requirements exceeds t he maximum powerhous e flow to meet the energy demands, the dif fe rence between the r e q~.ired outflow and the maximum power discharge ts released through the outlet works. This outlet works release is called an environmental release since it is made only to meet the environmental f low requirement and is not used ~o r po wer generation. The o utlet works capacity at Watana Stage I t s 24,000 cfs, while the powerhouse c apacity is about 14,000 cfs. In t he event that a flood could no t be pa ssed through the powerhouse and ou tlet works, bec ause of energy demand and hydraulic capacity limitations , the reserv o tr is allowed t o sur c harge above the normal max1mum water surface el ev ation . This so.Jrc harging is done to avoid the use of the spillwa y for floo ds less than the 50 -year event . A maximum surcharge lev el of el. 2 ,014 ft. is permitted before the spillway o p e rat es . :.25832 851111 3-8 o rder to satisfy certain water quality constraints while st ill meeting the sys tem power demand. Approximate streamflows s imulated t o be C!xc~eded Su percent o f the time for the staged h yd r oe l ect ri c project tn 1996 (St a ge I ), 2 0 07 (S tage II ), 20 08 (Stage III), 2020 (S tage III) have been displayed in Figures 3 .1, 3.2, 3.3, and 3.4 respectivel y . 3.2.1 Watana Stage I Operation Alone A minimum instream flow requirement 1s prescribed at Gold Creek to ensure that the project will release flows for enviro nmental purposes. The historical intervening flow between Watana and Gold Creek LS assumed to be available to supplement the project releases to meet the m1n1mum flow requirement. If the flow prescribed by the operating guide do e s not meet the environmental requirement, the operatio n program will attempt t o release more wat e r through the powerhouse in order to meet the requ i rement. If the release required to meet environmental flow requirement s exc eed s the maximum powerhouse flow to meet the energy demands, the di ffe rence between the required outflow and the maximum power discharge 1s released thro ugh the outlet works. This outlet works release is called an environmen t al release since it is made only to meet the environmental f low requirement and is not used for power generation. The outlet works capacity at Watana Stage 1 is 24,000 cfs, while the p owerhou se capacity is about 14,000 cfs. In the event that a f l ood could not be pa ss ed through the powerhouse and o utlet work s, because of energy demand and h yd rauli c capacity l imitations, th e res e rvo1 r 1s al lowed to su r c harge above the normal max1mum water surface elevat ion. This surcharging is done to avoid the use of the s p i l l wa y fo r floo d s less than the 50-year event. A maximum s urcharge l e v el of el. 2,0 14 ft. is permitted befo re the spillway operates. 425832 851111 3-8 D s c h a r g • n c f • w I '-D THOUSANDS 30 25 . .. .J • ~ ·"':O ~·· •·•• ••. '1 · ' ~ v. 'l' • ~·. ,.. ...... ~;.A, • • \ . ' 't ! '\: '> ~ ·; ., ,I -. J . ! . " !": • ;: .... ·~ . :, ,;• !,.,,I)~ . \:• UAXIMUU•31.000 ote .": I ' . ; ~ ; :;; ·._ CAll! E-VI UAX ...... fLOW ··"-'wu.t 20 IS 10 5 0 . · •. · ·• : RI!OUIRENINTI , -r. i • ,· ; •. ~ ..... J. ~\.I ··.~ '""' · .. t i ..... ;.~·\·r:--· ------·· ............. , -----------... , .............. __ ' JAN FEB . • ' ' . .. HAR --. .._ APR • • I •• ... • • • • • • , • • • \ . ' . ' . ... ... -. ·' ' . -.. .... . I : . • HAY CASE E-VI UIHIUUU FLO~· REOUIAEUENTI .. I , . • ~ i ~ .. o~~·1 r •· , JUN JUL AUG SEP OCT t1 on lh ,.. .. ~,~ ' ,_/ ,~ ....... / ,' ' ~ ,.. , ,~ ......... NOV DEC MOTU: 1. HYDROLOGICAL DATA FROU PERIOD 1860-11 8TAOED CQNSTRUCTIC ITAOF t 3. PROJECTED ENERQY DEMAND& FOR 1888' 4. E -VI FLOW REQUIRUAE LEGEND NATURAL CONOITIC FLOWS FOR LICEN~ APPLICA TaON PROJ FLOWS FOR STAOE CONSTRUCTION STAGE I FIGURE 3 .1 M.A-A POWUI AUJHOMI I ~,__.it C•-= ..... u · IUIII .. & IIIII I I fii&•PI IICIIIII ••• or ••• tuor --I·~~·.£!!!! ~;_... ~--- -------~------~-~--- D I • c h a r g • n c ...... I >-' 0 f • THOUSANDS 39 r •• ' 25 29 15 . .... '" l •• .. 4 19 --------, ...... ----...... ·---....... _ 5 .... _____ . 0 JAN FEB MAR APR HAY UAXIUUU•U.OOO ote • • I I I I • • \ ;, C.AIE E-VI UJHIUUW fLOW •' · REQUIAIUINTI · . I . ' ~ .. , ' ·~ IJ •• I l ·•,flt I I •· n 1!1'"-' ... -----" ~ro-' ,. • ~ ••• ,-.. ,/ "' ,/ .......... JUN JUL AUG SEP OCT NOV DEC Monl h NO Til: t. HYDROLOGICAL DA T FROU PERIOD 1 8~0 - 1 . STAGED ~ON&TRUCl 8TAO£ 2 3. PROJECTED ENERG't DEUAND8 fOR 2007· 4 . E -VI FLOW REQUIRE! LEGEND NATURAL CONDI' flOWS fOR LICE r APPLICATION PR• (2020 fHEAOY OEM. FLOWS fOR STA~ CONSTRUCTION (2007 ENERGY DE , FIGURE 3 2 AlA-A f'OWla A&ll-11 ._...........,,tc•• ..,.£, . ., .. , .. ·~··· ........ . IICIIIII ••• o., ....... __ 1 ., QOll C •11• === ~--, ---·----.. 0 l G c h a r g • n c r • w I ,...... ,...... THOUSANDS 30 25 29 15 10 5 0 ' '.:. .: • 1 :•_\.'-• ~ .l .~,:.·\~': ~ :·~~u .... ...,, t ' .' .... '• ,;•.r,C'Q"'t:~·\ ~ a _, .':"t (.J :.f}' 'IV l ~ •• ) ...... ~-\·~.:·:. 'l. ~· • t , , I , • l ,. 11 • . ' ~ .• : ~ ~ : r,; • :I(, ·.'. • , l.. ,. ·•z\o' ... ;,' ~;' ' . '· • , i . .. . .. • . ' I ,• -; "'".;' .t.l i1 'J .r. c i ( , .... -\ ~. ~;"':•: r ... ·\~t~· :: .:. ~ , ., • 4 ' .. ~ i'}~·J ,:'''•''l': ... -~ t t .... ·" ......... ~-~... .l . "'·" i. -·. H-: ~\:: \' CAll I-VI MA ..... r• \Vill/r•.~· ,r. . · AIOUIIINIII'fl "'·~•"'"ILK ~t . .--lr\, ..... ' • .. 't,J c \~ 0 4 .,l '!41>-V • •, , : ;,·;rr:. ll'~,-,'I }. • ., I, I ·..;.. •' t.,.:t·~~~·~~-~; !. .. \!i'':f · ~(~·jt ... /~:~ ,. ·' .. ~. ··)·.~. ; \1'~ : •. n • .,..·. . . ·, ·;'·. :·: :·, .,,,.._~';···.' .: .. 1 ,·· J • ·::.. ; 4·' • · • ., • • ·s~-~ ~!1 ,, .J ,.,. , •• ,·1·, ..... ... • 'l J"·..J "• . ' l . " ,~\~,,: .·,:-·,.. ··~,··'·,.: l. \J. • ~-,,;. • ._,_. • • • -a • ~··;..,~·.4\, ... · i"'~ --------........ ..... __ ------------. ------........... JAN FE B MAR APR NA " I" WAXIUU .. •II,OOO ote • • I I I I • • I I I I I I I I I , CA8E E -VI WIHIUUW FLOW REQUIR.EWENT8 .. ~ l ' '-'UN ~UL AUG SE P Mo nlhs ......... _ _,-"~~~ . -- _ .. , . "' , .. ... ----,. OCT NOV DEC NOTI!I: 1. HYDROLOGICAL OAT J FROW PERIOD 1850-1 2 . 8TAOEO CONSTRUCT ITAOE 3 I . PROJECTED ENERGY DEWAN08 FOR 2008 4. E-VI FLOW REQUIRE~ LEGEND NATURAL CONOil FLOWS FOR LICEt APPLICA liON PR< t2020 ENERGY oa.tJ FLOWS FOR &TAO CONSTRUCTION (2008 ENERGY Oft.A fiGURE 3 .3 ALA• II rowt:a WJHOMI ..... ....._,,,, •• ..o .. ~ "lllf .. A I l VIa lfii AM I au:••••• ......... ,.,. -=---;;;:.1" ' Q" • c .. !!.. .::..-;::. -I -- D 5 c h a ,. 9 • n c f • .w I ..... N THOUSANDS 30 25 20 15 l ..• -~:·_ :>.; .. ·;):.:'::.:·.,. .. t..;' ; ,, ... ,: h .• . · ·:~~:<:!.:~ :) . • • !' ~ i.~J· ~;~ u • .. :,~r.· CAIE ·I~Vi UAX...U.. fLOW .':•:: .• , aenueuwaTI . ·• ·:: 'J;.-t ' • ., 1 l" ' I ~ · '' ' '\ ./~ f ,\,.. • ... : ~r ' ..... ,.:.""~.~~~_.. . .,~ ·~·" .. ,\-:l~· ,. '..:h i~ ... ,~ ~~~· '!I ~ "',.t ·"' ~ ,, .t • .#' ~:-:; i· ~.~~ ...... ·,·', .. ~.·:,,.,."'-:1,"-;t#.'fr:t ~ ,~ . ~ .. .,: .. ,·~-t,'f "~'-"'·( ..... ~-. ' ·~--.f. it 1'' :' • • ~ I ;J ~~j·~·il t ".~~\~.l . : • i> '· . (-.. : .l ' . ..;.£ ... ! . ';~.·..P •• •• • lo; J~, '. · ' .; r· .._ I J t ~ .. t WAXIWUW•3I.OOO eta 10 -----........... *''----~. ,1' -' '-...... .. ....... __ 5 0 --. ~--.;:. "" . CAIE f-VI WIHIWUW FLOW REQUIRE WENT& ·! . ' . ~ t• 'J • ' .. { ..... ~ .. ~ "f ..... ,. I. • .. ~; J • . . • • • (\ ~ .. • .-· ~ ...... f ••• ', : • .. ~ ~-. ' , ... 'i .. !(! :' ' ' , ). ! . ..,.-;.a .'. ll; .. ~ . ' • '4 ) .~ l· ' t.r.t .... ' • \. • ·~,..;( • ~ .. JJ ~I·.. I • ·-. •· )'~':~: I~f~l ·· ., · .... :'; ..... _,,l.r .. ,'!'i .'J .. • \ . ·~;."f·v ···· ~" ·r .. ~ . :. l o,'·.·~>'i'l~.: ' ·r .: ~:'.!f' •r.J~ :t·,-:·S~"~ ; , ~, ,J, .. ·. • ' ).,; 1'J 1!!~41-r· t ' • •• !•t ) o · 1· · t , ;,' I t.,. v,. · ·J· • · ~ .. , ..... ~· .. ··:)··~t ·r" ~ • •1'. • .th . ) I ;~, .,. . . . I ' ~+5 L-~·t. ( t .. •:J ' ... '. . .~ 1 ... ~· ., . '·I'· . •. '•. ·;~~.···· '· 1 ,<;1 .. ~.. • •• , • . ,. . . ~.~v · ~ . ~·., ·.··: 'li:l c ~ .. • .. , 1• ·, ·t ~'J "I.l,;Jt•lf.'· ~. r:•;" ·.· 1,11 T• It• "' ) , • If I • ( 1{.~, .. ~~ ... ,..... . ' .. ~ ... J • ·~,~ /'' JAN FEB NAR APR MAY J UN JUL AUG SEP OCT NOV DEC Mon l h NO Til: 1. HYDROLOGICAL OAT A fROW PERIOD 1860-1 1 2. 8TAGEO CONSTRUC T~! llAGE ;t . 3 . PROJECTED ~RG Y OEWANDS fOR 2020 . •. E -VI FLOW REOUIR f U I LEGEND NATURAL CON Dill fLOWS FOR LIC E N APPLICATION PR O FLOWS FOR STA G I CON STRU CTION STAGE 3 f iGUR .4 A&.A•• ro-" ,.., .. ,...,' ---~-;;......!!~!~ ~!'. lllllfMA •• ., •• I T •I4.,,1 IIC:IIIII •• • o• ,,., uor- -"~L!~~!~~ =-:-:-=-·-,---·- 3.2.2 Operation of Either Watana Stage I or Stage III with Devil Canyon Stage II For double reservolr operation, Devil Canyon o perates as a run-of-river f acility as long as the reservoir is full. The Devil Canyo n Peservoir is to be refill ed if the reservoir lS not full, if the total inflow is greater than the release required to meet the environmental flow requirement. The t o tal energy g~nerated at Watana and Devil Canyon is compared to the system energy demand and adjusted Ln successive iterations by increasing o r decreasing powerhouse discharges to meet system energy demands. An operating guide lS developed and applied to optimize the Watana powerhouse releases for power generation. Minimum instream flow requireuents and constraints on rate of change of d i scharge are also applied. The intervening flow between Devil Canyon and Gold Creek is assumed t o be available to supplement the project releases to meet the minimum f low requirements. If the environmental flow r~quirement is not met by powerhouse discharges, more water lS released through the Devil Canyon powerhouse in order to meet the requirement and the Devil Canyon Reservoir will drawn down. If the increased release thr ough the Devil Canyon powerplant would cause the total energy generation t o be gre•.1ter than the s ystem demand, the release from the Watana powerplant is reduced. This lS done to minimize Devil Canyon outlet works releases whi ch ma y result Ln reduced temperatures downstream. If the release required to meet environmental flow requirements exceeds the Devil Canyon powerhouse discharge to meet energy demands, then the di f fer- ence is released from the Devil Canyon outlet works. In the s ummer of dr y years when the system energy demand lS low and the downstream flow requirement is high, Dev i 1 Canyon may be drawn down cone inuous ly. 425832 851111 3-13 1 f the water level at Devil Canyon reaches the minimum operating level of el. 1,405 ft, Watana mus~ then release water to satisfy the minimum fl~w req uiremen t. If t he release from Watana for the minimum flow requirement woul d generate more energy than the required amount part of the release would be diverted to the outlet works. The powerhouse hydrauli c capacities are about 14,000 cfs at both Watana Stage I and Devil Canyon. The capacity is about 22,000 cfs for Watana Stage III. The outlet works capacity at Devil Canyon is 42,000 cfs while the capac i t y at Watana is 24,0vG c:s 1n Stage I and 30,000 cfs in Stage III . In the event that a flood could not be passed through the powerhouse and outlet works, because of energy demand and hydraulic capacity limitations, Watana lS ~l lowed to surcharge above its normal maximum level . The maximum surcharge level lS el. 2,014 ft. for the Watana Stage I Dam and el. 2,193 ft , fo r the Stage III Dam. 425832 851111 )-14 4.0 BASELINE WATER QUALITY AND EXPECTED WATER QUALITY CHANCES 4 .1 BASELINE WATER QUALITY-THE ~!DOLE RIVER REACH The unreg ulated Susitna River exhibit s continuo u s l y ch ang in g ~o~ater qu ali.t y c haracteristies. As the continuum of c limat o l o gi c al c haract erist ics graduall y shi f ts through annual and seasonal c hanges the riveri n e ~o~ater quality follo~o~s suit. For the sake of limnological simpli ci t y, ~o~e c an briefly describe the t~o~v most c ontrasting periods o f ~o~ater q ual i t y ~o~hi c h c o nstit u te the "summer" or o pen ~o~ater season and the "~o~inter" o r ice c o ve red season. The spring and fall transition peri o ds !>et~o~een c haracteri s tic summer and ~o~inter ~o~ater quality period vary ~o~ith respect to their duratio n and annual timi ,~. Pr ~liminary observat i on of limnolo gical phen omena in the middle river reach, however, indicates that spring and fall ~o~ater quality transition periods may have substantial biologic al importance. The tee covered season is characterized by relatively lo~o~ and s tab~~ flows, as ts the case for many subar c tic riv ers (N.O.A.A 1982 ). It i s characterized by relatively high dissolved solids cont~nt and concentrations of suspended particulates, and both of these characteristics are due to the dominant influences of gound ~o~ater o n the river's ~o~i n ter surface flo~o~s . Lo~o~ and stable ~o~inter surface fl o~o~s are primarily due to intersection of mainstem river channels ~o~ith the surface of the ground ~o~ater table in t h e valley's subsurface aquifer . :;,e acidi c nature o f atmospheri c precipitation some of ~o~hich percolates thr~ugh the ~o~atershed soils and s ub- surface lithic materials 1s partially res~onsible for the di s solution of minerals and elements resulting tn the grJund waters's relativel y h igh dissolved solids content. Biological C ~(abolism of organic soil materials together ~o~ith abiotic chemical reactions often add to the di sso lved so lids c ontent of ground water but ma y also reduce its concentration o f disso lved oxygen and change concentrations other dissolved gases. Carbon dioxide contents of Sus itna River ground ~o~ater, for example , are often relativel y high ~o~hile di s solved ox y gen contents are relative ly lo~o~ compared to sur f ace 425832 851111 4-1 waters which are more nearly equilibrated with atmospheric gas concentrations. The open water season is characterized by relatively high and variable surface flows. It 1s also characterized by a more dilute chemical :nilieu and by higher suspended particulate concentrations tn the Susitna River. Approximate water quality characteristics of both the winter and summer season may be compared and contrasted (Table 4.1). Concentrations of selected metals, which have the potential to be toxic in some chemical states, are discussed in greater detail 1n another section of this report which deals primarily with heavy metals (eg. Ch. 7). Freshet runoff, atmospheric precipitation, glacial melt, and most other ~ributary runoff dilute river surface flow concentrations of many dissolved chemical entities duri~: ~he open water season. Higher r :vertne discharges during the open water season also erode and resuspend bed load and stream bank particulates resulting in large and variable concentrations of riverine suspended sediments. 425832 851111 4-2 Tab l e 4.1 SUSITNA HYD ROELE CTRIC PR OJEC T APPROXI~TE WA TER QUALITY CHARACTERISTIC S OF THE SUS rTNA RIV F.R AT GO LD CREEK DUR ING MAY-OCT OBER VS. NOVE~BER-APIIL. Paramet er Range Mean ~ean Flow (cf s ) 4,000-50 ,000 To tal Sus pended Sediments (mg /1 ) 10-2,600 Turbidity (NTU) 20-740 Total Diss olve d Solids (mg /1) 50-150 Conductivity (umhos /cm 2 ) 80-225 Color (platinum co balt unit s) 0-110 ph (ph units) 6.5-8.0 Alkalinity (mg /1 as Ca C03) 25-85 Hardness (mg/1 as CaC03) 30-110 Total Organic Carbon (mg /1) l-3 Chemical Oxygen Demand (mg/1) 2-22 Total Phosphorus (ug /1) 10-400 Total Nitr0gen (ug/1 ) 200-900 Temperature (°C) 2-13 Chloride (mg /1 ) 1-15 Calcium-dissolved (mg/1) 10-38 Sulfate (mg /1 ) 1-30 Dissolved Oxygen (mg/1) 8.5-13.5 Dissolved Oxygen (% of Saturat ion ) 80-110 Phosphate-ortho (ug/l) 0-100 Magnesium-dissolved (mg /1 ) 1-8 Sod ium-dissolved (mg /1) 2-1 0 Potassium -diss o lved (mg /1) 1-5 26,000 700 200 90 145 15 7.3 50 60 3 11 120 600 9 5 19 16 12 102 <10 3 4 2 Nov ember -April Range Mean 700 -4 ,000 1,600 0-8 <8 0-5 0 100-180 15 0 80-300 240 C-40 5 7 .0-8.0 7 .5 45 -90 70 60-120 100 1-5 3 2-16 9 10 -50 30 500-1000 7 so 0 -2 0 7-35 2 2 18-40 29 10 -38 20 l l . 0-1 6 . 0 l 4 76 -1 10 98 10 -30 20 3-1 0 5 5-21 13 1-5 2 Sou rce : Rand M Consultants, Inc. and L.A. Peterson and Assoc. 1982; APA 1983; Rand M Consultants, Inc. 1982. 425832 851111 4-3 4.2 EXPECTED ·WATER QUALITY CHANGES -GENERALIZED Construction and operation of the pr o p osed pr oject will al te r most water quality characteristics 1n t he reservo1rs a nd 1n do wn s tr eam rL verLne h abitat s whi ch are direct l y inundated by mai nstem f l ows. Im p oundment o f the r1ver will reduce the f requenc y and t he amplitude of the annua l ly cyclic water quality fluctuations observed i n the unregulated r1v~r. Pr oj e ct operation will also cause a temporal phase shift of many naturally occuring water quality regimes. Maximum suspended sediment co nc entrat ions, for example, will probably occur 1n the late summer, fa ll, and e ar ly win ter seasons, instead of during the late spring and summer whi c h i s wh~n natural maxima occur. Water quality and quantity changes induced by the project are no t expec ted to cause either the reservoir r. or downstream riverine hab itat s to be uninhabitable by most naturally occurring fl o ra and fauna. It is expected, however, that project induced water quality changes in the reservoi rs and in downstream riverine habitats will affect biomass production at all trophic levels, especially 1n the aquatic habitats which are constantly turbid . Reduced biological productivity at most trophic levels may be the effect if chronically high turbidity levels prevail. Mitigation measures are being proposed, however, to help maintain natural levels of fish product iv it y. Several commonly measured water quality c haracteristics have been ~xamined in order to estimate the approximate values and /or concentrations at which they will exist in the project reservoirs and downstream mains t em channels of the middle river reach (Table 4.2). Most project induced c hanges 1n water quality are expected to cause relatively unimportant environmental effects with respect to aquatic biology 1n both the res ervoirs and down s tream riverine habitats in the middle river. 4.3 SELECTED WATER QUALITY ISSUES Certain expected water quality changes have been labeled as environmental 425832 4-4 851111 "issues" and,· as such, have been more tho r oughly examined wi th regard to p o tent i.al environmental effects . ~ore detailed discussio n s o f these wa te r quality entities and their potential envi r onme ntal ef fects are fo und i n the follo wi ng chapters of tnis text (eg. Ch apt e r s 5, 6, 7, 8, 9, 10 an d ll. 425832 851111 4-5 TA BLE 4 .2 EST I ~TED APPRO X I ~TE ~A TER QU ALITY CHARA CT ERISTIC S OF TH£ S .H.P. RESERV OIRS AND CO WN ST R.EA11 RE LE ASE 'oiA TER Parame t er Est i mated Va lue Tr ue Colo r Tr o phi c S tat us ~ean Annual Primary Pr oductivi t y(Reservo irs ) ~ean Annual Primary Productiv i ty (Susi t na River Middle Reach) Maximal Euphotic Zone Tempertures Phytoplankton Standing Crop (Reservoirs ) Phytoplankton Volume (Reservo i rs ) Dominant Phytoplankters (Reservoirs ) Dominant Periphyton (Susitna River Middle Reac: h) Dominant Zooplankters (Reservoirs) Dominant ~··~oinvertebrates (Susitna River Middle Reach) total Dissolved Solids Euphotic Zone (to 1% of PAR) total Organic Carbon Particulate Organic Carbon Dis solved Organic Carbon Alkalinity pH Conductivity Dissolved Ox ygen Hardness total Filterable Sediments (0.45 u filters ) total Suspended Sediments (centrifuged) turbidity total Organic:+N03•+NH4 Nitrogen total Bioavailable P 425832 851111 4-6 <1 00 pc u Ul tra-oligo tr o phic l -20 g Car bo n m 2/y r Unknown <15 °C <1.0 gm /m3 (wet we igh t ) <1.0 cm3;m3 Chloroph yc eae Bacillariophyceae , Chrysophyc eae, Dinophyceae, Cyanophyceae Cyanophyceae, Chlorophyceae, Bac:illariophyceae Rotifera and Copepoda Chironomidae ~1 0 0 mg ll 0.1 -3 .0 meters (flu ctuat i ng ) <5 mg /1 <0.5 mgll <5 .0 mg/1 60-100 m g /l as Ca C03 6.0-8.0 range ; 7.0 • mean 100-150 umhos /cm2 8 .0+ mg /1 ; 80+% Sat u rat ion 70-100 mg /1 as CaCO) 0-200 q /1 5-200 mg /1 100-400 NTU < 1000 ug / 1 <2 0-30 ug /1 5.0 AM ALT!UD SUSPENDED SEDIMENT AND TURBIDITY REGIME The s igni ficance of ch anges in the natural regime of suspended sediments and turbidit y o n salmon and res ident fish habitats has been identified as a fishe ries issu e fo r this pro je~t . The fo ll o wi ng text summ arizes the curr ent sta t us of o ur knowledge regar din g this t o p ic. 5.1 INTRODUCTION All river s tend to establish a dynamic equilibrium with respect t o s ed iment transport and c hannel morphology . Sediment swept downstream from one reach during degradation tends to be replaced, on the average, by sediment inputs from some other upstream reach (Leopold et al . 19 64, Morisawa 1968, Fan 1976, Simmons 1979). Dams disturb the natural dynami c equilibrium of riverine sediment transport by stopping most downstream sediment transport and replacement . Host sediments which presently depend upon the river's tractive force fo r downstream movement are expected to be trapped upstream of the dams (R & M Consultants, Inc. l982c; Peratrovich, Nottignham and Drage , Inc. and I.P. Hutchinson 1982; FERC 1984; Harza-Ebasco Susitna Joint Venture 1984). Suspended particulates passing downstream through the ?roject structures wi 11 be fewer, smaller, and their average mineral compos it ion and three-dimensional shapes will be altered from the natural conditions (Anderson et al . 1972; Ostrem 1975; Ostrem et al. 1970; R & M Consultants, Inc. l982a; R & H Consultants, Inc. l982d; R & M Consultants, Inc. 1985). The present temporal regimes of bedload transport , sus pended sediment transport, turbidity and streambed substrate sedimentation are seasonally dichot o mous and variable. River regulation wi 11 make these regimes more seasonally continuous and less variable. Extensive modeling efforts utilizing DYRESM.!./ and espec i ally created sub- lfDYRESM : 425832 851111 Dynamic reservotr simulation model Hebbert and Loh 197 7) 5-1 (Patterson, Imberger, routines dea~ing with suspended sediments (TSS) have been used to estimate the size characteristtcs and mean monthly concent rati o n of partlculates whi c h will exit the project reservoirs during oper ational phas~s of Stage I, 11 and III. Sedimentation column studies using Susitna River water samples have been made to investigate settling patterns of particulates and the char a ctenstics of "suspendable" particles . Review of other settling column studies together with study of data from existing glacial lake and glacial river ecosystems has been used to esta b lish the best approximate relation- ship between sus pended sedimen ts and tu r bidity fo r use with this project . Because of the ba sic interaction between biological activity and light it seemed appropriate t o examine and attemp t to c a lib rate an approximate rela- tionship between turbidity and light trans mi ssion. An appr ox ima te relation bet ween tur bidity and the max i mum depth of the eupho t i c zone wa s developed . This re lationship gives us a co ar s e t ool fo r use in estimating the ma'<tmum volume a~d /o r area of the mos t biologically active sites whi ch wi ll re ceive incident light in both the res e rvoir and riverine aquati c habitats. To date, only generalizations can be made about the interactions between the altered sediment reg ime, the expected With-project flushing of existing fine sediments from some streambed s ubstrates , and the sedimentation dynamics associated with the Projec t 's estimated oper ati onal sediment regime. Pro jec t induced alterations of the s ediment and turbidity re gime are expected t o minimi ze potential bio logi cal productivit y in both reservoirs and ln some downstream riverine habi tats. We are presently unable to quant i tative ly estimate the Susitna River Middle Rea ch pr o duc tivit y changes t o be expected at the mi crobial detritovore, prtmary pro d ucer an d macroinvertebrate trophic levels when compared to natural conditio ns. However, a limited perspective of water quality characteri s tics estimat e d for down st ream discharges togeth e r with limited familiarity with various other riverine character istics indicates that : 425832 851111 5-2 o chronically turbid nvenne habitats may have their b1 ologi c a l productivity reduced when compared to the natural co n ditions because of high turbidity and reducti o ns of a l locht han ous o r g anic detritus inputs from upstream; o c lear and intermittently turbid habitats ma y exper1ence the same or increased biological productivity when compared t o the natural conditions because of t~e fertilization capabilities o f sedimented glacial flour juxtapositioned with epilithon, and impr o vement s of the condition of some streambed substrates. Extensive literature reviews have indicated that the estimated With-project suspended sediment and turbidity regime will have negligable direct affects on adult and juvenile resident fish and salmon . Direct affects on the fish are expected to result tn sublethal stress, but should not result in mortality. Although direct evidence is lacking of the effects of long-term exposure to the expected With-project levels of suspended sediments and turbidity under the expected environmental conditions, indirect evidence implies that most middle reach fish may survive if forced to ov~rwinter in turbid mainstem habitats. Approximate levels of suspended sediment and turbidity which are generally associated with various levels of aquatic habitat protection are presented. 5.2 SUSPENDED SEDIMENT AND TURBIDITY RELATIONSHIPS Turbidity should be clearly distinguished from a mass or concentration of suspended particles tn a liquid. Turbidity ts an expression of the optical property of a sample which causes light (generally white light) to be scattered and absorbed rather than transmitted in straight lines through the sample (Austin 1973, Gibbs 1974, A.P.H.A. 1980). The particulates suspended in a sample which contribute the greatest turbidity per unit weight are generally larger than 1.0 micron mean data diameter but ~ess than 10 micronsmean beta diameter (Gibbs 1974, Hecky and McCulloughj 1984, Peterson 425832 851111 5-3 ~t al. 1985 a L The li ght scattering and abs o rbing properties of i no r g an ic particulates sus pended in water are inf luenced not only by their s 1ze an d conce ntration, but al so by their e lementa l chem istry and mine ra logy . In the Susitna River it lS b elieved that the turb ldi ty wil l be influenced to a re lativel y mi nor degre e by dissolved and cc>lloid a l ino rgan ic a nd o rgani c entit ies , such as colloidal silic a and dissolved humic comp ou nd s . The relationships between s uspended sediment concentration and tu rbidit y (NTU's ) have been investigated in both large and small loti c env i r o nments in Alaska (R & M Consultants, Inc . 1982c, e, 1984b, 198 5; Peratr ovic h, Nott i ngham and Drage, Inc. and I.P. Hutchinson 1982; Lloy d 1985; Peters o n ec al. 1985a). Most data from lotic, glaciated habitats or from placer mine sluice box effluents (neither of which had lakes, reservoirs o r settling basins upstream) show that the calculated ratio of NTU /TSS is less than 1:1. In fact, the middle reach of the Susitna R1ver and other large Alaskan rivers draining glaciated watersheds have generalized NT ~/TSS ratios approximating 1:4 or 1:5. Wide variances among these rat~os exist (Figures 5.1; 5 .2). In relatively small glacial streams, ratios of NTU/TSS ma y al s o be highly variable, and may sometimes average slightl y ~reater than the ratios found in large glacial rivers (i.e. >1:1)(Figure 5 .3 and ;.4). Lloyd (1985), reviewed data gathered from relatively small , non-glacial streams in interior Alaska. Some of these streams were receiving placer mine wastes while others were not. Samples from these streams were also found to have rat1os of NTU /TSS with great variability, but had an average ratio of approximately 1:1 (Figure 5.5). Llyod (1985), using data from another study on wastewater discharge from sixteen placer mines in interior Alaska (R & M Consultants, Inc . 1982e), drew a figure relating turbidity and suspended sediment concentrati o n s at unaffected upstream sites and at sites downstream of mining wa s tewater effluents. Examination of Lloyd's plot (Figure 5.6) demonstrates that the ratio NT U/TSS again has wide variances and that the naturally clear streams generally exhibited NTU /TSS ratios '1 :1 while the same streem influenced b y 425832 851111 5-4 ----·-~r-------~~----~--r-.--r--:;, -----------,~------~--~--------·- 1 i l ~ I // ·~~------~----~--r-,_-+------~------~----~----~~--~/~.4 I ~~ ~~~ ·~~------,_----~~r-,_-r--~--~----?~.~r---~.~~-~~~'~--~6~.4 I / ..... ~/f I 1 - / 7 I l ~-~-------+----~--+--+~---+--+-----~A~~~--~~--4-----~--/f' ~~----~----~--~+-~--~~--~~~e~----~~--+--;---l-- -~~------~----+---r-~-+---r--~~-------r----~--+-~~~-----~ -.~o·_ 4 V/r NOTts : 1 ;: . T • O.lel(sc,O.JM ,2. o.•z T•TURiaTY !IO~------~----~--~~A~/+---~~------~ SC•~~S~ --• /., COMC!MT11tAT10111 I ·~------~----~--~~-+--~--~------~----4---~~-4---_.--*1 •~~~~/~v~~~----~~~~~~~-~ /" • I I ·~------~~--~--~~-+--~--~------~----4---~~~-----·- /7 I '/ Zt-:V~--------4-----+---+----if--+---~-+ LlG!NO : 6 • IUSITNA RIVU NUA c:AII'TWCLL G ·IUIITIIA ltiVCIIt ~eM CMAII X • SUSrfliiA ftiVIR AT IOU) CRIIK ·~~~~~~~-----~~~~~~''~~~~ 10 zo 30 ~ so eo eo 100 zoo 500 400 soo 100 100 TURBIDITY VS. SUSPENDED SEDIMENT CONCENTRATION SUSITNA RIVER 5-5 FIGURE 5.1 10 ,000 IOO<J -:) 100 .... z - ~ '= c:a ii = :) 10 .... T a 0 .44 t SSC ) 0.8~8 La. NTU/TSSa1/.t • .t ,2 2 0 .83 n a 229 • • • , ··"" .. -. • • • • • • • •• • • • ••• •• ~,. .. · ... • . .. • -· •• • • • • . .. • • • ••• .. • ... • • • • • • • • • • • • • • ' • • • • • • • 10 100 SUSP!NOED SEDIMENT CONC!NntATl ON ("" /lltw) • • TURBIDITY VS SUS PENDED SEDIMENT CONCENTAA TION IN SEVERAL ALASKAN RIVERS • • 10 1000 Fi9urt s-.2 Emclirical ,.tationsfti p of naturally oceutri"9 t urbi dity venua tuaoended tedimeftt conc~ntmi Oft far riven and strtamt in Alalia , samptect dur in9 May-Octoo.r 1 1911- 1983 ( dtrtved in tt'l ia report f rom data prov ided by USGS 1 19_.). SOURCE : t.t.OYO t 9d5 F1GUM 5.2 5-6 1000 •ao • 0 400 aoo ~Ill ,..., ::J 10 t-40 z ...., I ao >-•aL t- H Q • H 4 m ·f ~ ::J • t- IJ1 I .l I •• ....., .4 .a I I I PREPAR(P 8Y : J5 oo WA A&M CONSULTANTS, INC. .......... ----·· .... _..._ ........ ... ~ .. L • •v NTU I TSS~I : I • • • X . T~. •1.71 TS s• .. , 1111111 ~ ..... . . . • I I 1111111 I I " ~ • eo 0 ... .. TSS ( mg/ I ) 1e84 !AST FORK DATA : TURBIDITY VI. .... 0 .17 I I I I I II 0 0 00 • ••o ... TOTAL SUIPENili!D SOLIDI FOil LOTIC INFLU!NTS TO !KLUTNA LAKE I 0 0 0 oo 0 0 0 oo " • • • o - FIGURE 5 .3 PR E PARE D fOR : (}{)blfru (6 £o§[ID£®©@ SUSIJNA JOINJ VlNJUIIE 'f I 00 "" :J ..... z - >- t- H Q H Pl ~ :J t- ·uoo ?aa 699 sea 490 30" 209 ·uo ?a 69 s0 .. a 39 29 • • • • . ' . • •• • • •• ry... NTU / TSS ::::: 0 .6 :1 • • • • • • • • . TUitl a 1 .00 TSS -\. .... 0 .10 NT U ITS S :::: 2 : I It ••••• IBI I 'I,,,,,, I I I'''''' I I I'''''' - PREPARED BY : ~ R&M CONSULTANTS, INC. ---··-_ ............................ .., .. ... N PI • Ill tD f'.CII01Sa m m m m m mCSilSISJ -N Pl .-Ill tD ,-.axng ... TSS Cmg/ I) 1884 GLACIER FORK DATA: TURaiDITY va. TOTAL IUIP!NDED IOLIDI CS» CS» CS» CSJ CS» CS»CSl'iril m es» mmes»~ N f') • Ill tD f'. CII01Sa FIGURE 5 .4 PREPARED fOR : mJA\(ru~~a ~(IDB\@@@ FOR LOTIC INFLUENT& TO ~'<LUTNA LAKE SUSIINA JOIN I V(NIUIIf 10 ,000 I O<X) -100 :;) ~ z ->- ~ Q as a: :;) ~ 10 .I ~.I 1/1/ • T a 1.1 03 (SSC ) 0 ·968 r 2 : 0 .92 NTU ~ I T5S T n :279 • • • • • • • • • • • ' •• ••• • •• . ,._ .. . r.· .. ·I • , ... ' • • • • • I • • •• • • • • • • 10 100 SUSPENOEO SEDIMENT CONCENTRATIO~ ( "'9/liter) ICXXl 10,000 Fi qure 5.5 Empi r i ca l rel ationship of turbidity versus suspended sediment concentration for pl acer- mined and nei Qhbor inQ unmined streams in interior Alaska, sampled dutinq summer, 1983-1984 (derived i n tf'lis reoort from data provided by Post , 1984 ; Toland, 1984). (Adapted From Lloyd 1985 ) 5-9 100~0 -~ ~ z - )oo t: Q ai a: ~ ~ 10,000 1000 100 10 x a Downstream of mint • = Upltream of mlno I • /I I I • • . I ~_.~~~~~_.~~~--~~~~~~~~~~_._.~~~--~~.u.u 100,000 .I 10 100 1000 SUSPENDED SEDIMENT CONCENTRATION ( mea/ liter) Fic;urt 5 .6 Pl ot of t urbi dity and suspended sediment eonetntroti on for eertain placer-mined strtamt In AI atka ( olot1ed in tftit riDOft from data orHinted in RaM Consultants, 1982a ). <Adapted From L l oyd 1985) 5-10 mining wastewater effluents tended to exhibit NTU /TSS ratios >1 : l. An obvious cause of such results is that treatment of mining wastewater remov e s the coarser , heavier partic les while leaving the smaller, lighter parti c les in suspension. Such treatment could obviously shift the ratio ot NT U/TSS t o a greater value. Examination of settling column data from 15 separate placer mine sluic e box effluents (R & M consultants, Inc. 1982e) and from two separate settling columns utilizing water samples f<t.m the Susitna River (R & M Consultants, Inc. 1984b) indicates that the ratio NTU/TSS changes through time from <1:1 to >2 :1 after 72 to 96 hours of relatively quiescent settling (Tables 5.1, 5.2, 5.3). Plots of the NTU vs. TSS data pairs 1n the three former tables indicate that, under the relatively quiescent conditions existing in the settling columns, the ratio of NTU/TSS may ultimately have approached values >2: 1 (Figures 5.7, 5.8, and 5.9). If a continuous and unchanging ratio were to exist between turbidity and the suspended sediment concentration, then the slope of the lines in the three former figures would be exactly 45 ° from horizontal. And if turbidity were entirely caused by TSS then regression analyses would predict that zero turbidity would result from zero suspended solids. The three formerly depicted figures do ~.ot support either of these relationships. All three relationships do, however, indicate that the amount of turbidity produced per unit of suspended sediment (i.e. the ra~io NTU/TSS) increased as: 1) more settling time elapsed, and 2) the larger and heavier particles precipitated out of suspension leaving progressively less weight of suspended particles. Analysis of both Susitna River settling column experiments indicates that both turbidity and suspended sediment concentrations decline rapidl y in the initial hours of the expt!riments and that their rate of decline decreased with increasing settling time (Figure 5.10 and 5.11). Particle sue analysis indicated that relatively smaller particles (with greater surface area and consequently greater light scattering capabilities per unit weight) 425832 851111 5-11 s CD !! - a: 5 % N ... N ,.. • N N ... 0 g ... .. • • -., :)1"' z-J:j .. :) ;, --z -~} J:j .. :) ~... z ~= -z . -N "" 8 ,.. . "" 0 i .... N .,... .... .... ""' 8 • . -~ -0 ,._ . -. - . . N N 0 "" • 0 a 8 ..... . - . - 8 ""' 0 .... • . . . - -... -,._ ~ - 0 N "" . - 8 N . -. - . - ~ • . - 8 N j i § i ! ~ i N . N .,.. .,...· .. N ,: N 8 -• -i . • 0 ~ ~ ,.. . . N - . N 0 0> N N 0 N • i - i 8 ... - .... .... ~ ""' . - § . N . . . • i .... "" -... 8 -... ~ -. -. ""' . "' ~ • . ... 0 -- i - "" . N .,.. "' N N .,.. "" N "" N . - 0 i .... ,.. • N 8 -i ~ ~ i I ~ I i I ~ I I I . N ,.. ~ ~ • ~ N ~ • ~ ~ • ~ ~ N 0 .... ""' N 8 8 N N . "" . - 0 .... • ""' N "" 0 .... "" .,.. 0 ... ,.. N N N . '4 8 -. '4 8 ,.. "" .... CD 5-12 ,.. 8 • ,.. 8 -• - 0 - • i ,: • 8 ,.. 0 N . ,._ .,.. N N I ;, (I N "" . .. :. ! -Q. • j Cl > .... ~ !~ . ....... :! i' • 0 • N j f • N .. N • Tible 5 .2 Settling Column Run ., Totil Suspended Solids ind Turbidity Avg* TSS Avg Percent Turbidi ty Avg (mg/1) TSS Rem~en i ng (NTU) Turbidity Susitna River 181 (7/31 /84) 0 Hours Top 117 172 Middle 146 124 100 174 165 Bottom 108 148 3 Hours Top 120 134 Middle 115 119 96 154 141 Bottom 122 136 6 Hours Top 63 144 Middle 105 93 75 125 138 Bottom 111 144 12 Hours Top 49 100 Middle 85 78 63 118 115 Bottom 100 126 24 Hours Top 34 90 Middl e 64 57 46 108 101 Bottom 74 104 48 Hours Top 32 90 Middle 59 52 42 1, 0 104 Bottom 66 112 72 Hours Top 34 76 Middle 48 50 41 112 103 Bottom 69 120 96 Hours NTU/TSS Top 38 90 3 .00 Middle 49 48 39 94 96 I . 92 Bottom 56 104 I. 86 * Average p R . . Average ercent ema 1n 1ng :: TSS at Time (T) X 1()() X =2.26 Average TSS it Time 0 5-13 ( Source : R a M C'onsu I fonts I Inc. 1984 c ) Table 5 .3 Settl i ng Column Run •2 Total Suspended Solids and Turbidity Avg* TSS Avg Percent Turbidity Avg (mg/1) TSS Rema i ning (NTU) Turbidity S us •tna R1ver 410 (8 /6/~) 0 Hours Top Part 310 308 Middle Part 355 342 100 308 304 Bottom Part 350 296 3 Hours Top 130 304 . M i ddle 300 283 83 280 300 Bottom 320 316 6 Hours Top 190 280 Middle 260 243 71 316 291 Bottom 280 276 12 Hours Top 160 232 Middle 245 215 63 240 228 Bottom 240 212 24 Hours Top 145 244 Middle 220 190 55 280 268 Bottom 205 280 48 Hours Top 155 240 Middle 175 167 49 244 241 Bottom 170 240 72 Hours Top 93 220 Mi ddle 122 112 33 268 247 Bottom 120 252 96 Hours NTU/TSS Top 78 204 2 .62 Middle 106 101 30 208 210 1.96 Bottom 119 220 1.85 . Average * Average Percent Rema1nsng = TSS at Time (T) X 100 X=2.14 Average TSS at Time 0 I Source: R a M Con sul fonts, Inc . 1984 c l 5-14 ' r . -., .. ... 4ft 0 •••c-..,~ ....... i 1,000 Q I I 100 ~~~~~~~~--~--~~~-.~~~~--_. __ ._._ ..... ,~~~~--_.--~ TUR8101TY (T), NTU Fiqure 5 .7 RELATIONSHIP BETWEEN TURBIDITY AND TOTAL SUSPENDID SOLIDS SETTLING POND DEMONSTRATION ~J ECT 5-15 -:;) ~ z - .... :;) ~ z -.,.. ~ -Q i c :;) ~ TURBIDITY v s. SUSPENDED S 0 LIDS FROM SETTLING COLUMN SUSITNA RIVER SAMPLES RUN # 1 T o l t .S41 I T111°· 422 rl o 0 . II 40-~--------------------------------------------~--~------~~ I I I I I I I I 1000- soo- 10 100 1000 TOTAL IUiftiNDID SOLIDI <•til) RUN #2 ---- T t TO. ?II (TII)O.I4 ? ,a.o.eo IOO-·L---------~--~~--~--~----------~----~--~--~--~71~1 ~1 ~1 I I I 1000 ~ 100 TOTAL IUiftiNDED SOLIDI (mgll) lliGURI 5.8 R&M :CNSU&-TANTS, IN:. •-•·-•••• ••or..o•••~~ ..... .....,... aw•v•• .. • StJSITNA JOINT VENTtJRE 5-16 -::1 ... z -,.. ... 2 ID ~ ::1 ... 100- SUSITNA RIVER SAMPLES TURBIDITY v a. SUSPEND EO S 0 LIDS FROM SETTLING COLUMN RUN 1 and 2 COMBINED • , •• • T • 10 uo 1 r u ,o. Stt ,z •0 ., • ltUII-I • lt U II-Z so-~,------------------,--,--,-1-----------------------------,--,--,-, 10 100 1000 TOTAL IUIPINDID SOLIDI (mgll) R&M :CNSUL.TANTS, IN:. •-•·-•••• oeo-..o•••~• •"'• .. ,..•• •w•ve•o•• SUS I TNA JOINT VENTURE 5-17 .' -I , -,',--1 ,.:.' , ,--:::-' I ', \./ ; / / ' ' ' \ ' \ ' '. ' , ., .,, "'.-" ,, -:-" "" ~" ,, .._.,--:..:-::---., ..... -._ .... ___ _ w ------·--·------ -: ! .. : • : --· -: z 11.1 ~ ~~~~~~~-~-~-~-~~ --~~~ .. --~----· ~ ~ • ~-~-==-:..-~---;...-_·-;._·--:---~---:---~----~-· 3-=:r ! ! ! ! = ! ; 0 ti > IC u w <:J ~ > z t: -~ Q c iii TURIIDITY (NTU) ! • ! i ; f i • ::» , I • ... .. z ::» c ,-- , , , / , , , , I I \ \ \ I \ I \ I \I , I ~ ~ ,, 1\ I \ ~'.,"' .-7 ," / ._.;•'' ~ TURIIDITY (NTU) ,1GURI 5 .1 0 r:;&M :ONSU~iAI\!T£. IN:. e -.c;. . ...,.•c •• o co .. ao•tt"'~ • ...,.,,...,.••• •"'•""••o•· 5-18 -I 1-: -I -· -! I -• : -"' ! ... SUSITNA JOINT VENTURE z ::» a: z 2 = ..1 0 u c z -..1 ... .. "" cn "" 2 -... • • :Ill (;') a -..1 0 (I) a "" a z "" A. (I) :t en ... c .. 0 ... • ILl ..1 ~ .. z :t a: I I I I I I I I I I I I I ,' I I I I I / I ,/ I,' /I ,,I ,.., _,, -----::.: _, I I . . . . : -: -· I I -: ;-------.c~:~-~-~-~-~-~==========~----------------------------_j ! ! i ~-· A. a :.· c en a: "" > -a: c z ... -., :t (I) TOTAL IUI,INDID IOLIDI CIRt/1) ... .. z :t a: I I I I , I I I I I I I I I I I I I I ,I I I I I I f . I 1 I I i . . ! I 1-1 I I i -I I -t -s -: ~----~------~~-~-~-~-~~a---~------~--------------------~ ' I , i ;· TOTAL IUI,INDID SOLIDI (mell) ,ICIURI 5 .11 -• ,. • Q "" ! ... -• ~ • Q -Ill ! ... c:=&M :CNS::Ut..TAI\!T~, IN:. ,,..o ..... •••• oco.oa ••"~ ............. .~~.~ • ...,. •o•• SUS/TNA JOINT VENTURE 5-19 remained in sospension tn greater c oncentration a f ter 96 hours o f s ettling (R & H Consultants, Inc 1984b). It may be reasonable to deduce that the ratio NTU /TSS ma y have increased with increasing time elapsed Ln the settling columns . At some point, however, haa the experiments continued, the ratio NTU /TSS would have altered its rate of change from that shown in Figures 5.7, 5.8, and 5.9. This alteration would uot be predictable in time and would ultim~tely depend on the miniscule changes (in turbulence, biology, and chemistry, etc.) whi c h would occur within the settling columns. Prolonged rates of settling in large and relatively turbulent reservoirs experiencing hydrologic, climatic, geochemical and biological changes would also be expected to produce relatively large and variable ratios of NTU /TSS with little predictabl i t y as to absolute value or times of change. It may be hypothesized that ratios of NTU/TSS in a large reservoir like Watana and in its discharges may be >2:1 and highly variable in time. More than 200 NTU /TSS data pairs were collected tn Eklutna Lake (Figure 5.12) and more than 50 similar data pairs were collected in the Eklutna Lake tailrace (Figure 5.13) during 1984 (R & H Consultants, Inc. 1985). Ratios of NTU /TSS in the reservoir tailrace varied from <1 :1 to >20:1 with a mean value of 3.62:1. Ratios of NTU /TSS in Eklutna Lake acturall y varied fr om <0.6:1 to >50:1, with a mean value of 4.38:1. These data may be interpreted as sup~ortive of a hypothesis that glacial sediments settling for prolonged time periods in large lake/reservoirs in south central Alaska will produce highly variable and largely unpredictable values for the ratio NTU /TSS, and that the ratios of NTU/TSS will generally be ~2:1, and will probably average closer to 2-4:1 . Analysis of all the preceding data together with limited data from two other chronically turbid lakes in south central Alaska indicates that large, glacially affected lotic systems will generally exhibit NTU /TSS ratios of approximately 1:4-5, while large, glacially affected lentic systems will generally exhibit NTU /TSS ratios of approximately 2-4:1 (Figure 5.14). 425832 851111 5-20 V> I I N 1000 800 100 400 200 "" ::J t-100 z 80 '-J eo >-40 t- t-t Q 20 t-t en ~ 10 ::J 8 t-• 4 2 • • •• • •• • • • •• • •• • • • • • 3/1 • NTU/TSS RATIO LOCALIZED AT ~ 2/1 X NTU/ TSS a 4 .38 i MEDIAN NTU I TSS ~3 n=203 TURB. • 7 . 98 TSS •.•n R1 •0.33 l I J I I I I I II •• e .. N • • eo 0 000 0 0 ooo . PR EPARED BY : ..J~b====~======-====--=~~ R&M CONSULTANTS, INC. ............ ··-······ .............. ·~"···-· .. • • eo o o o oo TSS C mg/ I > EKLUTNA LAKE DATA: TURBIDITY ¥8. TOTAL SUSPENDED SOLIDS .-N "" • eo - FIGURE 5.12 PRE PARED FOR : G{)£(ru ~£c §@£@@@ SUS IT NA JOIN T V(NTUIIE l00 80 70 60 59 49 -39 ::J t-2B z ......, >-t-lB H Q a H 7 \,1'1 I m 6 I ct: N 5 N ::J t-4 3 2 PREPARED BY; _Roo (\VJ) R&M CONSULTANTS, INC. ............................ lk .......... v • ., ... . • • • • • • • • • • \ •• • • • • • • TUR8.•7.4. TSS0.367 R2 • 0.25 N Pl ~ Ill w~m -N rt ~ Ill w~m m TSS < mq/ I ) 1984 TAILRACE DATA: TURBIDITY va. TOTAL SUSPENDED SOLIDS 2/1 1/1 • NTU/TSS LOCALIZED AT :liJo • 2/1 RATIO X NTU/ TSS = 3 .62 n:60 m m m m m tSHSl ISl N ('t') VlllW~miSl FIGURE 5 .13 PRE PARED FOR : [}{]lj_\(ru ~£c~(ID£®©@ 5USII NI\J01NI VI Nllllll: -:) .... z - • l.AKU AND l.ENTIC SYST!MS • l. A,.G[ Gl..A CI AI. .. IV[M IILUTNA LAII fleiOI I•4.SI • • • • • • 15 'UCU MIN 72 Hit SITTI.ING C:OI.UMNS fi•IS 1•2.1 • • • • • • ?. ·~ .. • • ••• • • • • • .,. . • • • • • a.o 0.22 • ,l._ ............. ~ ....................... _ ...................... _ ................. ..w. __ ......,_...,. .1 1 10 100 1000 SUSPENDED SEDIMENT CONCENTRATION (ms/litw) EMPIRICA~ RE~ATIONSHIPS OF TU .. 8101TY VERSUS SUSPENDED SEDtMINT CONCIN1"AAT10N FOR RIVIR8 AND LAKU IN ALA1KA (MODIFIID AFTIR LLOYD 1811) 10 ,000 1J Ott Water Engin eers, Inc. 1981 'lJ Scott, K. M. 1982, and Koeninga, J .198~ 'ICILM 5 .14 5-23 ' 5.3 THE DYRESM MODEL AND ITS USE FOR ESTIMATING THE WITH-PROJE CT SEDIME NT REGIME CHANGE Predictions of reservoir ther-na l stratification, 1.ce cover and o u tf l o w thermal and hydraulic characteristics have been made using a numeri c al m0 del developed by Imberger, et al. (1978). Vertical distribution and o utflow concentrations of suspended sediment have also been estimated f or both Watana and Devil Canyon reservoirs using modifications o f DYRESM subroutines. The following summary provides a concise , simplified description of how the model operates, including a brief des c riptio n o f model calibration using data from Eklutna Lake. In the formulation of the modeling strategy of DYRESM, the principle physical processes responsible for the mixing of heat and other water quality components have been parameterized. This contrasts with other simulation models which are largely empirically based. The modeling philosophy employed in DYRESM requires a reasonable understanding of the key processes controlling water quality, so that they may be parameterized correctly. This process related approach to modeling has the advantage that the resulting model may require less calibration and 1.s more generally applicable than the empirically based methods. A second consideration 1.n model formulation has been to keep the computational costs as low as possible in order to keep running costs within reason. This allows for a greater number simulation runs to test ':~.e sensitivity of outflow characteristic predictions to major variables, such as intake operating policy and environmental flow requirements, than if more time consuming models were used. This has necessitated the restriction of spatial variability to one dimension (in the vertical) and the adoption of a fundamental time increment of one day. Certain physical processes require time steps shorter than one day. In this case the model allows for subdail y time intervals as small as one quarter hour. 4'25832 851111 5-24 The following discussion demonstrates that the principle processes responsible for reservoir mixing may be adequately parameterized and satisfactorily represented within a one-dimensional framework. First the reservoir or lake in question is subdivided into a series of hori7ontal slabs of varying thickness, volumes and cross-sectional areas in accordance with the prescribed reservoir geometry. The number of layers LS allowed to vary as required to represent the vertical distribution of heat and salt to within a specified accuracy. The uppermost layer may be thought of as corresponding to the lake's surface layer or epilimnion with its base being located at the thermocline depth and its top at the lake s urface. ThLs layer is the most important as it receLves the direct input of atmospheric forcing and is usually associated with the largest gradients Ln water quality properties. As discussed later this layer receives special attention in the model compared to other layers. Within each layer the variables are considered to be uniform. Heat in the form of solar radiation is input to each layer according to the physics of absorption of short wave radiation (Beer's Law). The trans fer of heat between all the layers (other than the upper two layers) is determined by the vertical turbulent fluxes as specified by the turbulent eddy diffusivity and the differences in properties between the layers. The value of the vertical diffusivity is not set empirically but follows the energy arguments of Ozmidov. In this way the vertical mixing process responds to changes in the level of energy available for mixing caused by storms (wind stirring) and also by the potential energy released from inflowing rivers. In addition, this internal mixing formulation includes the inhibiting effect of local stratification rates on the mixing process. Experience has shown that it is necessary to consider the individual processes controlling the mixing Ln the uppermost layer, known as the upper mixed layer, in a more detailed manner than in the deeper layers. 425832 851111 5-25 These processes are · wind stirring, convective cooling, the shear across the base of the mixed layer, the stabilizing effects of the absorption of short wave radiation and the density gradient at the base of the lay er. The method involves the consideration of three conservation equations within the layer, the conservation of heat, salt and turbulent kinetic energy. Solution of these equations provides an estimate of the energy available for mixing the upper layer with lower layers. One unique feature of this upper mixed layer formulation is that it allows for the influence of strong internal motions known as seiches, on the mixing and deepening of the upper layer to be taken into account. A brief explanation of wind generation of these internal motions or seiches provides an example of how a two and three-dimensional process occurring in a reservoir is treated within the context of a one-dimensional model. When the wind starts to blow along the longitudinal axis of the lake that is initially at rest, the shearing motion at the base of the upper layer is considered to grow at a constant rate until either the wind ceases or reverses in direction, a period of time equal to one quarter the period of the natural seiche has elasped, or the earth undergoes a period of revolution on its axis. When any one of these limits is attained the shear is set to zero and the build-up of internal motion recommences. Not only does the shear influence the deepening of the thermocline or the upper layer thickness but also the shear may destabilize the stra .:ification . In this latter case the temperature profile is then smoothed to the point where it remains stable with respect to shearing motion of the wind forced seiche. Another two-dimensional process is the r1ver inflow dynamics. If the nver water is lighter than the uppermost layer of the lake it forms a new upper layer over the old one which may ultimately be amalgamated into the former upper layer. Conversely, for an underflowing river an entrainment coefficient for the incorporation of the surrounding lake water into the descending river plume is computed from the r1ver discharge, the densit y constrast between lake and river water, the slope of the bottom and the 425832 851111 5-26 geometry of the rlver bed. The volumes of the layers are t hen decremented ac co rding to the computed daily entrainment volumes at the same time as the inflowing river water is diluted by lake water until it either reaches the deepest layer or the dam. Another possibility is that the density of the plunging river plume may be reduced to that of the adjacent layer density whereupon the inflow begins to intrude into the main body of reservoir. Whether this intrusion process lS dominated by viscous-buoyancy forces o r by an inert ia-huoyancy balance lS determined by the computation of a non-dimensional parameter depending on the discharge, the local density gradient and the mixing strength at the level of insertion. This parameter then sets the overall thickness of the inflow and therefore how the in flowing volume lS subdivided among the existing layers surrounding the in flowing depth. Similarly, outflows at a surface level and up to two subsurface levels are governed by the same parameter which determines the amounts to be withdrawn for each of the layers in the vicinity o~ the outflow points. To illustrate how this may work in practice, it is useful to consider two extreme cases. In one case the outflow volume lS large relative to the stabilizing effect of the ambient stratification (inertia-buoyancy balance) and the outflow is withdrawn nearly uniformly from all the layers. In the second case, when a weak outflow obtains a viscous-buoyancy balance, the density gradient severely confines the vertical range of outflow layers to those ln the immediate vicinity of the offtake. The model has been extended to include the influence of ice and snow cover, and suspended ice concentration in the inflowing rivers. The conduction of heat and the penetration of solar radiation across a composite of two layers, one composed of snow and the other of lce, lS com~uted from their physical properties, namely, thermal conductivities, extinction coefficients for solar radiation and densities, and from the energy transfers at the surface with the atmosphere. Components of the surface energy budget , as in the case of an ice-free surface, are the incoming and outgoing l o ngwave 4 25 832 /5 851111 27 radiation, sotar radiation, the sensible heat transfer and latent heat exchanges. Several cases may be distingui shed. If more heat flows upward ...... vu~r.u cue Lee cnan can be supplied by the turbulent and mol ecular trans fe rs of heat from the water to the ice, ice is created and added to the existing ice cover . Conversely, the ablation of ice at the base of the ice sheet o ccurs when an excess of heat is present. Similarly the snow or upper surface of the Lee as the case may be i 3 melted when sufficient heat LS present to elevate the surface temperature above the freezing point. An additional physical process incorporated in the model with ice cover LS an allowance for partial ice cover either during the freeze-up or break-up period. Partial ice cover accounts for the wind action in dispersing thin sheets that might be formed and is based on an assumed minimum ice thickness of 10 em. Furthermore, the thickness of the snow cover on the ice is limited by the supporting buoyancy force associated with a given thickness and density of ice. Finally the amount of solar radiation transmitted through the snow layer depends on the thickness, age and temperature of the snow cover. Frazil ice input from the in flowing rivers is either used to cool the upper layers if an ice cover is not present or is adder! t o the fraction of partial ice cover or to the thickness of the full ice cover . A more detailed discussion of DYRESM Ls provided 1n Imberger and Patterson ( 1980). 5.3.1 Testing of DYRESM model (Eklutna Lake Study) The DYRESH program has been used extensively in Australia and Canada to predict hydrothermal characteristics within lakes and reservoirs. To test DYRESH in predicting the thermal structure in glacially fed reservoirs , a data collection program was established Ln 1982 to obtain data on the thermal structure of Eklutna Lake located approximately 30 miles (SO km) north of Anchorage, Alaska. A weather station was also established to provide the necessary meteorological input to ov~~~w. 425832 851111 5-28 Detailed dail1 simulations wer e made of Eklutna Lake f r o m June 1 to De cembe r 31, 1982 for the 1983 Lic ens e Application (APA 198 3a , b) and from June 1, 1982 to May 31, 1983 for the studies mad e after submittal of the License Application (Harza-Ebasco 1984 g ). DYRESM mod el. These established t h e adequacy of the Simulated and measured vertical temperature profiles at a station Ln the approximate center of the lake were made. In general , most profiles are modeled to within 0.5°C (l°F). This is well within the observed variatio n of temperature at the data collection stations throughout the lake. Deviation in measured and simulated profiles can be explained through an assessment of the meteorological variables used and t he reliability of the measurement of these variables. However, even with errors due to estimating weather data from sources other than that of the station at Eklutna Lake, the temperature profiles are reasonably modeled. Outflow temperatures from Eklutna Lake for the period June 1982 through May 1983 were compared to simulated values. 1 1 general, for the entire simulated period of June 1982 through May 1983, simulated and measured outflow temperatures show excellent agreement. Deviations of up to 2 ,8°C occur between measured and simulated temperatures in late June and earl y July, 1982. This is believed to be the combined result of the approximate nature of the initial condition specified at the beginning (June 1, 1982) of the simulation, and, possible underestimation of wind speed. The simulated vertical temperature proiiles Ln the reservoir indicate reasonable agreement with measured profiles. This indicates that although average meteorological conditions over the entire period were suitabl y measured, conditions on a daily basis ma y be in error. Wind s peed, Ln particular, would have the major influence since an overestimation of wind speed would result in deepening of t .,e epilimnion whi c h would result Ln warmer outflow temperatures in summer. 4258J2 851111 5-29 Field observations in the winter of 1982-1983 and 1983-1984 indicate tha t the ice cover fortDation on Eklutna Lake would begin dur i ng the latter part of November with a full ice cover fortDed by mid-December. I n the 1982-1 9 83 1ce season, DYRESM estimated ice cover fortDati o n to beg i n on De c em b er 2 , with a full ice cover on December 20. Measurements made on Jan uar y 1 1 and 13, 1983 and February 18, 1983 indicate an ice c over t h i c kness o f 1 3 to 18 inches and 21 to 25 inches respectively. This compares fav o rably with a predicted ice thickness of 16.5 and 21.7 inches respectively. The study of Eklutna Lake as described above , has demonstrated the abilit y of the DYRESM model to predict the hydrothermal c ondition of a glacial lake under Alaskan meteorological and hydrological conditions. ~.~.~ ~uspended Sediments The concentration and distribution of suspended sediment 1n the project reservoirs and 1n the downstream river is an important water quality parameter affecting fishery resources. Two other water quality parameters, turbidity and vertical illumination, are related to the concentration and size of suspended material . Additionally, the settling 0 f material in the re~ervoir may affect the storage capacit y and thus, the energy production o f the project . Therefore , refined analyses were made us i ng two methods to estimate the concentration, distribution and s ize of material suspended 1n the reservo i r and its outflows, a.nd to estimate the amount o f material which, over time , could settle 1n the reservoir. The first of these analyses was made by extending the capabi l ity of the DYRESM model to include suspended sediment modeling capabilities, testing it with Eklutna Lake data and then applying it to Watana. The sec ond analysis was made using generalized trap efficiency estimates. In general, when the Susitna River enters the Watana Reservoir, the r1ver ve1oc1ty will decrease, and the larger diameter suspended s ediments will settle and fortD a delta at the upstream end o f the reservoir. 425832 851111 5-30 The delta formation will· adjust to the changing reservoir water level . Some sediment will pass through channels in the delta to be deposited further downstream 1n the reservoir. Depending on the relative densities of the reservoir water and the river water, the river water containing t he finer unsettled suspended sediments will either enter the reservo1r as an overflow, interflow, or underflow. To estimate the maximum amount of sediment deposition 1n t h e reservoir affecting storage capacity, generalized trap efficiency envelope curves developed by Brune (1953) were used. These indicated that 90-100 percent of the incoming sediment would be trapped in a reservoir the size of Watana. The results of the analysis using Brune's curves indicate sediment deposition will not affect the operation of any stage of the Project. A conservative assumption of a 100 percent trap efficiency was used to estimate the amount of time to fill the reservoir with sediment. The sediment deposited over the short operating period of Watana Stage I would be about 25,000 acre-feet, or less than two percent of the dead storage volume. The result showed the deposition of 410,000 acre-feet of sediment after 100 years (HE 1984a). The 100-year deposit is approximately 22 percent of the Stage I dead storage volume or 10 percent of the total Stage I volume. Sedimentation studies at glacial lakes indicate that the Brune curve may overestimate sediment deposition and would thus provide a conservatively high estimate of storage lost due to deposition. These studies have shown that the fine glacial sediment (flour) may pass through the reservoir. Some lakes immediately below glaciers have been reported to have trap efficiencies of 35-80 percent (Ostrem, et al. 1969; Andersson, et al. 1970; Ostrem, et al. 1970; Ostrem 1975; Kjeldsen and Ostrem 1975). Hydroelectric rese~voirs on three large r1vers 1n Sweden exhibited sediment trap efficiencies of 50-66 percent (Nilsson 1976). Kamloops Lake, British 425832 851111 5-31 Columbia, a deep glacial lake on the Th omps o n River, retai ns an estima te d 66 percent of the i ncoming sed i me nt (Phar o and Carmac k 19 79 ). Kl uane l a ke , Yukon Territory, a deep glacial lake o n the S l ims River, appar e ntl y r~tai n s an estimated 90 t o 100 perc ent o f it s s u spended s e diment i r.f low (Br ya n 19 74 a , 19 74 b, 1974c , Fahnesstock 19 74 , Barnet t 19 74 ). All studies examined have shown that particle sues o f s ed i men t s leav i ng glacial lakes are smaller than those entering (R & M Co nsultant s , I nc. 1982d , 1985; Ostrem, et al. 1969; Andersson , et al. 19 70 ; Ostrem, e t al. 1970 ; Ostrem 1975; Kjeldsen and Ostrem 19 7 5). The same studi es i nd ica t e that quartz, and orthoclase and plagioclase feldspars dominate the mineralogy of glacial lake inflow sediments , while mi c a, c hlorite , and amphibole show increasing percent compostion in glac i al lake e f fluent s . Studies of Eklutna Lake effluents and Susitna River samples anal y zed after settling column experiments indicate that c olloidal silic a , cal c ite, magnetite, clays and small, platy shaped quartz and fe l dspar particles may be more prominant in the effluents from the project reservoirs than they are 1n the influents (R & M Consultants, Inc. l982d , l984b, 198 5 ). Because the Brune curves may overestimate suspended sediment s ett l ing i n t h e reservoir the DYRESM model was extended. The extended model includ es t h e simulation of suspended sediment in the reservoir in o rder t o refine the estimates of suspended sediment concentration and turbidit y . Thi s v ers i o n of the DYRESM model was tested using suspended sediment data c ollected at the Eklutna Lake (R & M 1985) from November 1983 to Oc tober 1984. Good agreements on outflow suspended sediment concentration were obtained. The following sections described the model, the testing on Ek lutna Lake and the application to Watana and Devil Canyon Reservoirs . 5.3.3 DYRESM Model The ic e -co ver e d vers1 o n DYRESM, was extended to of the d y namic water include the modeling qualit y simulation mo del, of hor i zontall y averaged prof iles of s uspended sediment. foll o ws: A number of key processes ar e mo del ed a s 4 2 58 32 851111 5-32 o meteorological forcing, o turbulent mixing, o suspended sediment induced vertical mixing , and o winter 1ce cover and reduced vertical mixing. The model uses daily time s teps and vertical settling veloc i ties are specified externally. As with temperature and total dissolved solids , a suspended sediment profile is prescribed initially from field data or from esc1mat1on. Tne da11y inflow values of suspended sediment concentration are also input. The distribution of suspended sediment 1n the reservoir 1s changed by three processes; by mixing, by convective overturn, and by settling. The convective adjustment considers the density distribution 1n the reservoir, including the contribution to water density of the suspended sediment . mixed. A check is made for density inversion, and unstable layers are A method was developed to handle the changes 1n suspended sediment concentration due t ~ settling of the suspended sediment. In pre-determined time intervals, the vertical distance a sediment particle sinks at a prescribed velocity is compared to the minimum simulated layer thickness, then the subdaily time step is divided by a factor of two until the distance the particle sinks in the time step is less than the thickness of the layer it has entered . In each subdaily time step, the suspended sediment entering and leaving each layer is computed and added or removed from the layer. The portion of this sediment which falls into the layer below is added to that layer . 5.3.4 Eklutna Lake Modeling To te ti t this version of the DYRESM model for its applicabilit y to predict suspended sediment concentrations 1n the project reservoirs, the updat Pd 425832 851111 5-33 model was applied to Eklutna Lake, near Anchorage , a glacial la k e hydraulically, climatolog ~~ally and morphologically similar to the reservoirs. Watana and Eklutna lakes have similar average per c entages o f their drainage areas covered by glaciers, similar average residence times, similar climatological conditions, and are operated o r to be operated f o r hydroelectric power production. The hydrological and meteorologi c al data collection program at Eklutna was continued with emphasis on suspended sediment sampling from May to November 1984. Measured suspended sediment concentrations ranged from 0.15 to 570 mg /1 in the inflow streams , form 0.1 to 200 mg /1 in the lake, and from 0.56 to 36 mg I 1 in the out fl ow • Peak values in the inflow occurred in late July or early August, in the lake in about September, and in the outflow in late July to mid-August. During the winter, inflow, lake and outflow suspended sediment concentrations were on the order of 1-10 mg/1. During the summer, the average suspendeu sediment concentrations were substantially higher than winter values and were increased further following large rainfall events or periods of significant glacial melt. Turbidity values gener ~lly followed the trends 1n the suspended sediment concentration, dropping of t 1n the winter at inflow , lake , and outflow sites and peaking in mid-to-late summeL . Values observed ranged from 0.5 to 580 NTU in the inflow streams, from 1.8 to 220 NTU in the lake, and from 3.0 to 46 NTU in the outflow. The determinations of total incoming suspended sediments to the lake were based on the total suspended sediments measured for Glacier Fork and East Fork tributaries. To simulate the suspended sediment profile in the lake, the suspended sediments were divided into three particle size groups: 0-3 microns, 3-10 microns and greater than 10 microns. Test runs indicated that particles greater than 10 microns would settle rapidly to the bottom of the lake and contribute little to the suspended sediment profiles . they were not considered further in the study. Therefore The estimates of the total incoming suspended sediments of each group were based on the weighted particle size distributions . These distributio ns were 425832 851111 5-34 determined from samples taken from Ea st For k and Gl a cier Fork ob ta ined dun.ng field trips made on July 20, Augu s t 28 , and nc tober 23, 1984 . The daily particle size distributions were interpolated from these th ree bas ic di s tributions. Applicatio n of the extended DYRESM model requires the s peci fi cat ion of an initial distribution of settling velocit y and the dens i t y of the sedime n t. In the s tudy, the settling velocity of a particle size range was determi n ed in accordance with Stoke's Law. A settl i ng velocit y o f 1.53xl0-6th meter per second was used for the 0-3 micron sediments and 2.00xl0-5th meter per second for the 3-10 micron sediments. A particle den s i ty of 2.60 was used in the study, to represent the measured densit y of from 2 .50 to 3 .00 . The DYRESM sim~~ations for the 0-3 micron sediments and 3-1 0 m1cron sediments were made separately. The resulting outflow suspended sed iments of these two studies were then combined to indicate the total outfl ow suspended sediment concentrations. The predicted Eklutna outflow suspended sediment con centratio ns agr e e wi th data obtained from the powerhouse tailrace, and the model 1s theref o r e considered applicable to the Susitna Project reservoirs. On two occasion s, the field data show temporary increases in tailrace suspended sediment concentrations not predicted b y the DYRESH model. The temporary deviations are probably due to locally strong winds near the powerhous t:! intake, and , hence, more concentrated wind energy available f o r mixing the water and sediments near the intake . It 1s not possible to account for these temporary local fluctuations in the mo C:el since the weather sta::ions 1s located on the opposite end of the lake and can not register s uch local variation in wi nds. An additional reason for these deviations may be short-term fl uctuatio ns in incoming sediment concentrations or size di s tributions as a result of meteorological or hydrological event s . These short-term fluc tuations would not be accounted for by sampling the inflow at mont hl y intervals. 425832 85 llll 5-35 5.3.5 Susitna Reservoir Modeling The extended DYRESM model was applied to simulate the suspended sediments i n the Project reservoirs and 1n the project outflows. Case E-VI flow requirements and 1970 and 1981-82 meteorological conditions were considered . Data on the suspended sediment concentration and size in the Susitna River are available at Cantwell and Gold Creek. The particle size distribution of the suspended sediments at Cantwell is shown on Figure 5.15. Based on the Eklutna Lake study, the suspended sediment in the Watana Stage I Reservoir outflow is expected to be comprised primarily of particles of 3-4 microns or less. Larger particles will generally settle out rapidly without significantly affecting the average suspended sediment levels in the reservoir and outflow. Therefore, settling of sediments of up to 10 microns has been studied. The incoming suspended sediments of up to 10 microns were divided into two particle size ranges and an averaGe settling velocity was assigned to represent each size range. The 0-3 and 3-10 micron particles were represented by an average settling velocity of 1.5 x 10-6m/sec and 2.0 x lo-S m/sec respectively. The total amount of sediment influent to the reservoir was estimated form the USGS observations at the gaging station near the upstream end of the reservoir . Figure 5.16 shows the estimated relationship between discharge and sediment load at the USGS gaging station on the Susitna River near Cantwell. Based on this relationship the total amounts of sediment influent to the reservoir for 1970, 1981 and 1982, representing years of near minimum, maximum and average sediment inflow to the project were computed to be 4,200,000, 8,500,000 and 5,600,000 tons, respectively. Additional sediment load for the drainage area between the gage and the damsite was computed based on the drainage area ratio. The amount of sediment influent of each particle size range was determine from the suspended sediment particle s1ze distribution curve of samples taken near Cantwell as shown 1n Figure 5.15. Fifteen percent of the total sediment influent was assigned to the 3-10 micron range and 12 percent to the 3-10 micron range. 425832 851111 5-36 ~ ~ ~ ~ :" -"' --~ - -------~ ~ ~ ~ ---- ---~ ~ ~ .. ~ ~ ~ ---- 0 g ' ~ " '\ \ 0 • ' \ \ 0 N 32JS 03.1. V~ NVH.l. ~3NI:t .1.N301:Gd 5-37 -0 ----------z Q -~ ---- --- .:J ~ g Yl~ a:W ~-~~ ~ en~ o! -z O c ., W(J ~~ ~a: en enc --- - ------ w ~~ ~ ~ Wa: ~ ~~ ~ w- oCL en a: ~ oc wZ ot: 8 zrn w~ 0 a.. en en -~ -en -- - ---- ---- 0 .,. ~ u IU 0 • c :z: u "' ~I 0 """ . 00 1U ~ ) f toO,DOO .-----, J I t t t ' ~-,.-r,' '' ~ ~ 1- ~1,000 ,,7 I t/ .,., / , , , ' 1------lllfll T I 111111 , ~ --. - - ,tr 100 1 1 1 Jo • 1 1 t!o 1 1 1 J, 1 • •,fllo 1 1 loAo 1 1 ltJoo 1 1 sh.., 1 lJJObOO 1 1 WoJG 1 f.&lo,ooo I SUSPINOIO SIOIMINl OISCHAIGI lONI/OAY SUSPENDED SEDIMENT RA TINO CURVE AT USGS OAOINQ STATION SUSITNA RIVER NEAR CANTWELL, ALASKA fiGURE 5 16 The suspended -sediment concentrations 1n the reser voir and the o ut f l o ws were simulated for the 197 0, 1981, 1982 flow conditio n s with Ca s e E-VI do wnstream f l ow requirements and 2001 energy demand. The outflow suspended s ediment concentrations for these cases are shown 1n Figures 5 .17 , 5.18, and 5.19 respectively. The s e results show that 3 to 10 micron particles will generally settle out in the reservoir. The results also indicate that the outflow suspended sediment concentration would be more uniform throughout the and, hence, the turbidit y level, entire year than f or natural conditions. The outflow suspended sediment concentration 1n the "average" y ear would reach its lowest level of about 10 to 20 mg /1 1n early ~a y and increase its level toward a maximum of about 150 mg /1 in Jul y or Augus t , while the mainstem river sediment inflow may vary from about 2-180 mg /1 in October to April to as much as 200 to 2,200 mg /1 in July to September . During the winter months, because of the relatively long reservoir residence time, a large portion of the 0-3 m~cron sediments will remain in suspension for a relatively long period of time and continue to affect the suspended sediment level of the reservoir outflow. As shown 1n Figure 5.19, the outflow suspended sediment concentration would approach some what of an equilibrium level of about 100 mg/1 near the end of October, and then gradually decrease toward a minimum of about 10 to 20 mg /1 in early May. In summary, the downstream suspended sediment condition near the project site will be affected by the operation of Watana Stage I Reservoir. The summer suspended sediment level will be decreased from about 60-3000 mg /1 to about 60-150 mg /1 and, in the winter, the suspended sediment level will be increased from about 1-8 mg /1 to about 20 to 100 mg /1. Modeling techniques similar to those used for Watana Stage I have been used to estimate outflow sediment concentrations for Watana and Devil Can y on Stage II, using average year sediment inflow conditions and Case E-VI flows with 2002 Energy Demands (Figures 5.20 and 5.21). Using late S t age III energy demands, average year sediment inflow~ and Case E-VI flows, estimates 425832 8 5 1111 5-39 LP. SED . C3<. -·~' I I I ! ! • • II I I 5-40 Vl I ~ lEI II I I I 1-1 1~1 I I I J ---~liD 1.. -z. . • .-. .... . ' -' ; . ..:• ·-~--~·-.. . __!_ "" -! '"' ~ ~ IJ ~ U:-10 . • 1\ ~ ••n •• .. . lA · W UAl. ~ 0. . f¥-£ ' ..l'l ~ n .. -,: ltllo [-..... ::Jo.~ __!_ l.L '-"-..... w.·~ 1 .. ~ ~LJ'o. . ... . 1-lf:'ll • ~·:.&.. :.!_ ••• ...... -.),. "" . 'L .....,., -!!I ' ....... - ' .11 -~ I' ...... I ' .. ' "' ' I . ~· ' .a I -·-' _I_L r . :! ~ • • '-2. . . . .. . . . . • ..., IK ... ... .. .. "" ,., .AL .., •• IIU .., l(DEHD• R.. A5I<A f'OW( R AUt HCJ' I 1 f flttf01CTL03'Tf'LOI 8.JSP . ~. CONCENT,_.T ION I fG'll -·-~.I ..... _, ..... -. lttfLOW • 6(0. C(N;fH Mfl04 11101\.1 (0-1 MICRONI ONLY) ~~liN\ ~W,...RVOIR UTFLO 101o 8U8PENDED 80l ~= NDTll• ' I. S&C INFLOW VALUES REPRESENT THE 0 ·5 MICRON RANG£ AND Alll 10% HIUH IN FL OW YE AI Of TSS ._.,.__.IIWiro .JIINf Wllt1tlt( fiGURE ~.18 --... -... -·1 ..... V1 I ~ N It: I I I I I I I I I I I I .. -' -J \ f .. .• -~ •• I •' I 1 . I o . -I I . . ...... . ,, •• • I I I ....... ~ . :; • • I .. ~y •• • ! I t .• ~ ~--• . ~1 -... . . .. -l' I I • . 1 •'\! f! 0 ·10 ... . ft " .t_ l •• '-~Jf • _. .. ~ \ • • • l ... ll ... "'~ -• . ~ ....... ~ ··x s-~ • ' • fY .. _ji_ l'f IY ~ ~ .. ( .. .... ..,~ . . ~-~ ['...,. • ll.J O·SM 1J • • . ·-• -""" f"... • L!__ ••• : • !' : ' " r--II I ... ' -~ • [\ ~ • . .... .. __.... '\' ~ • ...JCJ.L .... '; '-.., ./ -. . ...... .. . . . . ... . • I --... ... -.. -.... .... -.,. •• UOIEtG• "-~ f'OD fiU11DI If NUJ~(D WT~~ ~~f CDNC£HIMflDN I tOIL I ••--..~ I ..... _._ ··-···· lift. &liP . • AA I~ lt'liiU (O ·S MICRONS) NAl~ ~rt'UfH" OUTFLOW 0-1 I AONI) Nl'lll• I. 8U8PEND ED IOLIDI SSC INFLOW ""LU£5 REPRESENT THE 0·3 MICRON HAH8E AND ARE r...A YEAAGE INFLOW VEAL. 15% OF TSS ..,.IIIW8NDI .1111« ti(IChlll F1GUR£ ~.19 ~-... ~·~--· ....... -~----- Sl.6P . SE: :x . :'"CI L I ,. ... ~ S l --I ~ I I ~ i 8 -.... 51 I 0 ~ 0 c i I ~ ...... It ., I I I I I i I ~~I I .. gQ> I I ! ~o ; 'i 7 II -~ ~ ~ z c s -:::: ~ ... > i .J,. .. Tt ~~ . ' j;;~ i . -Q ~ cJ t:t ~ . . . -~ ,. 1" .. ,r ... ~ ~0 ~ :I l jt ..... J. _.::::: .... -.. -... I) ' ~ 2 -c I v~,..~ 'r"-: ~ -r o ... : ' ~~~ . . I ~ a ~,... I ~ .. ~~ IC . ·1 I , . -~ "r-1'-r-- I .. . -~ n1 . ~ .. ~ . ~ !'-":' ~ ) ~--~ 0 > I • ' ~ , •. 1 -"· r--~ ~~ z ~ 0 ,.... .. ~ .., . 1-~,. ~~ -Z ~ II t'i I ' ...JQ 'Qii ~ II : l· I ! r-r-~u -.. t::l J:-ex I -~ r--i a6 ~ -D 5 -.... -I v cr -r ··.I ~~ m 1'""1-r-z ~ ' I 0 v i -1 I v uO .. I v I I -I ·-II I 8i ~ I II)~ I v -~ ~ ~ ~a 0. ll .~ ~ :A oc:i ~ "" :4 ~~ ~ ,..~~v .. > a· ~~ I 0 ~ 'I .... en !~ ~ .. ~~ 0.-1 ~~ l ( ' ~~ ..,_ 11.- I I l i t l I ~ I ~ i J' i I : . -•!'"' . Ill ~ ~~~ ~I ! ~ ~ ~ ~ ~ ~ a ~ ~ .. .. ""' I ~ I ~W• . ~:l :ns asre ~ -jltJ 5-43 ~S~. SE~ c:.-.c . •C/L I .. IIC . -I zo~ 3 ~I • ~ i ~ 8 -o · -3 :1 • % 5 1 ! I 0 ... ~ ~ •! I I i . I I -•o.~ I I I I I : : I I I -'i -.; . I ; I ! a.-c -·~~ ~ •• r I , I I ' I : I I I . ' 1!1 a: r-1 , I I 1 I I ~ ~0 zc I I L _l c; -~ i ~ I I I ! I I ~ . . -~---~ l-., • i I i >~~= I l I -••• w .. ,~ i I . ::rl ·k I I !.:~~~ ~ ~ ~; ... I I I . I . ""'-' -,I , I ! O•.;c ~ J I ; ! I J I : ~~ t i l 1 ..... .X i ~ ~ ~ . . • I I ! I ; I :!~~ . . ~ i · I I . I • I I I . I ~ l : I ~ 1 }~1t"i·J r : I I = . . ;, . ... ~ .. ~~~~ ~ I ! j -~· r-t' .. j rr---~r--~ ~ ~~ : . ( ~ -'II 2 10 . ! I (~ I ... . -l :"') I I .· . -. I ~ ::, . . --! ~ --I ~ I I ..... -I '~ I I l I I I ~ ! !cr I .. ~-:t I .. .. J. I I ~~ . . I I I ·r ! .... I I 1) ·.I -i I % I ~¢ ; I f't I I I I ...... e 0 I I I -! I I I ·-I I I 8 ~ I ... ' :n.-i I I I i I ij I:~ z ·I.J.I I v ~~ I I ~ eo I I :• ~~ i ... a · s~ > 'I ~ ~ ~~ 0 • ' ~~ I I I I I I ~-~ li I I I ..; I . I i --., I U2 ,. -0 ~ "' w • I . c ~· i ~ ~ ~ s .... OC1 '"' i , ., i ,,/~. -. :2'CJ 03! ~sns ..J ... ..,., 5-44 of sediment discharges from Devil Canyon and Watana Reservous have been modeled (Figure 5.22 and 5.23 ). Graphically displayed and tabularized results indicate that the a v erage monthly sediment concentration estimated to exist in the project discharges will be decreased during each successtve project stage (Figure 5.24, and Tables 5 .4, 5.5, 5.6). The results also indicate the expected decrease in sediment concentrations during suliiDer, and expected increase tn sediment concentrations in winter. Winter increases in sediment concentrations ma y exceed the applicable state water quality standard (A.A.C. 1984). 5.3.6 Other sources of Sediment Shoreline eroston will occur as a result of two geologic processes: beaching and mass movement. Through mass movement processes, an undetermined amount of material will be introduced into the reservoir as a consequence of skin and bimodal flows, and shallow rotational and block s lides. As a result of the slope instability along the shoreline, an indeterminate amount of material will be come suspended in the reservoir. The Watana Stage I Reservoir normal pool level of el. 2,000 1s generally within the confines of the rtver valley. As a result, the o verburden thickness along the shoreline which could be exposed to sliding would be less than during Stage III . Additionally, the reservoir shoreline length is less than during Stage III and would also contribute to a smaller amount of slides. It is not possible to accurately estimate the amount of material which will become unstable or suspended in the reservoir nor the amount which will pass through the reservo i r and contribute to suspended sediment in the r1ver. The shoreline deposits are primarily glacial till comprised of sitly-sands (SM) but including some sandy clays (SC). Geotechnical investigations near 425832 851111 5-45 Vl I ~ a-. tlf o.( Wh I ~ LlWh f t! ..... , ·-· .. t. Wlt. • ~·" ~"' ~~--t------ ... !10 . . -t-----11---+----f---+---1---1 .J ' o ;rt;D nu r -----~----;r-----~--_.----~----~----~-----i--·-----+----~------~------1 -------f-----~-----~.-+-----J------+---- • . ---t--. ~ '· ---.-• ----• I I ~ ;>U) -----r-----• l •• 2111 -·---·-') -.. . . . . --'-. . f\ --· I -.,_ ' tt I _:.- lJ ------• '... • • ... -f----.. ~ -------.~~ r-·, . ". • • , 1 ar.o , . am ·~ -~ ~ • w Ll • \ • -·~-------• • _ _..,-~. --t-------1 ~n n --~--'' ~ c-. -f-----1------'---+---.Jf-l,..::..<l"l(;;;;t'~-·-+~-~t---- • '.di::_"IUIII • ' • -IOU • 100 -----• ....-.. • • • ----+-----------i ---f-r-' • t • ~·---p-i I ~ ::....... .-.... --r--r--~-• . . .n...L ~ ..:_.....__ ""' -f--!'..--ll. ~ ~ • ~-,.... -- ___S t--· ['\, t3' -~-r-L1 R-ill... •• ........... •• v =I w wo \ ' ---f----f-a--..&. ~ • • ;:. ' ['-,._ • 11111. • • • ' ----~ I -......., . tr /' ~ ~--~t-----f----4---~~~~~L-~~~--+----r---_,r----;---~---~ 0 . . . . .. .. . . 0 101 Q[C ..AN JU IIAA ..,_ IIQf .AM ..U. RLQ 69 CICI IIG ltu l H£NO • A..RSKA PB.:R AUT tUf I TY ----PREOI C T£0 OU1fLG4 ~-6EO . CONC£NJRRT ION 111G/ll -···~" I -- . · · · · · INFLOW 6USP . SEO . CCN:ENTRflfl~ 111Gil. I STAGE 111 WATANA OUTflOW SUSPENDED ._OlE S SOliDS C0 -10 MICRONSI • -~\fER AGE YEAR ). SSC I Nr L0--4 VAll..£ S ~PRE SENT l H[ 0 -3 '11 CHON Af:NA: Ah() 1¥£ .... lA-f.lfUO .. (IIHr WlHH~l I 5 /. CE" TSS ... , ... ~ .... t• M-•t •.a.o.• fiGURE 5 .22 Vl I l:' ..... ~1:l~L ~g~-··: -~--- I I I I ~-I I J(XJ .. J -' (,l"hh J • -· . ' ?(I) ' -~ .. . . ' II '9 ... . ' :rloll ' -----. -n ' ~ 11.1) -' '-0 ' 0 -.. -.. . ... ...:w ace ..... na .. .... ., ..... ...u. ... .., L£.1INO o PAEOICT£0 OUlfL~ SUSP . SEO . CONCENTRATION IMG/LI . --.. -. INFLOW Sls>. S£0. C~CENTRAT 10.. AT WAT~ lt1Gill (0-1 M ONLYt ~OTES• 1. 8U8PKNDID IIDIMINT INfLOW VALUII IIPII81NT THI 0-1 M IANGI AND AI& u• Of THI TOTAL 8U8PINDID IIDIMINT INfLOW I I I .., no . '' '' 100~ "lJ -- (/) -norJ (") ~ ·I.:) I - ~ wo ~ - 0 QLG gp CICI R..RSAA f'UWER AUTI~l TY _,,..,.-..o -... -STAGE Ill DEVIL C ANY O N OUTFLOW SUSPENDED SOliDS 10-10 MI CRONSI AVERA GE YEAR • 01 0..0. FIGUR E 5 . 2 3 \J'I I ~ 00 TSS (mg/1) 1260 1000 760 "• MEAN NATURAL 600 260 .... ---0 200 1100000011 160 100 60 0 0 N D J F M A M J J A • FIGURE 5 .2 4 ESTIMATED MEAN MONTHLY SUSPENDED SEDIMENT CONCENTRATIONS FOR PROJECT DISCHARGES STAO E I STAOE n STAOE m the dam site indicate that, of the material smaller than three i n ches i n :;ize , less than 15 percent LS smaller the five micro ns. The reservoir suspended sediment modeling indicates that material of 3-4 micro ns o r l ess will generally comprise the material which remains in suspensio n. Therefore, most of the material which may become unstable and .na y potentially slide , will settle out in the immediate vicinity of the slide and not contribute to reservo1r sediment concentrations. On 1 y a s ro a l l portion of the material along the surface of a slide may become suspended. The bulk of the material may be expected to remain in a mass and not bec ome entrained. It 1s believed that shoreline instability and eros1o n wi l l contribute most significantly to suspended sediment concentrati0ns in the most surficial layers of the reservoirs. Although the time period during which bank instability would occur 1s unknown, slope failures are expected to be highest early 1n project operation and to decrease with time. Any resulting increase in suspended sediment concentration would follow the same pattern. 5 ,4 STUDIES OF THE EXISTING TURBIDITY REGIMES IN THE SUSITNA RIVER MIDDLE REACH, IN EKLUTNA LAKE, AND ESTIMATES OF THE WITH-PROJECT TURBIDITY REGIME Turbidity is a water quality characteristics important to all f orms of aquatLc life. for this reason relatively extensive surveys of turbidit y regime patterns have been made in the Susitna River middle reach, and in Eklutna Lake . By using knowledge about the exist i ng turbidit y regimes and c omparing them to estimated With-project conditions, it is hoped t h at some qualitative estimates of project effects can be made. 5.4 .1 Existing Middle Reach Turbidity Regime As discussed previously, the natural turbidity reg1me lS highly variable and seasonall y dichotomous. 425832 851111 During the 6 month winter period turbidity values 5-49 are extremely low (0-10 NT U). Duri ng the open water s eas o n (~a y -Octo ber ) turbidity values at Gold Creek have been measured from 0 to as high as 740 NT U, with average values of approximately 200 NTU. Frequent turbidity values were recorded during the open water sea so ns of 1983 and 1984 at variou s sampling stations (Figures 5.25; 5.26; 5.27; and 5.28). Analysis of the 1983 and 1984 data confirms the high variability and approximate average turbidity values which had been recorded from previous , less f requent sampling. 5.4.2 Eklutna Lake Turoidity Regimes Turbidity 1n a large environment 1s a function of thermal structure, wind-mixing, re-entrainment of fine particulates along shoreline boundaries, aeolian input of particles, the concentration and duration of tributary influent of particulates and the hydraulic and hydrologic characteristics of the system. The prevailing biogeochemical processes as well as the elemental and mineralogic characteristics of the particulates also contribute to turbidity regime patterns. Turbidity regime behavior patterns observed 1n Eklutna Lake provide a physical model which may be used to estimate generalized turbidity patterns in Watana Reservoir. When comparing the two reservoirs, however, at least the following facts should be kept in perspective: o The drainage area for Eklutna is less than 3 percent that of Watana ; o The glaciated area of Eklutna Lake is approximately 5 .2 percent of its total watershed area, which is comparable to the 5.9 percent g l acially covered watershed of Watana. The actual areas of glacial 1ce in Eklutna and Watana watersheds are 6.2 miles2 and 290 mi les2, re s pectively ; 425832 85111 1 5-50 I -~ • • - : .. ---..... . I ': .. ., .. I ( nu ... > .~...u a r e ~ru : • ! ! I • ··-· ·:··----,• .. .. ••••• J '•;) ... .. .. _.) .... ...-.-· .-.. ......... .,._ ,...--··· ··. ····· ......... ·-.... ... :: .... •• ":.l -c::.. -·· .. ~· ., ....... ----· ···----..... ~;..-<., .,:·· ····-/···-:: .... ~ ...... ~ . -0 i ... . ,-·' ... ! .. -... --,.. <' --·-----~ . .·· '···~· • I I I .. 5-51 .0 N .n w f a:. :l l 2 1 ~ > t:ct ow -m> ct-~ct t-< cZ zt: ctn ~ wtn ct • ~z t-0 <-a:t-w< Q.t-2CI) w~ t-W w a: a: W(J t-<0 I ,.. ,_, ·~ e -::» en .., : ~s . . ·~ w ~w a:~ liM z ::» ~ ... <t- ~._ (.)< 0 • • -o ow 20 c ,.. •c -2 wa: t-O Ul(J zw ca: I • 2 w • • ~ ~ • .. 0 .. ..; u • a .. I S -(,) • -w ,, a! ~ ~ < a! 5 w (l. 1: w ~ e • NOTES: I I 17 24 31 7 14 21 21 S 12 I I 28 2 8 II 23 38 I 13 28 27 4 MAY JUN JUL AUG SEP OC T 198 .. sae -·-~ z - 1 . DISCHARGI WAS MIASURID AT THE USGS GAGING STATION AT GOLD CREE K 2 . WATER TEM~IRATURI AND TU,.BIDITY WIRI MEASURED AT TALKEETNA STATION MAINSTEM DISCHARGE, WATER TEMPERATURE, AND TURBIDITY IN THE MIDDLE REACH OF THE SUSITNA RIVER, 1984. 1 10UitCI: 40' I II 1915 FIGUR[ ~.27 5-53 \J1 I \J1 ~ !• ' ( !!! ~!119 ....... _ ( ... ..... ............. ... .,. ........ , ......... ,... .... tAl" ~ ~. I I • .. ' .. .. 1~ .... . I ' I rr,t "' · .. ~·,; .!'-! . ••Ill ...&ell.. .. ... -... T tcua ,.., ... , ... ,_,........ -· ..... I ................... I I ••• ................... l.... .... .,. l I -... I • ..... " ... ,... ... ... I f--I'T.'l'ff.rfj~:.-Glfl'; •• eo ... l •• ., .... .,. ....... , ... w• ....... o .... , ...... I I I •• 10 I ~ I ••• I I !!~~ .. •• ......... ._ ........ ••.• Wll I i ••• , ........... u•••• eao w.e I l e & J I ••• , ... , • ., I IM I Ot IM.t J/t • ··~ I I I I --r I I 0 100 200 )()() 400 500 600 700 TURBIDITY CNTUt TURBIDITY DATA SUMM A RY SHOWING RANGE , 25th, 50th (MEDIAN), AND 75th PERCENTILE FOR MAINSTEM AND TRIBUTARY STUDY SITES. IOUIICI . ADf t 1i lt14 c fIGU RE 5 2 8 o Eklutna Lake has approximately 10 percent (3,420 acres) of the surface area of the proposed Watana Reservoir (38,000 acres); o Maximum depth of Eklutna Lake (200 ft.) ts less than o ne third that for Watana Reservoir (735ft.); o Mean depth of Eklutna Lake ( 121 ft.) ts less than one half that for Watana Reservoir (250 ft.); o Maximum length of Eklutna Lake (7 miles) ts less than one sixth that of Watana Reservoir (48 miles); o Maximum width of Eklutna Lake (0.7 miles) ts less than one tenth that of Watana Reservoir (8 miles); o Mean width of Eklutna Lake (0.6 miles) ts less than one half that of Watana Reservoir (1.5 miles); o Hydraulic residence time for Eklutna Lake (1.77 yr.) ts very similar to that of Watana Reservoir (1.65 yr.); o Annual wacer inflow to Eklutna Lake (234,300 acre feet) is less than 5 percent that for Watana Reservoir (5,750,263 acre feet). The maximum storage capacity for Eklutna Lake (415,000 acre ft.) is also less than 5 percent than for Watana (9.5 million acre ft. ) ; o Annual water inflow to Eklutna lake and Watana Reservoir ts approximately 60 percent of their respectiv~ storage capacities; and o Estimated annual sediment inflow to Eklutna Lake (less than 425832 851111 100,000 tons) is less than 2 percent of the estimated annual sediment inflow to Watana Reservoir (approximately 6.5 million tons). 5-55 Because of thes e di s par i ties b etween Ek lut n a and Watana i t c a n be e xpect ed t h at the annual turbidity patterns of the t wo l e nti c s ys t e ms wou l d be similar . Howe v er, the turbdit y l evel s and s ediment c o n c e n tratio n ar e e xpected t o be higher in Watana than what ha s be en observed in Ekl u t na. Data c o llected at the approximate centER of Eklutna Lake fr om Marc h 198 2 thro ugh June 1984 (R&M 1982d, 1985 ) demonstrate patter n s o f tu rb i dit y behavior which may be expected at Watana. In March 1 9 8 2 ( F i g u r e 5 • 2 9 , March, April and May 1983 (Figure 5.30), and March, April , Ma y a,d June 1984 (Figure 5 .31), turbidity beneath the Eklutna Lake ice cover decreased t o i ts annual minimum of less than 10 NTU. Shortly after the lake surface i c e melted 1n April or May, but before signif i cant glacial melt had commenced, turbidity was 7-10 NTU throughout the water column. Usually by June , the turbidity had begun to increase , but no distinc t surface turbidity plume wa s evident. This increase in turbidity was probabl y due to windmixing and /or vernal lake turn-over, and influent turbidit y . By mid-summer, slight increases in turbidity were noted at the lake bottom near the river inlet o r 1n the lake water column. Distinct turbidity plumes were evident as interflows , overflows , or underflows in the lake from late July through mid- September . Turbidity values had significantly decreased by the time the plume had traveled 5 miles down the lake. In late September of 1982 and 1984 , a turbid layer was noted at the bottom o f the lake as river water entered as underflow. By mid-October, the lake was usually either i n i ts fall overturn period or had progressed through it, with near-uniform t e mperatures at approximatel y 7 °C (44 .6°F ) and turbidities o f less than 30-35 NTU. 5.4 .3 Watana Reservo i r The results of the suspended sediment modeling of Watana Re s ervo ir ma y be used to estimate sediment concentrations and turbidities in the upper layer s of the main body o f the reservoir. These simulations indicate that the reservoir will be generally uniform in suspended sediment concentration i n No vember at a value o f approximately 100 mg /1 as a resu l t of isotherma l 425832 851 1 11 5-56 V1 I V1 ....... eo l 2 4 6 CIAMPLl f.lQUl.,Y, l f p .l..) 10, ' '\ / I II I I I ,~ 40 "" • -% ~ ~ 1M I 0 ao I 20 \ 1M " c _, ao 1~ II\.\ ·, I I " I I I I I 1111 4 60 8 ~0 800 ,- ~ X "' 7!1 0 "' r ... < .. -i 0 z -700 0 I I I I I J J I I • flU II u Ill ' I JAN fla MARCH APRIL NAY JUNE JULY • ··- PRfPARf0;:........::8~Y_: -------~M ~---·~~~--·~ - A&M CONSULTANTS. INC. .......................................... ~~·--· ISO-TURBIDITY va. TIME EKLUT"A LAKE at STATION 8 1982 PRfPARfO fOR . C{J&OO Zb Li\u§fiD&~CG@ IJ> I IJ> 00 eo ,.. ; I 1 I l I \ \ l ~ I~ ::r=== l ~ I 12 I -=1 laAWLI PMeuiMCY, ft•·· -8!10 ao .. I I I -~ --~ ! I Laa1 I ' -........._ I \ (/ ' 40 30 \ ; / \ 40 ... I -z ... ' I -....-----------.. 10 20 ... 10 a ao \ I I L~ ... " lj 10 I I "' r "' ... .. 101 ' I I I ~ 0 z --- -700 I I I I I 10 I \H I I J O JAN 1 fee 1 MARCH 1 APRIL 1 MAY 1 JUNE 1 JULY 1 'UG 1 IEPT 1 OC T 1 1 PREPARED BY : r----------------------r.l c.; 1\VA -=.C\t IVL . = . .. , R&M CONSULTANTS, INC. ................ --...................... _. ...... . ISO-TURBIDITY va. TIME EKLUTNA LAKE at STATION 8 1983 NOV DEC PA£ PAR£0 fOR : (}{]Li\00~£a §[ID£~©(Q) SliSII NA JOIN I VI NIIHII fiCIIUf ~ ~0 eo,_;:: I 2 I l f I I i J' f ; ; t i ••• ~ ·.·9 ~ ~ ~~ 1 UAMPLI faiQUIMC'fl '•• t •~o 60 ----- 8 00 401 I I I ~o I I \ I I :1\1 111 T &D \ \ \' I I 3 " I -:z: I 5 ~ ; ··j \ ~\\ lr\~~/ I ,,) 10 I ~ I c ~ ,\ fTI 0. ~ ,- -.a fTI 20-l I \\11 Ill \ I I ' r~ I I 700 zo 10 ~~~ I \ 11111111 \ 10 0 liiiii1J l, lllllllll!\\ I I I I JAN f£8 MARCH APRIL MAY JUNE JULY AUG SEPT OCT DEC NOV PRfPARfO BY : ------------------------~.00 rm . . -- R&M CONSULTANTS. INC. ......................................... "., ... ISO-TURBIDITY v•. TIME EKLUTNA LAKE at STATION 8 ~~84 PRfPARf O fOR : G{]Li\(ffi ~£o§@Li\~©@ SUS IINA JOIN I Vt Nllllll fiGUtU: ~ 31 .;. .. -· () z ---- c onditions and i fall overturn induced b y wi nds. When the reservo ir t c e cover forms tn mid to late November it mtn1m1zes windmixing of the upper layers of the reservoir. As clear, incoming river water e nters th e reservo1r near the surface, and as suspended glacial material settles, t he sediment concentration near the surface will decrease. By Januar y , concentr.1tions near the surface may be approximately 10 mg /1. Sed i ment concentrations will increase with depth in the reservoir. This pattern will be essentially unchanged throughout the ice cover period. However, concentrations near the surface may decrease to a low of 5 mg /1 later in the winter, just prior to ice cover melt-out or break-up . Beginning in May, the influx of suspended material caused by snowmelt r un o f f a:-l precipitation will increase susp~:aded sediment concentration near the surface. Flows will also enter the reservoir below the surface and concentrations may increase throughout the reservoir depth. Concentrations near the surface are simulated to increase from 70 mg /1 to 110 mg /1 by Jul y l and to remain at these levels through early August. These concentrations are simulated to increase to a maximum of approximately 200 mg /1 at a depth of approximately 100 feet. The concentration near the surface generally decreases to approximately 70 mg /1 by October, and the concentration at the 100-foot depth generally decreases to 150 mg /1 at the same time. Turbidity levels in the ma1n body of the reservoir will generally follow the same pattern as the suspended sediment concentration but may be 2-4 times greater. As discussed earlier, turbid ity can be related to the suspended sediment concentration by multiplying the sediment concentration, in mg /1, by at least two to get the turbidity 1n NTU. Thus, turbidities near the surface may be expected to be at least 200 NTU in November, decrease to 10-20 NTU by January, remain at that level throughout winter, increase between May and July to 200-300 NTU and rema1n at that level until November. Average monthly sediment concentrations and estimated minimal turbidities in With-project discharges have been calculated (Tables 5.4 , 5.5, 5 .6, and Figure 5 .32). 425832 851111 5-60 Month January February March April May June July August September October November December TABLE 5.4 SUSlTNA HYDROELECTRIC PROJECT NATURAL AND ESTIMATED MEAN MONTHLY SUSPENDED SEDIMENT CONCENTRATIONS AND MINIMAL TURBlDlTY VALUES EXPECTED TO EXIT WATANA RESERVOIR DURING STAGE I OPERATIONS STAGE I OPERATION Estimated Mean Estimated Observed Suspended Suspended Sediment Minimal Sediment Concentrations!/ Concentrations!/ Turbidity (mg/1) (mg / l) NTul/ <1-8 6j 130 N.A. 55 110 1-6 43 86 N.A. 30 60 65-1,110 35 70 151-1 '860 85 170 100-2,790 130 260 158-1,040 110 220 23-812 90 180 7-140 100 200 N.A. 95 190 N.A. 83 166 l/ Data derived from Table E.2.4.28; from Exhibit E, Chapter 2 data. ~/ Turbidity estimated by using factor of (2x) times TSS concentrations (See discussions in Exhibit E, Chapter 2). 425832 851111 5-61 TABLE 5.5 SUSITNA HYDROELECTRIC PROJECT NATURAL AND ESTIMATED MEAN MONTHLY SUSPENDED SEDIMENT CONCENTRATIONS AND MINIMAL TURBIDIT Y VALUES EXPECTED TO EXIT DEVIL CANYON RESERVOIR DURING STAGE II OPERATIONS STAGE II OPERATION Estimated Mean Estimated Observed Suspended Suspended Sediment Minimal Month Sediment Concentrationsl/ Concentrationsl/ Turbidity (mg/1) (mg /1 ) NTul/ January <1-8 60 120 February N.A. 45 90 March 1-6 40 an April N.A. 30 60 May 65-1,110 28 56 June 151-1,860 55 110 July 100-2 ,790 110 220 August 158-1,040 110 220 September 23-812 90 180 October 7-140 80 160 November N.A. 80 160 December N.A. 73 146 N.A. z Not Available. lf Data derived from Table E.2.4 .60 ; (in Exhibit E, Chapter 2). II Turbidity estimated by using factor of (2x) times TSS concentrations (See discussions in Exhibit E, Chapter 2). 425832 851111 5-62 Month January February March April May June July August September October November December TABLE 5 .6 SUSITNA HYDROELE CTRI C PROJE CT NAT URAL AND ES T IMATED ~AN ~O NTHLY SU S PENDED SEDIMENT CONCENTRATI ONS AND ~INIMAL TURBIDITY VAL UES EXPECTE D TO EXIT DE VIL CAN tO N RE SE RVO I R DURING STAGE II I OPERATI ONS STAGE III OPERATI ON Estimated Mean Observed Suspended Suspended Sediment Sedimen t Concentrationsl/ Co ncentrati o nsl/ (mg /l ) (mg /l) <1-8 55 N.A. so 1-6 25 N.A. 25 65-1,110 17 151-1,860 35 100-2,790 75 !58-1,040 75 23 -81 2 55 7-1 40 so N.A . 70 N.A. 68 Es tima t ed ~inimal Turbid it y Nr ul./ 11 0 100 50 50 34 70 15 0 1 50 11 0 10 0 140 136 N.A . =Not Available. l / Data derived from Table E.2.4.8S; (in Exhibit E, Chapter 2) l.l Turbidity estimated by usi ng factor of (2x) times TSS concentration s (See discussions in Exhibit E, Chapter 2). 425832 851111 5-63 verticall y transmitted PAR per unit of turbidit y . For this relati o nship data co llected in the glacial flour impacted Ek lutna Lake, f r om undisturbed and placer-mine affected streams in interior Alaska, from various s amplin g points Ln the Susitna River drainage basin, and from Knik Arm have be e n pooled f o r use in synthesizing a model relating turbidities and maximum euphotic zone depths (i .e . the depth to 1 percent PAR ) • Thi s empiri c all y derived relationship has been graphically represented (Fig ure 5.33). It ma y may be expressed as the relation between maximum euphotic zone depth in :eet (Z ft.) and turbidit y (T) Ln nephelometric turbidity units (N TU) a s follows: Z ft. a 4.605 ------~~~----- (0.543 + 0.0177 T ) 5.6 ESTIMATED FISHERIES IMPACTS OF AN ALTERED SEDIMENT AND TURBIDITY REGIME IN THE MIDDLE REACH Organisms existing Ln rivers, whether glacial l y influenced or not, are likely to be specialized to exist Ln lotic environment s (Lagler et al . 1962 ; Gill 1971; Hynes 1970, 1973; Merrit and Cummins 1978 ). Salmon , both Salmo ~ and Onchorhyncus ~· have probably evolved through at least four major ice ages, several minor ice ages, and interglacial periods whi c h took place during the Pleistocene (Flint and Skinner 1977; Netboy 1974 and 1980; Dott and Batten 1981). During their natural di s persions and spec iations in European, Asian and North American waters between 35° and 70° North latitudes salmon have undoubtedly encountered and endured highl y varied riverine sediment regimes . All existing species of salmon have evolved behavioral and presumably genetic adaptations for selecting and surviving in aquatic environments which are subject to variable amounts of suspended sediment , turbidity and sedimentation. Most researchers have concluded that the productivit y , bioma s s and health of most aquatic o rgani s ms (including most salmon life cycle stages) in cold 425832 851111 5-66 0.0 ° 100 -0.5 fl) a: 1.0 w .,_ w ~ - X 2 .0 ..... ~ w V1 I 0 I 3 .0 0\ w ...... z 0 N 0 4.0 -t- 0 X ~ 5.0 ::> w 6 .0 TURBIDITY (NTUa) 200 300 400 500 600 700 800 900 lUPHOTIC ZOMl OlPTH :X E~::~: +0.0171'1"10·3041 METERS /FOOT) ( l . WOOOY UIHIY AND ASIOCIATU IN4 ~ l AN EMPIRICALLY DERIVED, GENERALIZED RELATIONSHIP BETWEEN TURBIDITY AND THE MAXIMUM EUPHOTIC ZONE DEPTH (1 .0-. P .A .R) 1000 fIGURE ::> 3:3 water, lotic · habitats are particulates in sus pens ion or inversely related to the mass of small settled in t :1e intersti c es of the streambed substrate (Shaw and Maga 1942; Stuart 1953a, Kelley 1961; Cooper 1965; Einstein !~68 a~d 1953b and 19 54; Cordone and 1972; Gibbons and Salo 1973; Nat. Acad. Sciences 1973; Hynes l ~t70 and 19 7 3; 5ru sven and Prather 1974; Bjornn, et al. 1977; Iwamoto, et al. 1978; Sorenson, et al. 1977 ; Ward and Stanford 1979; Muncy et al. 1979; Reiser and Bjorn 1979; Alabaster and Lloy d 1980; Bell 1980; McClelland and Brusven 1980; Wilber 1983; Lloyd 198 5 ; Peterson et al . 1985a). Acute affects of suspended sediments o n either rearing juvenile or mig~ating adult salmonids are usuall y not detectable at concentrations less than multi-hundreds or even multi-thous ands of milligrams per liter (Noggle 1978; Smith 1978; Ross 1982; Gibbons and Salo 1973; Bjornn, et al. 1977; Iwamoto et al. 1978; Bell 1980; Lloyd 1985; Peterson et al. 1985a). Chronic effects of 1norganic suspended sediments at concentrations between 0 and 100 milligrams /liter on rearing juvenile and adult salmonids are usually noted as either negligable or as slight ly reducing their health and survivability. Chronic exposure to fine sediments of freshly fertilized eggs, incubating eggs and developing a levins is frequently noted as stressful if not lethal. Studies have not yet been found which have investigated and reported the effects of chronic exposure to suspended sediments which have las ted more than 9-10 months, and most experiments lasted for only a few days to a few months (Iwamoto et al. 1978; Bell 1980; Lloyd 1985; Peterson et al. 1985a). No experimental results have been located to date which examine the e ff ect s of continuous exposure of rearing salmonids to the expected With-projec t winter c onditions in mainstem affected channels (i.e. 0-2°C, <less than 15 0 milligrams per liter of predominately small suspended sediments; and les s than 300 NTU). The evidence which has been examined , however, suggests that the effects of overwintering i.n chronic suspended sediment l e vel s such a s those expected in the mainstem habitats might be stress f ull but pro babl y survivable . It should also be remembered that many clear water peripheral habitats, and c lear water upwellings and tributary in f lows may provide 425832 851111 5-68 nu ·uerous suitable niches for middle reach fishes during all periods of the annual cycle. Any Project-induced detrimental impacts which may occur 1n chronically turbid channels would likely result from sedimentation effects on streambed substrate habitat, on early fish life cycle stage (egg and alevin incubation), and on optically related fish behavior. These ef fee ts ma y largely result from intrusion of fine particulates into interstial spaces of some streambed substrates and to relatively high turbidity (Stuart 1953a and 1953b; Cooper 1965; Einstein 1968; Alabaster and Lloyd 1980; Beschta and Jackson 1979; Iwamoto et al., 1978; Carling 1984; Bell 1980; Bisson and Bilby 1982; Milhous 1982; Sigler et al. 1984; Ll oy d 1985; and Peterson et al . 1985a). Cursory information about the suspended sediment concentraticn and turbidity levels in two other glacially affected rivers in south central Alaska have been assembled. With-project conditions in mainstem affected channels of the Susitna River middle reach are expected to be more biologically detrimental than either the Kenai or Kasilof Rivers (Table 5.7). 5.6.1 Recommended Criteria Recommendations for the upper tolerable limit of chronic exposure to TSS which can support good fisheries are approximately 25 mg/1 (Alabaster and Lloyd 1980; Bell 1980; Wilber 1983). Chronic exposure to concentrations of 25-80 mg/1 TSS are commonly expressed as being potentially hazardous and detrimental, or providing only good-to-moderate protect ion for fresh water aquatic life (Hynes 1973; National Academy of Science 1973; Alabaster and Lloyd 1980; Wilber 1983). Chronic exposure to TSS concentrations of 80-400 mg/1 is reported to be considered "not good', "poor", providing only "low levels of protection" and being "possible lethal" to aquatic organisms (Gibbons and Salo 1983; Alabaster and Lloyd 1980; Bell 1980; and Wilber 1983). Chronic exposure to TSS concentrations in excess of 400 mg /1 should be considered extremely bad and potentially lethal (Gibbons and Salo 1983 ; Alabast e r and Lloyd 1980; Bell 1980; and Wilber 1983). 425832 851111 5-69 River Kenai Kenai Kasilof Susitna Susitna Sus itna TABLE 5.7 SUSITNA HYDROELECTRIC PROJECT APPROXIMATE ANNUAL RANGE AND MEAN VALUES OF TSS AND TURBIDITY IN SELECTED REACHES OF TWO SOUTH CENTRAL ALASKAN GLACIAL RIVERS COMPARED TO WITH-PROJECT ESTIMATES FOR THE SUSITNA RIVER MIDDLE REACH Reach TSS/Turbidity Observation Period below Kenai Range 2-26mg/l ; mean N.A.l/ 1956-1974 Lake o-32 NTulJ 19 79 -1981 at Soldotna Range 1-151mg /l; mean <40mg /ll/ 1967-1979 Bridge 0-32 NTU.~/ 1979-1981 below Tustumena Range 15-45mg /l; mean N.A.l/ 1953-1968 Lake 38-60 Nrul/ 1983-1985 Watana Range 30-130mg / 1; mean•77mg / 1 Stage I Mean Discharge 60-260 NTU (minimum) Annual Estimate Devil Canyon Range 28-ll Omg / 1; mean•62mg /l Stage II Mean Discharge 56-220 NTU (minimum) Annual Estimate Devil Canyon Range 17-70mg /l; mean•50 Stage III Mean Discharge 34-150 (minimum) Annual Estimate 1/ Source : Scott 1982 II Source: Burger, et al. 1982 ll Source: Pers. comm.: Koenings, J. 1983-1985; Van Nieuwenhuyse, E. 1985 425832 851111 5-70 5.6.2 Present Conditions Pre-project water quality conditions in the mainstem Susitna River channels (regarding suspended sediments) range from extremely poor during much of the open water season to excellent during the winter season. Nevertheless, some rearing juvenile s almon survive the high suspended sediment concentrati0ns and high turbidity levels during portions of the summer diel c ycl es . Some Susitna specific data indicates that a limited portion of the middle reach juvenile salmon (especially chinook) may even prefer the high suspended sediment concentrations and turbidit y of mainst~m affected habitats (ADF&G 1984b and 1985a, c). It is well known that intermittent high TSS Concentrations, and darkness each seem to be causally related to benthic invertebrate drift (Hynes 1970; Muller 1974; Rosenberg and Wiens 1978). In fact chronically high turbidity, with its attendent reduction of vertical ligh penetration, ma y help stimulate fairly continuous drift during summer in certain habitats in the Susitna River middle reach. Artificial darkness has be .~n known to enhance daytime drift under experimental conditions (Hynes 1970; ~uller 1974). One possible explanation for the apparent preference of some rearing juvenile chinook for relatively turbid waters documented during Susitna River studies is that they were permanently or transiently selecting turbid waters to take advantage of a relatively good drifting food supply. Much evidence supports the concept that f~eding juvenile chinook are opportunistic feeders specializing ~n drifting, autochthonously produced invertebrates (mostly Chironomidae ) (Becker 1973; Oauble et al . 1980; Burger et al. 1983; ADF&G 1985b). A second, but not mutually exclusive explanation of the apparent juvenile chinook preference for relatively high turbid i ty, ~s that they employ the turbidity as cover. 425832 851111 5-71 5.6.3 With-project Turbidity Regime The biological significance of chronic exposure to high turbidity is likely to be minimzat ion of riverine biomass product ion at all t rophi c levels. Autochthonous primary productivity may begin to be reduced at appr oximatel y 25 NTU (Bell 1980; Van Nieuwenhu yse 1983; Lloyd 1985 ), but stream depth will be an important factor in determining the amoun t of PAR reaching the streambed substrate . Even highly turbid glacial streams may have moderate or high autochthonous productivity at subvertebrate trophic levels 1n sufficient l y shallow habitats (Milner 1983). At low turbidity (0-25 NTU), disregarding other environmental limiting factors, authochthonous primary productivity and perhaps it may be surmized that productivity at higher trophic levels would be enhanced by the fertilizing effects of nutrients associated with the suspended inorganic particulates. The upper tolerable limit of chronic turbidity to which all stream habitats and inhabitants may be exposed while still maintaining a self sustaining salmon population has not been established. It is likely that each riverine ha~itat type would respond to different turbidity exposures (different turbidity levels; intermittent versus chronic, etc.) 1n different ways . Very coarse estimates of the max1mum tolerable chronic turbidity f o r maintaining a viable salmonid fishery in subarctic Alaska ma y be within the 100-200 NT U range for streams with mean depths of 0.5 feet or greater. The Kasilof River, which is one of the more chronically turbid rivers in south central Alaska known to maintain a self sustaining salmonid fishery probably rarely exceeds 15-45 mg/1 TSS (Scott 1982) and probably rarely exceeds 100 NTU (Koenings, J. 1983, Lloyd 1985). 425832 851111 5-72 . 6.0 HYDROGEN ION CONCENTRATION AND ALKALINITY The significance of potential changes in pH on salmon and resident fish habitats due to inundation of soils, organic detritus and lithic materials in the project reservoirs has been identified as a fisheries is.>ue. chapter examines the current status of our knowlege on the subject. 6.1 Discussion This The physical, chemical and biological characteristics of a water body (including its pH and alkalinity) wili reflect the basic climatic, hydrologic, and biogeochemical regimes of its entire drainage basin, and not merely the small portion of the drainage which is under water (Welch 1952, Hutchinson 1967, 1973, 1975, Wetzel 1975, Vollenweider and Kerekes 1980). The pH of upstream and dcwnstream mainstem Susitna riverine habitats is presently regulated by the carbon dioxide-bicarbonate-carbonate and aluminum silicate dissolution buffering systems (Wetzel 1975, Stumm and Morgan 1970). These two buffering systems maintain pH values between 6.0 and 8.3 in most fresh water ecosystems of North America including the Susitna River. The drainage bas in of the Sus itna River upstream of the proposed Devi 1 Canyon dam site encompasses approximately 5,810 square miles of unvegetated mountains and subarctic tundra. The watershed's bedrock, glacial till and glacial outwash mal:erials contain alkalinity-producing carbonate and silicate minerals (APA 1983a, R&M Consultants Inc. 1982a,b). Overlying the watershed~s lithic material is a substantial area of tundra consisting of saturated, peaty soils, which may be acidic in nature. Sphagnum bogs are frequent on the tundra and they commonly have a pH less than 4.5. Despite sustantial inflow from tributary drainages with acidic soils and acidic bogs, the ionic composition of the mainstem river is presently sufficient to buffer tributary acidity and maintain low to moderate alkalinity values. Changes in mainstem pH values are seasonally variable but remain between 6.0 and 8.1. The mean annual pH is greater than 7.0 in the mainstem water of the Susitna river watershed (Figure 6.1). The pH of intragravel waters of 425832 851111 6-1 ~ M01n11em : ....... ....... ••1411 .......... f .......... t-. Cwr, ClltiUI LIU 211 Got• c,..~ C... 0' I Lilli ~1 N ..... ( ... ........... uc., ... Tubulorr: ....... , ••-CfltMOI) O...IN lltwe~::aMO•I Figure 6 .1 u ~=!.J -t-,.,. 1 ~ •••• .... ~"'-. .... --tt--• ; 82 IOJ.O MI·IIIJ-1 • • ,. 12 ~.. ,..,_ .... 101~ Pern•IU• •·o.·· ............. 1100 llte-4011 -1 -tn;l iletleUut .... , ••• .... US-1112-I • + ""1 ..... <M·IW] • • ---t:l!l-,.. 10 M:tO --1-•.• .111-l&n 11100 , .. ., .... I • .. a 1111 ·ltl-1011 I n •6 •o W -1011 I •=• I 50 6 .0 1.0 8 .0 e .o 10.0 pH pH data summary showing rang e , 25th, 50th (median). and 75th percentile for main s t em and tributary water qua 1 tty s tudy sites I S ource : ADF a G 1984 c I tributary, peTipheral and main st em habita ts lS s imilar to t h a t of mainstem su rface waters (Figures 6.2, 6.3 ). A wetlands mapptng projec t has been completed by th e US FWS tn o r de r to quantify the amount of different wetland t y pe s in bo th Watana and Dev il Canyon impoundment zones . The estimated total o f vege tated areas which are classifiable as wetlands equals 8,316 acres o r 18.8 percent of the combined impoundment areas. The estimated total of all "bog -like" wetlands equal s 1,182 acres or approximately 2. 7 percent o f the combined impoundmen t z o ne areas. The pH of the proposed reservoirs and downstream riverine h abi tats under with-project conditions will be reg•1lated by the same chemical bu fte ring system existing at present. Flooding of the s mall area of bog habitats is not anticipated to cause a biologically significant change of pH 1n rlverLne habitats downstream of the proposed pr oject o r tn the reservo1rs. The overall effec t of the project will be t o buffer the amplitude of pH changes 1n both the reservo1rs and ln the downstream riverine habitats, just as the project will buffer the amplitude of changes in the flow, temperature and TSS regimes. A large 11umber of references, including rev lew arti cles, re search report s and texts h="e been reviewed for any discussion of pH changes i n reserv oirs or their downstream habitat r due to bog inundation (S ee referen ce sec tion of this text ). No documentation of such a problem has been located in the open literature dealing with lake or large reserv oir limnology tn subart ic environments. No pH problems due to bog inundation are expected to be as sociated with this project. 425832 851111 6-3 a- I ~ 8LOU8H 10 C• =n• OLOU8H II C• =u• 8LOU8H II •·=•• oma CH. 10 •·=•• U. 010• CH. II •·=•• 8K»R Ott. It •·= ., 4TH OP .IULY ca. C•= I) MAIIIOTRM Ill. I C• :I) ~ • -·-no;:;.~····\ • • • • . . . . . ......... _. . ...... . ...... _ ........ , .. ·-· --------.------1 I t I 1----- --------•---------·----- •••·--•ae ,,. ..... . ··-~·· wa&.UI •• -·-WM.UI •·-•-MMC~•t 'MUll •· •u .,,_ OM&.UI • --1----• I 1----•-------- -------------· ----------1 I •----I --------· ----·---------------------1---1 • 1 r------ --•----------------·-------11 • 1----------·-- ---------·---------------1 • 11------------------ ---------·--------------------------------------·-----------------1 I • I -------------------------·------·--- C--1 • H --·--· 1 .0 8.6 7.0 7.6 8 .0 INTRAGRAVEL pH Figure 6 .2 St.mnary, by stldy site, of the intragravel ~data periodically ~TEasured within standpipes cklring the 1983-84 winter period in the midlle Susitna Ri.\el", Alaska (Source : ADF 6 G 1985 d) 13' I VI 8LOU8H ••=41t 81DR CH. •·= 1tt TIU8UT ARY C•; t) MAIN8TRM C•= I) e.o I ----------·----- ---1 •• ··---------t-------------·---- ---!7~~~····\ • • • . . . . . ··~ -·· ...... . ...... --I I• M~ C. I . aaouf ····~'MAe , ........ fo-~ ""'-111 ••Wl-WA&.YI .......... M.-c•f .... • .... _,_ ..... .,. --------------1 • • 11----------------------t-------------------t-----------1 I t I ---------------------t---··•·-- ·--· t H ·-•--· I I .---T -,----·--,--~ ••• 7.0 7.1 1.0 8 .6 INTRA ORA VEL pH Fi~ 6 .3 Sulmiuy, by habitat type, of the intragravel ffl data pe.r.iDdically neasuced within s~ipes wdng the 1983-84 winter period in the aWW.e Susitna River, Alaak.a (Source : AOF a G 1985 d l 7.0 GENERALIZED INFORMATION REGARDING PROJECT EFFECTS ON HEAVY METALS 7.1 INTRODUCTION Leaching of potentially toxic heavy metels from newly inundated reservoir vegetation and soils may occur during the early life o f an y reservoir. In the Sus i tna River some trace metals presently exist Ln con::antrations higher than agency limits for protection of freshwater organisms (APA 1983a, b). Knowledge of the potential for the pro ject reservoirs to create toxic metal problems lS useful for addressing public and agency concerns. The purpose of this chapter is to summarize Lhe potential for leaching of heavy metals from soils and organic matter within the newly impounded reservoirs, and the potential project induced biological effects to be expected, if any, due to heavy metal probilization. Literature on the subject was searched by both manually and electronicallyll . There are few cases studies. Most water quality studies of newly impounded reservoirs have been related to trophic status, not metal dynamics. The studies we found focused upon mer c ur y bioaccumulation , as mercury l S the only heavy metal known to enter the foo d chain as a direct result of river impoundment. (Abernathy and Cumb i e 19 77; Bodaly et al. In press; Meister et al. 1~7 9). 1 / DIALOG a databases searched included Pollution Abstracts , Aquatic Sciences and Fisheries Abstracts, and Water Resources Abstracts . Cold Regions database, maintained by the Cold Regi o ns Research and Engineering Laboratory in Hanover, New Hampshire , was also searc hed. 4 25832 851111 7-1 The original ·License Application (1983a, b) reviews the concentrations oi metals in Susitna River water and evaluates them using published criteria and guidelines (AAC 1984; EPA 1976; McNeely et al. 1979; Sittig 1981). Many metals violated these criteria and guidelines. As stated tn the original License ' Application, the measured levels of heavy metals tn the Susitna River represent natural conditions. With the except ion of some placer mining operations, the water shed supports no significant industries, agriculture, or urbanization. Consequently, it was concluded that the violations of water quality criteria represent a naturally affected aquatic ecosystem . Nevertheless, the high levels of certain heavy metals warrant further investigation. Metals which exceeded applicable criteria included both dissolved and total recoverable aluminum (Al), cadmium (Cd), copper (Cu), manganese (Mn), mercury (Hg), and zinc (Zn). In addition, the dissolved fraction of bismuth and the total recoverable qu?.nt1t1es of iron (Fe), lead (Pb), and nickel (Ni) also exceeded the criterial/. I I In this report, total recoverable metal is used synonymously with total metal. Total recoverable is the amount of a given constituent that is in solution after a representative water-suspended sediment sample has been digested by a method (usually using a dilute acid solutio n) that results in dissolution of only readily soluble substances . Complete dissolution of all particulate matter is not achieved by the digestion treatment, and thus the determination represents something less than the "total" amount (that is, less than 95 percent) of the constituent present in the dissolved and suspended phases of the sample. Dissolved metals are operationally defined as those that pass through 0.45 um pore filters 425832 851111 7-2 As soils weat-her and undergo development, water transports materia ls f r om upper alluvial horizons to lower alluvial horizons. The migration of ions, molecules, and particles from rock surfaces and through soil material is a very impcrtant process of soil development; water is the essential transport vehicle . As rainwater drains over rocks and percolates through the soil, its chemistry is very dynamic and the percolating water reaching each soil horizon has a composition determined by its previous path. In a reservoir, the same processes occur but downward transport of solutes from soil and rock surfaces may no longer be the dominant direction of solute transport. Rather, the materials may be carried up into the water column by advective forces, and be reflected in the limnology of the reservoir. Geochemical weathering is accelerated by organic humic substances~/ (Baker 1973; Schalscha et al. 1igands1/, particularly 1967; Singer and Navrot 1976; Huang and Keller 1970). Humic substances and their abilities to complex trace metals are well studied (Schnitzer and Khan 1972; Christman and Gjessing 1983). Humic substances are mild leaching agents. they have the ability to mobilize a wide variety of metal ions in rock weathering processes. Their metal leaching ability is due to their role as a li gand in natural solutions . Metal complexing capacities of humic substances vary with the sources of humus as well as the metal (Jackson, et al. 1978; Pott 1 1 In coordination chemistry, the metal cation is called the central atom. The ligands are anions or molecules which donate electrons to form a coordinate bond (Stumm and Morgan 1981). f±/ Humic substances encompass a heterogenous polymer system composed of complex organic molecules, usually with molecular weights of 300-200,000; some of which are insoluble (humins), base soluble (humic a c id), or acid soluble (fulvic acid); and all of which are derived from the decomposition of vegetable or animal materials. 425832 851111 7-3 el al. In pr~s s; Schnitzer and Khan 1972; Singer and Navrot, 1976 ). Humic substances are common throughout ~he soils of the Watana and Devil Canyon Reservoir watersheds. Another geochemical process that will influence metal concentration tn the proposed Susitna reservoirs ts ion exchange. Sorption and desorption of metal cations at the solid-solution interface will strongly influence prevailing metal speciation in the reservoirs (Stumm and Horgan 1981). As the reservoir fills, the metal ions available for sorption will adsorb o nto the suspended solids until the sorption capacity or the sorbate limit is reached. If the sorbate (metal ion) concentration is limiting, then free metal concentrations will be generally low after sorption equilibrium is reached. If the sorbant (suspended solids) concentration 1s the limiting factor, then the equilibrium free metal concentrations will be higher. The former case, sorbate limiting, will likely be dominant tn the proposed Susitna Reservoirs due to the tremendous suspended solids load in the river ( APA 1983a, b). 7.2 MERCURY OCCURRENCE IN THE SUSITNA RIVER The U.S. Geological Survey (USGS) has monitored dissolved and t o tal recoverable mercury at various points in the Susitna River. These data were presented in the original License Application as Figures E.2.ll5 and E.2.ll6. The detailed mercury data, taken directl y from the annual USGS Water Resource Data reports, are shown in Table 7.1. Total recoverable Hg averaged 0.2 ug /L and ranged from zero to 0.8 ug /L. Dissolved Hg averaged 0.06 ug /L, ranging from zero to less than 0.5 ug /L. The levels of dissolved Hg shown in Table 7 .l are on the high end of the range of Hg concentrations typically found in unpolluted North American surface waters (M oore and Ramamoorth y 1984). The Hg concentrations probably 425832 851111 7-4 ...... I V1 Lloto d ·•)' 01 ec:ftor.,. (cfo) SU4111Jended !ooltd (-.JL) Oleeolw•d Orewu.c (-.JL) ~hi ton: !>watt no ltwor ol Cold CrMk (IU9209011) 140611 H,WO 100111 041017 210611 210711 100)12 010112 11>11912 20,000 I, '100 11,'100 .2,600 l,HO 24, '100 14,600 91) 6~ 22 121 610 I 101 112 2 .1 11 .0 1.6 2.0 Stet1o1u ~ealne law•r •I ~urWu,. (1')292110) 25UIIl 2~1 210111 020112 1~2 1,100 H ,OOO 16, lOU )1,100 10,100 I)) Ill 6)9 l,UO 2 •• 4 .1 4 .1 ~ lolol 14,000 u,ooo 100 !:alata01u ~•&trw lhwer el !)ue&tne ~•••on (J)294J~) OJIOI) 41, '100 liOH6 ), )10 210)16 61,900 2.0176 99,100 041016 10,600 IMIIII o,790 210HI 16,100 190117 141,000 111211 0)0411 240HI 110111 lSUI19 l40H9 1,020 6,420 )),100 120,000 9 ,1'10 16 ,100 190419 9). 21111 liU9 19 II, 100 120 JIU 9, 1611 160680 144,01111 JOOIIO 201,01111 ll'J10411 7,710 121»111 11,600 lSU/11 lll,UOO 0'10412 4 ,WO 190)12 ~.eoo 140112 101,000 1)9 2 2H /1) I'll Ill l,•WJ 10 2 Ill , .. ~ 416 901 6)1 1 ,4~ J2• 920 9 )I~ /Y I O.l 0 .1 1 .1 2 . I '·, 6 .1 0 .9 0 .6 ).Y J .l 2 .1 1 .4 2 •• Ulll 1.1 SU~llllll HYOIIC.UClllC PIIO~CI AVAllAIU USGS DAIA -II I AI. -l YSI ~ C•'*-'•u. C-r Iron lolol Dio-lot•l Oio-lotol Oio- <10 <10 <10 0 ( l I 0 0 <I <I 10 10 <10 <10 <10 <10 10 0 l 0 0 I 0 0 0 u u 2 u <l < l aolwed <I l <) I <l <I <I 0 <l <I 0 0 0 0 0 0 0 0 <I 0 0 <l <l <I <I <I <I su su <10 Jl 190 2 ZJ ~ )2 u 10 I) 20 10 .0 su <10 <10 20 90 26 4) 2) 29 II 21o I) 21 90 2 21 II eohed 4 ) 4 4 , u 10 0 4 l 4 4 I 2 2 0 •ohed 20,0110 100 11,0110 ISU .0 1),000 90 19,0110 120 .0 I) IZ, 0111 1.0 14,0110 uo 160 .0 U,OOO ltD lJ,OOO 2SU 20,000 220 29,000 200 1,100 120 260 60 ), JOO 1.0 u,ooo 10 ),400 .0 '160 90 10,0110 lSU u,uoo 10 "0 60 210 60 ),600 llO 24,000 20 4'10 90 14 ,000 110 12 ,0011 0 u ,uoo .0 4SU lSU 16 ,000 20 II, UUil 1.0 1'10 160 1),000 90 21,000 su 120 6) 9 ,900 190 I , 900 69 J/ All co1a:enlretau•• •r• '" atc:riJilir ... ~r hler u.ll••• vtl .. r•••• 11w.hl~•ted . l./ , ...... ~ U)IIJ/1/Ita ..1!!!!._ lolol 100 <100 <100 II 41 ) <I l) 0 H 21 <I 41 <100 <100 l6 <100 <100 <IOU <100 ( 100 I 10 21 ll 60 12 l6 2 4 l6 l , ~ <l 14 --lolol Oio- 170 120 20 2SU )20 10 210 ao 10 ))U 4SU 100 6211 llO Ill 100 ~o 110 .0 210 110 20 20 120 suo 60 10 2SU )10 10 210 IW 10 410 '>110 10 240 )JU eahed .0 110 0 10 I 4 I 10 10 14 10 10 0 0 0 10 I 20 20 20 10 0 10 10 10 4 10 10 lO • I II I I .. Mtrcvn• lolol ou- eolved 0 .2 0., 0.2 0 .4 0 O.J 0 .2 <O.l <0.1 <0. 2 <0.1 <0 .2 <O.l O.l O.l 0 .6 0 0.) 0 .1 0.2 <0.1 0 .2 0 .1 0.2 0.2 0 O.l <0.) <0 .) O.J 0 O.J 0 .4 0 0 0 0 0 .2 0 0 0 0 0 0 .1 0 0 .2 0 .1 0 .1 0 0 .2 0 O.l 0 0.1 0 0 .1 0 0 .1 0 O.l 0 0.1 0 0 .1 0 0 .1 0 .2 <O.l <0.1 U.l <U.l U.2 U.l ~ lolo l su <SU <SU 21 29 2 u " II )2 29 , .0 4 " 60 • 22 '" II )j ,.,,., l olel D••· 10 IU Ill 60 120 10 su 90 20 200 90 10 110 IU Ill 20 100 Ill 20 su 1110 lU 10 Ill 9U 10 su 60 10 lll su IW w su I I>IJ IU 60 llU .oheO 6 10 <12 14 JO 6 20 9 II IU 0 0 0 lO IU lU 10 IU IU 10 IU IU <I <I <I I " iU • <U <II reflect the n·atural mercury deposits in south central Alaska (Johasson and Boyle 1972 as cited by Moore and Ramamoorthy 1984). Twenty-five to fifty percent of the total mercury 1n the Sus i tna River occurs as the dissolved species. Published investigations generally show less than ten percent of the total mercury is dissolved Hg. Mercur y is usually associated with suspended particles (Jackson et al. 1978; Lockwood and Chen 1973; McNeely et al . 1979; Moore and Ramamoorthy 1984; Rudd et al. 1983). A bivariate correlation analysis was performed to elucidate phenomena controlling Hg (and other metals) speciation 1n the Susitna River (see Appendix 7.20). Total recoverable Hg was significantly correlated with total recoverable Zn (r•0.5471) at least to the 0.01 level and with total recoverable lead (r•0.5538) and total recoverable copper (r•0.3936) at or beyond the 0.05 level. Dissolved Hg was not significantly corro!latd with any other variable included in the analysis. Neither total nor dissolv~d Hg were significantly linked with river discharge , total suspended solids, or dissolved organic carbon. POTENTIAL FOR LEACHING AND BIOACCUMULATION OF MERCURY - A LITERATURE REVIEW Research has shown that mercury levels 1n aquatic biota can 1ncrease following impoundment and reservoir formation (Abernathy and Cumb:.e 1977; Bodaly et al. In press; Cox et al. 1979; Meister et al. 1979). The source of the mercury is the inundated soils. Bodaly et al. (In press) implicated organic topsoil horizons as the major source of accumulated mercury. Rudd et at. (1983), studying industrially produced mercur y pollution 1n a northwest Ontario river system, reported that most mercury in the system was buried below surficial sediments (in organic-poor sediments ). They found that this Hg probably did not contribute substantially to mercury bioaccumulation, whi c h was found to occur primariiy in the water column and surficial organic sedimen:s . 425832 851111 7 -6 Mercury lS generally bioaccumulated 1n the me t hylated form (EPA 1980). ~ethlyation occurs by microbial action on the Hg(II) ion in both aerobic and anaerobic environments. In general , conditions enhancing the metabolism of soil and aquatic microorganisms will enhance mercur y bi omethy lation. Rudd and Turner ( 1983b) demonstrated increased mercury bio ac c umulati o n in fish was related to increased primary productivity . Wright and Hamilton (1982) showed that an increase in microbial nutrients 1n sediments resulted 1n higher rates of mercury methylation upon addition of microbial nutrients to the water column, indicating that methylation occurs primaril y at the sediment-water interface. In contrast to methylmercury's tendancy to bioaccumulate, inorganic mercury strongly favors association with particulate phases (Cranston and Buckley 1972; Hannan and Thompson 1977; Lockwood and Chen 1973; Moore and Ramamoorthy 1984). In fact, application of organic-poor sediments to 1n situ enclosures 1.n a mercury contaminated system in Ontario resulted 1n decreased rates of Hg bioaccumulation (Rudd and Turner 1983a). Laboratory tests by Jernelov and Lann (1973) showed that Hg biomethylation was reduced to less than 0.1 percent after treatment with freshly ground silica. The sediments apparently bound the mercury, making it less available for bio- methylation and/or accumulation. In their mercur y amelioration study, Rudd et al. (1983) concluded that elevated concentrations of suspended sediments substantially reduced methylmercury accumulation i n fish, while s timulation o f primary productivity increased methylmercur y bioaccumulati on . This concept has direct implications for assessing the potential bioaccumulation of Hg in the pr o posed Susitna reservoirs . Bioaccumulation is a function of an organism's rates of uptake v er sus elimination. The bioaccumulation factor for mercury lS high because its uptake is relatively fast, but its elimination relatively slow . High temperature accelerates the uptake of mercury compounds by accelerating the metabolic and respiratory rates of the organisms and increasing the need fo r food (EPA 1980 ; Wright and Hamilton 1982; Shin and Krenkel Similarl y, low temperatures depress the rate of Hg bio accumulation. 425832 851111 7-7 19 76). Mercury levels tn organisms seem to vary directly with trophic positi o n. Piscivorous fish and fish predators generall y ha v e the highe s t c o ncentrations (Phillips et al., 1980; Potter <!t al., 1975 ; O'Conner and Nielson 1981; Kucera 1982). Work by Fimreite et al . (1971) 1n Canada showed the magnification of mercury from fish to fish-eating birds. Swedish research (Skedving et al. 1970) has demonstrated the transference of methylmercury to humans eating contaminated fish; this same resear c h showed a statistically significant (r•0.6; P<0.05) correlation between mercury concentrations and the frequency of and chromosome breaks in red blood cells. Implications for the Susitna Hydroelectric Project Data on mercury occurrence 1n the Susitna watershed 1n insufficient to make conclusive statements on Hg speciation and present levels in the watershed biota. However, this review of relevant literature supports the following conclusions regarding the potential bioaccumulacion of mercury in fishes in the Susitna Reservoirs. Soils 1n the project impoundment zones are fairly typical of those formed in cold, wet climates on glacial till or outwash. They include acidic , saturated, peaty soils of wet areas; acidic, relatively infertile soils of the forests; and raw gravels and sands along the river. After inundation, microbiological methylation of mercury from the organic soil horizons of Watana and Devil Canyon Reservoirs is likely to result tn mercur y levels tn the reservoir fish higher than current concentrations. Environmental conditions at the sediment-water interface in Watana and Devil Canyon Reservoirs will tend to minimize biomethylation and subsequent bio- accumual t ion of natural mercury in the reservo1rs. Methylmercury release from sediments at 4°C has been found to be SO to 70 percent of that at 20°C, in laboratory studies (Wright and Hamilton 1982). Biomethylation is directly related to microbiological activity 1n sediments (Bisogni and 425832 851111 7-8 Lawrence, 1975; Shin and Krenke1 1976; Wright and Hamilton 1982). This implies that biomethylation will be low ln the oligotrophic Susitna Reservoirs. Additionally, the high inputs of inorganic suspended sediments (glacial flour) may scavenge mercury from the water column. Much of the suspended solids will settle to the floor of the reservoir and blanket the inundated soils and vegetation. This wi 11 tend to isolate the organic matter reported to be the major source of mercury for u.ethylation and bioaccumualtion. Thus, even though there will likely be some detectable increases of mercur y in reservoir fishes in both impoundments, natural conditions may tend to keep these increas~s low. Furthermore, fish populations in the reservoirs are not expected to be high, nor are they expected to be significantly harvested by man (APA 1983a, b; FERC 1984). Bioaccumulation of mercury occurs rapidly, within one to three years of impoundment. Abernathy and Cumbie (1977) showed that mercury bioaccumulation by fish ln new South Carolina impoundments decreases with reservoir age, beginning as early as five years after i mpoundment . However ln northern Manitoba, Bodaly et al. (In press) found no significant declines in fish mercury levels within five to eight years after impoundment, with the possible exception of whitefish (Coregonus clu.,eaformis). Reservoirs age more quickly ln the temperate climate of South Carolina than Ln subarctic northern Manitoba. The mercury methylation and bioacc ·1m u latio n rates, which vary directly with the aging process, may decr~ase du ~ to the following combination of factors : o Relatively cold temperture; o Low levels of reservoir primary productivity ; o Death and ~eplacement of the initial fish populatio n; o A continually deepening layer of predominately inorganic s ediment which is expected to act as a blanket to isolate the inundated soils and vegetation from the overlying water c olumn. 425832 85llll 7-9 It LS therefor~. likely that biota Ln the proposed impoundments wi l l exf>erlence an initial Lncrease ln bioaccumulation of mercur y during and after filling, however, the bioaccumulation should decrease as the reser v oir ages. We have found no studies of mercury accumulation Ln fish downstream fr om newly impo~nded reservoLrs. The impact of the Project o n mercur y accumulation in fish downstream will be a function of mercury exported from the reservoirs and in situ affects on mercury in downstream habitats. Since mercury is transported primarily Ln suspension (inorganic Hg), a net reduction Ln the flux of mercury downstream will result from impoundment construction. The extent of transport of methylmercury from the reservoirs cannot be predicted. Mercury accumulation in fish downstream from the dams may be largely a process of in situ (riverbed) methylation and uptake. This will be influenced by Project-related changes in river productivity at all trophic levels. Instream mercury methylation (and accumulation) may change with alterations in microbial action resulting from changes Ln streamflow variability, suspended sediments, turbidity, temperature, productivit y , and supply of organic carbon to methylating bacteria. RISK TO THE PUBLIC State water quality criteria for the "growth and propagation" of fish, shellfish and other aquatic life and wildlife (ACC 1984 ) cite federal criteria for toxic metals. The criterion for mer c ury o f all f o rms (total recoverable Hg) is 0.05 ug/L (EPA 1976). A critique of this criteri o n states that many natural waters exceed this level of Hg (Klein et al. l979) and suggests future criteria distinguish between van.ous mercury species. Upon examination of the Hg levels shown in Table 7.1, it is obvi o us that the Hg criterion is consistently being exceeded in the Susitna River, although 0 .05 ug /L is below the 0.1 ug /L limit of dete~tability for the USGS method ( APA 1983a, b). 425832 851111 7-10 A complete risk assessment lS not possible with the existing data base. Dose (dietary Hg) and effect (somatic and genetic) relationships would need to be estimated. Current levels of Hg in resident fishes are not known. The incremental increase 1n health risk due to impoundment, leaching and bioaccumulation of Hg is not yet quantifiable. SUMMARY Post-impoundment water quality studies have shown only one metal, mercury, to systematically bioaccumulate to ecologically dangerous concentrations as a direct result of river impoundment (Abernathy and Cumbie 1977; Boda1y et al. In press; Meister et al. 1987). After impoundment, microbial methylation of mercury from organic ~atter in soils and newly inundated detritus of Watana and Devil Canyon Reservoirs 1s likely to result in mercury levels in reservoir fish higher than current concentrations. However, certain environmental conditions in the reservoirs will tend to minimize mercury biomethylation and subsequent bioaccumulation notably: o Low year-round water temperature; o Low benthic microbiological activity; o Continual Blanketing of inundated organic matter with a layer of inorganic sediments; o Relatively limited fish populations. The impact of the Project or mercury in downstream fishes will be a function of two things: mercury exported from the reservoirs and in situ methylation and uptake of mercury in downstceam habitats. Total flux of mercury down- stream of the proposed reservoirs will be substantially less than under current conditions. Methylmercury leaving the reservoirs 1s not predictable. Mercury accumulation in fish downstream may be largely due to in situ methylation and uptake, but will likely be influenced by Project- induced changes in stream biological productivity. 425832 851111 7-11 7 .3 CADMIUM OCCURRENCE IN THE SUSITNA RIVER As with mercury, the USGS has monitored cadmium (Cd ) level s 1n the Susitna Ri v er in recent years. The results of their monitoring are shown in Table 7 .1 and appear in the original License Application a s Figure E. 2.107 and E.2.108. Total recoverable Cd ranged from z~ro to ten ug /L; dissolved Cd was always measured to be to be less than three ug /L. These concentrations are not unusual for surface waters (Giesy and Briese 1977; Giesy and Briese 1980; McNeely et al. 1979; Moore and Ramamoorthy 1984; Steinberg 1980 ). Total and dissolved Cd were not significantly correlated to any other variable, including Zn, a common associate of Cd in nature. POTENTIAL FOR LEACHING AND BIOACCUMULATION OF CADMIUM We have found no published studies on cadmium leachi:1g from inu .. dated soils at new impoundments. Some leaching of Cd may be expected, but the amount should be rather low. A more quantitative estimate is not possible using the existing data base. Assuming soil Cd levels are not high, Cd leaching by humic substances will be less than many other metals, (such as Cu of Pb) because cadmium has a lower affinity for humic ligands (Giesy et :~1. 1978; Schnitzer and Khan 1972). Cadmium is not known to biomagnify in the food chain (McNeely et al, 1979; Selby et al. 1983). RISK TO THE PUBLIC State water quality criteria cite EPA (1976) standards: 1.2 ug Cd /L in hard water , 0.4 ug Cd /L 10 soft water. Total hardness in the Susitna River 1s :ypically between 45 and 70 mg /L as Caco 3 , so it is considered a mo derately hard water (Todd 1970; Britton et al. 1983). Confusion about the criterion LS added as EPA ( 1976) does not distinguish between total o r dissolved cadmium. 4~.5832 851111 The International Join Commission ( 1977, as cited by 7-12 McNeely et al~ 1979) has set a limit, for protect of aquatic life, at 0.2 ug/L. Comparison of these criteria with the Cd levels found in the Susitna River (Table 7.1) indicates that the levels for protection of freshwater aquatic life may be exceeded on occasion by natural variation. More accurate data and criteria are needed to completely elucidate the situation. Cadmium does accumulate 1n exposed biota; accumulation is not related to trophic position. Moore and Ramamoorthy (1984) summar1ze Cd bioa:cumulation; Cd is accumulated primarily in major organs of fish (liver, gut, skin) rather than muscle tissue so it is little threat to consumers of fish meat. Cadmium uptake is lessened by the presence of chelating agents, including humic acids (Giesy et al. 1977). With the above discussion in mind, impoundment of the Susitna River does not present a significant risk to public health, with regard to the leaching and bioaccumulat i on of cadmium in the proposed reservoirs. 7.4 COPPER Total and dissolved copper (Cu) -~oncentrations 1n the Susitna River are included tn Table 7.1 and 1n the original License Application as Figures E.2.109 and E .2.110. These data have been compiled from the annual USGS Water Resources Data Reports. Total recoverable Cu averaged 43 ug /L and ranged from less than ten ug/L to 190 ug/L. Dissolved Cu av e raged 3.3 ug /L, ranging from zero to twelve ug/L. These levels of Cu are on the higher end of the range of concentrations found in unpolluted surface waters (McNeely et al. 1979; Moore and Ramamorhy 1984). Copper 1s transported 1n th~ Susitna River primarily tn the particulate phase; this agrees with Gibbs' ( 1977) study of Cu transport 1n the Yukon River. In warmer areas, having streams with lower levels of suspended solid, higher levels of organic carbon, and pH values less than neutral, Cu is transported primarily as the soluble form (Eisenreich et al. 1980; Geisy and Briese 1978; Tessier et al. 1980). 425832 851111 7-13 Total recoverable Cu concentrations Ln the Susitna R1ver were significantly correlated with river discharge (r=0.4413), total suspended solids (r=0.6584), dissolved organic carbon (r=0.5974), total recove rable Fe (r=0.6634), total recoverable Mn (r=0.6025) and total recoverable Zn (r=0.7053), at least to the 0 .01 level. Total recoverable Cu was correlated to total recoverable lead, total recoverable Hg and total recoverable Ni at least to the 0.05 level of significance (r=0.4998, 0.3936, and 0.4773 respectively). Dissolved Cu was found only to be correlated to dissolved Fe (r=0.4634, P<O.Ol). The correlation analyses strongly suggests the geochemical abundance of Cu in the watershed; the strongest correlations of total Cu were found with suspended solids, total Fe, total Mn and total Zn. Copper is frequently found Ln natural deposits with Zn, particularly Ln mining areas (McNeely et al. 1979). POTENTIAL FOR LEACHING AND BIOACCUMULATION OF COPPER AND RISK TO THE PUBLIC We have found no specific studies on Cu leaching from the soils of newly impounded reservoLrs. No data on the content or form of Cu in the impound- ment zone soils and rocks are available. However, the potential for leach- ing of Cu exists. Singer and Navrot (1976) showed that humic acids extract Cu (preferentially according to the relative amounts or other metals) from basalt rocks. Baker (1973) demonstrated the role of soil humic acids Ln solubilizing metals from various minerals; again, Cu was highly extracted, relative to other metals. Schnitzer and Khan (1972) noted copper's particular affinity for humic and fulvic ligands. This affinity lS the basis for the ability of these materials to extract Cu from minerals . However, organocopper complexes are significantly less toxic than free Cu or hydroxocopper, so increased levels of dissolved Cu do not necessarily indicate a more biologically toxic condition in the aquatic habitat (Moore and Ramamoorthy 1984). Several field studies have shown that Cu does n.Jt biomagniEy Ln the food chain. In fi sh, the primary site of Cu accumulation is the liver; muscle residues are generally low, even in polluted waters (M oor e and Ramamoorthy 425832 851111 7-14 1984). Humans possess a natural excretion mechanism for excess Cu (McNeel y et al. 1979). As such, copper does not pose a significant threat to fisheries in the Susitna River. 7.5 ZINC OCCURRENCE IN THE SUS ITNA RIVER Total recoverable and dissolved zinc concentrations 1n the Susitna River, as reported by USGS, are shown in Table 7 .1. Total Zn varies from ten to 200 ug/L, averaging 66 ug/L. Dissolved Zn never measured over 30 ug/L and was typically between zero and ten ug/L. These levels of Zn are within typical ranges found 1n natural surface waters (McNeely et al. 1979; Moore and Ramamoorthy 1984). A 1967 nationwide survey reported a mean concentration of 64 ug/L (Kopp and Kroner 1967 as cited by EPA 1976). The bivariate correlation analysis indicates that Zn behaves similar to Cu in the system; to each other this is not unusual given the proximity of the two elements in the Periodic Table of the Elements. Similar behavior of the two metals has been observed 1n other systems (Giesy and Briese 1978 ). Total Zn in the Susitna River is correlated to river discharge (r=0.6376), total suspended solids (r=0.8403), total Cu (r=0.7053), total Fe (r=0.8722 ), total Mn (r=0.8840), total Hg (r=r.5471) and total Ni (r=0.8123) at least to the 0.01 level of significance. '.'otal Zn is also correlated to total Pb (r=0.4406, ?<0.05). Dissolved '-u 1s negatively correlated to total Ni (r=0.6158, ?<0.05). Contrary to studies of trace metal speciation in other systems, Zn is transported in the Susitna River primarily in the particulate phase. As is the case with copper, studies elsewhere have shown that Zn is transported primarily in the soluble phase (Benes and Steinnes 1974; Giesy and Briese 1978; Moore and Ramamoorthy, 1984; Tessier et al. 1980). The significant association between Zn, Cu and Pb suggests deposits of their carbonate and/or sulfide ores 1n the watershed, as these minerals frequently occur together in nature (McNeely et al. 1979). 425832 851111 7-15 POTENTIAL FOR. LEACHING AND BIOACCUMULATION OF ZINC We have found no studies of c hanges Ln z1nc concentrat i ons 1n the water column or biota of newly impounded reservoirs. It may be possible that some Zn will be leached from inundated rocks and soils, but it is impossible to quantify this with the existing data base. Studies have shown that Zn c an be leached from soils and rocks by humic acids. Singer and Navrot (1976) demonstrated Zn is second only to Cu in transition metal extractability by humic acid (relative to the metal's content) from basalt rock. Baker (1973) demonstrated the ability of humic acids to extract trace quantities of Zn from various minerals and soils. Zinc does not biomagnify as a function of trophic position. Fi s h normally obtain the majority of Zn from dietary sources rather than from water, with the highest residues found Ln spec i fic organs : liver, kidney, spleen , gonads, pancreas. Relatively low levels of zinc are generally found 1n muscle tissue (Moore and Ramamoorthy 1984). RISK TO THE PUBLIC The original License Application states that water qualit y c riteria for Zn have been exceeded on one or more occasions. It reference s the McNe e l y et al. (1979) criterion of 0.03 mg Zn/L for the protection of aquati c life. The State of Alaska's criterion 1s 1% of the 96-hour LCso-~/ d •:!termined via continuous flow b ioass ay or 5 mgiL, whichever LS less (ACC 1984). No Zn bioassay tests have been performed using the Project waters. Regardless of the criterion, aquatic life appP ~rs to be functioning in the Susitna River with the natural levels of Zn (ther e 1s the possib i lit y o f some anthropogenic Zn from placer min i ng activities and atmospheri c ~/ Lethal co ncentration killing 50 % of the organ1sms 1n 96 hours. 4 2 5832 851111 7-16 deposition). ·This element does not appear to present a hazard to the public from impoundment of the river. Zinc accumulates 1n fish organs, not muscle tissue, so dietary sources to man would be minimal even if Zn bioaccumulation was greater than present conditions. 7.6 MANGANESE OCCURRENCE IN THE SUSITNA RIVER As with other metals, total recoverable and dissolved manganese levels have been monitored in the Susitna River. These data are included in Table 7.1. Total recoverable Mn ranged from ten to 700 ug/L, averaging 2 70 ug/L. Dissolved Mn had a mean concentration of 15.6 ug/L and varied from zero to 180 ug/L. These values, although stated to exceed applicable water quality criteria, are typic a l of those found in natural surface waters (Chapnick et al. 1982; Eisenreich et al. 1980; Gibbs 1977). The total ~n concentrations are probably high, due to the high suspended sediment concentrations; total recoverable Mn in the Susitna River is significantly correlated to suspended solids (r=0.8997, P<O.Ol). Total recoverable Mn is also correlated to river discharge (r=0.7664), total recoverable Cu (r=0.8482) and total recoverable Zn (r=0.8840) at least to the 0.01 level of significance. Dissolved Mn was not found to correlate to any other variable included in the correlation analysis. Obviously, Mn is transported primarily as part of the suspended sediment load in the Susitna River. Similarly, Gibbs (1977) found about 90% of the total Mn in the Yukon River to be transported 1n the particulate phase. Hydroxide coatings on particles and crystalline solids accounted for 46% and 3 7%, respectively, of the total Mn in the Yukon River. 104 of the total Mn to be the dissolved form. Gibbs found about Laxen, et al. (1984) have suggested a "decoupling" of the traditional process oriented interpretation of Mn speciation; their observations do not 423832 851111 7-17 support a link between particulate and soluble Mn phases tn rtvers and streams (their conclusions are not applicable to lakes). They describe cwo sources of manganese. One, the result of weathering processes, produces particulate Mn, a part of the suspended sediment load. The other ac co unts for dissolved Mn: the influx of reduced, soluble Mn (II) species leached from anoxic soil and groundwaters. Hence, hydrogeological conditions seem to govern Mn speciation tn riverine systems with short residence times. Equilibrium chemistry and biological mediation govern Mn speciation in lakes and reservoirs having longer residence times. The Mn data of preproject conditions may therefore not be of great value tn predicting reservoir and downstream Mn levels following river impoundment. POTENTIAL FOR LEACHING AND BIOACCUMULATION OF MANGANESE A number of laboratory and field studies expose the speciation d y namics of Mn tn lakes and reservoirs. The chemistry of Mn ts dominated by redox transitions between the relatively soluble reduced Mn (II) species and the highly insoluble oxidized Mn (IV) form. In aerated freshwaters, the equilibrium spectes are Mn (IV) phases (Stumm and Morgan 1981). As reservoirs stratify, anaerobiosis may develop tn the h y polimnion, and Mn (II) will become the dominate form. (Hutchinson 1975). This phenomenon is well docume nted The potential for leaching Mn from inundated soils and ro c ks ts directl y related to the potential for anaerobiosis in the proposed reservotrs. The likelyhood of the latter is a function of many factors , the primary two b e i ng the amount of organic material rema ining tn the reservoir zones upon impoundiOe -• and seasonal hydrodynamics of the reservoirs. Little if any anaerobiosis i :. "Xpected tn either reservoir. Therefore, little leachin g (or solubilization) o f Mn is predi c ted. Without elevated conce ntrations of soluble Mn, levels of Mn tn biota are not expected to be above current concentrations. 425832 851111 7-18 RISK TO THE PtlBLIC No bioaccumulation of manganese is expected to result from impoundment o f the Susitna River. As such, the incremental risk to the public is nil. 7. 7 IRON OCCURRENCE IN THE SUSITNA RIVER Total and dissolved 1ron concentrations 1n the Susitna River, as published annually by the USGS, are tabulated (Table 7.1). Total Fe varied from 40 to 42,000 ug/L, averaging 12,8 16 ,1g/l. Dissolved Fe averaged 103 ug /L and ranged from zero to 250 ug/L. The concentrations of dissolved Fe are within natural ranges for surface waters, and, considering the suspended solids load, the total Fe levels are not unexpected. The high total 1ron concentrations are probably due to the suspended sediments : total Fe 1n the Susitna River is significantly correlated to total suspended solids (r=0.9248; P<O.Ol). Total Fe concentration is also correlated to river discharge (ra0.7713), total Cu (r=0.6634), total ~n (r=0.9306), total Ni (r=0.7190), and total Zn (r=0.8722) at or be yond the 0.01 level of significance. Total Fe 1s also correlated to total Pb (r=0.4994, P<0.05). Dissolved Fe significantly correlated only to dissolved Cu (r=0.4634, P<O.Ol). The primary mechanism of Fe transport in the Susitna River is suspensi o n tn the water column as particles. A similar conclusion for Fe transport in a glacial river was reached by Gibbs (1977) studying the Yukon River. Gibbs found less than l% of total Fe to be the dissolved species. He found 48% of the Yukon's total transported Fe to be in crystalline particles and another 40% as sorbed metallic coatings (mainly ferric hydroxide) on these crystalline substrata. Eleven percent was an organic solid phase. Only the latter 4 2 5832 851111 two Fe fractions may be considered biologically available. 7-19 Ther-~for-e, if gener-alizations can be per-mitted, per-haps about SO % of the total r-ecover-able ir-on concentr-ations in the Susitna River (Table 7.1) ar-e availabl e to biota. In studies on non-glacial systems, Gibbs (1977) showed a similar-Fe speciation for the Amazon River. Tessier-et al. (1980) found similar-Fe speciation in 2 Quebec rivers. Eisenreich et al. (1980) found about 68 % or total Fe to be crystalline particles in suspension at nonurban sites on the upper Mississippi River ( 194 was the dissolved specie). Numer-ous authors have found dissolved Fe to be contr-olled by the dissolved or-ganic carbon concentr-ation, but our correlation analysis showed no significant (P>O.OS) relationship in the Susitna River (Beck et al. 1974; Giesy and ~riese 1978). POTENTIAL FOR LEACHING AND BIOACCUMULATION OF IRON Four published studies relating to changes in 1r-on concentrations in planned impoundments have been located and reviewed. Sylvester and Seabloom (1965) studied soils in the preimpoundment zone and water-in the developed Howar-d A. Hanson Reservoir-, near Tacoma, WA. In batch soil reaction studies they found anaerobiosis caused elevated Fe levels which continued until a time (about 25 days) when Fe began to coagulate with tannin and lignin compounds and precipitate. Following impoundment, a slight r-ise occur-r-ed in Fe levels 1n Reser-voir water. Another batch lea..:hing study on pr-eimpoundment zone soils was done by Keup et al. (1970) on the Northeast Cape Fear-River in eastern Nor-th Carol ina. They concluded that elevated ir-on concentrations would r-esult due to the high organic content of the impoundment zone soils. Keup et al. (1970) also found higher levels of Fe in anaer-obic batches than 1n aer-obic exper-iments . In soil leaching studies of var1ous pr-oposed r-eservo1r sites in Alaska, Smith (1980) and Smith and Justice (1975) found Fe in the leachates (which were oxygen deficient or anaerobic) to increase with time in soils with substantial organic mats. 425832 851111 7-20 Much research· has indicted organic solutes 1n Fe mobilizat1on. Singer and ~avrot (1976) found Fe to be the most humic acid-extractable met a l in basalt rock (it was however poorly extractable, relative to the amount present ). Baker ( 1973) showed the ability of humic acid to extract Fe from various silicate minerals (i.e. feldspar, biotite, enstatite, actinolite, and epidote). Perdue, et al. (1976) demonstrated the correlation between dissolved Fe and dissolved organtc carbon 1n southeastern US surface waters. Hence it appears reasonable to predict that Fe leaching will be exacerbated in the proposed Susitna reservoirs if the organic material 1s not c leared prior to impoundment. Organic material 1n the reservoir will decompose, exert an oxygen demand, and if the reservoir thermally stratifies, reduce less soluble ferric ion (Fe3+) to the much more soluble ferrous iron (Fe2•). This will lead to elevated iron concentrations in the reservoirs. We have found no evidence that tron bioaccumulates with trophi c position; iron bioaccumulation is not expected to occur in the Project Reservoirs. RISK TO THE PUBLIC The original License Application states that total (recoverable) 1ron 1n the Susitna River exceeded the water quality criterion on numerous occasi o ns. The original License Application cites the EPA (1976) and Sittig (1981) criteria of l mg Fe/L for the protection of freshwater organisms. The State of Alaska water quality standards reference the federal criteria or one percent of the lowest measured 96-hour LC50 bioassay test, whichever 1s lower. These criteria however do not distinguish between total Fe and dis- solved Fe. This discrepancy necessitated that total Fe must meet the criterion, an unrealistic expectation for streams carry1ng glacial flour. Generally, about 99% of the Fe in the Susitna River is carried in the sus - pended sediment load. The dissolved Fe concentrations do not exceed the 1 mg /L limit (Table 7.1), presenting little risk to the public. The total Fe 425832 851111 7-21 concentrations will decease following impoundment s1nce the suspended sediment load will decrease substantially (APA 1983). 7 .8 ALUMINUM, LEAD, NICKEL, AND BISMUTH ALUMINUM Occurrence 1n the Susitna River Limited monitoring of Al has been done in the Susitna River. Data provided by USGS is given in Table 7.1. R and M Consultants, Inc. ( 1982) provide data on dissolved aluminum concentrations. Total and dissolved alluminum data are presented in the original License Application as Figures E.2.104 and E.2.105. Total Al levels are high, but not unexpected for glacial rivers such as Susitna. The high total Al concentrations are likely associated with the large suspended sediment loads. Dissolved Al levels are very high, these levels are beyond the concentrations expected in natural waters and suggest significant acid m1ne drainage 1n the water~hed or contamination during sampling (Jones et al. 1974; Stumm and Morgan 1981 ). Potential for Leaching and Bioaccumulation of Aluminum Aluminum is a practically ubiquitous element on earth, but surprisingl y , its environmental behavior, toxicity and bioavailability 1s not completel y understood. No reports have been found indicating Al leachin g occurs rollowing reservoir impoundment. minerals are not very soluble. Nor 1s Al leaching likely. Aluminum Admittedly, humi c acids do bind Al b ut concentrations or organic acids 1n the Susitna River are insuffi c i.~nt to cause ecologically hazardous levels of leaching (Perdue et al. 1976; Pott et al. In press; Singer and Navrot 1976). Relatively little research has been performed on bioaccumulation of Al 1n 425832 851111 7-22 aquatic animals. Al can be found at t race levels ir. the t issue s or 3 l:nost every organism (Burrows 1 977). Litt l e evidence exi sts t o ind ic at e an A1 ~ioaccumulation problem in the potential reservoirs. LEAD Occurrence in the Susitna River Total recoverable lead concentrations are included in Table 7 .1. Total recoverable Pb was typically 23 ug /L, ranging from z ero to 199 ug /L. Although not unusual for mining areas, these concentrations of Pb are rather high (Giesy and Briese 1978; Moore and Ramamoorthy 1984; Tessier et al. 1980). The high levels of Pb in the Susitna River are probabl y due t o the high suspended sediment load. Total recoverable Pb correlated wi th suspended solids (r=0.4709), total recoverable Cu (r=0.4998), total reco ve rab l e Fe (r=).4994), total recoverable mercury (r =0.440 6) at least to the 0 .05 L~v el of significance. Potential for Leaching and Bioaccumulation of Lead There i s very little pot e ntial for Pb t o be leached from the newly flooded soils. Lead minerals are not ver y soluble (McNeely et al. 19 77). We hav e fo und no recorded instances of elevated Pb concentrations in newl y impounded reservoirs. Although Pb can be isolated from the tissues of many aquatic or g an isms , residu es 1n organisms from unpolluted waters are not great. Pb is not a threat to fishery resources except in cases of extreme pollution (~o o re and Ramamoorthy 1984). Methylation of Pb iS rare in nature and consequentl y organolead is seldom found in fish ti ss ues. The 96-hr LCso fo r total Pb generally falls within the range 500 to 10,000 ug /L, well above the level s r eco rded in the Susitna Riv e r (Moore and Ramamoorthy 1984 ). 425832 851111 7-23 ~ICKEL Occurrence Ln the Susitna River Total recoverabl~ Ni concentrations Ln the Susitna River are shown Ln Tabl~ 7 .l. Averaging 27 ug/L, the concentrations range from one t o 53 ug ~i /L. These levels are comparable to those found Ln the Yukon River by Gibbs (1977). McNeely et al. (1979) report that the median fre s hwater co n centration of Ni in North American river is 100 ug /L, however our review of the literature suggests a typical concentration closer to 20 ug /L (Gibbs 1977 ; Giesy and Briese 1978, Moore and Ramamoorthy t984; Steinberg 1980 ). Total recoverable Ni in the Susitna River correlated with total recoverable Mn (r=0.8482) and total recoverable Zn (r=0.8123) at least to the 0.01 level of significance. Total Ni also significantly corr~lat~d to dis so lved Zn (r=0.6158, P<O.OS). Potential for Leaching and Bioaccumulation of Nickel No evidence has been found to indicate that elevat~d Ni concentrations occur Ln new reservoLrs. Humic acids can leach limited amounts of ~i from basalt rock, but these products will likel y be rapidl y adsorb~d o nto suspended particles (Singer and Navrot 1976). ~ickel does not bioaccumulate as a function of trophic posit ion. N i ck ~l accumulates more readily in fish organs (liver, kidne y , gills) than mu scle (Hutchinson et al. 1975 as cited by Moore and Ramamoorthy 1984). In the heavily polluted Illinois River , average concentrations of Ni in sediments, invertebrates, and in the muscle of omnivorous and carnivorous f 1sh were 27, 11, 0 .18, and 0.13 mg /kg respectfully (Mathis and Cu mmings 197 3 as c ited by Moore and Ramamoorthy 1984). L i t t 1 e r i s k f r om N i i s t her e f o r e 1 i k e 1 y t 0 consumers of resident fishes following impoundment of the Susitna River. 425832 85ltll 7-24 BISMUTH Very little ecological information o n bi5muth has ~e en located. 'lan ual search for such included Chemical Abstracts, Biol o gical abstracts, Pollution Abstracts, and various texts on toxicology and environmental health. The original License Application states that dissolved Bi exceeded the recommended criterion of 3.5 ug Bi/L. However the detection limi t for the analytical method was 50 ug /L (Rand '1 Consultants, Inc. 1982 as cited by APA l983a, b). The or iginal License Application contained information on 26 analyses of Bi tn Susitna River water, of tnese 26, dissolved Bi was detected 3 times. Data on Bi occurrence tn the Susitna River, and the ecological significance of such t s insufficient to generate conclusive statements on potential leaching and /or bioaccumulation tn th e proposed rescrvotrs. However, we have not found any reports or publicattons s uggesting Bi-relat e d ecological problems in water development projects. 7.9 CONCLUSIONS AND RECOMMENDATIONS This review of the literature has resulted tn an understanding or the risk to the general public due t o leaching of metals from 5oils tn the impoundment zone of the pr o posed Susitna Reservoirs. Incr eased co ncentrations of toxic metals in the reservoir water s ma y result from: l. Dissolution of inundated soils and rocks; 2. Increased rates of mineral dissolution due t o the chelation or 3. ~2 5832 851 111 metals by humic subst~nces; Biologi ca lly mediated reaction s involving metals tn tlooded topsoil horizons. 7 -25 Our literature r~v1ew has found only one metal, mercury, t o s y st~matically bioaccumulate to ecolog1cally dangerous concentrations as a direct r esult of imp c .. ~dment (Abernathy and Cumbi~ 1977; Bodal y et al. In pr~ss, Cox et al. 1971; :teister et al. 1979). Other :netals, even though present tn relatively high concentrations 1n the Susitna River, are not lik~ly t o pre sent a leaching on bioaccumulation problem following impoundment. After impoundment , microbial methylation of mercury from newly inundated materials of Watana and Devil canyon Reservoir s 1s likel y to result in mercury l~vels 1n reservo1r fish higher than current co ncentrati ons. Environmental conditions 1n the reservoirs will tend to m1n1m1ze mer.::ur y biomethylati o n and subsequent bioaccumulation. The impact of the Project o n mercury 1n fishes downstream o f the r ese rvo1rs will be a function of two things : mercury exported from the reservoirs and tn situ methylati o n and uptake of mercury in downstream habitats. Total flux of mercury downstream of the pr o posed reservoirs will be substantially less than under c urr~nt conditions. Methylmercury concentrations leaving the reservoirs are not predi ct able. Mercur y accumulation in fish downstr~am may be largel y due to in situ methylation and uptake , but will likel y b~ influenced by Pr o ject-induced changes in stream biological iJroductivity at all trophic levels. Total recoverab ~e concentrations of all metal s transported downstr~am wi ll decline fol lowing river impoundment. Much of the total recoverabl~ moieties ar~ associated with the suspend~d solids; since the r~servotrs will trap much of the suspended sediment load, total metal conce ntrations downstr~am o f the project should decrease following impoundment. There appears t o be little potential for leaching and bioac c umulation of heavy metals 1n the proposed resecvo1rs, with the notabl~ ex ce ption or mer c ur y . No mitigation plans have been f o rmulated; rather studi~s shoul:l first defin~ the occurrence of heavy metals in the water and aquatic biota. ~25832 851 111 7 .1 0 Appendi~ -Correla tion Analysis of ~etals and other Aquatic Habitat Characteristics 425832 851111 7 -27 PROBLMMETALS17 3881 DELETE0EI01 <F6.EI.F4 .0.F3.1.2F2.8.F3.8.F2.8.F5.8.4F3.8.1X.2FI.I.IX.F2.8.F3.8.F2.8) 52~00 915 5U 2U8H81H81H0378 40 2 58 08 20U~H 65G 5U 1UOH0 32818H 3 00 8!:iEl0 2::! USU 48 20 U 2 3El 175ElEI 327 28 8 31 41 ~.6011 98 102~EI 4 48 23 6El 6 4~GOO 600188 5 1198 51~HUU128 473~EI IU 32 2912018 1528 U 16 2 I 4U 15 3 10 3 2 10 24580 3113 2~ 1 I 23 312060148 218 7 22 5814 3•1600 812 1 56 71..WUHI2B 15200 8 36 !J8 5 3000 2 26 8 54 16H 48 B 18 4 11 18 2036 55088 735 8 52 42GUUU198 25558 7 68 522UO 6 86380 713 47 1 0 4~ 3~3UUU~58 ~1458 10 31 29 9tl28 58106 65~ 47 3U 52UUOU22EI 4HH IU 2 33 ~El 9 7EI10EI1628 751229U0~2El8 41G28 14 21 4813817 4750H 15~ IEl 8 2U 5 ~UU0128 110 111 22 1010 538EI 2 1H tl 1tl 2 240 GEl 30 3U 81 30 H 67900 25 7 2 1 4U1El 3 ~0U14EI 1GIU8 U 2EI U 991El0 7U!:i El 5U U2GU8EI 30 ~-W 0 3U 100 U 38uU0 191 U 1 5-~U 48 13~ U 34 3EllU 6~90 tl 2 ~GU ~EI ·~ 3B 88 2Ultl 8600EI 370 El 20 110U~U15EI 'JB 0 OEI 5U~tl 148Ul:li:I149UOEI110 1 98 142lJUU 10 EUU 2U 2U lllEJ 4 7U2EI 10UU7 tl El 7 4 3GU GEl 3 ;~ 2U tlU ~018 6~2 EI 2 l l 3 l 2 3U GU 7 2U 2U Otl lUlU 55 ~~0 10 0 l 24 4 5GUU11EI lU12U 18 lEI JI:IIEl 12ElUliEI 773 23 2 l 4~i 124UUE.I 2U 2/SUU 8 21 ~U lU 9U9EI 3 93 U 1 3 2 <I~U 9b II 40 lEI HJ lEI 3 868UEI 603 GO I El 25 414000170 G8 18 18 26 5618 952UEI 41 GUU9 l 1 29 li2UIIU U 12~~0 l 0 lU LEI I tl 877U0 9El1~1:16 tl 37 l~6UUU 4U 16~~1:1 4 lU ~U 9360 3 0 8 5 2 45H150 2 36 38 18 4 20 144888 458 59 8 26 2168UEI 28 4278 5 18 19 SEI 2878EI81498 37 8 8 75 338888148 l67EI8 18 18 48148 7 7788 4 21 8 3 8 39816EI l 38 28 18 6 68 88688 326 34 2 28 715888 98 33418 6 38 22 5828 173ullU 9<:u 29 U !JU ~.::UUt•...J ~u !J£.:..;:u 7 ~2 :::GtGlJ G 41JJ6 'J 2 1 ::;; .u L!.J .;u II I 1U 54~Utl 5 ?(, :~0 ~ !J!JL J 19lJ 142 ... J II I 1/ GU 103llUU 7~7 I 32 ~ 7!JUU 6~ ~~i·tl 6 :~2 5311U ~ FINI SH PAGE 1 OF 31 DEC na in put ~·le ''METALS" +o BMDD3DX 8MDB3D -CORRELATION WITH ITEM DELETIOH -REVISED DECEMBER 24. 1975 HEALTH SCIEHCES COMPUTING FACILITY. UCLA f'ROBLEM CODE ..................... tETALS HUMBER OF VA RIABLES .............. 17 I tUM8ER OF CA SE S.. . . . . . . . . . . . . . . . . 38 UUt13ER OF TRfiHSGEI~ERATIOH CARDS.. 8 UUt'IJER OF Vflr~ lADLES ADDED. . . . . . . . l:l liUI"tiER OF VARIABLE FORr-v:IT CAI<D ( S) 81 TRAHSGEHERATIOH <IF AHY> OCCURS BEFORE ITEM DELETIOH VARIABLE FORtVH C(IRD < S) <F6.8.F4.8.F3.1.2f2.0.F3.8.F2.8.F5.8.4F3.B.IX.2Fl.l. IX.F2.B.F3.B.F2.B> MEAHS AHD STAHDARD DEVIATIOHS VARIABLE MEftH STOHDARD HUM8ER OF DEVIATIOH ITEMS 81 5868G .B42 151892.5819 38 82 sou.9 n2 45EL 7~74 36 83 3.84!.;8 4.8358 28 84 3.4~U6 3.7151 14 85 1.8088 0.8UI:JO ()9 EIC 37.0U~7 3C.EI7 :3 0 35 El l 3.51~2 ~.C~35 33 88 12815.5 2 G311559.75~3 38 89 11:J3.0 270 61.5£37 3(j lEI ~4. I ~I:JI:l 2C.643~ 25 11 271LI:lUI:lEI 236.41:J32 38 12 17.9U91 3H .4::i~9 33 13 u. ~~!06 ll. 16U7 ~u 14 1:1. l7UEI El.8949 ll:l IS 26. £,utJEI 16.1454 2EI 16 65 .5~G3 4~.5~19 3U 17 lU. U811EI 6.2538 25 CORRELATIOH MATRIX <SAMPLE SIZES IH PARENTHESES> VARIABLE HO. 01 82 El3 84 fl5 06 e7 HB VARIABLE NUMBER 1 Discharge PAGE 2 OF 4 VARIABLE NAME 2 Total Suspended Solids 31 ('EC 84 3 Dissolved Organic Carbo~ 4 Total Cadmiun 5 Dissolved Cd 6 Total Copper 7 Dissolved Cu 8 Total Iron 9 Dissolved Fe 10 Total Lead 11 Total Manganese 12 Dissolved Mn 13 Total Mercury 14 Dissolved Hg 15 Total Nickel 16 Total Zinc 17 Dissolved Zn 69 18 Ell * l.UI:JUUH fl .73136 -O.fl9025 -8.03328 H.OEIEIOI:l$ 8.44128 8.84265 8.77128 B.EI215H 8.328 17 PAGE 3 OF 4 31 DEC 84 38) ( 36) ( 28) ( 14) ( 09) ( 35) ( 33) ( 38) ( 36) ( 25> 82 * 0.7313El I. 80El0El -6 .81278 0.El4817 El.ElBE.IUElS 0.65845 8 .38878 0.92483 El.25354 8.47091 ( 36) ( 36> ( 19) ( 14) ( 001 ( 34) ( 31) ( 36) ( 34) ( 24> 03 * -0.89825 -EI .61278 1 .66U06 0.05444 0.06081:1$ 8.597 37 0.32186 -8.02258 e.23u;·3 0.29727 ( 26> ( 19) ( 2H> ( 08) ( en ( 26) ( 19) ( 28) ( I S ) ( 16) 64 * -8.83328 8.64017 8.05444 1. 88688 8.68080$ I:L 18418 -B. 140lJ7 6.12954 -0.28064 0.46743 ( 14) ( 14) ( ~0) ( 14) ( ()7) ( 14) ( 14) ( 14) ( 13) ( lB> 65 * e.eeoeas 8.00EIBBS B.BEIUBBS B.EJBB OEIS 1. 080()8 EI.B0U8es B.El8ElOUS 0:eeee8s o.6BU8DS B.BEIUI:IElS ( 69) ( U8> ( I:S7> ( 07> ( 69) ( 89) ( 0~J> ( 09) ( 08) ( an 86 * 0 .44128 8.65045 6.59737 8. 18410 8.0000EI$ 1. 8EifJ(10 8.30420 0.66341 e. 11408 8.49!..178 ( 35) ( 34) ( 2EJ) ( 14) ( 89) ( 3~) ( 31> ( 35) ( 33) ( 25) 87 * 8.84265 8.31:1878 8.3211:16 -e. 14tlU7 B.B08fll:lt> U.3li42El 1 . EIOOUB e. 15807 0.46336 El.34319 ( 33) ( 31) ( l!J) ( 14) ( I:S9) ( 31> ( 33) ( 33) ( 32> ( ~3) 88 * 8.77128 8.92483 -0.622~8 a. 12954 a.ea0ees 6.66341 0. 15UU7 1.88000 0. 188El5 6.49939 ( 38) ( 3 6 ) ( 21:J) ( 14) ( El9) ( :::5> ( 33> ( 38) ( 36) ( 25) 09 * 0.62150 8.25354 0.230/3 -0.28064 0.80EIBeS e. 11488 0.46336 8. 10lJ85 1 • eeeee EI.B5233 ( 36) ( 34) ( l!J) ( 13) ( UU> ( ~3) ( 32) ( 36) ( 3u> ( 24) 18 * 0.32017 El.47El91 8.29727 8.46743 e.eeOUEJ$ 0.49978 e.34319 8.49939 0.EI5233 1 . 80El£Je ( 25> ( 24> ( 10) ( 1(:)) ( U7> ( 25> ( 23) ( 25) ( 24) ( 2~) 11 * 0.76639 e.89967 -e. 12~G9 8. 11304 O.BElUeU:£ 8.61:S253 B. 14932 0.93063 0.11033 8.34~12 38) ( 36) ( 2(:)) ( 14) ( U9> ( 3:)) ( 33) ( 38) ( 36> ( 25) 12 * -e.2EJG98 8.03251:) -e.U92i'O O.GI:I72~ 0 . I:Stnl8 El :J; ti .I:S4fll:l9 -a. 18<;62 8.01737 O.Ul8~3 e.26G35 ( 33) ( 31> ( 19) ( 12) ( un ( 32J ( 30> ( 33) ( 31) ( 23) 13 * 8. 18239 IL 16927 6.077U6 -l:l.el641 B.BOI:IEW::; 8.39~SC B.214!JH 0.34184 -B .EJ1249 8.55377 ( 20) ( ;,:n ( 17> ( 69) ( l:lu> ( 26> ( l,!j) ( 28> ( 2C> ( 21:1) 14 * -8.04369 -U.224G 7 U.59114 e. 12851 8.0lJOUB:t. 0.43G91 -e.2B317 -El.23568 -1:!.30749 B.34272 ( 11:1) ( li:J) ( 05) ( BG> ( U2) ( I:J9) ( IU> ( 18) ( 11:1) ( UG> 15 * e.50199 8. 7U%::.i U.2 UB99 -8.2 2 74~ U.Elfli:IIJU ~ EJ.47?31 e.44!..143 e. 71098 El .2 4232 1:1.4U11:11 ( 28) ( 28> ( 12> ( 11G> ( U2> ( ~f)) ( HJ) ( 2EI> ( 20> ( 16> I G * O.G 37~U e.041:1 i!l:1 £.1.01'41~ E:l . 124<14 O.l:lfleOI:J:Ji 6.7£1 529 El. l91:J44 0.87219 e.2411'9 1:). 4 .:11161 ( 3U) ( 3G> ( 21:J) ( 14> ( 89) ( 35) ( J3) ( 38> ( 30) ( 25 ) 17 * -e .1U 3U] -U.2J i'l:l~ -0.0~3ll 1 -U.3e320 e .BOI:!OI:l$ -I:J.217fl8 e. 10 •U4 -B.20286 fl. 13UUU a. e n67 PAGE 4 OF 4 31 DEC 84 25) 23 ) 16) 12) £)8) 23) 25) 25) 2 4) 17> A $ IUDICfHES TliE CUEFFICIEHT IS HOT COI ·flUTED DUE TO A ZERO IJIVISUR. (I ZERO IS IHSERTED . CORRELATIOH ttHRIX < SAI'f SIZES IIi Pflf~EHTHESES > VARIABLE HO. <CUHTIHUED) II 12 13 14 15 16 17 01 * 0 .76639 -El.20G9 8 I:L 18239 -EI.l:l4309 El.50199 0.63758 -0. 18 303 ( 3U) ( 33) ( 28) ( 10) ( 2!:)) ( 38) ( 25) 02 * 0 .09%7 0.032~0 H. 169 27 -0.224G7 0.78963 0.84EI28 -0.23 711 5 ( 3L) ( 31) ( 27> ( IE)) ( 20) ( 36) ( 2~) 133 * -e . 1256 9 -0.09270 e .uno6 e . 59114 El.2 0099 U.07415 -6 .U9JUI ( 2u> ( 19) ( 17> ( UJl ' 12) ( 2tl) ( ILl 04 * 6 .1 UU4 u . 6072 9 -0.0161\1 o. 128~1 -0.22745 e . 12444 -8.30 3/'U ( 1·1> ( 12) ( 09) ( 66) ( UG) ( 14 ) ( 12 ) 65 * 0. OOUUt:l$ 11. E.IUOE.II::I$ 0 .UUUUUS 0. OElOOUS 6. OOUIJO$ 6. UU~lJU$ El. OUUUUS ( U~) ( 07> ( UG> ( 02> ( 0 2 ) ( 0 ~> ( UUl 66 * 0 .60 2S 3 O.U40U~ 0.3~H~U EI.4J691 0.41'73 1 O.i'U5 2 9 -0.21700 ( 3:.)) ( 32> ( 2(;) ( U9> ( 2U> ( 3 5) ( 2...;) 67 * e. 14~32 -u. 10662 U.2149t:l -0 .20377 0.44943 0 . 19044 El . lU·lA ( 33) ( 3l:l) ( 23) ( lU) ( IU> ( 3 ::i) ( ~J) 68 * l:l.93U G3 U.61 73i' 0.34104 -U .2.l~6tl 0.710~0 0 .(.;12 19 -U.2 U:..'llG ( ~J ) ( :;)j) ( 2 U) ( li:J) ( 2U> ( 3l.J) ( ~~) 09 * e . 1 w ..;J U.OIU~3 -e1. u 1 2,1~ -0.38 1'49 0.242 :1 :! 0.24 1 7~ U. 13CIJi J ( 3 G) ( 3 1) ( <!(;) ( IUl ( 2lu ( 3Gl ( 2•J) ·~ * 1:1. 3•1J 12 0.26635 u .~~3i'7 u. 3 4 :!n 6. 4U IIJ I U.<~G I U. U ~:!t,l ( 2~) ( 2~) ( <!Ul ( ULl ( ILl ( 2~) ( I () II * I.UUUUU -U.021JU S U.J:UOG -u . 1711 2 6 .U4 U22 U.l:GJ% -u. 22JlJU ( 3 t.;) ( ...;3} ( 2 0) ( IUl ( 2Ul ( 3Ul ( 2~) 12 "' -o .u;_o uu:.J I . UUIJUEl U. U4 LiU -U.4112U -O .O Ol j~ -U.£JlJ477 -u. IU i'<,o ( Jj ) ( ;.;.H ( 24 l ( UUl ( 2 UJ ( :lJl ( 23) 13 * El.32 i'U6 U.U41 3 0 I . tJUUUU 0 .23 %~ e . 3~J794 0 .5·1? 14 -U .2U~I j PAGE 5 OF 4 20> ( 24 ) ( 20> ( 09) ( 1(j) ( 28> ( 19) 14 * -B. 1711 2 -6 .411 20 B.239 G ~ 1 .0ooe0 0.47GU2 -0. 13975 -0.49931 ( 11:1 ) ( ElB> ( H~> ( 11:)) ( l:J()) ( Ul> ( 1:19) 15 * 0.0 40 2~ -I::I.U IH5 ~ El.397~4 B.47t.i02 1. OEIOU0 0 .0123£:1 -O,(jl577 ( 2u> ( . 2U > ( 1G> ( I:IG> ( 2U> ( 26> ( 13) 16 * 0 .003% -O.EJU477 El.54714 -a. 13975 0.812 30 1.01:101:l U -0.30717 ( 3U> ( 33) ( 20> ( Hl> ( 2U> ( 38> ( 2~) 17 * -0.223UU -u. lU76o -8.20915 -0.49931 -0.61577 -8.30717 1.00000 ( 2~) ( 23) ( 19) ( (19) ( 13> ( 25) ( 25> A S INDICATES THE COEFFICIENT IS HOT COn)UTED DUE TO A ZERO DIVISOR. A ZERO IS INSERTED. •••> Ll OUT ···> ···> ···> ···> •••> Ll ···> ···> ···> ···> ···> ·--> FLUSH .... > HARDB ~p: 1563 X<192f.:OUT DO DF•4 P•3 C•36 31 DEC 0 4 8.0 THE. POTENTIAL FOR GAS SUPERSATURATION RELATED TO THE PROJECT The s ignificance of potential c hanges in dissolved gas o n salmo n and resident fish habitat s and populations has been identified as a fis herie s issue f or thi s project. The following in format ion discusses the curr~nt status of our knowledge regarding these topics. 8.1 DISCUSSION The absolute quantity of dissolved gas that wat e r can hold 1s a fu nction of water temperature and pressure. The capacity of water to hold gas 1:-. svlution (dissolved) increases with increasing pressure and decreases with increasing temperature. Dissolved gas supersaturation occurs when either the temperature or pressure of water with a given amount of dissolved gas concentration changes to the extent that it exceeds saturated levels at the new conditions. Gas supersaturation can affect the biochemistry, ph ys iolvgy, and behavior of aquatic organisms by causing gas bubble disease. When fish encounter wat er having dissolved gas concentrations in excess of s aturation, the gas in the water diffuses through the gills, tending towards equilibrium within the fis h at the supersaturated level. Then, when the fish leaves the zone of supersaturated water, gases in the blood and other bod y fluids begin to com~ out of s o 1 u t ion , forming bub b 1 e s ins ide the f i s h . The bubbles can c aus~ circulation bl o ckages and disruption o f tissues. The overall effects o n an o rgan1sm can vary from sublethal stress to death (Fickeison and Schnei der 1976). 8.1.1 Causes of Supersaturation Supersatura t ed dissolved gas concentr ati ons may occ ur h yd roelectric f a c ilities by an y of the foll o wing mechani sms: 425832 851111 8-1 at dams and 1. Sp~llway discharges entering the receiving stream c an cause entrainment of air bubbles to depth where the change 1n h y drostatic pressure results in higher dissolved gas concentrations. 2. Leakage of at r into powerhouse turbines, where sufficient pressur es may exist to force excess gas concentrations into solution. In some hydroelectric facilities au 1s "bled" into turbines to prevent cavitation damage to turbine runners. 3. Withdrawal of nitrogen saturated water from depth 1n a bod y of water, such as the cold hypolimnion layers of a reservoir, and delivery to warmer temperatures and lower pressures, which may then result in a temporary condition of gas supersaturation, until aquatic gas concentrations can equilibrate with the atmosphere. This situation does not have any turbulence associated with it; turbulence would result tn more rapid equilibration to ambiant conditions. Gas su persaturation has not been observed in the Susitna River upstream of Devil Canyon (e.g. upstream of nver mile 150-163). Gold Creek, loc ated below Devil Canyon, enters the Susitna mainstem at approximatel y 100 percent gas saturation. It is presumed that other rapidly flo wing tributaries al so enter the mainstem Susitna with approximately 100 percent gas saturation levels. Gas supersaturaion is apparently produced in the main stem Susitna, under natural conditions, within Devil Canyon rapids. Gas supersaturated water appears to be caused by the entrainment of a1r tn the rapids and pressurization of the water tn plunge pools. The measured levels of gas concentration appear to be directly related to rtver discharge rates f l o wi ng through the canyon, within the discharge ranges observed to date (i.e. 10,000-32,500 cfs) (ADF&G 1982; APA 1983a,b, Fig. 8.1 ). A1 though gas concentrations of 115 to 116 percent have been observed at the mouth of Devil Canyon, neither fish embolisms nor evidence of gas bubble disease have been observed 1n the Sus itna River to date (ADF&G 1982). ~25832 851111 8-2 Alaska water IJJ <.:) a: ~ ~ 0 ~ -z 0 ~ a: :;) = ~ .. <n 1-z IJJ u a: LtJ ~ -<n ct <.:) 0 UJ d <n <n 0 ..J < 1- 0 1- ,., 2 ~ "' ~ S! <l. ~ ... u a:: 5 (f) -) quality standards specify max1mum allowable t o tal dissolved gas l~v~L; oi 110 percent of saturation at any point of sample collection (18 AlasKa Administrative Code 70.020). An additional concern regarding gas supersaturation ts the rate at whi c h supersaturated gas 1n flowing nver water returns to equilibrium thr o ugh contact with the atmosphere. The rate at which gas will come out o f solution is dependent on the water temperature and the exposure of the water to lower gas pressures. Gas supersaturated water has bee n observed to persist for long downstream distances where adequate o ppor tu ni ties did not exist for the dissolved gases to equilibrate with the atmosphere (Bo y er 1974; Fickeison and Schneider 1976 ). Measurements oi total gas concentration 1n several reaches downstream of Devil Canyon at 16,000 cfs and 32,500 cfs have been used t o stud y the rate of dissipation of gas supersaturation in the Susitna. Anal y si s of the data indicates that the dissipation rate can be modeled by an exponent1al dec ay function and that the amount of supersaturation is reduced b y approximatel y 50 percent in the first 20 miles downstream. The di ssipation rates have not been modeled further than 20 miles downstream, but any c ontinuing supersaturated conditions would be expected to co ntinue de c reasing, p oss ibl y at faster rates of decline due to s hall o wer cha nnel depths, mor~ wa ter surface area in c o ntact with the atmosphere , and dilution of mainst em wat e r ~ by tributary influent (ADF&G 1982 ). 8.1.2 Biological Effects The potential biologi c al ef fects of excess1ve gas supersat ur ati on below Devil Canyon rapids , sho u l d the s ituation occu r , woul d depend on several f a c tors, including : l. The s easonal timing of supe rsaturat ion. 2. The l e v e l of s upersaturation. 42':"~32 8 ::i 1 Ill 8-4 3. Th~ downstream extent of supersaturated water. 4. The amount of time that the organLsms are exposed to the co ndition. 5. The biological characteristics or the organisms Ln question. Large controlled releases are most likely to occur during middle to late summer or early fall when the reservoir(s) are full, under most conditions, according to proposed operational schemes (APA 1983a,b, H-E 1984f). At th is time, adult s almon will be using the ~iddle River mainstem channel as a migratory route to spawning habitats . The mainstem channel and peripheral habitats will also be utilized for rearing by juvenile salmon and resident fish during this period. Under with-project conditions, and without any mitigation measures, potential biologi.:al effects of excessLve gas supersaturation might involve disruptions of adult salmon inmigration to spawning areas, and/or detriment al effects on rearLng juvenile salmon or resident fish. The effects of gas supersaturation are often less severe and less pr0l o nged on smaller organisms (Fickeison and SchneLder 19 7 6; Dawley e t al. 1975). Consequently, impacts on small organisms might be less than fvr inmigrant adult s almon. In addition, high levels of gas supersaturation will most likely c oincide with hi g h volume flow events of relatively sho r:: duration. During high flow events, mobile aquatic organisms such a s juvenile fish will likely seek the slower vel ocities and be tt e r water quality conditions Ln the more shallow, peripheral habitats. In any case, high flow e vents will be shorter in duration and will occur less frequently with the Project in place as compared to natural co nditi o ns. 8.2 ~ITIGATTON 8.2.1 Mitigation Measures to Avoid Negative Biologi ca l Impact Project design and operations have been proposed to mLnLmLze the potential for impacts o n downstream fisheries due t o excessi v e gas su per sa turati o n . 425832 851111 8-5 For normal powerhouse discharges, and for all floods wich recurrence intervals of less than 50 years, the Project LS not expected to cause excessive concentrations of supersaturated gas. The operational plans would usually result Ln gas saturation levels which are equal to or less than naturally existing levels, primarily because the frequency and magnitude o f high flows through Devil Canyon would be diminished. 8.2.2 Structural and Operational Mechanisms for Avoiding Gas Supersaturation By using the reservoir storage capacity coupled with specialized powerhouse tailrace and outlet works designs, floods with recurrence intervals of up to 50 years can be discharged without spillway usage thus minimizing the potential for dissolved gas concentrations which will exceed naturally o ccurring levels. Turbine tailrace waters from Watana Stages I and III will be discharged thorough two 34 foot diameter tunnels beneath the surface of the r1ver at the downscream toe of the dam . This method of discharge will avoid entrainment of air, excesstve turbulence and pressurization of any gas-water mixture which might result in dissolved gas supersaturation. Fixed-cone valves have been selected to be used at Watana Dam during Stages I and III to minimize the potential for gas supersaturation in controlled spi~ls. Watana Dam will withdraw water for controlled spills from el. 1930. The discharges will be released through any of s1x, 78 inch fixed cone valves located approximately lOS feet above tailwater on the downstream toe vf the dam. Water released through the fixed-cone valves will form a dispersed jet which LS designed to dissipate the energy of the r el eased water. It is not possible to prevent outlet work releases from entraining a1r, therefore it LS necessary to prevent the release waters from penetrating to a great enough depth 1n tailwaters to prevent excesstve pressures whi c h can cause gas supersaturation. 425832 851111 8-6 Fixed-cone valves were :>elected to be used on outlet works because they can disperse the flow of water and decrease it:> intensit y and velocity ot impact with tailwaters. Little literature and no precedent data are available regarding the performance of fix:ed-cone valves 1n reducing or preventing supersaturated discharges. As such, a theoretical assessment of their anticipated performance was conducted based upon available studies of the aeration efficiency of similar Howell-Bunger valves (fixed-cone) and the physical and geometric characteristics of diffused jets discharging freely into the atmosphere (Elder and Dougherty 1952, Allis Chalmers, Chen and Davis 1964, Falvey 1980, Johnson 1967, Johnson 1975). The results of the assessment indicate that estimated gas concentrations that would occur as a result of a flow release are 100 to 105 percent of saturation downstream of Watana Dam. Concentrations will be within this range for up to the 50-year flood. Supersaturation will still occur 1n Devil Canyon, but with-project levels are expected to be less than naturally-occurring levels because of regulation of flood peaks by the project and the use of the outlet works cone valves. Operation of the spillway for flooJs less frequent than the 50-year flood lS expected to result 1n increased gas concentrations. However, because the dam wi 11 reduce downstream flood peaks, gas concentrations may be less than those occurring naturally for these floods. To support these conclusions, a field test of similar valves was undertaken at the Lake Comanche Dam on the Mokelume River in California (Ecological Analysts 1982). The results of the tests indicate that the valves prevented supersaturation and, to a limited extent, may have reduced existing nitrogen concentrations. Flows of 4,000 cfs with a dissolved nitrogen concentration of 101 percent at the intake structure were passed through four Howell-Bunger valves. Gas concentrations in the discharge were 97 percent. At 330 feet and 660 feet (100 and 200m) downstream, concentrations were 95 and 97 percent, respectively. 425d32 851111 8-7 The outlet works capacity for Watana Stage lS 24,000 cfs, while the powerhouse capacity is about l4,000 cfs. Maximum downstream dischar g e from the dam except in cases exceeding the 50 year flood event and when the reservolr surcharge capacity has been exceeded, will theref o re not exceed 38,000 cfs. Fixed cone valves have been included at Devil Canyon, and a flood storage pool provided to allow storage and release of all floods up to the 50-year event without using the spillway and thus minimizing gas supersaturation downstream. The Devil Canyon Dam will include seven valves at two levels wit i; a total design capacity of 42,000 cfs. Four 102-inch diameter valves, each with a capacity of 6,300 cfs, will be located approximately 1 70 feet above normal tailwater. Three more valves, with diameters of 90 inches and capacities of 5,600 cfs, will be located approximately 50 feet above normal tailwater elevations. The Devil Canyon powerhouse capacity for both Stage II and III is 14,000 cfs. Operation of these valves is expected to result in a maxlmum dissolved gas concentration of between 105 and 110 percent for the 50-vear flood event, immediately downstream of Devil Canyon Dam. This assumes that gas concentrations from use of the Watana cone valves of 100 to 105 percent a :e not dissipated in the Devil Canyon Reservoir. This is a reduction from naturally-occurring levels which would annually exceed 115 percent. Fixed cone valves will be provided on the Watana and Devil Canyon outlet works to disperse excess releases and mtnlmlze the potential for gas supersaturation in excess of naturally occurring levels. The capacity of the Watana outlet works will be approximately 30,000 cfs during Stage III as compared to 24,000 cfs during Stage I because of the additional hyd rauli c head on the valves. Likewise, the powerhouse capacity for Watana Stage III is increased to about 22,000 cfs. During the early y ears of Stage III operation the outlet works will be operated approximately as frequently in St P.ge III as in Stage II. However, as energy demands in c rease, more water will be used f o r power and outlet 425832 851111 8-8 works operati.on will decrease. The ability of the project to control floods in excess of the 50-year event will be improved. In addition to us1ng reservo1r s torage to control and reduce pea !~ flows, and the use of fixed-cone valves to dissipate energy from controlled sp ill s, one additional fact o r will help m1n1m1ze dissolved gas s up e rsaturati on 1n downstream habitats. At Devil Canyon dam the powerhouse tailrace will route turbine tailwaters downstream through a tunnel 38 feet 1n diameter and approximately 6,800 feet long. The tailrace waters will be discharged under the river surface and downstream of nearly all the violent Devil Canyon rapids. This long tailrace tunnel discharge will help dilute any flows still discharged through Devil Canyon out let works and/or spillways, and will thereby help avoid an y downstream gas supersaturation co ndition s . 425832 85 1111 8-9 9.0 AQUATIC NUTRIENT CFANGES RELATED TO THE PROJECT Th e s ignificance of c hange Ln water qualit y parameters (nu t rient s) t o salmo n and resident fish habitats and populations downstream o f the dam s ha s b een identified as a fisheries issue for this project. The fo llowing inf ormation discusse s the current status of our knowledge regarding thi s topic. 9.1 Discussion 9.1.1 B:sic Considerations. The primary tssue concerning nutrients and the Susitna Hydroelectric Project ts the effect that project construction and operation will have on the trophic status and fish resources of the proposed reservoirs and the rtvenne habitats downstream from the Project (FERC 1984). An aquatic habitat's trophic status ts an indication of its relative degree o f richness or poverty with regard to the rate of suppl y of its biologically useful organic energy. Generally, the richer the trophic status of an aquatic subsystem , the greater its ability to contribute biologicall y useful e nergy to fish productivity. The trophic status of an aquatic habitat, whether that habitat t s characterized by slow (lent ic) or fast (lot i.e) flowing water, is largel y determined by the rate at which biologicall y useful organtc material LS recruited from two basic sources : primary production of new organi c material s produced by aquatic photosynthesis (autochthony) and organtc materials derived from terrestrial sources (allochthony). Limnolog i sts have long recognized the importance of aquatically produced organic carbon c ompounds to the trophi c status of lakes, ponds and reservoirs (Wetzel 1975), and they are recently becoming more aware of the importance of aquatic 425832 851111 productivity Ln unshaded riverine habitats as well 9-1 (Wetzel 1975 , "Min s hall 19 78 , Cummins 1979, Murphy et al. 1981, Conne-:-s and Naiman 1984 ). Mos t freshwater lake and reservo i r habitats of temperat e North Ameri c a hav e their aquatic production of new organic material limited by low supplies of biologi c all y available phosphorus and/or nitrogen (Wetzel 1975, Hut ch inson 1973, Rast and Lee 1978, Vollenweider and Kerekes 1980). The data supporting macronutrient limitation of autochthonous productivity tn lotic habitats is much more iimited (Huntsman 1948; Moore 1977 ; Peterson et al. 1985b). The aquatic productivity of new o rganic material tn loti c habita ts , on the other hand, lS frequently limited by a more complex array of environmental variables which includes not only macronutrient concentrations but also temperature, high flow variabilit y , high velocities, turbulence, low light levels, and unst ..:ble substrate for attached algae an c hor point s (Cushing et al. 1980, Lowe 1979, Newbold et al. 1981 , Minshall 1978 , Minshall et al. 1983, Murphy et al. 1 981, Vannote et al. 1980 ). Observation of the Susitna River mainstem and peripheral habitats during recent field seasons has so far di s closed only two brief peri o ds when substantial standing crops of attached algae c o nsistentl y occur ( ie., tn spring , before intensive and highly turbid freshet flows, and in fall, after high volume and highly turbid summer flows begin to diminish). In fall 1984 and 1985 luxuriant crops of attached filamentou s algae were phot o - graphed along many reaches of the ma i nstem c hannel and in many side-channel s and side-sloughs. The attached algae appeared to grow luxuriantl y in man y places where incident solar radiation could penetrate to stable streambed substrate. Quantifications of aquatic primary produ c tivit y and standing c rops of attached algae are not available for any reach of the Susitna. The relative importance of autochthonous vs. allochthonous production to the f low of energy between trophic levels leading to fish resources or to the trophi c status of the Susitna River is unknown. Nevertheless, regardless of the actual quantity of newly produced organic material Ln the river, it 1 ikel y serves as a very impor-tant, high quality food source for microbial populations with varied food requirements as well as for invertebrate 425832 851111 9-2 and vertebrate herbivores and detritus feeders (Cummins, 1979). These detri·•ores and herbivores, in turn, may become food for vertebrate predat o rs such as juvenile salmonids and resident fishes which, in turn, ma y become food for birds and mammals (Hynes 1970). 9.1.2 Aquatic Primary Productivity. Under natural conditions, the factors which appear to be the most important 1n limiting aquatic prtmary productivity in the Susitna River are: o Highly variable water stages which cause desiccation or freezing of dewatered attached algae, o Relatively cold thermal regimes with low mean and maximal temperatures, o Unstable streambed substrate, o Scour by suspended sediment particles, o Scour by frazil ice, anchor ice, or other ice processes, o Sedimentation of streambed substrate and smothering of small organisms by small particulates, o Light limitation, during most seasons, by 1ce and snow cover or high turbidity levels. Substantial growth of attached algae occurs in spring and fall when flows in the mainstem and peripheral river habitats are relatively stable and the negative effects of suspended sediments are reduced. The occurrence o f rapidly growing standing crops of attached algae observed during these periods is indirect evidence that at least minimal supplies of biologically available phosphorus and nitrogen were present in the river water during at least the spring and fall. 425832 851111 9-3 Shortages of the major macronutrients such as phosphorus and nitrogen whi c h are sufficient to dramatically limit aquatic primary productivity are not e xpected to occur in the unregulated Sus itna River during any s eason, nor during any year. Concentrations of total phosphorus and total nitrogen which are general r~presentative indicators of different trophic categories tn relatively clear, freshwater lakes of north temperate latitudes have been fairly w~ll established (Table 9.1). However, for turbid lakes and turbid reservotrs (Jones and Bachman 1978, Kerekes 1982, Walker 1982 ), or for nvers and streams of any size, comparable relationships between representative macronutrient concentrations and different trophic categories have not been well established (Cushing et al. 1980, Moore 1977). In fact, the science of stream limnology, in contrast to lake and reservoir limnolog y , has not been able to establish any generalized categories or terminology d~scribing the relative troph·~ status of streams and rtvers tn terms of oligotrophy (impoverished or low rates of biological energy supply), mesotrophy (medium rates of biological energy supply) and eutrophy (high levels of biological energy supply) (Cushing, et al. 1980). Chemical assays for phosphorus and nitrogen levels in the Susitna River have shown highly variable macronutrient concentrations occurring tn the river during summer, winter and breakup (APA 1983a,b). During most sampling periods and at most sampling stations, concentrations of the vartous phosphorus and nitrogen compounds have been found to vary from less than detectable levels to much greater total concentrations than would be necessary to support moderate biomass ( 10-20 ug/1 Total P and <500 ug /1 Total N) or even excessive bi~mass (>20 ug/1 Total P and >500 ug /1 Total N) of phytoplankton (See Figures 9.1 and 9.2) if the nutrier.ts were in a cl ear temperature latitude lake. Although concentrations of total nitrogen and phosphorus which are gener.1lly representative of any given trophic status of subarctic rivers have not been established , it is reasonable to assume that c oncentrations generally accepted as indicators of lake trophic status, and possibly even lower 425832 851111 9-4 Table 9.1 SUSITNA HYDROELECTRIC PROJECT GENERAL RANGES OF TOTAL PHOSPHORUS AND TOTAL NITROGEN WHICH ARE RELATIVELY CHARACTERISTIC OF DIFFERENT TROPHIC CATEGORIES IN RELATIVELY CLEAR LAKES AND RESERVOIRS Trophic Type Total P(ug/1) Total N (ug /1) Ultra-oligotrophic < 5 < 1-250 Oligotrophic 5-10 Oligo-mesotrophic < 10 250-600 :-tesotrophic 10-30 Meso-eutrophic 10-30 500-l J 100 Eutrophic 10 -30 Hyper eutrophic 30-> 5,000 500-15,000 Source: Adopted from Wetzel (1975) 42583 2 9-5 851111 a a ~ ~ a z ! • c z c J i 2 • • I I ' I ' ' ' ' ' ' ' ' I - I I I ' ' I I ~-· ~- I I I I ' ' I ' I I ' I • • N ~ 0 0 0 c - 9 -fi . ~ -c ~ z ... 4 ! z 2 3 -c i ~ .. -::t -' o•E ..... ;.. ' o~E -... ,. "" ->~ ~ oa~ 2:C ._ . .;; ~ ... § ._ 0~!: =~E -•>: ... OQ._ ... '1,. NVI;.. i: ~~ N ',. au= ~ ~.; l<t "" ~>~ g 1- ' ~ I oa~ I ~ I J z g -c -" c a - • • ... • i • • 2 • " c a ,.. ... .. • . ~ ... ~ .. a i J .. -; 1.1 1.1 -; ! 0 -·' : ., z -! --z J'l .. J'l • .. J'l 1 I ... c J :> ..., a ! ~ -! ~ a a ... j -! • C N i i : ; : I • • ~ ! ! ' z z 2 2 ~ 0 ~ """ 2 ~ < ... z 2 > ~ :I )( < z ~ ... < loU loU ., 2 2 i VI -! ~ .. z -• • • lol ... -• :.. :.. :) • -----I • • -. ~ ., = ~ ~ • :.:1 ~ I ~ "' :11: ~ = .:l. I ... 111 ~ • C\1 ai :11: ' ' c G a ~ :c ~ ~ ~ ...1 • ~ ~ • -0 lll :.. ac Q 4 » c :: I ' ~ z < z 1.41 -• ~ <.:1 .. 0 -:t.l a: -= c ~ ,_ a :t.l oc "' ~ z a 1--' I 4 -~ ~ -J : < ~ -z ,;.. .., 0 -I -: .., • > ~ Ill Ill = 3 ' ' c c g I ~I ~ ~ z Cl = • en :< I "':: = Gl ] < e-... 0 "' = e-a -~ 2 0 -Q -,.. ~ -2 a :s Q: = c w "" Q = ... --(I) ~ "" • 2 Ill c: c I ' , 0 a: ' ' ... f I ... , ~ ... --~ ... c ~ a 1M 0 N -0 Q z I Q 9-7 concentrations·, would be applicable to north temperate or subarctic r1ver~. Under such an assumption, concentrations of macronutrients tn the Susitna River would not appear to be limiting to aquatic primary productivity under present environmental conditions during summer, win~er or breakup time periods (See Figures 9.1 and 9.2). 9.1.3 Anticipated With-Project Conditions-Reservoirs Construction and operation of the proposed project will produce a reservoir habitat in which phosphorus and nitrogen are both added to and removed from the impounded river water. Additions of phosphorus and nitrogen to the proposed reservoirs are expected to occur primarily due to: o Mainstem river, tributary and groundwater influents; o Surface runoff from eroding reservo1r sidewalls and reservo1r drawdown zones; o Liberation of nutrients due to microbial decay of inundated organic material; o Leaching of nutrients from newl y inundated soils by chemica 1 and biochemical processes; 0 Treated secondary facilities; sewage effluents from construction-related o Particulate fallout from atmospheric sources; o Direct precipitation 1n the form of ra1n and snow; 425832 851111 9-8 Substantial lasses of macronutrients which enter the project reservotrs will be expected to occur. The majority of phosphorus atoms entering the project reservoirs are expected to precipitate out with the sediment particles on which they arrive and to remain permanently stored on the reservoir bottom. Microbial denitrification activity and precipitation of nitrogen compounds attached to particulates will be expected to remove some of the nitr oge n added to the reservo1rs. However, nitrogen fixation by aquatic microbes may add small quantities of biologically available nitrogen compounds to the reservotrs. Overall, the reservoirs are expected to act as nutrient sinks, and phosphorus and nitrogen exports to downstream areas should be reduced (Hannan 1979, Wetzel 1975, Stuart 1983). 9.1.4 Expected Reservoir Trophic Status The present state of knowledge of subarctic reservoir limnolog y indicates that both project reservotrs will be classifiable as having extremely unproductive trophic states. The major factors limiting the aquatic primary productivity of both project reservoirs are not expected to be nitrogen or phosphorus supplies, but rather low light conditions (due to turbidity and to ice and snow cover), cold temperatures, lack of any substantial littoral zone, and large drawdown zones due to project operations. During most of the project's lifetime, organtc material recruited from terrestrial sources is not expected to add substantial amounts of readi ly usable organic matter to the reservoirs' detritus food base (Wetzel 19 75 ; Hobbie 1980) and it may even help depress the potential primary production (Jackson and Hecky 1980). The relatively short bul k residence time estimated for the reservoir waters and the relatively refractile nature of most of the influent organic material indicates that little chemicall y or biochemically mediated change tn the food quality of the terrestrially produced organtc material will occur before it ts discharged f rom the reservoirs . Thus the project reservoirs will not be expected to contribute large amounts of high quality organic food materials to downstream riverine habitats, and will be likely to serve as traps and permanent storage sights 425832 851111 9-9 for much of their allochthonously derived macronutrients and organic car b 0 n (We tzel 1975, Hannan 1979, Stuart 1983). The project reservoirs, like most reservotrs around the worid, will be expected to go through a mild "trophic upsurge" period after filling, characterized by slight increases Ln biologically avai l able phosphorus, nitrogen, organic detritus and suspended sediments (G rimard and Jones 1982, Therien, et al. 1982, Ostrofsky and Duthie 1980, Jackson and Hecky 1980; Crawford and Rosenberg 1984). Both reservoirs are expected to experience slight oxygen declines 1n their deeper zones , especially during winter stratification. Both reservoirs are expected to have relatively low rates of biologically mediated nutrient flow during their entire lifetimes, and are expected to support only minimal bacteria, fungi, phytoplankton, zooplankton, benthic invertebrate and fish populations. 9.2 Anticipated With-Project Conditions: Riverine Habitats Downstream With-project conditions Ln the mainstem and peripheral habitats dire c tl y affected by mainstem flows from May to September are expected to be slightly more favorable to primary productivity than preproject conditions. Several characteristics thought to severely limit primary productivit y (substrate scour, substrate instability, streambed sedimentation by fine parti cles, high turbidity , high flow variability) are expected to have less negative influence on aquatic primary productivity by periphyton under with-pr oject summer conditions. Regulation of river flows to provide lower than natural water stages during summer may also prevent highly turbid mainstem waters from affecting the aquatic periphyton productivity of many clear, running water habitats peripheral to the mainstem. Any enhancement o f primary p ~o duction tn peripheral riverine habitats during summer may serve to enhance the troph ic status and biological productivity at all trophic levels of the Middle river reach. 425832 851111 9-10 9.2.1 Downstream Nutrients Flow The total amount of phosphorus transported to downstream rtvertne habitats will undoubtedly be reduced, but the relative concentration of phosphorus per unit weight of suspended sediment will probably be increased by proje c t operations. This phenomenon is expected to occur because the smal ter average size of suspended particulates discharged from the Project should have a much larger ratio of surface area to weight compared to preproject suspended sediments, and because phosphorus is frequently complexed to the surfaces of suspended particles (Schreiber and Rausch 1979). Various forms of phosphorus were analyzed 1n the two Susitna River samples collected for analyses in the settling column experiments conducted in the s umme r o f 1 9 84 • The result~ (Table 9.2) indicated that the first sample collected, which had a TSS concentration of 181 mg /1, had a total phosph o rus (TP-by acid persulfate digestion) content of approximately 190 ug/1. Approximately 85 percent of that TP was inorganic particulate phosphorus (IPP). The second sample collected contained 410 mg /1 TSS and 532 ug /1 TP. Approximately 65 percent of the TP in the second sample was IPP. In both samples the organic particulate phosphorus (OPP) was approximately 12-13 percent of the TP, while the orthophosphate (FRP) content was 8-15 percent of the TP. Mean annual values of particulates 1n the chronically turbid efflue nts discharged from the project wi 11 be at least 50 mg / 1 TSS. If one assumes that these particulates will contain al least the same amount of TP per unit of mass as the "natural" TSS (i.e. 0.1 percent by weight ), then the annual average TP of the project discharges will contain at least 50 ug /1 TP associated with the TSS particl es . Large di&c repancies exist tn the literature regarding the amount of the "particulat e phosphorus" wh ic h mi g ht be "biologically available" (i.e. BAP). Conservative estimates of BAP o n aquatic sediment s range from 5-10 percent 425832 851111 9-11 TP TFP FRP IPP OPP TP TFP FRP IPP OPP "' TP Table 9.2 SUSITNA HYDROELECTRIC PROJECT PHOSPHORUS IN SUSITNA RIVER SAMPLE S All values are reported as ugL-1 (ppb ) as 7/31 /84 8/06/84 190.4 532.4 16.9 82.1 15.9 77.1 161.5 343.5 24.9 62.9 total phosphorus total filterable phosphorus fil t erable reactive phosphorus (orthophosphate ) inorganic particulate phosphorus organic particulate phosphorus TFP + IPP + OPP P. Data Analyses: ADF&G FRED Limnology Laboratory, Soldotna, Ak . 425832 851111 9-1 2 by weight, more liberal estimates may be much larger. The techniques used to estimate BAP are not standardized or agreed upon (Lee, Jones and Rast 1980; Wildung and Schmidt 1973; Grobler and Davies 1979; Rast and Lee 1978; Stanford, et al. 1984). However, little doubt exists that phosphorus atoms associated with inorganic and organic materials are exchangeable, and to a limited extent biological available, to micro-organisms positioned nearby (Golterman 1975; Lean 1973; 1973a; Lean and Rigler 1974; Paerl and Lean 1976; Ammerman and Azam :985). In areas where substrates become "dusted" by glacial flour, epilithic communities which are dominated by mucilage secreting/mat forming microbes will cause nutrient rich suspended par,: iculates to accumulate Ln aufwuchs type communities (Smith 1950; Prescott 19t.2; 1970; Hobbie 1980). Cyanophyta with the capacity to fix their own nit::-ogen source and secrete copius mucilage may have an obvious competitive advantage compared to other periphyton in such habitats. In habitats with suitable illumination, temperature, velocity, turbulence and substrate, etc., aufwuchs communities incorporating inorganic particulates wi 11 have a concentrated and usable source of metaboll ica lly essential phosphorus and other trace elements due to suspended sediments. Although the concentration of nitrogen may decrease during passage through the project reservoirs, additional sources of nitrogen are expected to be added to riverine habitats downstream of the project by tributary and groundwater influents, by aeolian inputs of nitrogen in rainfall and precipitating particulates, by organic detritus de:ived from the terrestrial environment and by instream nitrogen fixation (Fontaine and Bartell 1983; Triska, et al. 1984; Peterson, et al. 1985b). Riparian vegetation, especially alder (Alnus sp.), is an excellent and well recognized source of fixed nitrogen for nearby aquatic environments (We~zel 1975, Livingston 1963), and alder 1s a common component of the riparian vegetation along the Susitna Rive:". Excess nitrogen appeared to be available for biota in the phosphorus-limited Kuparuk River, and increased nitrate removal from the 425832 851111 9-13 river water was associated with experimental additions of readily biologically available phosphorus (Peterson, et al. 1985b). 9.2.2 Trophic Status and Fisheries Effects Summary The trophic status of both project reservoirs ts expected to be classified as ultra-oligotrophic (i.e. a low rate of biological productivity at all trophic levels) for the lifetime of the project. Project-induced changes tn nitrogen and phosphorus concentrations in the reservoirs are not expected to be sufficient to alter their relative importance in the hierarchy of factors which will act to limit aquatic primary productivity (i.e. 1 i gh t I temperature, hydraulic residence time, etc.). The trophic status of glacial streams and rtvers ts usually relatively impoverished (Milner 1983, Steffan 1971, Van Stappen 1984, Ward, et al. 1982), as are streams receiving particulate placer mine wastes (Lloyd 1985, Van Nieuwenhuyse 1983). The trophic status of the Middle River mainstem ts presumed to be relatively impoverished at present, especially relative to non-glacial rivers at the same latitude. Project-induced changes in macronutrients are not expected to change the Middle River trophic status. Periodic high turbidity and suspended sediment levels presently act to limit Middle rtver aquatic productivity at all trophic levels. Chronic, moderate to high turbidity and suspended sediment levels, expected under with-project conditions, are expected to continue to minimize aquatic productivity at all trophic levels and in many habitats of the river carrying constantly turbid mainstem flows. Although mainstem aquatic productivity is still expected to be strongly limited by the projected with-project suspended sediment regime, conditions for attached algal productivity on the margins of the turbid mainstem may be improved under with-project conditions in areas where sunlight can penetrate to stable streambed substrate. 425832 851111 A somewhat ana logo us situation has been 9-14 observed tn the chronically turbid Kasilof River of the Kenai peninsula. Peripheral riverine habitats that may be inundated less often by mainstem flows under with-project conditions are expected to maintain o r increase their aquatic productivity relative to natural conditions. 425832 851111 9-15 10.0· DISSOL\~D OXYGEN, ORGANIC CARBON AND PROJECT EFFECTS Concentrations of dissolved oxygen 1n the natural r1ver1ne habitats have been found to be moderately high or very high during all seasons. Winter values have been found to vary from 11.6 to 13.9 mg /1. Winter dissolved oxygen concentrations have averaged being approximately 98 percent saturated at Gold Creek, and 80 percent saturated further downstream at Susitna Station. Summer dissolved oxygen concentrations at Gold Creek have frequently ranged from 11.5 mg/1 to 12.0 mg /1 which equates to summer saturation levels of approximately 97-105 percent. Dissolved oxygen concentration and percent saturation data collected at several stations during different seasons have been presented as they were in the original license application (Figures 10.1 and 10.2). Additional dissolved oxygen data were obtained from several Susitna River mainstem and tributary habitats during field surveys in 1983 (Figures 10.3 and 10.4). All existing data have consistently indicated relatively high dissolved ox y gen concentrations during all seasons in all Susitna River surface waters. Total organ1c carbon (TOC) concentrations have been analyzed 1n several Susitna River samples and have varied between 1.0 and 41.0 mg /1 (R.S.M Consultants, Inc. 1982a, 1982b). Most measured TOC values have been les;:; than 5 mg/1 at various Susitna River stations during both winter and summer seasons (U .S .G .S . 1980, 1981, 1982, 1983). Susitna River TOC concentrations are similar to TOC values from other large rivers in Alaska whi c h drain watersheds containing similar vegetation (R&M Consultants, Inc. and Peterson and Assoc. 1982; US.S.G.S. 1980, 1981, 1982, 1983). The majori~y of the TOC is composed of dissolved organic carbo n (DOC), with the remainder being found in the particulate from (POC). These findings are completely within the realm of the values to be expected for both lent ic and lot ic fr esh waters (Wetzel 1975; Ward and Stanford 1979; Hobbie 1980; Naiman 1982, 1983a). 425!:!32 851111 10-1 ,_. I 0 I '" ' ... IE z w ~ li 0 ~ a 0 I.A. liS . I - 14 -- 12 - - IQ 1.0 - --· 0 ' ·: 0 I !. IS IS ~ 4 • 0 10 s 14 0 I s 0 4 0 4 ·1 D v c T I .. v ' c T I .. D v • c T I .. IT I I TTl _l ·r I I I I I SUMMER WINTER 8R£AKUP 0 -0fMALI V -VH CANYON 8 -IOLD CRflK C-CHULITNA T-TAlkU TNA S -SUN SHIN( 51-SUIITNA STATION MOTtS I . A . CIUTEIIA • GM.AIER lttAH 7 .. ./1 . .-uTIH NO CAS( SHALL Ol$50l.VED OXYG£N EIICEED 17 .. /1 (ADEC lll7~). I . e. UTAILISHI:D fOR nt( f'ROTlCTION Of ANADROMOUI AND Rls.olNT fiSH. DATA SUMMARY-DISSOLVED OXYGEN ......_, u~a~••,. e MAICIMUM -MEAN e MINIMUM NO. Of 08SERVATIONS LOCATION f IGUIU II ) I 0 I '-' I -- 120 I .A -- z 0 1-.. II: ::l 1-.. lA ~ 0 z ... " ,... )( 0 0 ... ~ 0 ., ., 0 10 0 -- 1 0 - - •o .. - -- 0 1 ·~ 0 • 2 • 0 4 • 0 • s ' 0 I : 0 I 0 2 p v ' c T • as 0 v e c T • .. () v c T s IS I I I I I I I I I I I I I r SUMMER WINTER 8R£AI(UP 0 -0ENALI V-VU CANYON 8 -IOL.O CRfU C-CHULITNA T -TALK(( T N A S -SUN SHIN( Sl -SU.ITNA STA TION Nons: I. A . Cfl TU UON• T H£ CONC(N TRATION OF TOTAL OtSSOLV£0 GAS IHAU.. HOT fl(C£(0 110% SATURATION AT ANY POIN T IAOEC ,It Tt l . I . I ESTABLISHE D fOft THE PRO TECTION OF ANAOftOMOUS AND RESIDE NT f iSH DATA SUMMARY-DIS SOLVE D OXYGEN % SATURATION e MAXIMUM MUN e IIII I NIMUIIII NO.~ 086fRVATIO NS LOCATION t II>UHt o,) .' ~~-ou--~~'~'--u~a~a~•--&-M~O~~~·~·~------------------------~--------------------------------------------------------------------------------------------------~~~~-------- ,...... 0 I f'• !!!! ~ rug . I .. ' •• ~~-... , ... ~e.-.... , . ....... _ .. '-.. •• ,,. .. ,. ......... -~ .... .,.. . .,. ~ ... ~, .. . .....:..., ...... _ 10 ......... .... ..... -· ........ le '-• ....... 1100 .... ..... ·-••• r ....,.. .... -···· l ... .... .... . ..,. I . .. • -c-c-. -· .,....,. f!t!ln • •. n lila ar Maa t.M ·IIII ~ ... -···· eeoo .... IQM , __ , __ , -I ••• ~l ......... , •--•-n-oaa IU ..... ..r-..• __ .. _ .... 011 :.~ ...... "'.. .u, • " .••• ' .... ..... ~ 40 - 1 60 +··· 10 100 IZO HO DISSOlVED OXYOEN fat/11 , liO , •o Dissolved oxygen data su~ry showing range, 25 th, 50th (.edlan), and 75th percentile for lola Ins te• and tr tbutary water qua 1 tty s tudy sUes OISSOL VED OXYGEN DATA SUMMARY I I\;IIHI 10 ~ 0 . I U l . mt I!! tl!J!!! ...... _ ...... -----............... ... ... ,. .... -·-c.. ... .,....,. C...•t llDIII ... .,..... lUll ••• .,. . ..,. -'-··'-... ... .,. l .. ., .... ..., . .,. -· .... , __ , __ , liDO , . ...,. .......... ··-··· ............ ... ... .... , ..... -·· ........ • ••• ~-.. ~ 10 eo -• .. , , --m'lp!l •••• ~ ... i ..• . ..,. T 80 ..J • •• , f •.• ~ ... f ••• I 100 I 110 I IZO DIIIOLVlD OJCY8lN ""IAIWIATIONt I 150 ~ ... ~,. .. .......:...\• .. ....... .. ......... ... ............... le . .......... _ .. , ... I 140 lll s\o lv ed oxygen perce nt saturatton data su..ary showtng range. 25th. 50th (.edtan), and 7~th percenttle for ~tnste• and trtbutary water qualtty study sttes. DISSOLVED OXY GEN DATA SUMMARY touau 1101 • e oH•• I luliH~ 10 4 Chemical oxygen demand (COD) values for Susitna Ri ve r s ample s ar e relatively low. Summer COD values ranged rm 8 to 39 mg /1 at Vee Can yon , and ranged from l to 24 mg /1 at Gold Creek. Winter COD value s wer e t y picall y lower than summer values, ranging from 6 to 13 mg /1 at Vee Canyon and from 2 to 16 mg /1 at Gold Creek (U .S.G.S. 1980, 1981, 1982, 1983). No bi ochemic al oxygen demand (BOD) data have been analyzed fo r the Susitna River, but BOD values would also be expected to be relatively low. As previously discussed, much of the organ1c carbon recruited from allochthonous sources into lotic habitats is suspected as having relati vely poor food quality (Cummins 1979) and as being relatively re f ractor y to microbial degredation (Hutchinson 1975; Hobbie 1980). I t is assumed that most of the TOC in the Susitna River mainstem i s largel y composed of humic materials derived from tundra runoff. This humic material lS pr ob abl y primarily composed of complex molecules with high mol ec ular weights , and which can be generally categorized as humic acids , fu lv i c acids and insoluble humins. Humic materials behave as weakl y acidic polyelectr o l y tes, have a strong propensity for complexing with metallic ca tions (Hg , Pb, Cu, Xn, Cd, Ni, Cr, Co, V and especially Fe , etc.), and for interacting s tr ong l y with the mineral surfaces o f suspended sediments by ab sorpti on processes (Jackson, et.al. 1978; Hobbie 1980). Studies by Naiman ( 1982, l983a, l983b) and Conner s and Naiman ( 1984 ) have indicated the decrea s ing importance of allochthonously derived organic ca r- bon with increasing stream size in community oxygen me t abloli s m of bo r eal forest watersheds Ln eastern Canada. Naiman's work also emphasi zes the i ncreasing importance of autochthonous l o tic periph yton pr oduction with increasing stream size in these same open cano pied boreal st reams . Rec ~n t work in a n Alaskan arctic stream (Peterson, et al. l985b) ind icated that the biological productivity of this naturally heter o trophi c stream depended in large part on the metabolism of allochthonously d~rived o rgan ic matter o r ig - i n ating in its tundra watershed. Pe t e rson, et al. (l 985b) demonstrated t h at 425832 10-6 851111 the biologic·al productivity of this open canopied stream could be significantly enhanced by stimulating the autochthonous productivity of the epilithic community by experimental phosphorus addition. 10.1 WITH-PROJECT CONDITIONS AND EFFECTS Li~nological conditions in both project reservoirs are expected to mtntmtze the formation of oxygen deficient water layers at most depths. No significant BOD loading lS expected for either reservoir from the construction camp or village, due to the wastewater treatment facilities currently proposed (APA 1983a). Selective removal o ( large timber from certain areas of the inundation zone will eliminate a small amount of as soc ia ted oxygen demand. Flooded organic matter on the reservoir bottom and sidewalls will still rematn and may create some localized oxygen depletion. However, the process of decomposition will be relatively slow at the prevailing cold temperatures, and any waters experiencing oxygen depletion are expected to be substantially diluted by the large volume of reservoir water which is expected to have a relatively high dissolved oxygen content. A large volume of literature related to Alaskan, Canadian, Swedish and Norwegian lakes and reservotrs was examined with no mention found of problems due to oxygen deficits tn epilimnion release waters of large resPrvoirs (Grimas 1961; Grimas and Nilsson 1965; Gill 1971; Gill and Cooke 1974; Geen 1975; Campbell, et al. 1975; Ward and Stanford 1979; Baxter and Glaude 1980; Acres Consulting Services Limited 1981; Koenings and Kyle 1982; Koenings 1983, 1984; Hecky, et al. 1984). The stratification that ts anticipated tn the reservotrs ts expected to minimize oxygen replenishment to the hypolimnion, especially during the tee covered periods. However, spring turnover, together with the large freshet inflow of highly oxygenated (probably o2 saturated) water will cause substantial reoxygenat ion of of any hypolimnion oxygen def ic ic ient waters which may occur. It is anticipated that the upper 2 0 0 feet (6l)m) of the impoundments will maintain high enough oxygen c oncentrations (>8.0) to avoid any biological problems for native fish. 425832 851111 10-7 Quantitative estimates of any oxygen deficiencies which ma y occu r cannot be presently determined. This would require more extensive knowledge than i s presently available regarding the quantit y and quality of organic detritus to be inundated, f biological and chemical o xygen demand rates, and more detailed knowledge of reservoir hydrodynamics, including density currents (Grimas 1961 ; Grimas and Nilsson 1965; Wunderlich 1967 and 1971; Allanson 1973; Slotta 1973; Straskraba 1973; Williams 1973 ; Wunderlich and Elder 1973; Soltero, et al 1974; Hutchinson 1975; Cornett and Rigler 1979; Dut h ie 1979, Hannan 1979; Therien, et al. 1982). Downstream from the reservoirs biologically important ox yg en defici t s are not expected. Most discharge waters will be drawn from well oxygenated surficial layers in both reservoirs. Any oxygen deficient water released from either dam will be rapidly reox yg enated due t o turbulen ce and and equilibration with the atmosphere during discharg e from the outlet works and during downstream flow. Detrimental biological effect s are not ex pected tn either the project reservoirs or rtvertne habitats immediately downstream d ue t o pro j e c t induced changes in dissolved oxygen co ncentrations . Lakes and reservo1rs allochthonously and c arbon (Wetzel 19 75 ; with surrace di sc harges are well autochthonously derived material s, Stuart 1983; Whalen and Cornwell known trap s fo r includi~g o rgan1c 1985; Soballe an d Bachman 1984. It can be concluded, therefore, that in the l o ng term of t h e project lifetime the project will decrease the amount of allochthonousl y supplied organtc carbon to th e downstream riverine habitats. The project reservoirs, during their early filling and o peration phases, will likely caus~ a short term increase in downstream o r g anic c ar bo n transpor t (C raw fo r d and Rosenberg 1984). Th is ef fect sho uld decr e a se, ho wever , as the reservoirs age . Although the allochthonous organ1c carbon input to the reser vo 1rs wil l like ly b e relativ ely refract o ry t o mi c robial degradation (Hut ch inson 1975, 425832 851111 10-8 Hobbie 1980),· and the overall quantity exiting from the reservoirs will be reduced when compared to the inflow, heterotropic microbial processtng o f the organics within the reservoir may somewhat improve the food quality o r that organ1c material which is exported from the reservoirs (C rawf o rd and Rosenberg 1984). It is presently impossible to quantitatively estimate the long term impact of reduced inputs of allochthonously derived organic carbon (TOC, DOC or POC) to the biological productivity of the Susitna River middle reach mainstem habitats. Qualitatively, it may be safe to assume a decrease 1n biological productivity in downstream mainstem riverine habitats due to: l) substantial reservoir trapping of allochthonously derived organic carbon; 2) virtually no production in nor export from the reservoirs of autochtho- nously derived organic carbon, and 3) minimal mainstem rtvertne autochtho- nous primary production due to high, chronic turbidity. 425832 851111 10-9 11.0 BRIEF SUMMARY OF PROJECTED WATER QUALITY CHARACTERISTICS IN RELATION TO TROPHIC STATUS AND COMPOSITION OF THE AQUATIC COMMUNITY 11.1 RESERVIOR BIOTIC COMMUNITIES AND TROPHIC STATUS Impoundment of the Susitna River will produce a wide variety of physical, chemical and biological changes 1n the newly created lent ic environment s which will affect their potential trophic status and biological communities. Within the project reservtors morphological as well as other limnological characteristics indicate that biological activity 1n the water column will be the most important site of metabolic activit y with regard to the long term reservoir biological productivity and trophic status (Hutchinson 1967 and 1975; Wetzel 1975). The newly flooded surfaces of the reservoir floors and sidewalls will be of lesser importance as sites of biologi ca l activity when compared to metabolism tn the water column. The importanc e of biological activity in and on flooded reservoir substrates is expected t o decline with reservotr aging because of gradually decreasing release s of orga ntc matter and nutri <'nts into the overlying wate r column (Grimas 1961; Nilsson 1964; RodhE: 1964; Grimas and Nilsson 1965; Lindstr om 1973; O stro L;~y and Duthie 1975; Ostrofsky and Duthie 1978; Ostrofsky and Duthie 1980; He c~y et al. 1984; Hannan 1979; Duthie 1979; Baxter and Glaude 1980; Pet e r so n and Associates and R & M Consultants 1982; Grimard and Jones 1982). The project reservotrs are expected to be relatively unpr o du ct i ve compar e d to the known trophic status of many bodies of fresh water (Tabl~ ll .l). Among the key limnological characteristics which are anticipated t o minimize the productive potential of the projec t reservoirs are: ~25832 351111 ll-1 Table 11.1 SUSITNA HYDROELECTRIC PROJECT TROPHIC STATUS AND RATES OF ANNUAL PRIMARY PRODUCTIVITY OBSERVED IN VARIOUS LAKES, LAKE-RESERVOIRS AND RESERVOIRS I~ TEMPERATURE, SUBARCTIC AND ARCTIC REGIONS OF THE NORTHERN HE:-iiSPHERE Annual Primary Productivi tyll gcm -2 yr-1 Water Bod y Trophic Classification Approximate Estimates Latitude Tundra Ponds (Barrow, Alaska) Waldo (Oregon) Experimental Lakes Area (Canada) Char (N .W.T. Canada) Meretta (NW.T. -Canada) Great Bear (N.W.T. Canada) Great Slave (N.W .T. Canada) Winni pe g (Manitoba, Canada) Sma llwood Res. (Labrador Plateau, Ca nada ) Watana -Dev il Canyon Reservoir (Alaska) Gabbro Lake (Labrador Plat eau, Canada) Lobst ick Lake (Lab rador Plateau , Canada) Tustumena Lake (Al a ska) LaGrande Lake-Reservoirs Quebec, Ca nada ) Southern Indian LK Reservoirs (~anitoba, Ca n ada) Koocanusa Reservo ir (Montana-British Columbia) Kamloops (British Columbia, Ca nada ) Castle (C alif o rnia) Lawrence (Michigan) L11nzar Un ter s ee (A ustria ) Sup e rior (USA-Canada) Tah oe (Nevada-California) Cresent Lake (Alaska) George (Ne w Yor k) Huron (USA -Canada) :lathead (Montana) Michigan (US A) 1 / E:>t imated Ultra-Oligotrophic Ultra-Oligotrophic Ultra-Oligotrophicl/ Ultra-Oligotrophicl/ Ultra-Oligotrophic Ultra -Oligot ro ph icl/ Ultra -O ligotrop hicl/ Ultra-Oligotrophicl/ Ult ra-Oligotrophicl/ Ult ra-Oligotr o phi cl/ Ul:ra-Oligotrophi c l / Ult ra-Oligotrophi c l / Ultra-Oligot r oph ic Ultra-Oligotrophi c Oli~otrophi.; Ultra-Oligotr o phi c Ultra -Oligotrophic Ultra-Oligotrophi c Oligotrophic Oligotrophic Oligotrophic Oligotrophic 0 l i got r o phi c l / Oligo-~esotrophic 0 1 igot: rohp ic Oligo-Mesotrophic Mesotrophic £1 Primaril y composed of phytoplankton studies Sour c e : (MODIFIED AFTER ST UART, 1983 ) ll-2 <1 <l <2 4 1 l 5-20 5-20 5-20 5-20 1-20 5-20 5-20 5-20 <30 -...60 29 32 36 41 45 50 70 <90 72 100 123 130-150 71 50 74 66 62 53 53 )4 )3 57 Table 11.1 (Cont 'd ) I·Jater Body Clear (Calfornia) Crooked (Indiana) Ontario (USA-Canada) Erie (USA-Canada) (East Basin) Belwood Reservoir (Ontario) Cayuga (New York) North Lake Reservoir (Texas) Sammamish (Washington) Esrom (Denmark-1959) Lac Leman (Switzerland-1975) Minnetonka (Minnesota) Erie (USA-Canada) (West Basin) Waco Reservoir (Texas) WashLngton (Washington-1971) Frederiksborg Slotssc(Denmark) Wintergreen (Michigan) So llercd So (Denmark) Sylvan (Indiana) Lanao (Philippines) Victoria (Africa ) Washington (Washington 1963-64 Pre Diversion of Sewage) ~endota (Wisconsin 1965-1966) Trophic Classification ~esotrophic ~esotrophic ~esotrophic Mesotrophic !iesotrophic Meso trophic ~esotrophic Mesotrophic ~esotrophic Eutrophic Eutrophic Eutrophic Eutrophic Mesotrophic Eutrophic Eutrophic Eutrophic Eutrophic Eutrophi c Eutrophic Eutrophic Eutrophi c 11-3 Annual Primary Productivit y gcm-2 y r-1 Approximate Estimat e s Lat it u de 160 42 171 :.o 180 4 4 180 42 <200 4 3 200 4 3 200 33 238 4d 260 55 300 46 300 4 6 310 ~2 310 31 354 48 376 56 369 43 522 56 570 ' .... 620 1 ) 640 0 76 6 4d 1100 -+3 o Refatively high turbidity values and consequently shallow euphotic zones; o Relatively low mean annual temperatures; o Relatively great maximum and mean depths; o Relatively short hydraulic residence times; o Relatively large total volume per unit of surface area ; o Large total volume for dilution of inundation zone leachates; o "Sediment blanket" effect for ret<:ding and mtnlmtztng leachates; o Near surface withdrawal of water and entrained plankt e r$; o Possibilities of a relativel y unstable vertical density structure and the consequent potential for a relativel y deep ;nixed :>ur face layer compared to the euphotic zone depth. Reservoir trophic status is typically determined 1n part bv the relative amounts of critical nutrients (carbon, silicon, nitrogen and phosphorus, etc.) as well as by the morphology, and hydraulic, thermal, optical, and climatological regimes, and the geographic location, etc. The most recent estimates of Stage I, rr, and III reservoir suspended sediment concentrations and turbidity indicate that the euphotic zone of both reservotrs will be substantially restricted during most, if not all, seasons. The productivit y of the project reservoirs is expected to be primarily light limited. An analagous situation of a continuously turbid, subarctic reservotr exhibiting light limited prtmary production has been observed (Hecky and Guildford 1984; Planas and Hecky 1984; Hecky 1984; Hecky et al. 1984). 425832 85llll Both project reservoirs are expected to be classified as ll-4 ultra-oligotr.ophic for their operational lifetime. Due to the expected light limitation, the standard types of emperically derived models fo r predicting reservoir trophic response from nutrient loading and n utrient concentration relationships (Vollenweider 1975; Dillon 1975; Jones and Backman 1976; and Larcen and ~ercier 1976) are not expected to be applicable for predicting the trophic status of the project reservoirs (Kerekes 1982; Walker 1982; Rast and Lee 1978; Mueller 1982; and Soballe and Bachman 1984 ). Artificial phosphorus loading of the Watana reservoir from domestic sources was investigated by Peterson and Nichols (1982). They concluded that the maximum allowable artificial loading is equivalent to the waste from 115,800 permanent residents, if oligotrophic conditions are to be maintained and if the reservoir was expected to be clear. However, their estimate ts conservative Since the effects of low light penetration have been neglected. Reduction of riverine born suspended sediments by settling within the reservoir will result tn a sediment blanket effect. Organic materia ls on the reservoir floor and side walls will eventually become coated and /o r buried by settled (mostly inorganic) particulates. The sediment blanket effect will have a retardant effect on leaching and biologtcal :;ycling oi macro and micro nutrient tons, prtmary and secondary productivity and organic detritus oxidation (Wetzel 1975, Campbell et al. 1975, Cr awf o rd and Rosenberg 1984, Wiens and Rosenberg 1984, Hecky and ~cCollough 1984). Development of a small but viable phytoplankton population composed of primarily Bacillariophyceae, Chrysophaecae, Dinofyceae and Chlorophyceae with a microplankton community of ?hotosynthetic bacteria and mostl y unicellular Cyanophyceae ts expected to be formed within the pr o ject reservoir(s). The plankton community is expected to remain at low or very low densities and to be primarily located within the wind mixed surface strata. Heterotrophic bacteria, fungi and actinomycetes are expected to dominate the hypolimnion biological communities (Grimas and Nilsson i.965; Geen 1974, Wetzel 1975, Duthie 1979, Baxter and Claude 1980, Hecky and 425832 851111 11-5 Guildford 19~4, Hecky et al. 1984, Koenings and Kyle 1982 ). Development of a limited but viable zooplankton community primaril y c o mposed of Protozoa, Rotifera, Copepoda and very low densities of Cladocera an d Insecta is expected in the project reservoirs. Cladocera typically exist at low or very low densities in natural lakes heavily influenced by glacial flour Ln subarctic lentic environments (Wetzel 1985, Grimas and Nilsson 1965, Pinel-Alloul et al. 1982, Patalis and Salki 1984, Koenings and Ky le 1982). A macrobenthic community with relatively low densities of Insecta, Oligochaeta, and Mollusca is expected to form immediately after impoundment. Macrobenthos densities will probably decrease after the first 5-10 years o f reservou agLng (Wetzel 1975, Grimas 1965, Hutchinson 1967, Grimas and Nilsson 1965, Wiens and Ro~enberg 1984, Crawford and Rosenberg 1984, Bi l yj 1984, Rosenberg et al. 1984, Hecky et al. 1984 ). The density of resident fish communities Ln the project reservoirs lS expected to be low throughout the project life time. 11.2 MIDDLE RIVER BIOLOGY AND PROJECTED TROPHIC STATUS With regard to general metabolic activi~y, the r1ver habitats are expected to present a contrasting situation to that 1n the reservoirs. The mo st important site of biological activity affecting the productivity and trophic status of the riverine habitats will be the streambed substrate and streambed interstitial spaces (Hynes 1970; Cummins 1974; Moore 19 7 1; Kawecka et al. 1978; Barton and Lock 1979; Ward and Stanford 1979; Cushing et al. 1980; Ward et al. 1982; Vannote et al. 1980; Newbold et al. 1981; ~urph y et al. 1981; Minshall et al. 1983; Conners and Naiman 1984; ScSballe and Bachmann 1984; Lloyd 1985; Peterson et al. 1985b). Biological activit y in the riverine water column is expected to be of minimal importance t o the overall stream biological productivity and trophic status. 425832 851111 11-6 Although qua!1titati v e estimates of the tr o phi c status of the S u sitna River middle reach do not exi s t, cu r sory qualitative o bservati o ns by several re sear chers have estimated the pr o ductivit y to be r e lati vely low at all trophic level s . This observation is in agreement with o b se rvati o n s ~ade on several lotic habitats having glacial stream characteristics w hi~h indicate that they appear relativel y unproductive compared to other l o ti ..: habitats (Hynes 197 0 , Steffan 1971, Ward and Stanford 1979, Ward et al. 1982, ~!ilne r 1983, Van Stappen 1984, Lloyd 1985). The complex arra y o f environmental variables which present ly appear to m1n1m1ze the middle reach biologi c al productivit y at the mi c r o bial , macroinvertebrate, and perhaps the fishe~y tr o phi c l evels inc lud e: o Relatively low mean annual temperatures; o Relativel y hi g h flow variability during the annual hyd r ologic cyc le; and associated with the high flo ws the assoc iat e d high turbulence, velocities and related d rag wh ich co ntri bute to st reambed s ub s trate ins tabi lity; o Relat i vel y hig h suspended sedimen t and bed l o ad co n centra ti o n s =or fo ur to f ive month s of each year which co ntr ibutes t o at least the following effec t s: :..25832 851 111 Re lativel y hi gh sedimentatio n of streamb ed su bstrates r es ulting 1n detrimentall y high co ncentrations of fin e particu lates 1n th e s tr eambed material and the associa t ed e mbedd e d quality of mu ch of the s treambed subst r ate; Relativ e ly la rge parti cle s1ze of the sus pended sedimen t whi c h c-:>ntr ibutes to h ig h r a t es of sedimentatio n , scour o f mic r obial epilithic communiti es on l arge st reamb ed subst r a te, a n d unstable s tr eamb ed substra t es wh ich are less t han o ptima l f o r mi c r o bial o r macr oi nvertebrat e colonization ; 11 -7 Relatively high turbidity values resulting 1n ver y li mited euphotic zones during the more potentiall y productive portion of each annual cycle when the maximal sola r irradiance occurs. Anti c ipated dtects of the project include modifications to all o f the previously listed environmental variables. However, of the previousl y listed variables which the project will affect, an altered suspended sediment reg1me 1s likely to cause two of the more profound effects wh ic h will impact the potential productivity of the microbial, macroinvertebrate, and perhaps the fisheries communities in the middle river reach. These two effects, as briefly discussed below, may have ecological interactions which are fundamentally antagonistic and offsetting to each other with regar d t o their effects on aquatic community ecology of the middle river reach. Decreased biological productivity, as yet unquantified, 1s expected t o occu r in mainstem channels with constantly turbid r1ver1ne flows. The chronic turbidity may substantially limit the penetration of incident light and the productivity and standing crops of the microbial epilithic community 1n most mainstem influenced habitat ~ during most sea so ns. At least two concepts should be considered 1n relation to the potentiall y detrimental effects of a chronically high turbidity regime: o Although the high natural pr o ductivity and stan d in g crop of 425832 851111 microbial epilithon occurr1ng 1n naturally clear sprlng and fall transition periods will likely be attenuated, the predicted With -project turbidity reg1me may reach low enough turbidity values during the early spr1ng (Ma r ch -~a y) to allow fo r adequate light penetration to so me s ha llow and stabl e substrate and st imulate a brief and l imit e d growth pulse of e pilithon. The most dominant algal genera are expected to include Spirogyra, Zygnema, Ulothrix, Hydrurus, Mic rospora, Lyngb ya, Phormidium, Anaba ena, Nostoc, Nitzschia, Go mphonema, Cocco neis, ~eridi o n, Cymbella and ll-8 Achnanthes. Such a spr1ng periphyton growth pulse may potentially be beneficial to a portion of the existing macroinvertebrate community (i.e. most likely generalist-omnivores tn the gr o up Chironomidae). o Although highly turbid conditions will substantiall y restrict light penetration, the small SlZe and large collective su rface area of the suspended particulates which cause the turbidity ma y also serve as a basic source of phosphorus and mi c ronutrient s t o any juxtapositioned microbial epilithic community. Thus, t n habitats peripheral to the mainstem where wetted areas are shallow enough to allow adequate light penetration to reach stable streambed substrate and where other environmental factors are suitable, the attached epilithon community may thrive at rates in excess of those presently occurring (especially mucous secreting, mat forming algae like cyanophyta). A somewhat analagous situation has been observed in some shallow water micr ohabitats of the chronically turbid, but very fertile waters of the Kasilof River, draining chronically turbid Tustumena Lake on the Alaskan Kenai Peninsula. Reduced scour of microbial epilithic communi ties by relativel y large particulates (si lt, san d and g ra vel) is expected to enhance the probability o f ~reater standing crops or microbial epilithic communities o n stable, wetted substrates in shallow peripheral habitats existing tn the middle reach. has also been hypothesized and o bserved o n the Kasil o f River. This A seco nd major effect of the antic ipated altered suspended sediment regtme ts the permanent storage of most particulates co arser than 10 -20 microns diameter (silt, sand, gravel, etc.) behind the dams while simultaneously f lushing and removing the same s ized parti c ulat es f rom some surricial and shallow interstitial layer s of the miadl e river st r eambed. Relativel y large flushing flows to help facilitate this removal of fi nes (simulated maxima 425832 851111 ll-9 may reach 38,000 cfs) are anticipated to be available from combined powerhouse and/or cone valve discharges within portions of several summer3 du r ing the second stage of project operations. Streambed s ubstrate disturbance during these high flow events and the attendant flushing o f fine streambed particulates from the system, without their replacement f rom upstream sources, is expected to substantially enhance the heterogeneity and volume of streambed substrate niches. Such changes should enhance the potential for greater biomass production of benthic macroinvertebrates and the smaller, immature life stages of fishes which may utilize these niches. The current state of impact assessment regarding these latter two changes resulting from the anticipated altered suspended sediment regime leads to two tentative conclusions : First: Second: the chronically high turbidity will detrimentally impact the productivity of biological communities Ln most relatively deep riverine habitats, while possibly enhancing the productivities of biological communities in relatively shallow, peripheral habitats where incident light can penetrate to wetted streambed substrate; removal of surficial fines by scour and degradation without replacement from upstream may create substantial additional habitat on and within the coarser streambed substrate in most riverine habitats. Conclusive estimates of the overall, combined impact on the middle reach trophic status from both of these expected changes are not pcesently possible to make with high confidence. It presently appears that the expected benficial impacts resulting from more extensive and heterogenous coarse substrate habitat may be negated, at least Ln part, by food limitation due to chronically high turbidity and reduction of allochthonous organic carbon inputs from upstream. 425832 851111 11-10 11.3 SUMMARY THOUGHTS REGARDING POTENTIAL PROJECT INDUCED WATER QUALITY CHANGES Changes of the natural reg1me of suspended sediments ma y potentially be o ne of the more biologically offensive water quality consequences of this project. For these and other reasons, mitigation plans are being proposed to improve and protect important aquatic habitats peripheral to mainstem river channels. Although much aquatic literature emphasizes the more negative aspects of suspended sediments and turbidity, it may also be useful to briefly examine other knowledge regarding this subject. In this vein of thought, it should be remembered that small, suspendable, inorganic particulates are historically among the oldest and most natural entities found in water and are also primary sources of essential elements needed by all forms of life, including aquatic biota. The elemental and mineralogic properties of ;mall inorganic particulates often enable them to be efficient focal point s for the concentration ot dissolved and particulate inorganic materials. Otten these "scavenging" effects help to bind, and make l es s bioloically available, otherwise potentiall y toxic ions, like heavy metal ca tion s. Tin y inorganic particulat es are also known to aid 1n ad so rbing and co ncentrating dissolved organ1c detritus, thus enhancing and facilitatin g one of the more important biol og.i.cal processe s Ol all the micr o bial catabolism and recycling of fo rmerly living biota . Without aquatic and terrestrial recycling of organic detritus, future life could not exist. The theoretical assumption that an infinite continuum of :-ITU /TSS relation- s hips exists within aquatic environments is a co ncept whi c h ma y need t o be em pirically te s ted with regard t o this project. It ma y b e empiri c all y testable and documentable that a u sef ul generalization ma y e xi s t f o r a sepa- rate and fairl y distinct lentic and lotic relationship between turbidit y and suspended sediments. 425832 851111 It a sufficiently distinct lentic relationship can be l l-ll documented as a reality, then better projections for Watana discharge turbi- dities may be estimateable. Better estimates of the potential effects of the project will obviously be a valuable tool for decision making regarding any potentially necessary mitigation. It l S worth mentioning that much evidence exists that aquatic o rganisms 1n lotic environments are often endowed with specialized attributes which promot e relatively efficient functioning 1n their particular environmental niche. Aquatic insects are often noted in biological literature for their extensive morphological and behavioral specializations which apparentl y aid their successful coloni?.atio n of many diverse aquatic habitats (Hy nes 1970; :oierritt and Cummins 1978). Dipterans 1n general, and Chironomidae 1n particular, are an extremely diverse insect group with specialized characteristics allowing them to occupy a varied range of both terrestri al and aquatic habitats. Chironomidae are able to successfully colonize an extraordinarily diverse array of both lentic and lotic aquatic habitats, among them are included relatively harsh environments including ver y co ld and turbid glacial melt water streams (Merritt and Cummins 1978; Kawecka et al. 1978; Hobbie 1980; Milner 1983). If Susit na mainstem habitats become a more harsh lot ic environment due to Project operations, the Ch i ronomi dae may be among the more likel y invertebrates to successfully colonize even the more demanding lotic environments. In addition, chironomid la rvae and adults are preferred food items for some species of juvenile Oncorhynchus . Another note lS worth considering with regard to project induced water quality considerations for the Susitna River. Salmon as a g roup, including both Salmo and Onc orh ynchus spec1es, have probably evolved for at l east 500,000 to 1,000,000 years through at least four major and several ~1nor Ice Ages 1n Europe, Asia and North America. During their s peciations and dispersions in streams and oceans between 35° anJ 75° north latitudes they have undoubtedly encountered and endured extremely varied riverine suspended sediment reg1mes including s ituations of chro ni c turbidity and high suspended sedi:nenc loading. All existing sp ecies of salmon appear to have evolved ce rtain behavioral and presumably ph y si olog ical adaptations fo r 425832 851111 11-12 selecting and surviving in lotic environments which are subject to variable suspended sediment regimes. Present Susitna River salmon stoc k s, as have their historical relatives, will adjust to project-in d uced water qualit y changes. One final note should be considered regarding potential project induced limnological changes. To the extent of our present knowledge, the potential for a mercury bioaccumulation hazard due to construction and operation of the project exists. This does not mean that a mer c ury bioaccumultion prob- lem presently exists nor does it mean that it will exist. The environment ts replete with potential hazards for all forms of biota. Awa r eness or potential environmental hazards, to the lives of humans and other biota, ts a wtse entity to cultivate. By being aware or environmental actions and using o ur capacity for forethought, many environmental hazards may be negated, rendered negligable and/or avoided. 42 5832 851111 11-13 REFERENCES Alaska Administrative Code (A.A.C) 1984. Title 18, Environmental Conservation, Chapter 70, Water Quality Standards. Last Amended 30 ~arch 1984. Abernathy A.R., and P.M. Cumbie 1977. Mercury accumulation by largemouth bass (~icropterus salmoides) in recently impounded reservoirs. Bull. Environ. contam. Taxicol. 17(55): 595-602. Acres Consulting Services Limited 1981. Reservoir clearing and preparation - environmental protection strategies, Niagara Falls, Ontario, 112 pp., plus biolography and 3 appendices. Alabaster, J.S. and R. Lloyd 1980. Water Quality Criteria for Freshwater Fish, Butterworths, London, 283 pp. Alaska Department of Fish and Game 1982. Susitna Hydro Aquatic Studies Re~ort Phase II. Basic Data Report Vol. 4. Aquatic Habitat and Instream Flow Studies. Prepared for Alaska Power Authority, Anchorage, Alaska. , 1983a. Susitna Hydro Aquatic Studies. Phase Il, Basic Data Report. -----Vol. 5, Upper Susitna River Impoundment Studies, 1982. Prepared for Alaska Power Authority, Anchorage, Alaska. , 1983b. Susitna Hydro Aquatic Studies. Phase Il, Basic Data Report. Vol. 4. Aquatic Habitat and Instream Flow Studies, 1982. Parts I and II. Prepared for Alaska Power Authority, Anchorage, Alaska. , 1984a. Susitna Hydro Aquatic Studies Report Series Adult Anadromous -----Fish Investigations: May -October 1983. Report No. l. Prepared f o r Alaska Power Authority, Anchorage, Alaska. , 1984b. Susitna Hydro Aquatic Studies. Report No. 2. Resident and -----Juvenile Anadromous Fish Investigations, May-October 1983. Prepared f or Alaska Power Authority, Anchorage, Alaska. , 1984c. Susitna Hydro Aquatic Studies. Report No. 3. Aquatic Habitat -----and Instream Investigations. Ch. 4. Water Quality Investigations: May-October 1983. Prepared for Alaska Power Authority, Anchorage, Alaska. , l985a. Draft. Susitna Hydro Aquatic Studies. Report No. 7, Part 2 . -----The Relative Abundance, Distribution, and Instream Flow Relationships of Juvenile Salmon in the Lower Susitna River. Prepared for Alaska Power Authority, Anchorage, Alaska. , 1985b. Susitna Hydro Aquatic Studies Report No. 8. Availability o f -----Invertebrate Food Sources for Rearing Juvenile Chinook Salmon in Turbid Susitna River Habitats. Prepared for Alaska Power Authority, Anchorage, Alaska. 4 25832 851111 _____ , 1985c. Susitna Hydro Aquatic Studies. Resident and Juvenile Anadromous Fish Investigations, ~ay -October 1984. Report ~o. 7, ?art 1. The migration and Growth of Juvenile Salmon in the Susitna River. Prepared for Alaska Power Authority, Anchorage, Alaska. , 1985d. Susitna Hydro Aquatic Studies. Winter Aquatic Investigati o ns, September 1983 -~ay 1984. Vol. An Evaluation of the Incubation Life-Phase of Chum Salmon in the Middle Susitna River, Alaska. Prepared for Alaska Power Authority, Anchorage, Alaska. Alaska Power Authority 1983a. Final application for license for major project. Susitna Hydroelectric Project. Before the Federal Energy Regulatory Commission, accepted by FERC 27 July, 1983. Vol. SA, Exh. E, Chapters l and 2. Alaska Power Authority. Susitna Hydroelectric Project. , 1983b. Final application for license for major project. Susitna -----Hydroelectric Project. Before the Federal Energy Regulatory Commission, accepted by FERC 27 July 1983. Vol. SB, Exh. E, Chapter 2 -Figures. Alaska Power Authority. Susitna Hydroelectric Project. , l983c. Final applica:ion for license for major project. Susitna -----Hydroelectric Project. Before the Federal Energy Regulatory Commission. Exh. F, Vol. 3, Supporting Design Report. Alaska Power Authority. Susitna Hydroelectric Project. 1 Vol. , 1983d. Final application for license for major project. Susitna -----Hydroelectric Project. Before the :ederal Energy Regulatory Commission. Exh. F, Vol. 3-Plates, Supporting Design Report. Alaska Power Authority. Susitna Hydroelctric Project. 1 Vol. , 1983e. Final application for license for major project. Susitna -----Hydroelectric Project. Before the Federal Energy Regulatory Commission Accepted by FERC 27 July 1983. Exh. e, Vol. 7, Ch. 6 Geological and soil Resources. Alska Power Authority. Susitna Hydroelectric Project . , l983f. Final application for license for major project. Susitna -----Hydroelectric Project. Before the Federal Energy Regulatory Commission, accepted by FERC 27 July 1983. Vol. 6A, Exh. E. Ch. 3. Fish, Wildlife, and Botanical Resources, Text. Alaska Power Authority. Susitna Hydroelectric Project. , l983g. Final Application for license for major project. Susitna -----Hydroelectric Project. Before the Federal Energy Regulator y Commission, accepted by FERC 27 July 1983. Vol. 68 Figures, Exh. E., Ch. 3. Fish, Wildlife and Botanical Resources. Alaska Power Authority. Susitna Hydroelectric Project . Allan, R.J. 1978. Natural c ontrols of dissolved solids in Boundary Reservoir, Saskatchewan. Canadian \o/at. Res. J. 3(3):78-96. 425832 851111 2 Allanson, B.R.· 1973. Summary : Physical limnol o gy of man-made l akes. tn: ~an-~ade Lakes: Their Problems and Environmental Effects. W.C. Ackerman, G.F. White, and E.B. Worthington, edis. Am. Geophys. Uni o n, washington, D.C. 1134 pp. Allis-Chalmers. No Date. Howell-Bunger and Ring-Jet Valves. American Public Health Association (APHA) 1980. Standard ~ethods for the Examination of Water and Waste Water . Fifteenth edition. Am. Pub. Health Ass ',c. Press, Washington, D.C. 1134 pp. Ammerman, J.W. and F. Azam 1985. Bacterial )'-nucleotidase in aquatic ecosystems : a novel mechanism of phosphrous regeneration. Science, Vo l. 227: 1338-1340. Anderson, J.E., S.R. Ekman, B. Lunden, H.C. Olsen, T. Ziegler and G. Ostrem 1970. English summary: Sediment transport studies at s~lected glacial streams in Norway. Report No. 1 /72, Vasdragsdirecttor~tet, Hydrologisk Avdeling, Oslo, Norway. 00: 110-131. Arctic Environmental Information and Data Center 1984. Susitna Hydroelectric Project Aq~atic Impact Assessment : Effects of Project-Related Changes in Temperature, Turbidity and Stream Discharge on Upper Su s itna Salmon Resources During June through September. Prepared for Alaska Power Authority, Anchorage, Alaska. , 1985. Geomorphic Change in the ~iddle Susitna River Since 1949. -----Prepared under contract to Harza-Ebasco Susitna Joi nt Venture for Alaska Power Authority, Anchorage, Alaska. Austin, R.W. 1973. Problems in measuring turbidity as a water quality parameter. Paper presented at USEPA seminar on ~ethodology for Monitoring the Marine Environment at Seattle, WA. Oct. 16 -18, 19 73. Reprinted with author's permission by ~artek Instruments , Inc. Baker, W.E. 1973. The role of humic acids from Tasmanian podzolic soils tn mineral degradation and metal mobilizat~on. Geochim. Co smochim. Acta 37: 269-281. Barnett, A.P. 1974. Hydrological Studies of Slims River, Yukon, June -A ugust 1970. Icefield Ranges Research Project: Scientific Results. Vo l. 4. Amer. Geographical Society -1974. pp. 143-150. Barton, D.R. 1980. Benthic macroinvertebrate communities of the Athabasca River near Ft. Mackay, Alberta. Hydrobiologia 74; 15 1-160. Barton, D.R. and M.A. Lock 1979. Numerical abundance and biomass of bacteria, algae, and macrobenthos of a large northern river, the Athabasca. Int. Revue Ges. Hydrobiol. 64; 3: 345-359. Brvan M.L. l974a. Sublacustrine ~orphology and Deposition, Kluane Lake, · Yukon Territory. Icefield Ranges Research Project: Scientific Results. Vol. 4. Amer. Geographical Socieity-1974. pp. 171-187. 425832 851111 3 _____ , 1974b. Sedimentation in Kluane Lake. Icefielj Ranges Research Project : Scientific Results. Vol. 4. Amer. Geographical Society-!9 74 . pp. 171-187. , 1974c. Water ~asses in Southern Kluane Lake. Icefield Ranges Re s earch -----Project : Scientific Results. Vol. 4. Amer. Geographical Society -1974. pp. 163-169. Baxter, R.~. and P. Glaude 1980. Environmental effects of dams and impoundments in Canada: experience and prospects. Can Bull. Fish. aquat. Sci. 205: 34 pp. Beck, K.C., J.H. Reuter, and E.M. Perdue 1974. Org anic and i no r ganic geochemistry of some coastal plain rivers of the southeastern United States. Geochim. Cosmochim. Acta 38 : 3410364. Becker, C.D. 1973. Food and growth parameters of juvenile chinook salmon (Oncortghyncus tshawytscha) in central Columbia River. Fishery Bulletin : Vol. 71, No. 2: 387-400. Bell, M.C. 1980 . Fisheries handboo~ of Engineering Requirements and Biological Criteria. U.S. Army Corps of Engineers, North Pacific Division, Portland, Oregon. Benes, P. and E. Steinnes 1974. In S itu dialysis for the det~rminat io n of the state of trace elements-rn natural waters. Water Research 8:947-953. Beschta, R.L. and W.L. Jackson 19 79 . The intrusi o n of fine sediments tn a stable gravel bed. J. Fish. Res. Bd . Can. 36 : 204 -2 10. Bilyj, B. 1984. Des cri ptions of two new species of Tanypodinae (Diptera : Chironomidae) from Southern Indian Lake, Ca nada. Ca n. J. F ish. Aquat . Sci. 41 (4): 659-681. Bisogni, J.J. Jr., A.W. La wrence 1975. Kinetics of mercury methylation in aerobic and anaerobic aquatic e nvir onments. J. Water Poll. Cont . Fed. 74(1): 135-152. Bisson, P.A. and R.E. Bi l by 1982. Avoidance of s uspe nd e d sediments by juvenile coho salmon. North Am. J . of Fish Mana ge me nt 4: 371-3 74. Bjurnn, T.C., ~.A. Brusven, ~.P. Molnau, J.H. Milligan, R.A. Ka mpt, E. Chacho, and C. Schaye 1977. Transport of grani t ic sedimen t in streams and its effects on insects and fish. bulletin No. 17, College of Forestry, Wildlife and Range Scie nc es, Uni v . Of Idaho, 43 pp. Bodaly, R.A., R.E. Hecky, and R.J.P. Fud ge (In Pre ss) ~ncreases in fish mercury levels in lakes flooded by the Chu r chi ll River diversion, northern Manitoba. Can. J. Fish. Aquat. Sci . 425832 851111 4 ___ , T.W.D. ·Johnson, R.J.P. Fudge and J.W. Cla y t o n 1984 , Co ll apse .:>f l a k e whitefish (Coregonus clupeaformis) f i shery in Souther n I nd i an l ak e, ~anitoba, following lake impoundment and river di version. Can. J. Fish. Aquat. Sci. 41: 692-700. , D.~. Rosenberg, M.N. Goboury , R.E . He c ky, R.W. Newbur y a nd K. Pata l is 1983. Ecological effects of hydroelectric development in northern ~anitoba, Canada : the Churchhill-Nelson River Diversion. in: "Ef fects of Pollutants at the Ecosystem Level, "SCOPE, 22 , John '.Iiley and S.:>ns, Toronto. pp. 273-310. Boyer , P.B. 1974. Gas supersaturation problems in the Co lumbia River. in : Man-Made Lakes: their Problems and Environmental Effects. W.C. Akerman , F.G. White and E.B. Worthington, ed.s. Am. Geophys. Un i on, Wash i ngt o n , D.C. pp. 701-705. Britton, L.J. K.E. Goddard and J.C. Briggs 1983 . Quality o f Rivers o f the United States, 1976 Water Year, Based on che National Stream Qualit y Accounting Network (NASQAN ). U.S. Geolog i cal Survey Open-File Report 80-594. 423 pp. Brune, G.M. 1953. Trap efficiencies of reservoirs. Trans. Amer. Geophys. Union. ~isc. Publication 970. U.S. Department of Agr i culture. Brusven, M.A. and K.V. Prather 1974. Influence of stream sediments o n distribution of macrobenthos. J. Entomol. Soc . Brit. Columbia ; pp. 25-32. Burger, C.V., D.B. Wangard, R.L. Wilmot and A.N. Palmisano 1982. Salmon investigations in the Kenai nver, Alaska, 19 79-1981. U.S.F&W; 181 pp. Burrows , W.O. 1977. Aquatic alumi n um : ch em i str y, t o xi c ol o g y , a nd environmental prevalence. Critical Reviews in Envir o nmenta l Contr o l 7 ; 167-209 . Campbell, P.G., B. Bebee, A. Caille, M.J . Demalsy, P. Demalsy , J .L. Sasserville and S.A. Visser 1975 . Pre-impoundment site preparatio n : a study of the effects of topsoil stripping on reservoir water q ua l it y . Verh. Internat. Verein. Limnol. 19 :1768-1777. Carling, P.A. 1984. Deposition of fine and coarse sand in an o pen-work gravel bed. Can. J. Fish. Aquat. Sci. 41 :236-270. Chapin, F.S. III and K. VanCleve 1978. Nitrogen and phosphorus distributi o n in an Alaskan tussock tundra ecosystem : natura l patt e rns an d i mpl i cations for development. In : Environmental Chemistry on Cy cling Processes . D.C . Adrians and I.L. Brisbain, ed.s. Washington : Energy Research and Development Agency. Chapni c k, S.D., W.S. Moore, manganese o xidation tn 1004-101 4 . 4 25832 851111 and K.H. Nealson a f reshwater lake. 5 1982. Microbiall y mediated L imnol. Oceanogr . 27 (6 ): Chen, T.F. and J.R. Davis. 1964. Disintegration of a turbulent water jet . Journal of the Hydraulics Division, American Society of C ivil Engineers. HY1. Ch ristman, R.F. and E.T. Gjessing, ed.s. 1983. Aquatic and terrest ri al humic materials. Ann Arbor Science Publishers, Ann Arbor, ~I. 538 pp. Conners, M.E. and R.J. Naiman 1984. Particulate all oc hthanous inputs: relationships with stream size in an undisturbed waters he~. Can. J. Fish Aquat. Sci. 41: 1473-1484. Cooper, A.C. 1965. The effect of transported stream sediments o n t he survival of sockeye and pink salmon eggs and alevins. [nt. Pa. Sal. Fish. Comm. Bull. 18. 71 pp. Cordone, A.J. and D.E. Kelley 1961. The influence of ino r ganic sediment on the aquatic life of streams. Calif. Fish and Game 47: 189-228. Cox, J.A., Carnahan, J. DiNunzio, J., McCoy, J., and Meister, J., 1979. Source of mercury in fish in new impoundments. Bull. Environ. Co ntam. Toxicol. 23:779-783. Cranston, R.E. and Buckley , D.E. 1972. Mercur y pathways tn a river and estuary. Enviro n. Sci. Technol. 6:274-278. Crawford, P.J. and D.M. Rosenberg 1984. Breakd o wn of conifer needle debris in a new northern reservoir, Southern Indian Lake, ~anit o ba. Can J . Fish. Aquat. Sci. 41 :649-658. Csejtey, B., W.H. Nelson, D.L. Jones, N.J. Siberling, R.M. Dean, M.S. Morris, M.A. Lamphere , J.G. Smith, and ~.L. S ilberman. 1978. Reconnaissance Geologic Map and Geo chr o n ology, Tal keet na ~ountains Quadrangle, Northern Part of Anchorage Qu adrangle, and Southwest Co rner o f Healy Quadrangle, Alaska. USGS. Open File Report 78-558-H, 60 pp . Cornett, R.J. and F.H. Rigler 1979. Hypolimnetic o xygen defi ci ts: their prediction and interpretation. Science, V ol. 205. pp. 580 -581. Cummins, K.W., 1974. Structure on function of s tr e am exosystems. Bioscience 24: 631-641. , 1979. The natural stream ec osy stem. In: ward, J .V . no J.A. Stanfo rd, ---e ds, "The Ecology of Regulated S treams~ New Yo r k, pp . 7-24. Cu shing, C.E., C.D. Mcintire, J.R. Sedell, K.W. Cummins , G.W. ~insh a ll, R.C . Peterson and R.L. Vannote. 1980. Comparative s tud y of phy si cal-chem i cal variables of streams using multivariate analysis. Ar ch. Hy dr obiol ., 89( 3): 343-352. Da ub 1e, D.D., R.H. Gra y and T.L. Page . 1980. Importance of insects and zooplankt o n i n t he diet of 0 -age chinook salmon (O nc o r hvnchus tshawvtscha ) in t he ce ntral Columbia River. ~o rthwest Scie'1ce, Vol . 54, ~o. 4, pp 253-258. 425832 8 51111 6 Davis, J.A. 1984. Complexation of trace metals by absorbed natural o rganic matter. Geochim. Cosmochim. Acta 48:679-691. Dawley, E., B. ~onk, ~.Schiewe, F. Ossiander, and W. Ebel. 1976. Salmonid bioassay of supersaturated dissolved air in water. EPA-600 /3-76-056. 49 pp. Denisova, A. I. 1977. Factors governing the biological productivity, regime, and content of biogenic and organic substances in the sequence of Dniepr reservoirs. Water Resources 5(6):885-895. Dillion, P.J. 1975. The phosphorus budget of Cameron Lake, Ontario: The importance of flushing rate to the degree of eutrophy in lakes. Limnol. Oceanogr. 19:28-39. Dott, R.H. and R.L. Batten. 1981. Evolution of the Earth. McGraw-Hill , Inc., New York, 573 pp. plus appendices and index. Duffer, W.R., and C.C. Harlin. 1971. Changes in water quality resulting from impoundment. National Water Quality Control Research Program, R.S. Kerr Water Research Center, USEPA, Ada, Oklahoma, 110 pp • • Duthie, H.C. 1979. Limnology of subarctic Canadian lakes and some effec ts of impoundment. Arctic and Alpine Research, 11(2 ):145-158. Ecological Analysts Inc. 1982. Lake Comanche Dissolved Nitrogen Stud y , Concord California. Prepared for Milo Bell. Efford, I.E. 1975. Assessment of the impact of hydro-dams. J. Fish. Res. Board Can. 32: 196-209. ::instein, H.A. 1968. Deposition of suspended particles in a gravel bed. J . Hydraulics Division, Pr o ceedings of the American Society of Civil Engineers, V. 94, p. 1197-1205. 1972. Sedimentation (Suspended Solids). in: River Ecology and ~an , -----ed's R.T. Oglesby, C.A. Carlson, and J.A. McCann., ed.s., Acad. Press , New York, Eisenreich, S.J., ~.R. Hoffman, D, Rastetter, D., E. Yost, and W.J. ~aier, 1980. Metal transport phases in the upper ~ississippi River. Adv. Chern. Ser. 189:135-176. ~lder, R.A. and G.B. Dougherty. 1952. Characteristics o f Fi x ed Dispersion Cone Valves. Transactions of the American Society of Civil Engineers. Paper No. 2567. EPA (Environmental Pr o tection Agency ). 1976. Qualit y Criteria for Water. United States Environmental Protection Ag e ncy, Washington, D.C. , Ambient Water Quality for Mercury. EPA 440-5-80-0 58, Unit e d S tate s -----Envir o nmental Protection Agency, Washington, DC 136 p. 425832 851111 7 Fahnesstock, R.K. 1974. Morphology of Slims River. Icefield Ranges Research Project: Scientific Results. Vol. 4. Amer. Geographical Society-1974. pp. 161-172. Falvey, H.T. 1980. Air-Water Flow in Hydraulic Structures. U.S. Department of the Interior, Bureau of Reclamation. Engineering ~onograph No. 41. Fan, S. 1976. The role of sediment problems in hydroelectric development. Federal Interagency Sedimentation Conference. Federal Energy Regulatory Commission. 1984. Draft Environmental Impact Statement for Susitna Hydroelectic Project. FERC No. 7114-Alaska, FERC/DEIS-0038. Washington, D.C. Fi.ckeison, D.H. and M.J. Schneider. 1976. Gas Bubble Disease: Proceeding s of Workshop held Richland, Washington, 1974. NTIS Office of Public Affairs, Energy R~search and Development Administration, 122 pp. Fimreite, N., W.N. Holswort'1, J.A. Keith, P.A. Pearce, and l.M. Gruchy, 1971. Mercury in fish and fish-eating birds near sites of industrial contamination in Canada. Can. Field. Nat. 85:211-220. Flint, R.F. and B.J. Skinner !977. Physical Geology, second edition, Joh n Wiley and Sons, New York. Fontaine, W.T. and S.M. Bartell 1983. [Editors] Dynamics of Lotic Ecosystems. Ann Arbor Science Publishers, Ann Arbor, Mi ch igan, U.S.A. Fudge, R.J.P. and R.A. Bodaly 1984. Post impoundment winter sedimentation and survival of lake white fish (Co regonus clupeaformis ) eggs tn Southern Indian Lake, Manitoba. Can. J. Fish . Aquat. Sci. 41: 701-705. Geen, G.H. 1975. Ecological consequences of the proposed ~o ran Dam on the Fraser River. J. Fish. Res. Bd. Can. 32 ( 1 ): 126-135. Gibbons, D.R. and E.O. Sale. 1973. An annotated bibliography o f the effe c ts of logging on fish of the western United States and Can ada. U.S.D.A. Forest Service General Technical Report PNW-10, Pacifi c Northwest Forest and Range Experiment Station, Portland, Oregon, 145 pp. Gibbs, R.J. 1974 Principles of studying suspended solids in water. I n: Suspended solids in Water, edited by R.J. Gibbs. An Office of ~ava l Research Symposium, Dept. of the Navy, pp.1-15. , Transport phases of transition metals in the Amazon and Yukon rtvers. -----Geol. Soc. Amer. Bull 88:829-843. Giesy, J.P. and Briese, L.A. 1977. Metals associated with organic c arbon extracted from Okefenokee Swamp water. Chern. Geol. 20:109-120. , a nd Briese, L.A . 1978. Trace metal transpo ,·t by particulat es and 0 ~·gantc ca rbon in two South Ca rolina streams. Verh. Internat. Ve r ein. Limnol. 20:1401-1417. 425832 851111 8 ___ , and Briese, L.A. 1980. Metal binding capacity of northern Eu r o pean surface waters for Cd, Cu, and Pb. Organic Geochem. 2:57-67. , Briese, L.A. and Leversee, G.J. 1978. Meta l binding capacity of selected Maine surface waters. Environ. Geol. 2 (5 ):257 -268. , Leversee, G.J., and Williams, D.R. 1977. Effects of naturally ---occurring aquatic organic fractions on cadmium toxicity to Simocephalus serrulatus (Daphnidae) and Gambusia affinis (Poeciliidae). Water Re s. 12:1013-1020. Gill, D. 1971. Damming the Mackenzie: A theoretical assessment of the long-term influence of the river impoundment on the ecology of the Mackenzie river delta. Proc. Peach-Athabasca Delta Symp. Jan. 14-15, 1971, Univ. of Alberta, Edmonton, pp. 204-234. , and A.D. Cooke, 1974. Controversies over hydroele c tric developments tn sub-arctic Canada. Polar Record 17(10 7): 109-127. Godin, J.G. 1980. Temporal aspects of juvenile pink salmon (O norhynchus gorbuscha) emergence from a simulated gravel redd. Canadian Journal of Zoology. 58(5):735-744. Colterman, H.L. 1975. Physiological Limnology : An Approach to the Physiolog y of Lake Ecosystems. Elsevier Scientific Publ. Co., Amsterdam. 48 9 pp . Grimard, Y. and H.G. Jones 1982. Trophic upsurge in new reservoirs: a mode l for total phosphorus concentrations. Can J . Fish. Aquat. Sci 39 :1473-1483. Grimas, U. 1961. The bottom fauna of natural and impounded lakes in northern S weden (Amkarvattnet and Blasjon ). Rep. No. 42 :183-23 7 , Institute of Freshwater Research, Drottingholm, Sweden. 1965 . Inlet impoundments. An attempt to preserve litt o ra l animals in regulated subarctic lakes. Rep. No 46: 22-)0. Institut e for Fresh wat er Resear c h, Drottningholm, Sweden. , 1 nd N.A. Nilsson, 1965. On the food chain in some north Swedi s h r iver reservoirs. Rep. No. 46: 31-48. Institute o f Freshwat e r Resear c h, Drottningholm, Sweden. Gr ob l e r, D.C. a nd E. Davies 1979 . The availability of sedi me n t pho spha te t o algae. Water. S .A. 5 (3): 11 4 -12 2 . Gr oo t, C . 198 2. Modificati o n o n a theme-a perspective on migratory beh !i vior of Pacific salmon. Pages 1-2 1 in E.L. Br a nn o n and E.O . Sal o , ed s . Proceedings o f the Sa lmon a nd Tro ut Migrat o ry Behavior Sym p osium, 1st, Universit y of Washingt o n, Seattle, J une 3-5 . Gunni son , D., R.L. Che n, and J .M. Brannon. 1983. Relati o nships o f materials of f l o oded soi ls and se diment s t o the water quality of reservo ir s -I . Oxyge n cons umption rat es . Wat e r Res. 1 7(11 ): 16 09-1617 . 425832 851111 9 Haag, R.W. 197'4. Nutrient limitat io ns t o plant pr o ducti o n tn tw o tund ra c ommunities. Can. J, Bot . 5 2:103-116. Ha nnan, H.H. 1979. Chemi c al modifi c ations in reser vo ir-r eg ula t e d s t r e ams . In: Ward , J.V. and J.A. Stanfo rd, eds , "The Ecol og y o f Regula te d Streams," New Yo rk, pp.75-94. Hannan, P.J. and Thompson, N.P., 1977. Uptake and release o f Hg-203 b y selected soil and sediment samples. J. Water Poll. Control. Fed. 49:842-84 7. Harvey, H.H. 1976 . Aquatic environmental quality : problems and proposa l s. J. Fish. Res. Board Can. 33: 2634-2670. Harza-Ebasco Susitna Joint Venture. 1984a. Susitna Hydroelectic Project. Reservoir and River Sedimentation Report. Prepared for Alaska Power Authority, Anchorage, AK. , l984b. Instream Ice Calibration of Computer Model. F inal report. -----Alaska Power Authorit y . Susitna Hyroelectric Projec t . Alaska Power Authority Document 11 2 2. , 1984c. Lower Susitna River Sedimentation Study : Project Effec ts o n -----Suspended Sediment Concentration. Prepared for Alaska Power Authority. 4 7 pp. plus appendices and exhibits. , 1984e. Susitna Hydroelectric Projec t Slough Geoh ydr o logy Stud i es. -----Alaska Power Authority. , l984g. Eklutna Lake temperature and ice study with six mont h s im u l a- -----tion f or Watana Reservoir. Prepared f or Al aska Power Authori ty, Anchorage , Alaska. l984f. Evaluation of alternative flow requirements. Prepared fo r -----Alaska Power Authority, Anchorage, Alaska. 55 pp. Hecky , R.E., and H.A. Ayles, 1974 . Summary of fisheries-l i mnol o g y investigations on Southern Indian Lake . Report for t he L>ke Winni pe g, Churchill and Nelson Rivers Stud y Board, Fisheries and Marine S erv i~e , Environment Canada, Winnipeg, Manitoba. 26 pp. , 1984. Thermal and optical c haracteristics of So uthern I ndian Lake -----before, during and after impoundment and Churchi l l Rive r di versi o n. Can. J. Fish. Aquat. Sci. 4 1 :5 79-590. , and S.J. Gildford. 1984. Primary productity of Southern Indian Lake -----before, during and after impoundment. Can. J. Fish. Aquat. Sci. 4 1 :591-604. , and G.K . Mc Cullough. 19 84. Effects o f impoundment and diversi o n the sediment budget and ~earsh o re s edimentation of Southern Indian La ke Can. J . F ish Aqua t . S c i . 4 l : 56 7-57 8. 425 832 851111 10 ___ , R.W. Newbury, R.A. Bodaly, K. Patalas and D.M. Rosenburg. 1985 Environmental impact prediction and assessment : the Southern Indian Lake experie n ce. Can. J. Fish. Aquat. Sci. 41:720-732. Hobbie, J.E. 1980. Editor : Limnology of Tundra P o nds. US/rBP Synthests Series 13, Dowded, Hutchinson and Ross, Inc., Strousberg, Pennsylvan ia. 514 pp. Huang, W.H. and Keller, W.O. 1970. Dissolution of rock-forming silicate minerals in organic acids: simulated first-stage weathering of fresh minerals surfaces. The Amer. Mineral. 55 :2076-2095. Huntsman, A.G. 1948. Fertility and fertilization of streams. J. Fish . Res. Bd. Can. 7(5), pp. 248-253. Hutchinson, G.E. 1975. A Treatise on Limnology. Vol. 1: Geog raph y , Physics and Chemistry. John Wiley, New York. 1015 pp. , 1967. A Treatise on Limnology. Vol. IL Intr od ucti o n t o Lake Biology and the Linmoplankton. J. Wiley and Sons, New York, 1115 pp. 1973. Eutrophication. Amer. Sci. 61(3):269-279. Hutchinson, T.C ., A. Fedore nko, J. Fitchko, A. Kufa, J. Va n Loon, and J. Lichwa, 1975 . Movement and compartmentatio n of ni c kel and co pper tn an aquatic ecosystem. In: Hemphill, D.O. [Editor], Trace Substances in Environmental Health -IX. A Symposium. Univ. ~issouri Pr e ss, Co l umbia, MO. pp. 89-105. Hynes, H.B.N. 1970. The Ecology of Running Water s . Univ. of Toronto Pr ess . Totonto. 555 pp. , 1973. The effects of sediment on th e bi o ta in runnin g wat e r. pp. ---652-663, In: Fluvial Processes and Sedimentation. Pr oc . Hyd r ology Symp., Edmonton, Alberta, May 8-9 , 19 73 . Pr e par ed fo r the Sub commit t e e on Hydrology by the Inland Waters Directorate Canada, 759 pp. lmberger, J ., J, Patterson , B. Hebbe rt, and I. Loh. 1978. Dynami cs of r ese rvoirs of medium size. Jour. Hydraulic De v., Proc. Ameri ca n Soc;e t y of Civil Engineers. 104 (No. H45): 725-743. , and J.C. Patterson 1980. A dynamic r ese rvoir si mul ation model - ---DYRES M: 5 . Proc. Symposium o n Predi c tive Ab i lit y of su r f ace Wate r Fl o w and Transport Models. Berkel y , Ca lif. International Joint Co mmission. 1977. New and Revi sed S pecifi c Wat e r Qua lit 1 Objective s. Vol. II. Great Lakes Wat e r Quality Bo ard Report. Iwamoto, R.N., E.O. Salo., M.A. Madej a nd R.L. Mc Co mas 19 78 . Sediment a nd wat e r quality : A review o f t h e lit e ratur e in c lud ing a s ugges t e d approach fo r wat er quality c riter ia wi th s ummary of wo rk s h op an d c o n c l usio n s a nd r eco m~~ndati o ns. EP~ 9 10 /9-78-048; 2 5 2 pp. 425832 8 5 1111 11 Jackson, K.S., Jonasson, I.R. and Skippen, G.B. 1978. The nature of metals- sediment -water interaction in freshwater bodies, with e mpha~i s o n the role of organic matter. Earth-Sci. Rev. 14:97-146. Jackson, T.A. and R.E. Hecky. 1980. Depression of primary productivity b y humic matter in lake and reservoir waters of the boreal forest zone. Can. Fish. Aquae. Sci.37:2300-2317. Jernelov, A. and Lann, H. 1973. Studies in Sweden on feasibility of some Sci. Methods for restoration of mercury-contaminated bodies of water. Environ. Sci. Techno!. 7(8): 712-718. Johasson, l.R., and Boyle, R.W. 1972. Geochemistry of mercury .1nd o rig ins natural contamination of the environment. Can. Mining & Mettalurg. Bu ll January, 1972. pp. 1-8. Johnson, G. 1967. The Effect of Entrained Air on the Scouring Capacity of Water Jets. Proceedings of the 12th Congress of the lnternatiJnal Association for Hydraulic Research, Fort Collins, Co. Vol. 3. Johnson, P.L. 1975. Prediction of Dissolved Gas at Hydrauli c Structures. U.S. Department of the Interior, Bureau of Reclamation. Report No. Gr-8-75. Jones, B.F., Kennedy, V.C., and Zellweger, G.W. 1974. Comparison of observation and calculated concentrations of dissolved Al and Fe in stream water. Water Resources Research 10 (4):79 1-793 . Jones, J.R. and R.W. Bachman 1976. Prediction of phosphorus and chlorophyl l levels in lakes. J. Wat. Poll. Control Fed. 48 (9 ): 2176-2186. _____ , and R.W. Bachman. 1978. Phosphorus removal by sedimentation some Iowa reservoirs. Ver. Internat. Verei.n Limnol., 20, pp. 1576-1580. Kawecka, B., A. Kownacki and M. Kownacka 1978. Food relati ons between a l gae and bottom fauna communities in glacial streams. Verh. Internat. Verein. Limnol. 20: 1527-1530. Kerekes, J.J. 1982. The application of phosphorus load-trophic response relationships to reservoirs. Ca n. Wat. Res. J., Vol. 7, No. 1, pp. 349-354. Kjeldson, 0. and G. Ostrem 19 75 . English Summary : Sediment transport in Norwegian glacier streams. Report No. 3-77. Norges vassdrags -og elektri.sitetsvesen, Hydrologisk avdeling, pp. 44-47. Keup, L.E., McKee, G. D., Raabe, E.W., and Warner, R.W. 1970 . Water quality effects of lea c hing f rom submerged soils. J. Amer. Water Wrks. Assoc. 62 (6):391-396. 425832 851111 12 Klein, D.H., Calabrese, A., D'Itri, F.M., McKim, J.M., Phillips, G .R., Reish, D.J., and Willford, W.A. 1979. Mercury. In Thursto n, R.V., Russo, R.C., Fettt::rolf, C.M., Edsal, T.A., and Barber, Y.M . [Ed ]. A Review of the E.P.A. Red Book: Quality Criteria for water. Ameri c an Fisheries Society, Beth esda, MD. Koenings, J. 1983. ADF&G FRED Division. Personna! communication. Koenings, J.P. 1984 and 1985. Unpublished data and per sonal communications, F.R.E.D. Division, ADF&G, Soldotna, Alaska . , and G.B. Kyle 1982. Limnology and fisheries investigation Cresent -----Lake (1979 -1982). Alaska Dept. of Fish and Game, Division of risheries Rehabilitation , Enhancement and Development (FRED). Soldotna, Alaska, 11 o Pr. Kopp, J.F. and R.C. Kroner, 1967. Trace Metals in Waters of the United States. U.S. Dept. Interior, Federal Water Pollution Control Administration Cincinnati, Ohio. Kownacka, M. and A. Kownacki 1972. Vertical distribution of zoocenoses in the streams of the Tatra, Caucasus and Balkans Mts . Verh. Internati. Verein. Limnol. 18: 742-750. Kubanis, S.B. 1982. Revegetation techniques in arctic and subarcti c environments. Office of the Federal Inspector, Alaska Natural Ga s Transportation System, 40 pp. Kucera, E. 1983. Mink and otter as indicators of mercury tn Manit o ba wat e rs. Can. J. Zoot. 61 : 2250-2256. Larcen, D.P. and H.T. Mercier 1976. Phosphorus retention c apa c ity of lakes. J. Fish • Res • Bd . Can • 33 : 1 7 4 2-1 7 50. Laughlin, W.M. 1973. Fertilizers. P. 24-36. In: Un iver sity o f Ala ska (d ) Revegetation Workshp. Notes. Fairbanks : Univ. of Alaska coo perative Extensions Service. 239 pp. Lagler, K.F., J.E. Bardach, and R.R. Miller 1962. Ichthyol og y. John Wi.ley & Sons,. New York, 545 pp. Laxen, D.P.H., W. Davidson, and C . Woof, 1984. Manganese chemistry Ln rtvers and streams. Geochim. Cosmochim. Acta. 48:2107-2111. Lean, D.R.S. 197'3. Phosphorus dynamics in lake water. Science 1979: 678 -680. l973a. Movements of phosphorus between its biologi ca lly important forms in lake water. J . Fish. Res. Db. Can. 30: 1525-1536. and F.H. Rigler. 1974. A test of the hypo thesis that abiotic phosphate complexing influences ph c.s phorus kinetics in epilimnetic lake wat e r. Limnol. Oceanogr . 19 (5): 784-788. 425832 851111 13 Lee, G. F., R.A. Jones and W. Rast. 1980. Availabi li t y of ph o sph o r us to phytoplankton and its implications for phosph o rus managem~nt strategies. IN: Loehr, R.C., C.S. ~artin and W. Rast (Ed.). Phosphorus :1anagement Strategies for Lakes. Ann Arbor Science Publ., Inc . 490 pp. Lehumkuhl, D.M. 1979. Environmental disturbance and life histories: principles and examples. J. Fish. Res. board Can. 37:329-334. Leopold, L.B., M.G. Wolman and J.P. Mill e r 1964. Fluvial Process In Geomorphology. Feeman, San Francisco, Calif. 55 2 p. Lindstrom, T. 1973. Life in a lake reservoi r : fewer options, d ecreased production. AMBIO, pp. 145-15 3. Livingston, D.A. 1963. Alaska , Yukon, Northwest T~rritories and G r ee nland. In: Frey, D.G., ed. "Limnology in North America", Univ. of Wise. Press , Madison, pp. 559-574. Lloyd, D.S. 1985. Turbidity In Freshwater Habitats o f Alaska : A Review of Pulblished and Unpublished Literature Relative to the use o f Turbidit y as a Water Quality Standard. Report No. 85-l, Alaska Department o f Fish and Game, Habitat Division, Juneau, Alaska, 101 pp. Lockwood, R.A. and K.Y. Chen, 1973. Absorption o f ~g (II) b y Hydrous Manganese Oxides. Environ. Sci. Technol. 7(11):1028-1034. Lowe, R.L. 1979. Phytobenthic ecology and regulat e d streams. In : Ward, J .V . and J.A. Stanford, eds, "The Ecology o f Regulated Stream-;:-", New Yo rk , pp.25-34. Mathis, B.J . and Cummings, T.F. 1973 . Se lecte d metals in sediments, wa t e r , and biota in the Illinoi s River. J. Water Po l l. Contr. Fe d. 45 :1573-1583. :1cClelland, W.T. and M.A. Brusven 1980. Effec ts of sedimen t ati o n on th~ behavior and distribution of riffl e i nsec ts in a laborat o r y stream . Aquatic Insects Vol. 2(No. 3); pp. 161 -169. ~cKendrick, J.D. 19 78. Revegetati o n of disturbed sand dunes nea r No r thwa y, Alaska. First Year Pro gress Report to Northwest Alaskan Pipeline Company. Palmer, Alaska. 69 pp. :1cNeely, R.N., Neimanis , V.P. an d Dwyer, L. 1979. Water Quality S o ur cebook , a Guide t o Water Quality Parameters. Environment Canada. Ottawa, Ca nada. 89 pp. :1ei.ster, J.F., J . DiNunzi o and T.A. Cox 1979. So ur ce and level of me r cu r y tn a new imp o undment. J . Amer . Water Wrks. As soc. 1979 : 574 -576 . :-ferri.tt, R.W . a nd K.W. Cummins 1978. A.n Introduction t o the Aquatic Insects of ~orth Am e ri ca . Kendail/Hunt Publishing Co., Dubque, Iowa. 441 pp. 42 583 2 8511 11 14 Milner, A.M. (983. The ecology of post-glacial streams in Glacier Bay National Park, South-Eastern Alaska, Ph. D. Dissertation, Univ . .:>f London, London, England, 239 pp. ~ilhous, R.T. 1982. Effect of sediment transport and flow regulati on o f the ecology of gravel-bed rivers. in: Gravel-Bed Rivers: Fluvial Pr ocesses, Engineering and Management". Hey, R.D., F.C. Bathurst, and C.R . Tho rne, Edis. John Wiley & Sons, New York, pp. 819-842. Morrow, J.E. 1980. The Freshwater Fishes of Alaska. Anchorage 248 pp. Minshall, G.W. 1978. Autotrophy in stream ecosystems. Biosctence 28; No. 12: pp. 767-771. , R.C. Peterson, K.W. Cummins, T.L. Bott, J.R. Sedell, C.E . Cushing and -----R.L. Vannote. 1983. Interbiome ccmpartson of stream ~cosystem dynamics. Ecol. mono. 53( 1): 1-25. Moore, J.W. 1977. Ecology of algae tn a s ubarcti c stream. Can J. Bot.55: 1838-1847. Mosley, M.P. 1982. Analysis of the effect of changing discharge on cha nnel morphology and instream uses in a braided river, Ohau River, New Zealand. Water Resources Research. Vol. 18, No. 4, pp. 800-812. Moore, J .W., and Ramamoorthy, S. 1984. Heavy Metals in Natural Waters : Applied Monitoring and Impact assessment. Springer-Verlag, New Yo rk. Morisawa, M. 1968. Streams: Their Dynamics and Morphology. McGraw-Hill, New York. Mu lle r, O.K. 1982. "'ass balance model estimation of phosphorus co ncentrations in reservoirs. Water Resource Bull. 18(3 ): 377-382. Mu l ler, K. 1974. Stream drift as a chronobiological phenomenon in running water ecosystems. Ann. Rev. Ecol. Systematics. Vol. 5; pp. 309-323. Murphy, M.L., C.P. Hawkins and S.H •. -\nderson. 1981. Effects of canopy modification a~d a~c umulated sediment o n s tream c ommunities. Trans. Am Fish. Soc. 110 :4 6 9 -478. Naiman, R .J. 1982. Characteristics of sed im ent a nd o r gan t c cargon e xport from pristine boreal f o rest wat e rsheds. Can. J . Fish . Aquat. Sci . 39 : 1699-1718. 1983a. The influence of stream stze o n the food quality of section, Ca n. J. Zoo t. 61: 1995-20 10. 1983 b. The annual pattern and s patial distribution of aq uati c o x yg e n metabolism in boreal forest boreal forest watersh eds . Eco l og i cal Mo no graphs 53 (1): pp. 73-94. 425832 851111 15 National Academy of Sciences 1973. Water Quality Criteria -1972, Environmental Studies Board, National Academy of Engineering, Wash. D.C., 594 pp. National Oceanic and Atmospheric Administration 1982. Dail y flow statistics of Alaskan streams. D.L. Chapman Alaskan River Forecast Center, National Water Service, NOAA Tech. ~emorandum NWS AR-35, Anchorage, AK. Netboy, A. 1974. The Salmon : Their Fight for S~rvival. Houghton Mifflin Co, Boston, 595 pp. , 1980. Salmon: World's Most Harassed Fish. Winchester Press, Tulsa -----Oklahoma, 301 pp. Newbold, J.D., J.W. Elwood, R.V. O'Neil and W. Van Winkle. 1981. Measuring nutrient spiralling tn streams. Can. J. Fish and Aquat. Sci. 38 :860-863 Newbury, R.W. and G.K. McCullough 1984. Shoreline erosion and restabili- zation in the Southern Indian Lake reservoir. Can. J. Fish Aquat. Sci. 41:558-566. Nilsson, B. 1976. The influence of man's activities tn rtvers on sediment trans;:>Ort. Nordic Hydrology, 7, pp. 145-160. Nilsson, Nils-Arvid. 1964. Effects of impoundment on the feeding habits o f brown trout and char in Lake Ransaren (Swedish Lappland ). Verh. Internat. Verein. Limnol., XV: 444-452. Noggle, C.C. 1978. Behavioral, Physiological, and lethal effe c ts of suspended sediment on juvenile salmonids. Master of Sci~nce Thesis, Univ. of Wash;, 87 pp. O'Conner, D.J. and S.W. Wielson 1981. Environmental survey o f methylmercur y levels in wild mink (Mustela vison) and otter (Lutra canadensis) fr om north eastern United States and experimental pathology of methylmercurialism in the otter. in: Worldwide Furbearer Conference, J.A. Chapman and D. Pursley, Edia. Vol. Ill. Worldwide Furbearer Conference Inc., pp. 1728-1745. Ostrem G. 1975 Sediment transport in glacial meltwater streams. In : Glaciofluvial on Glaciolacstrine Sedimentation. A.V. Jopling and B.C. McDonald, [ecl..s.] Special Publication No. 23, Soci~ty of Economic Pal~ontologists and Mineralogists, Tulsa, Oklahoma. pp. 55-63. , T. Ziegler, S.R. Ekm a n, H.C. Olsen, J.E. Anderson, B. Lunden 1970. -----English Summary: Sediment transport studies at selected glaci~r streams in Norwa y . Report No. 12. Stockholm Universit y . , T. Ziegl~r, S.R. E~man 1969. English S ummary. Sediment transpo rt -----s tudi e s at sel~cted glaci~r s treams in Norway. Report 9, Stoc k h o lm University, St o ckholm, Sweden, pp. 55-63. 425832 851111 16 Ostrofsky, M.L., and H.C. Duthie. 1975 . Primary productivity, phyt o p lankt ,)n and limiting nutrient factors in Labrador Lakes. Int . Rev. Ges. Hydrobiol. 60 (3 ):245-158. , and H.C. Duthie. 1978. V. ~anmade Lakes: An appr o ach to mo de lling productivity in reservoirs. Verh. Internat. Verein. Limnol. 20 : 1562-1567. , and H.C . ~~thie. 1980. Trophic upsurge and the relationships between phytoplankton biomass and productivity in Smallwood Reservo i r , Canada. Can J. Bot. 58:1174-1180. Ott Water Engineers, Inc. 1981. Bradley Lake Water Qualit y Report prepar ed for U.S. Army Corp. of Engineers, Alaska District, Anchorage, AK. September 1981. Paerl, H.W. and D.R.S. Lean. 1976. Visual observation of phosphorus movemen t between algae, bacteria, and abiotic particles in lake wat~rs. J. Fish. Res. Bd. Can. 33: 2805-2813. Patalas, K. and A . Salki. 1984. Effects of impoundment and diversion on the crustacean plankton of Southern Indian Lake. Can. J. Fish. Aquat. Sc i. 41:631-637. Patterson, J., J. Imberger , B. Hebbert, and I. Loh 1977. A simulation model for reservoirs of medium size. Report No. EFM-3. Peratrovich, Nottingham and Drage, Inc. and I.P. Hutchins o n 198 2 . S us itna reservoirs sedimentation and water clarity stud y . Prepared for Acres American, Inc Anchorage , Ak. 35 pp. Pe:rdue, E.M., K.C. Beck, and J.H. Reuter 19 76 . Or g ani c compl exels of i r o n and aluminum in natural waters. Nature 260: 418-420. Peterson, and Associates, and R&M Consultants, Inc. 1982 . water quality e ffects resulting from impoundment of the Susitna River. Prepared for Acres American, Inc. and the Alaka Power Authority. 4 3 pp. 1985a. Draft. Alaska Particulates Criteria Review. Prepared for ADEC, Juneau, AK., 130 pp . plus appendices A-D. , 1982. Water Qu ,...lit y Interpretation 1981 , Pr e pared fo r Ac re s Am e r i c an Incorporated under contract to the Alaska Power Authority. Anchorage, Alaska. Peterson, B.J., J.E. Hobbie, A.E. Hershey, M.A. Loc k, T.E. Ford, J.R. Vestal, V.L. McKinley M.A.J. Huller, M.C. Miller, R.M. Ventullo, G.S. Volk 1985b. Transf o rmation of a tundra river from heterotroph y to autotrophy by addition of phosphorus Science, Vel. 22 9, pp, 1383-1386. Pinell-Alloul, B., E . ~agmin, G. Godin-Blumer and P. Ro s s. 1982. Zoo pla nkt o n population dynamics during and after impou ndmen t in a s mall reser vo Lr (James Ba y , Quebec). Ca n. Wat. Res. J. 7 (1): 168-1 88 . 42 5832 851111 1 7 Phillips, G.R., Lenhart, T.E., and Gregory, R.W. 1980. Relation bet we en trophic position and mercury accumulation among fi s hes from the Tounge River Reservoir, Montana. Environ. Res. 22:73-80. Planas , D. and R.E. Hecky 1984. Comparison of phosphorus turnovei·times 1n northern Manitoba reservoirs with lakes of the Experimental Lakes Area. Can. J. F:.sh. Aquat. Sci. 41: 605-612. Pott, D.B., Alberts, J.J. and Elzerman, A.W. 1985. The inf luenc e of pH on the binding c ~pacity and conditional stability co nstants of aluminum and naturally occurring organic matter. Chemical Geology 48. (In !'ress ) Potter, L., Kidd, D. and Strandiford, D. 197 5 . Mercury levels 1n Lake Powell. bioamplification of mercur y in a man-made desert reservo 1r. Environ. Sci. Technol. 9(1):41-46. Prescott, G.W. 1962. Algae of the Great Lakes. Wm. C. Br own Co., Dubuque. 9 77 pp. , 1970. The Freshwater Algae. Wm . C. Brown Co., Dubuque. 348 pp. R&M Consultants, Inc. 198la. Susitna Hydroeclectric Pro jec t, water Qualit y Annual Report 1981. Alaska Power Authority, Anchorage, Ak. Prepared (o r Acres American , Inc. , 1982b. Water Quality Annual Report, 1982. Alaska Power Auth o r ity, Anchorage, Ak. Prepared for Acres American, Inc. , 1982c. Reservoir sedimentation. Prepared for Acres American, Inc ., -----Anchorage, Ak. 41 pp. , l982d. Glacial lake studies. Prepared fo r Acres American, Inc. -----Anchorage, Alaska 198 pp. , l982e. Placer mining wastewater settling pond demonstration pr o ject. -----Prepared for the State of Alaska, Department of Environmental co n se rvation. 60 pp. with additional appendices. , 1982f. Susitna Hydroelectric Proje c t. River Morpho logy Repo rt. Prepared for Acres American, Inc. 1 Vol. , 1984a. Susitna Hydroelectric Project. Susitna River lee Study Prepared under contract to Harza-Ebasco Susit na Joint Venture for the Alaska Power Authority, Anchorage, AK 1 Vol. , 1984b. Draft-Suspenr ed sediment and turbidity sett ling co l umn -----study. 74 pp. , Woodward-Clyde Consultants Inc., and Harza-Ebasc o Susitna Joint -----Venture. 1985. Susi.tna Hydroel ectric Pro ject. Instream Flo~o~ Rela ::ion Shi ps Report Seri es. Physical Processes of ~~e ~iddle Susitna Ri v ~r . Technical Repor t ~o. 2. Prepared under co ntract ~o Harza -Ebasco Sus i tna Joint Venture for Alaska Power Authority, Anchorage, Alas ka. 425832 851111 18 Stumm, W., and' Morgan, J.J., 1981. Aquatic Chemistry, 2nd Edition. John Wiley and Sons, New York, 780 pp. Sylvester, R.O. and Seabloom, R.W. 1965. Influence of site c haracterist ic s on quality of im~ounded water. J. Amer. Water Wrks. Assoc. 61( 12): 1528-1546. Tessier, A., Campbell, P.G.C. and Bisson, M. 1980. Trace metal speciation tn the Yamaska and St. Francois Rivers (Quebec). Can. J. Earth Sci. 17:90-105. upstream and downstream of a mainstream impoundment. J. Fish. Res. Board Can. 28:45-46. Therien, N., G. Spiller and B. Coupal. 1982. Simulation de la decomposi.ti o n la matiere vegetate et des sols inondes dams les reservoirs de la region la Baie de James Canadian Water Resources Journal, Vol. 7, No. 1' pp. 375-396. Todd, O.K. 1970. The Water Encyclopedia. Water Information Center, New York, Tri~ka, F.J., F.R. Sedell, K. Cromack Jr., S.V. Gregory, and F.M. McCorison. 1984 Mitrogen budget for a small coniferous forest stream. Ecological Monographs 54(1): pp. 119-140. U.S.G.S. 1980 Water Resources Data, Alaska. Data Report AK-80-1. , 1981. Water Resources Data, Alaska , 1982. Water Resources Data, Alaska 1983. Water Resources Data, Alaska. Data Report AK-83-l. U.S. Geological Survey. 1983. Sediment Discharge for the Susitna River Basin Alaska, 1981-1982. Prepared for the Alaska Power Authority, Anchorage, AK Van theuwenhuyse, E.E. 1983. the effects of placer mining on the primary productivity of interior Alaska streams. M.S. thesis, Univ. of Alaska, Fairbanks, Alaska, 120 pp. , and E.W. Trihey and Associates. 1984. Technical Memorandum. -----Preliminary analysis of the relationships between turbidity and light penetration in the Susitna River, Alaska. Prepared for Harza-Ebasc o Susitna Joint Venture for Alaska Power Authori =y, Anchorage, Alaska. Van Stappen, J.F. 1984. A comparison of benthic invertebrate communities three habitats of the Hoh River Valley, Olympic national Park , Washington M.A. Thesis, Univ. o f Wisconsin, Stevens Point, Wisc o nsin. 63 pp. Vollenweider, R.A. and J. Kerekes. 1980. The lo ad i.ng c onc e pt a s bas i s f. c ontrolling eutrophication . Philosophy and preliminar y results o f the I Programm on eutrophication. Prog. Wat. Te ch., Vo l. 12 , Norway, LAWPR /Pergamon Press Ltd. 518 pp. 425832 851111 2 2 Vannote, R.L., G.W. Minshall, K.W. Cummins, J.R. Sedell and C.E. Cushing. 1980. The river continuum concept. Can. J. Fish and Aqat. Sci. 37:130-137. Walker, W.W. 1982. An empirical analysis of phophorus, nitrogen .. nd turbidity effects on reservoir chlorophyll-A levels. Canadian Water Resources Journal, Vol. y, No. 1, 1982. Wangaard, D.B., and C.V. Burger. 1983. Effects of various water temperatur es regimes on the egg and alevin incubation of Susitna River chum and sockeye salmon. Final Report. National Fishery Research Center, U.S. Fish and Wildlife Service, Anchorage, Alaska 43 pp. Ward, G.M., K.W. Cummins, S.V. Gregory , R.W. Speaker, T.L. Dudley, A.K. Ward. 1982. Habitat and Food resources of invertebrate communities tn South Fork Hoh river, Olympic National Park. p. 9-14, In Ecologi c al research in-national parks of the Pacific Northwest: Compiled from proceedings of the second conference on scientific research in the national parks (Nov. 1979, San Francisco, Calif. Oregon State Univ. for Res. Lab. Pub. Wetzel, R.G. 1975. Limnology. W.B. Saunders, Co., Philadelphia, 743 pp. Whalen, S.C. and J.C. Cornwell 1985. Nitrogen, phosphorus , and organic carbon cycling in an arctic la l~e . Can. J. Fi s h. Aquat. Sci. 42 8 797-808. Wiens A.P. and D.M. Rosenberg 1984. Effect of diversion on profundal macrobenthos of Southern Can. J. Fish. Aquat. Sci. 41 :638-648. impoundment and river Indian Lake, ~anitoba. Wildung, R.E. and R.L. Schmidt 1973. Phosph o rus release from lake ,;ediments. EPA-R3-73-024. 185 pp. Wilber, C.G. 1983 . Turbidity In the Aquatic Environment. Charles C . Thomas, Springfield, Illinois, U.S.A. 133 pp. Williams, W.O. 1973. Man-made lakes and changing limno logica l ~nvironment tn Australia. in: Man-Made Lakes : Their Problems and Environmental Effects. W.C. Ackerman, G.F. White and E.B. Worthington, ed;s. Am. Geophs. Union, Washington, D.C. Wright, D.R. and R.D. Hamilton, 1982. Release of methylmer c ury from sediments: effects of mercury concentration, low tem perat~ce a nd nutrient addition . Can. J. Fish. Aquat. Sci. 39:1459-1466. Welch, P.S. 1952. Limnology. McGraw-Hill book Co., New York. 538 pp. Wunderlich, W.O. 1967. The mechanics of stratified flow in reservoirs. in: "Reservoir Fishery Resources Symposium", Am. Fish. Soc., Washington, D.C. 425832 851111 23 , 1971. The dynamics of density-stratified reservoirs. in: "Reservoir ---Fisheries and Limnology", G.E. Hall, ed. Spec. Publ. No. 8, Am. Fish. Society, Washington, D.C. , and R.A. Elder 1973. Mechanics of flow through man-made lake s . In: ---Man-Made Lakes : Their Problems and Environmental Effects, W.C. Ackerman, G.F . White and E.B. Worthington, ed.s Am. Geophs. Union, Washington, D.C. 425832 851111 24