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HomeMy WebLinkAboutSuWa Yenta to talkeetna river 1985||iGEEELEARUSTISUSITNA HYDRCELECTRIC PROJECT FEDERAL ENERGY REGULATORY COMMISSION PROJECT No.7114 HtIh3.3799000444562INPREPARED BY =U rs OUaaEWTG@A R&EM SONSULTANTS,INC.:; ENGINSSRS GEOLOGISTS SLaNNERS SURVEYOSS E.WOODY TRIHEY &ASSOCIATES UNDER CONTRACT TO NAIR Z/Ac[S VAS COSUSITNAJOINTVENTURE (ESPONSE. EAST ALASKA POWER AU?OR C O MAINSTEBE eatenyyesoowhettnth . BebeHORAUE.ELAS Esone®SEPT.'OFFish&GAME REGION IlHABITATDIVISION TY F AQUATIC HASITAT SUR M DISCHARGE NA TO TALKEETNA REACH Faen a] L._REPORT, JUNE 1925. DOCUMENT No.2774. Lib ARLIS Alaska Resourcesrary&Informat Anct 1on ServicesOrage,Alaska SUSITNA HYDROELECTRIC PROJECT RESPONSE OF AQUATIC HABITAT SURFACE AREAS TO MAINSTEM DISCHARGE IN THE YENTNA TO TALKEETNA REACH OF THE SUSITNA RIVER Prepared by R&M Consultants,Inc. William S.Ashton and E.Woody Trihey and Associates Sharon A.Klinger-Kingsley Under Contract To Harza Ebasco Susitna Joint Venture Prepared for Alaska Power Authority Final Report June 1985 pocument Wo.2044 Susitna File No.4.2.2.1 NED Hab as Fut No.2+ R23/1 2 TABLE OF CONTENTS List of Tables List of Figures Acknowledgment 1.0 2.0 3.0 4.0 INTRODUCTION SEGMENT IDENTIFICATION AND WETTED SURFACE AREA DETERMINATION 2.1 Lower River Segments 2.2 Channel and Island Classifications 2.3 Photography 2.4 Results 2.5 Discussion HABITAT DELINEATION AND SURFACE AREA MEASUREMENTS FOR SELECTED STUDY AREAS 3.1 Study Sites 3.2 Habitat Type Designations 3.3 Methods 3.3.1 Field Methods 3.3.2 Office Procedure 3.4 Results 3.4.1 General 3.4.2 Study Site 3.5 Discussion MORPHOLOGIC RESPONSE OF SIDE CHANNEL COMPLEXES 4.1 General 4.2 Methods 4.3 Site Specific Descriptions 4.4 Results and Discussion ownNNR23/13 TABLE OF CONTENTS 5.0 COMBINED EVALUATION OF LOWER RIVER SIDE CHANNEL COMPLEXES 5.1 General 5.2 Channel Hydraulic Parameters 5.3 Aerial Photography 5.4 Summary 6.0 REFERENCES EXHIBIT A EXHIBIT B Aerial Photography Showing Mainstem and Side Channel Classifications of the Lower Susitna River Aerial Photography for Selected Represent- ative Areas Showing Habitat Types at Selected Mainstem Discharges Page 36 36 36 37 38 38 33755000444562R23/1 4 - Table Number 2.1 2.2 3.1 3.2 3.3 LIST OF TABLES Description Date and Discharge at Which Aerial Photography Was Obtained Wetted Surface Area at Selected Mainstem Discharges in the Yentna to Talkeetna Reach of the Susitna River Representative Areas for the Lower Susitna River Dates and Susitna River Discharges (as Measured at Sunshine)at Which Aerial Photography was Obtained and Helicopter Mapping Flights Were Flown. Wetted Surface Areas and Percent of Total Wetted Surface Area by Habitat Type at Five Mainstem Discharges for Selected Representative Areas. Page 10 13 16 R23/1 5 Figure Number LIST OF FIGURES Description Study Site Location Map,Lower Susitna River. Surface Area Responses to Mainstem Discharge in the Lower Susitna River:Mainstem and Segment |Side Channel Complexes. Surface Area Responses to Mainstem Discharge in the Lower Susitna River:Segment II Side Channel Complexes. Surface Area Responses to Mainstem Discharge in the Lower Susitna River:Segment III and IV Side Channel Complexes. Surface Area Responses to Mainstem Discharge in the Lower Susitna River:SC IV-4 and. Willow Creek (SC II1-1). Surface Area Responses to Mainstem Discharge in the Lower Susitna River:Caswell Creek and Sheep Creek. Surface Area Responses to Mainstem Discharge in the Lower Susitna River:Goose Creek (SC 11-4)and Montana Creek (SC II-1). Surface Area Responses to Mainstem Discharge in the Lower Susitna River:Sunshine Slough (SC 1-5). Page 15 19 20 21 R23/1 6 Figure .Number 4.1 4.2 4.3 4.4 4.5 4.6 4.7 LIST OF FIGURES Description Comparison of Vegetated Riverbanks and Islands 1951,1962 and 1983:SC IV-4. Comparison of Vegetated Riverbanks and Islands 1951,1962 and 1983:Willow Creek. Comparison of Vegetated Riverbanks and Islands 1951,1962 and 1983:Sheep Creek and Caswell Creek. Comparison of Vegetated Riverbanks and Islands 1951,1962 and 1983:Goose Creek. Comparison of Vegetated Riverbanks and Islands 1951,1962 and 1983:Montana Creek. Comparison of Vegetated Riverbanks and Islands 1951,1962 and 1983:Sunshine Slough. Comparison of Vegetated Riverbanks and Islands 1951,1962 and 1983:Birch Creek Slough. Page 25 26 27 29 31 32 34 R23/1 7 ACKNOWLEDGMENTS This study was conducted under contract to Harza-Ebasco Susitna Joint Venture.Funding was provided by the Alaska Power Authority in conjunction with environmental impact assessment studies for the proposed Susitna Hydroelectric Project. The aerial photographs were taken by Air Photo Tech with photograph printing and enlargements by North Pacific Aerial Surveys.Bill Ashton, Sharon Klinger-Kingsley and Steve Bredthauer did the field checking of the habitat type designations.Jack Bolke,Rick Bennett and Len Story digitized the wetted surface.areas and Debbie Stephens assisted in data analysis.Steve Bredthauer,Woody Trihey and,Carl Schoch provided many useful review comments.Orlando Paraoan and Mark Cordery drafted the figures and Barb Estus typed the report. R23/1 8 1.0 INTRODUCTION The proposed Susitna Hydroelectric Project will alter the natural streamflow regimes of the Susitna River.In general,with-project flows will be lower than natural flows during the summer and higher during the winter. These altered flows will affect the amount and seasonal availability of aquatic habitats present in the river. This report presents the results of three studies which examined the response of wetted surface areas to changes in mainstem discharge in the Yentna River Confluence to Talkeetna reach of the Susitna River (River Mile (RM)28.5 to RM 98)(hereafter referred to as the lower river).The three studies were:1)to define segments of 'similar morphologic characteristics and determine the response of wetted surface area of the lower river (RM 28.5 to RM 98)to changes in mainstem discharge; 2)identification,mapping,and surface area determination of aquatic habitat types in selected study areas in the lower river and evaluating the surface area response to discharge for these habitat types;and 3)an evaluation of the morphologic stability of islands and side channels in the study areas using aerial photography taken during the period 1951 to 1983. The scope of this study is to present the results of the three subjects described above for natural flow conditions.Although wetted surface areas may be used as an indicator of habitat availability,it does not represent habitat quality.This report does not contain any statements concerning the suitability of the various habitat types for fish,nor does it address how the quality of these habitats may respond to changes in mainstem discharge.Subsequent reports will detail the effects of the with-project flow regime on these three subjects. Previous work on the Susitna River has used aerial photography for aquatic habitat analysis.Klinger and Trihey (1984)and Klinger-Kingsley (1985)measured wetted surface areas of aquatic habitat types in the R23/1 9 Susitna River between Talkeetna and Devil Canyon (RM 98 to RM 149) (referred to as the middle river)and evaluated changes in wetted surface area aS a response to mainstem discharge.These studies provided background and served as the basis from which sections of this particular study were developed.Both of these studies have shown that repeatable, visual identification of the wetted surface areas associated with different aquatic habitat types can be made by various observers.Secondly,it was shown that accurate surface area measurements can be obtained by digitizing the aerial photography.The ability to achieve both these goals is essential for the successful completion of a study such as the present one.To adequately interpret the result of surface area measurements,an evaluation must be made of the relative stability of channels and islands in the study =area.For this reason,the morphologic assessment was performed. This report consists of five sections.Section 1 provides background on the scope of this report.Section 2 describes the wetted surface area response to discharge for the entire lower river between Talkeetna and the Yentna River confluence.Section 3 presents results of delineating aquatic habitat types and measuring their surface area response to discharge in selected representative areas.Section 4 addresses the relative stability of the channels and islands in the selected representative areas.The results of this evaluation will provide some limits within which the surface area response data can be interpreted and will indicate to what extent extrapolations can be made from them.Section 5 combines the results and discusses their applicability to the lower river.All mainstem flows referenced in this report are based on the U.S.Geological Survey streamflow gage at Sunshine (No.15292780). R23/1 10 2.0 SEGMENT IDENTIFICATION AND WETTED SURFACE AREA DETERMINATION 2.1 Lower River Segments The water area of the lower Susitna River was measured to provide an initial estimate of changes in wetted surface area in response to changes in mainstem discharge.This estimate was then used to select representative side channel complexes for detailed analysis (see Section 3).The Jower river was divided into 5S segments based on river morphology and hydrology (Figure 2.1).The segments are described below and are delinated on aerial photographs in Exhibit A. Segment |:RM 98.5 to RM 78 This segment extends from the Chulitna River confluence downstream to the head of the side channel complex just upstream of Montana Creek. The river is braided,with the main channel meandering through a wide gravel floodplain.Large expanses of gravel bars are exposed at low. flows.The channel is constricted to a single channel at the Parks Highway Bridge (RM 83.8).Significant tributaries in this segment include Birch Creek,Trapper Creek,Sunshine Creek,and Rabideux Creek.A total of six side channel complexes were identified. Segment Il:RM 78 to RM 51 _This segment extends from the side channel above Montana Creek to the headof Delta Islands where the river splits into two main channels.The morphology in segment II is complex,with a total of 9 side channel complexes along the floodplain margin,and two additional side channel complexes located within mid-channel islands.Significant tributaries in this segment include Montana Creek,Goose Creek,Sheep Creek,Caswell Creek and the Kashwitna River. R23/1 11 Segment If]:RM 51 to RM 42.5 This segment encompasses the Delta Islands reach where two main channels exist,one on the east and one on the west.A total of five side channel! complexes exist in this segment,with a major complex between the two main channels.The segment ends where the two main channels rejoin. Significant tributaries in this segment include Little Willow Creek and Willow Creek. ) Segment IV:RM 42.5 to RM 28.5 This segment extends from the lower end of the Delta Islands to the confluence with the Yentna River.The reach is characterized by a braided pattern,with seven side channel complexes.The Deshka River enters the upper end of this reach.Kroto Slough branches off from this segment,and extends to the Yentna River. Segment V:RM 28.5 to RM 0 This segment extends from the Yentna_River,which contributes approximately 40 percent of the total flow of the Susitna River,to Cook Inlet.The segment is primarily a split-channel configuration down to RM 19,the head of Alexander Slough.The Susitna River has two channels from RM 19 to Cook Inlet,with the main channel on the east side.The west channel is primarily an overflow.channel.Its upper section dewaters at low flow,while the lower section is fed by Alexander Creek. Other tributaries entering this segment include Anderson Creek and Fish Creek. 2.2 Channel and Island Classifications Two main classifications were identified within the segments,with subclassifications recognized for purpose of future discussion but were not differentiated in this analysis. ey d rasowsRive9° Wg RyiS DEVIL CANYONyy<qwer OAM SITE 'aa wy -SGold\J i OY Creek (Pay v Bridge ¥ColdaecetCreeg ra u 7o.R TALKEETNA Fiver.i 2 STATION1WY24(RM 103) B\«hq 23S r eeSEGMENTxNial Sheen ;Ow y/)e..NUMBER SNS Railroad Bridge .BIRCH CREEK SLOUGHmiwageTALKEETNA EY)refs2olfre)Ce x 1 SUNSHINE SLOUGH{7)g \i eo ,SUNSHINELXHinesTATIO =one?eeMONTANA.CREEK Sra\(EME,S GOOSE CREEK A SHEEP CREEK elec Riveratis CASWELL CREEK Iv 0 §10 1§Kllometers Vv Pod ANCHORAGE EWT&A oT Sees P WOUDY FRIHEY&ASNOCTATES COOK INLET FIGU RE 2.1 PREPARED BY:PREPARED FOR:SewM STUDY SITE LOCATION MAP R&M CONSULTANTS,INC.LOWER SUSITNA RIVER RARZA:EBASGO SUSITNA JOINT VENTURE R23/1 12 Mainstem Channel is that portion of the river floodplain between the vegetated boundaries,including the wide gravel floodplain and isolated vegetated islands in mid-channel.Two subclassifications are: 1.Mainstem river -the thalweg channel and main subchannels. 2.Alluvial island complexes -areas of broad gravel islands with numerous subchannels which dewater as flow decreases. Side Channel Complexes consist of oneor more channels flowing among a group of vegetated islands.These complexes are usually located along the edge of the mainstem river but,in areas such as the Delta Islands,may occur in the middle of the river.The side channel complexes were numbered in downstream order within each segment. Channels within the side channel complexes are classified within one of three groups.These groups are differentiated by the presence or absence of overtopping flow in the photography used in this analysis (see Section -2.3).Once a subclassification is determined for a channel,the channel will have that subclassification throughout the range of mainstem flows. This subclassification is based solely on overtopping flows and does not consider potential habitat characteristics of the channel. 1.Major side channels are overtopped at mainstem flows of 13,900 cfs and lower.They tend to be,but are not limited to,the outside-most channel of.a complex,closest to the edge of the floodplain.These channels may collect groundwater seepage and tributary flow. 2.Intermediate side channels dewater at their upstream berm in the mainstem flow range of 13,900 cfs to 59,100 cfs.After their upstream berm dewaters,some intermediate channels maintain turbid water to a mainstem flow of 21,100 cfs or less,while others contain clearwater from groundwater and/or surface water inflow.Other intermediate side channels dewater the complete length of the channel before the R23/1 13. mainstem flow decreases to 21,100 cfs.Intermediate side channels may be extensions of tributaries once their upper berms dewater. 3.Minor side channels dewater at their upstream berm at mainstem flows of 59,100 cfs and higher.These channels tend to be dewatered the complete length of the channel at mainstem flows of 36,600 cfs. 2.3.Photography Black and white aerial photography at a scale of 1"=2,000'was obtained of the lower Susitna River at five mainstem discharges (Table 2.1). TABLE 2.1.DATES AND DISCHARGE AT WHICH AERIAL PHOTOGRAPHY WAS OBTAINED Discharge Date at Sunshine Remarks 8-27-84 75,200 cfs Typical July-August natural flow 8-27-83 59,100 cfs Typical July-August flow during project operation. 9-6-83 | 36,600 cfs Transitional natural flow and project operation flow during May and September. 9-16-83 21,100 cfs High winter flow during project operation. 10-25-83 13,900 cfs Low winter flow during project operation. R23/1 14 Photo mosaics were prepared from each set of photography for river Seg- ments 1 through 4.Segment 5 was not included due to inflow from the Yentna River and tidal influences which were assumed to mask changes in 'habitat surface areas due to project operation. Boundaries of each mainstem or side channel complex were defined.Each island and gravel bar was numbered and its boundary delineated.The total area of the segment was determined.Areas of islands and gravel bars were subtracted from the total area to obtain wetted surface area (WSA)of the subsegment.Channels which extended through an_island complex were delineated.Backwater areas were also included,but isolated pools were not digitized,as these areas were not considered usable habitat. Surface area determinations were made using a HP-9845 computer and area measurements were calculated and displayed to an accuracy of 0.0049 inches.This represents an accuracy of 10 feet for photography at a scale of 1"=2000'.Individual measurements were replicated 2-4 times and the average value used.All measurements were adjusted for a common scale due to minor scale differences between flights.The September 16,1983 set of photography was used as the base and all measurements adjusted to match that scale. 2.4 Results Segment | The response of the wetted surface area in side channel complex (SC)1-5 to mainstem discharge is indicative of a side channel complex with a mix of major,intermediate,and minor side channels (Figure 2.2,Table 2.2 and Exhibit A).SC 1-4,a side channel complex with few intermediate and minor side channels and no major side channels,has a slight change in wetted surface area with decreasing mainstem discharge (Figure 2.2).For SC I-1 and SC 1-2 the slight rise in wetted surface area at 13,900 cfs is R23/1 15 due to the problem of delinating the edge of water with the ice cover in the photographs. Segment I] SC II-6 is a large side channel complex with many minor and intermediate channels (Figure 2.3).The sharp drop in wetted surface area at 21,100 cfs is due to dewatering of many intermediate channels.SC II-1 shows the wetted surface area response of a side channel complex with no major channels and a few intermediate channels.SC II-9 consists of intermediate channels which rapidly dewater at mainstem discharges below 59,100 cfs (Figure 2.3).At SC I1-8 the wetted surface area at 75,200 cfs and 59,100 cfs are approximately equal,but due to slight local scale changes in the air photos the wetted surface area at 59,100 cfs digitized slighty larger. Segment III SC Ill-2 has many minor and intermediate channels.The rate at which intermediate channels are dewatering increases below 36,600 cfs,indicated by the increased slope of the wetted surface area response curve (Figure 2.4).In contrast,the rate at which intermediate channels dewater in SC HI-5 is greater between 59,100 cfs and 36,600 cfs than between 36,600 cfs and 21,100 cfs (Figure.2.4).This is probably due to the wider shallower channels of SC III-5. Segment IV SC IV-5 and SC IV-7 are side channel complexes with one intermediate side channel and no major or minor side channels (Figure 2.4).SC IV-1 and SC IV-2 are side channel complexes with many minor and intermediate side channels and no major side channels.The slope of the wetted surface area response curve is steeper at flows above 36,600 cfs because the channels in SC IV-1 and SC !V-2 are generally wide and shallow whereas the channels in SC IV-5 and SC IV-7 are generally deep and narrow. 20 SEGMENT |]SIDE CHANNEL COMPLEXES sc 1-8 ot MAINSTEM WETTEDSURFACEAREA(rT?x108).26WETTEDSURFACEAREA(FT X10°)I q q J T T 1 oO. 10 20 30 40 50 60 TO q i T J 't qt 80 10 20 30 40 50 60 70 -80 MAINSTEM DISCHARGE AT SUNSHINE (cfs X 10°)MAINSTEM DISCHARGE AT SUNSHINE (cfs X 10°) PREPARED BY:PREPARED FOR:IRV;|gewrea |SURFACE AREA RESPONSES TO MAINSTEM DISCHARGE FIGURE 2.2 =, aoe SSO ANTSING.IN THE.LOWER SUSITNA RIVER:HARZA*EBASCO, SNGINEERD GEOLOGISTS HYOROLOGISTS SURVEYORS MAINSTEM AND SEGMENT l SIDE CHANNEL COMPLEXES SUSITNA JOINT VENTURE R22/5a TABLE 2.2.CHANGES IN WETTED SURFACE AREA AT SELECTED MAINSTEMDISCHARGESINTHEYENTNATOTALKEETNAREACHOFTHESUSITNARIVER Date 8-27-84 8-27-83 9-6-83 9-16-83 10-25-83Discharge(cfs)75,200 59,100 36,600 21,100 13,900@Sunshine Percent of Percent of Percent of Percent of Percent of WSA Subsegment WSA Subsegment WSA Subsegment WSA Subsegment WSA SubsegmentSubsegment(10°sq ft)Area!(10°sq ft)Area (10®sq ft)Area _(i0®sq ft)Area (10°sq ft)Area Mainstem |230 70.6 203 62.8 156 48.2 123 38.1 110 34.1 SC 1-1 1.10 23.6 0.82 17.3 0.67 14.1 0.44 9.3 0.46 9.8SC1-2 4.66 14.4.3.83 11.8 3.31 10.2 2.47 7.6 2.52 7.8SC1-3 2.84 41.0 2.76 40.0 2.27 32.9 1.63 23.6 1.14 16.6SC1-4 0.51 36.8 0.42 30.2 0.40 28.6 0.41 29.9 0.37 26.5 SC 1-5 15.6 29.7 14 26.7 11.5 21.9 8.47 16.2 6.84 13.0 SC 1-6 2.06 25.9 1.67 20.9 1.29 16.2 1.14 14.3 0.55 6.9 Total SC |26.8 26.6 23.5 22.2 19.4 18.3 14.6 13.8 11.9 11.2 Mainstem II 339 :63.4 292 64.2 229 50.3 199 43.8 160 35.2 SC lf-1 1.41 13.5 1.16 11.2 1.16 11.2 0.58 5.6 0.25 2.4SCII-2 7.42 25.6 6.33 21.8 4.27 14.7 3.12 10.8 1.41 4.9SC11-3 3.90 27.5 3.20 22.5 2.38 16.8 2.39 16.8 0.79 5.5SC11-4 9.95 17.6 8.34 15.5 4.97 8.5 3.69 6.5 2.59 4.6SCII-5 6.24 31.7 6.22 39.7 4.77 28.0 4.20 24.6 2.13 12.5SC1-6 42.6 ;27.3 42.8 27.4 32.1 20.5 27.1 17.3 11.9 7.6SCII-7 1.46 23.6 1.10 17.8 0.63 10.2 0.51 8.2 0.36 5.8SCII-8 13.1 24.1 13.5 24.9 10.1 18.7 9.25 17.0 5.88 10.8SC11-9 0.76 11.5 0.74 11.3 0.19 3.0 _0.00 0.0 0.00 0.0SC11-10 1.79 38.6 1.50 32.5 1.29 27.9 1.25 27.0 0.59 12.8SCII-11 39.5 18.7 33.1 15.7 18.1 8.6 16.8 7.9 6.84 3.2 Total SC I]128 22.5 118 21.7 80.0 13.9 68.9 12.2 32.7 5.8 Mainstem 111 103 79.3 91.9 70.7 74.7 57.5 61.9 47.7 52.4 40.3 SC HNI-1 (3)-11.8 29.2 11.4 28.1 10.4 25.6 7.54 18.6 6.28 15.5SCIN-2 16.0 20.8 14.1 17.9 11.5 14.6 6.91 8.8 4.59 5.8SCIII-3 47.8 16.5 46.3 16.0 38.2 13.2 27.6 9.5 26.6 9.2SCIll-4 7.18 31.6 7.23 31.8 5.34 23.5 3.87 17.0 3.11 13.7SCHl-5 1.75 21.2 1.34 16.5 0.57 6.9 0.47 5.7 0.33 4.0 Total SC III 84.5 19.2 80.4 18.6 66.0 15.0 46.4 10.5 40.9 9.3 Mainstem IV 120 82.0 103 69.8 87.5 59.5 75.0 51.1 66.3 45.2 SC IV-1 4.15 22.4 2.94 15.8 1.52 8.2 1.05 5.6 0.62 3.3SCIV-2 2.98 41.7 2.32 32.5 1.72 24.1 1.31 18.3 0.53 7.4SCIV-3 12.9 23.2 12.6 22.6 10.5 18.9 8.16 14.7 5.84 10.5SCIV-4 9.25 29.2 8.08 25.5 6.64 20.9 4.76 15.0 2.80 8.8SCIV-5 0.86 28.6 0.82 27.1 0.74 24.4 0.38 12.4 0.13 4.4SCIV-6 30.4 35.7 26.8 31.5 22.0 25.9 17.2 20.2 12.2 14.4SCIV-7 0.77 29.2 0.77 29.1 0.66 25.2 0.36 13.7 0.14 5.4 Total SC IV 61.3 30.2 54.3 26.7 43.8 21.5 33.2 16.3 22.3 10.9 NOTES: 1)(Wetted curface area/side channel complex or mainstem area)yx 100 6WETTEDSURFACEAREA(FT"X10°)50 SEGMENT Il SIDE CHANNEL COMPLEXES .°sc 1-5 SC N-5 °!WETTEDSURFACEAREA(FT?x10©)°ISEGMENT Il SIDE CHANNEL COMPLEXES nana Ms to %oo fo 70 To Xo 35 a Jo :DISCHARGE (cfs X 107)DISCHARGE (ets x 10°) PREPARED BY:-PREPARED FOR: ery EWT&A |SURFACE AREA RESPONSES TO MAINSTEM DISCHARGEAEMCONSULTANTS,ING,|tom mmsoennn IN THE.LOWER SUSITNA RIVER:FIGURE 2-30 MAIR M\>EBASCO SUSITNA JOINT VENTURE ane oroLooers Hy re sunvevone SEGMENT Il SIDE CHANNEL COMPLEXES WETTEDSURFACEAREA(FT?x10°)SEGMENT Il!50.SEGMENT IV SIDE CHANNEL COMPLEXES SIDE CHANNEL COMPLEXES sc} sc We sc wi-2 Sc ii-1 WETTEDSURFACEAREA(FT2x108)|1.04 1.0.4 02 20 30 40 50 60 70 80 01 20 30 40 50 60 70 80 DISCHARGE (cfs X 109) ;DISCHARGE (cfs X 10) PREPARED BY::PREPARED FOR::SURFACE AREA RESPONSES TO MAINSTEM DISCHARGE |YSN,EWT&A ,_FIGURE 2.4 -oe eae ine |See IN THE.LOWER SUSITNA RIVER:HARZA=EBASGCO. rvemeene erotooiare nronotoniers eunvevont SEGMENT Ill AND IV SIDE CHANNEL COMPLEXES eee NT ENTURE R23/1 16 2.5 Discussion The response of wetted surface area to discharge for side channel complexes is generally indicative of the mix of major,intermediate and minor side channels within a specific side channel complex and _the cross-sectional shape of those side channels.For example,when the mainstem discharge decreases from 75,200 cfs to 59,100 cfs side channel complexes with relatively few minor side channels and relatively deep narrow intermediate side channels have little or no decrease in wetted surface area (see SC IV-5 and SC IV-7).As the mainstem discharge decreases from 59,100 cfs to 21,100 cfs the slope of the wetted surface area response curves in Figures 2.2 through 2.4,indicates the mix of intermediate and major side channels and their cross-sectional shape.For example,side channel complexes with wide.shallow intermediate side channels will have a steeper sloping line in Figures 2.2 through 2.4 than will a side channel complex with predominately narrow deep channels. As the mainstem discharge decreases to 13,900 cfs intermediate channels have dewatered completely or have substantially smaller wetted surface area than at 21,100 cfs.The wetted surface area at 13,900 cfs was difficultto digitize because the aerial photographs were taken after ice had covered low velocity areas.Therefore the wetted surface area for the 13,900 cfs aerial photography is probably underestimated for most side channels and overestimated for a few side channels. | -10- R23/1 17 3.0 HABITAT DELINEATION AND SURFACE AREA MEASUREMENTS FOR SELECTED STUDY AREAS 3.1 Study Sites The lower Susitna River encompasses an extensive area of braided channels and side channel complexes.Representative areas were chosen in the lower river for which habitat types would be mapped and wetted surface 'areas measured (Figure 2.1).Eight areas were selected as representative of the downstream variation in channel morphology present in the lower river (Table 3.1). TABLE 3.1.REPRESENTATIVE AREAS FOR THE LOWER SUSITNA RIVER -Area Name Inclusive River Miles SC IV-4 32.5 -36.0 Willow Creek (SC III-1)49.0 -52.0 Caswell Creek 64.0 Sheep Creek 66.1. Goose Creek (SC I1-4)68.5 -72.5 Montana Creek (SC II-1)77.0 -78.0 Sunshine Slough (SC 1-5)84.0 -86.5 Birch Creek Slough 88.5 -93:0 SC IV-4 Side channel complex SC IV-4 is located between RM 32.5 and RM 36 on the east bank of the Susitna River.This representative area has two major side channels that remain breached at 13,900 cfs.One intermediate side channel becomes nonbreached between 21,100 and 13,900 cfs. R23/1 18 Several smaller intermediate and minor side channels exist.Most become dewatered as mainstem discharge drops from 59,100 to 21,100 cfs. Willow Creek (SC III-1) SC Itt-1 extends from RM 49 to RM 52.Willow Creek enters the side channel complex at approximately RM 49,while Little Willow Creek enters at RM 50.5.This representative area has one main major side channel flowing through the upper two-thirds of the complex with a major side channel branching off and continuing through the rest of the complex. 'There are several intermediate side channels.Little Willow Creek flows into an intermediate channel creating in clearwater area as mainstem stage decreases and/or tributary flow increases. Caswell Creek Caswell Creek is a tributary entering a side channel of the Susitna River at approximately RM 64.The upstream end of this side channel is dewatered at 37,000 cfs.When this occurs the tributary mouth extends | approximately 800 feet downstream. Sheep Creek Sheep Creek is a tributary entering a side channel of the Susitna River at RM 66.1.Backwater effects due to side channel stage range from no effect at low mainstem discharges (13,900 cfs},to a backwater zone of approximately 5,000 feet at a mainstem discharge of 52,000 cfs,with a greater extent of backwater at higher flows. Goose Creek (SC 11-4) Goose Creek Side Channel,located between RM 68.5 and RM 72.5,is a large side channel complex.The complex has one main intermediate side channel and numerous smaller intermediate and minor side channels.Goose -11- R23/1 19 Creek enters the main intermediate side channel of the side channel complex at approximately RM 72. Montana Creek (SC II-1) SC 11-1 extends from RM 77 to RM 78 with Montana Creek entering SC II-1 at its downstream extent.SC Ii-1 is a relatively small side channel complex with one main intermediate side channel and _several smaller intermediate and minor side channels.Montana Creek has a relatively steep gradient resulting in no backwater area until mainstem flow increases to approximately 38,000 cfs. Sunshine Slough (SC 1-5) Sunshine Side Channel complex is located between RM 84 and RM &6.5 on the east bank of the Susitna River.The side channel complex consists of one major side channel,two main intermediate side channels and several smaller intermediate and minor side channels.Only the major channel conveys water throughout the flow range investigated.The other channels become side sloughs,contain isolated ponded water,or dewater completely at 13,900 cfs.Sunshine Creek flows into the major side channel at a point approximately 8,000 feet upstream from the confluence of the side channel with the mainstem Susitna. Birch Creek Slough Birch Creek Slough is a single channel extending from approximately RM 88.5 to RM 93 on the east bank of the Susitna River.Birch Creek enters the slough at a point slightly less than a mile upstream from its confluence with the Susitna.Birch Creek Slough was chosen as a study site to be representative of single channel sites in the river. R23/1 20 3.2 Habitat Type Designations Aquatic habitats associated with the lower Susitna River were classified into eight general categories:mainstem,primary side channel,secondary side channel,turbid backwater,clearwater,side slough,tributary mouth, and tributary.These categories represent physical characteristics of the habitat type visually discernible from aerial reconnaissance or examination of aerial photography.As such,these do not necessarily convey any specific biological significance nor do they indicate specific geographical locations.In some instances,transformation of one habitat type into another may occur as river stage increases or decreases.These habitat type designations differ from the channel classifications in Section 2 in that these are associated with aquatic habitat where as the channel classifications are associated with channel geometry. Characteristics used to delineate the eight aquatic habitat types are de- scribed below.These descriptions represent physical attributes of the habitat type during ice-free conditions.These physical attributes are visually recognizable during helicopter reconnaissance flights. Mainstem habitats represent the mainstem river,consisting of the thalweg channel,major subchannels and alluvial island complexes.This habitat type was,in most cases,outside the boundaries of the control areas used to define representative areas. Primary side channel habitats are those channels which normally convey streamflow throughout the entire year.They exhibit characteristics similar to middle Susitna River mainstem habitat types,as described by Klinger and Trihey (1984).They are characterized by turbid glacial water,high velocities,and few mid-channel gravel bars. Secondary side channel habitats also have turbid water,but exhibit char- acteristics of the middle river side channels.For example,there are -12- R23/1 21 mid-channel gravel bars and riffles or water surface features that indicate slower-moving,shallower water. Turbid backwater habitats are nonbreached channels containing turbid water.They have non-vegetated upper thalwegs that are overtopped during periods of moderate to high mainstem discharge.They represent a transitional habitat type between breached secondary side channel habitats and nonbreached clearwater or side slough habitats. Clearwater habitats are nonbreached channels containing clear water that dewater completely at a mainstem discharge of 13,900 cfs or higher.These channels have non-vegetated upper thalwegs that are overtopped during periods of moderate to high mainstem discharge.Groundwater and local surface runoff appear to supply water to these areas at mainstem flows above 13,900 cfs. Side slough habitats contain clear water.Upwelling and local surface runoff appear to supply sufficient clear water to these areas to maintain wetted areas at a mainstem dischargeof 13,900 cfs.Side sloughs also have non-vegetated upper thalwegs that are overtopped at moderate to high mainstem discharges. Tributary mouth habitats are clear water habitats that exist between the downstream extent of a clear-water plume and upstream into the tributary, to the upper extent of the backwater influence.The surface area depends on the discharge of both the tributary and mainstem. Tributary habitat exists upstream of the tributary mouth habitat.In this analysis,tributary habitat was measured only to the boundary of the digitized photo enlargement.Tributary habitat may increase dramatically when the tributary flows into a nonbreached side channel and the clear tributary flows through the side channel to join the Susitna River. R23/1 22 Non-wetted areas were classified as gravel bars or vegetated islands. Wetted areas that were not contiguous and connected to a side channel or 'mainstem were considered ""ponded water”and their surface area was included in the measurement of gravel bars.Areas which were within the river corridor but were not relevant to the analysis were classified as "background". 3.3 3.3.1 Methods Field Methods Black and white aerial photography at.a scale of 1 inch =2,000 feet was obtained of 'the lower Susitna River at five mainstem discharges as measured at the USGS Sunshine gage. Helicopter mapping flights were conducted over the eight representative areas at mainstem .discharges similar to those at which the aerial!photography was obtained (Table 3.2).During these flights,aquatic habitat types were identified and their locations mapped on blue-line prints made from 1 inch =500 feet enlargements of the study area.Gravel bars and dewatered streambank areas were sketched on the bluelines along with the boundaries of the various habitat types. TABLE 3.2.DATES AND SUSITNA RIVER DISCHARGE (AS MEASURED AT SUNSHINE)AT WHICH AERIAL PHOTOGRAPHY WAS OBTAINED AND HELICOPTER MAPPING FLIGHTS WERE FLOWN Aerial Photography Mapping Flight Instantaneous -Mean Daily Date Discharge (cfs)Date Discharge (cfs) 08/27/84 75,200 08/27/84 81,600 08/27/83 59,100 07/24/84 55,200 .08/22/84 96,300 09/06/83 36,600 .08/31/84 38,000 09/16/83 21,100 09/11/84 23,600 10/25/83 .13,900 10/13/84 12,100 -13- R23/1 23 3.3.2 Office Procedure Habitat Type Delineations Photo enlargements at a scale of -1 inch =500 feet were prepared for each of the eight representative areas at each of the five discharges. Aquatic habitat boundaries that had been mapped on the blueline prints during the helicopter reconnaissance flights were transferred to acetate overlays on these enlargements. External boundaries of the representative area (hereafter referred to as control areas)to be included in the surface area analysis were defined on each enlargement.Control area boundaries were estab- lished using features identifiable on all five sets of photography.In some cases,a given enlargement was broken into more than one control area to accommodate the size of the digitizer tablet used in the analysis.Control areas served as an index of quality control. Surface areas of the individual elements within each control area were summed and compared to the total area of the control area.This insured that no habitat elements were left undigitized. Digitizing Boundaries were drawn around each wetted and non wetted habitat element on each enlargement for each of the five flows.Individual area elements were identified as to habitat type and assigned unique sequential identifier numbers.Channels which contained water at the 75,200 cfs flow were assigned unique identifier numbers that were used for the same channel at lower flows.Gravel bars and vegetated islands were assigned unique numbers for a given photo enlargement. Surface area determinations were made using an HP-9845 computer and area measurements were calculated and displayed to an accuracy of 0.0049 inches.This represents an accuracy of 2.5 feet for R23/1 24 3.4 3.4.1 photography at a scale of 1"=500'.The total surface area of a control area was digitized. control area were then digitized and their areas summed for comparison to the control area.Replicate measurements were made for each area digitized to ensure repeatability within five percent. Comparisons between summed individual areas and the total control area were considered acceptable if the difference was less than five percent. Analysis Procedures Each individual surface area measurement entered into the data base had an identifier number that allowed identification by discharge, representative area,habitat type,and specific area identification number.In this way,data may be displayed by study area,by tracking a specific channel,or using a variety of other formats. Due to weather conditions during aerial photography flights,the different sets of photographs were obtained at slightly different scales.To make direct comparisons between flight lines,the September 16,1983,21,100 cfs set of photography was chosen as a base and correction factors were determined to standardize measure- ments to a common scale. Results General The general response for total wetted surface in all representative areasis a decrease with decreasing mainstem discharge (Figures 3.1 - 3.4).The representative areas are described below and the habitat type designations are shown on aerial photographs in Exhibit B. Mainstem,primary and secondary side channel surface area decreases with decreasing discharge.The response of wetted surface area for Individual habitat areas within that© -14- R23/1 25 3.4.2 tributaries varies depending on the tributaries confluence with the mainstem or side channel. The amount of clearwater wetted surface area increases with decreasing mainstem flow.As mainstem discharge decreases many channels transform from side channels through turbid backwaters and clearwater areas to gravel bars.The discharge at which the change occurs varies for each side channel complex.Some channels transform directly from side channel to side slough skipping turbid backwater and maintain a base winter flow.Turbid backwater wetted surface area increases with decreasing discharge as the heads of side channels dewater,then decreases as channels change to clearwater areas or dewater completely at lower discharges. Study Sites SC IV-4 Secondary side channel surface area decreases with decreasing discharge below 59,100 cfs as secondary side channels dewater or become turbid backwaters,clear water areas,and_=side 'sloughs (Figure 3.1).The increase in secondary side channel area from 75,200 cfs to 59,100 cfs is due to the transformation of a primary side channel to a secondary side channel.Turbid backwaters and clearwater areas form as the discharge decreases from 75,200 cfs to 59,100 cfs.As the discharge decreases to 36,600 cfs turbid backwaters typically transition from turbid water to clearwater as intragravel flow flushes the turbid water out thus forming clearwater areas.Clearwater habitat disappears at 21,100 cfs because the areas present at 36,600 cfs dry up but no new ones are formed by the heads of other side channels dewatering or turbid backwaters clearing up.Below 21,100 cfs the turbid backwaters transform to side sloughs. SC IV-4 WILLOW.CREEK (SC II=1) 80 1 20,000_, URFACE AREATOTALWETTEDS 10,000 _]10,000 a CHANNEL 4 7 SIDE J 7 MAINSTEM 71 ]sECONDAS : -_g -_RA VEL 84 AR 7 "5 Py >-1,000_]= 4 x 1 2 -1,000. 0 7 <4 =4 x=7 4L.7 )&4 ;taf.<cs ;<7uwCLEARWATER2uwwe7()a 4 aq . < J aS 4uJ ©=,CraJ=uu =rr ra 5 &5 :CLEARWATER "”a n-%Q Qa " 100 bE 100-©a 4 be 5 '¥ w 4 uJ 4 oO =4 3 4 A 4 7 Ss 4 4 iT] 4 4 2 onda[ 4 4 »/2 af2 </< 4 4 x=Zs [ia a lo T T T T T 1 . 1 10 T T T T T T 1 10 20 30 40 50 60 70 80 10 20 30 40 50 60 70 MAINSTEM DISCHARGE AT SUNSHINE (cfs X 10°)MAINSTEM DISCHARGE AT SUNSHINE (cfs X 10°) PREPARED BY: SSM.EWTS&A SURFACE AREA RESPONSES TO MAINSTEM DISCHARGE R&M CONSULTANTS,INC. oro.Te HY TS SUAVEVYORS La Soopr tuners e aeemtanes IN THE.LOWER SUSITNA RIVER: --SC IV-4 AND WILLOW CREEK FIGURE 3.1 PREPARED FOR: RHARZA*EBASGCO SUSITNA JOINT VENTURE TABLE 3.3 WETTED SURFACE AREAS AND PERCENT OF TOTAL WETTED SURFACE AREA BY HABITAT TYPE AT FIVE MAINSTEM DISCHARGES FOR SELECTED REPRESENTATIVE AREAS Mainstem Primary Side Channel Secondary Side Channel Turbid Backwater Clearwater _ Discharge at WSA Percent of WSA Percent of WSA Percent of WSA Percent of WSA Percent of Sunshine (cfs)(ft?x 10°)Total WSA (ft?x 10°)Total WSA (ft?x 10°)Total WSA (ft?x 10°)Total WSA (ft?x 10°)Total WSA SC 1V-4 75,200 7470 46.4 3510 21.8 5030 31.6 -------- 59,100 6270 41.6 ----7900 52.4 491 3.3 427 2.8 36,600 5880 47.6 ----5990 48.5 79.4 0.6 386 3.1 21,100 5510 57.3 ----4050 42.1 59.4 0.6 ---- 13,900 5450 67.1 ----2580 31.8 -------- WILLOW CREEK (SC I11-1) 75,200 3420 17.6 6870 35.4 7930 40.9 145 0.7 31.7 0.2 59,100 2990 16.2 --ee 13300 72.1 247 1.3 153 0.8 36,600 2970 19.3 ----10100 65.7 320 2.1 169 1.1 21,100 2270 17.8 ----7700 60.3 249 1.9 178 1.4 13,900 2030 20.2 ----3020 50.0 67.9 0.7 ---- CASWELL CREEK 75,200 ----143 23.4 343 56.2 -------- 59,100 --------402 77.3 -------- 36,600 Does ------259 66.4 -------- 21,100 --------73.4 35.0 -------- 13,900 --------53.7 31.6 -------- :SHEEP CREEK , 75,200 --------319 25.9 -------- 59,100 --Sse ----309 -23.4 -------- 36,600 ---- ---336 24.5 -------- 21,100 --------158 14.9 -------- 13,900 --------116 .11.6 -------- GOOSE CREEK (SC I1-4) 75,200 8120 48.0 ----7840 46.3 A416 2.5 ---- 59,100 7040 49.2 ----6340 44.3 178 1.2 62.9 0.4 -36,600 3590 37.2 ----4240 43.9 338 3.5 334 3.5 21,100 943 13.9 ----4650 68.6 35.7 0.5 147 2.2 13,900 --------2880 48.7 15.0 0.3 ---- MONTANA CREEK (SC 11-1) 75,200 5000 68.9 ----1740 24.0 16.3 0.2 ---- 59,100 4580 72.1 ----1120 17.6 118 1.9 173 2.7 36,600 3890 76.7 ----590 11.6 ----273 5.4 21,100 3320 81.6 --------425 10.4 ---- 13,900 1920 62.3 ----859 27.9 -------- SUNSHINE CREEK (SC 1-5) 75,200 9520 37.8 5860 23.3 9480 37.6 261 1.0 ---- 59,100 8840 36.2 5720 23.4 9160 37.5 179 0.7 87.7 0.4 36,600 ;7460 40.0 ----10300 55.3 448 2.4 ---- 21,100 6800 47.9 ----6330 -44.5 660 4.6 8.9 0.1 13,900 5540 52.7 ----3350 _31.9 95.8 0.9 ---- TABLE 3.3 (Continued)WETTED SURFACE AREAS AND PERCENT OF TOTAL M WETTED SURFACE AREA BY HABITAT TYPE AT FIVE MAINSTEM DISCHARGES FOR SELECTED REPRESENTATIVE AREAS Side Slough Tributary Mouth Tributary Gravel Bar Total Wetted Of Total WSA of Incremental Change Discharge at WSA Percent of WSA Percent of WSA Percent of Area Percent of Surface Area Given Discharge from Next Sunshine (cfs)(ft?x 10°)Total WSA (ft?x 10°)Total WSA_(ft?x 10°)Total WSA (ft?x 10°)Total Area (ft?x 10°)Lower Discharge (Percent) SC IV-4 75,200 ------------1750 3.6 16.07 6.559,100 --= "7 ------3140 6.5 15.09 22.336,600 77 77 77 ------5700 11.7 12.34 28.321,100 ------------8520 17.5 9.62 18.513,900 85.4 1.0 ------oe 12400 25.5 8.12 -- WILLOW CREEK (SC III-1) 75,200 ----260 1.3 732 3.8 2080 2.0 19.39 5.159,100 ----784 4,2 973 5.2 2950 2.9 18.45 20.036,600 ----284 1.8 1540 10.0 5870 5.7 15.38 20.521,100 ----558 4,3 1800 14.1 8680 8.5 12.76 27.013,900 762 7.6 131 1.3 2040 20.3 12600 12.3 10.05 -- CASWELL CREEK 75,200 -*--71.7 1.7.51.8 8.5 183 5.5 0.61 17.359,100 ----104 20.0 16.6 3.2 247 7.4 0.52 33.336,600 -- -25.3 6.5 101 25.9 402 12.1 0.39 85.721,100 13.1 6.2 45.3 21.5 76.4 36.4 582 -17.5 0.21 23.513,900 13.2 7.8 ----102 60.0 611 18.4 0.17 -- SHEEP CREEK 75,200 ----352 28.6 581 45.8 162 1.1 1.25 -5.759,100 ----649 49.2 362 27.4 249 1.6 1.32 -3.636,600 ----349 25.5 681 49.7 213 1.4 1.37 29.221,100 ----19.8 1.9 883 83.3 508 3.3 1.06 6.013,900 ----10.4 :1.0 875 87.5 573 3.8 1.00 -- GOOSE CREEK (SC 11-4)75,200 ----39.0 0.2 517.3.1 5700 6.2 16.93 18.359,100 ----141 1.0 553 3.9 9570 10.4 14.31 48.136,600 651 6.7 66.1 0.7 445 4.6 13500 14.8 9.66 42.521,100 471 6.9 30.4 0.4 -501 7.4 16000 17.5 6.78 14.713,900 751 12.7 ----2260 38.2 18100 19.7 5.91 -- MONTANA CREEK (SC II-1)75,200 ----132 1.8 372 5.1 2170 10.0 7.26 14.359,100 ----131 2.1 226 3.6 2970 13.7 6.35 25.336,600 ----10.9 0.2 309 6.1 4140 19.0 5.07 24.621,100 41.4 1.0 27.0 0.7 260 6.4 5370 24.7 4.07 32.113,900 29.8 9.7 7.5 0.2 168 5.5 6430 29.6 3.08 -- |SUNSHINE SLOUGH (SC 1I-5)75,100 --- 57.9 0.2 727 0.1 5920 5.5 25.19 3.259,100 361 1.5 76.2 0.3 ----7580 7.1 24.42 31.036,600 335 1.8 37.6 0.2 61.2 0.3 12700 11.9 18.64 31.221,100 338 2.4 ----73.5 0.5 16900 15.8 14.21 35.213,900 1390 13.2 --oe 134 1.3 22000 20.6 10.51 -- -17- R23/1 26 Willow Creek (SC III-1) The area of secondary side channel increases as mainstem discharge decreases from 75,200 cfs to 59,100 cfs because the primary side channel transforms to a secondary side channel (Figure 3.1). Tributary surface area increases with decreasing discharge because the head of side channels dewater with decreasing mainstem discharge and the tributary extends down the side channels.With decreasing mainstem discharge tributary mouth surface area fluctuates depending on the tributary discharge.Turbid backwater area increases with. decreasing discharge as the heads of more side channels become dewatered at 36,600 cfs.Turbid backwaters transforms to.side sloughs and gravel bars from 21,100 cfs to 13,900 cfs. Caswell Creek Tributary and tributary mouth wetted surface areas vary depending on both mainstem and tributary discharge (Figure 3.2).Between 21,100 cfs and 13,900 cfs the tributary area increases because the head of the side channel dewaters and the tributary extends down the side channel. Sheep Creek Tributary mouth surface area dramatically decreases with decreasing mainstem discharge because of the flat gradient of Sheep Creek (Figure 3.2).As mainstem discharge decreases,the side channel into which Sheep Creek flows has less flow resulting in less backwater effects.Tributary area increases as the tributary mouth area decreases,however the total wetted surface area stays approximately the same.The slight rise in wetted surface area with decreasing flow is because of slight differences between the 1983 and 1984 photography. -18- R23/1 27 Goose Creek (SC It-4) Tributary surface area increases at 13,900 cfs because the head of the side channel becomes dewatered and the side channel into which the tributary flows becomes an extension of the tributary (Figure 3.3).Tributary mouth area is low at 75,200 cfs relative to 59,100 cfs- due to the rainstorms prior to the 75,200 cfs aerial photography. The heavy rain resulted in higher tributary flow which therefore lessened the backwater effect due to mainstem stage for this steep gradient tributary.Turbid backwater surface area increases between 59,100 and 36,600 cfs as various channels become dewatered at their upper berms and then decreases below 36,600 cfs.Clearwater areas appear at 59,100 cfs,increase in surface area at 36,600 cfs,and then decrease at lower discharges.Side sloughs appear at 36,600 cfs, decrease in surface area slightly at 21,100 cfs and then increase at 13,900 cfs as turbid backwaters transform to side sloughs. Montana Creek (SC II-1) Mainstem surface area decreases slightly as mainstem discharge decreases from 75,200 cfs to 21,000 cfs (Figure 3.3).At 13,900 cfs, part of the mainstem area dewaters creating a secondary side channel. Secondary side channels transform to turbid backwaters at 21,100 cfs. The turbid backwater transforms to side slough at 13,900 cfs. Sunshine Slough (SC [-5). From 21,100 cfs to 13,900 cfs some mainstem area becomes secondary side channel.Primary side channel stays relatively constant from 75,200 cfs to 59,100 cfs then transforms to secondary side channel at 36,600 cfs (Figure 3.4).With decreasing discharge secondary side channels become turbid backwaters,clearwater areas,side sloughs or gravel bars.Tributary area decreases at 59,100 cfs because the tributary mouth habitat extended to the edge of the control area. 10,000.CASWELL CREEK 10,000.SHEEP CREEK . .TOTAL WETTED SURFACE AREA6o- oO *1,000_]7 1,000-]__ N - EF 4 tL 7LeREAbor5ros-GRAVE URFACE A -L eDd_$a<4 Ba TOTAL wet i =<SECONDARY SIDE CHANNEL wi CHANNEL w 4 <<GRAVEL BAR L Re Le 4ne7NYiva 2 4 3 .7)oe ool oy +RIBUTARY re 100-Go u =>4 =4 8y 4 4 Our,- ID 0 T 1 r 1 I 1 0 1 T T 1 10 20 30 40 50 60 70 80 10 20 30 40 50 60 70 . '3MAINSTEMDISCHARGEATSUNSHINE(cfs X 70°)_MAINSTEM DISCHARGE AT SUNSHINE (cfs X 10 ) PREPARED BY: San ]SURFACE AREA RESPONSES TO MAINSTEM DISCHARGE PREPARED FOR: aol WA EWT&A _ .FIGURE 3.2 MARZA>EBASCOR&EM CONSULTANTS,INC.Bb WADIDY THIEL &ADM EOE IN THE.LOWER SUSITNA RIVER: ENGINEERS GNoLOGIETe HYOROLOGISTS SURVEYORS CASWELL Cc REEK AND SHEEP CREEK SUSITNA JOINT VENTURE 8,0004 4 GOOSE CREEK (SC 1I-4)- EAGRAVELBapETTEDSURFACEARE . WANNES10,000 $,000 o\0E&: _ 4 ¥1 4 ;DAB 4 4 m seco" 4 . L 'el a 7 SECONDARY SIDE CHANNE 7 S 4 4 o Pd anery™. J Re i'>s AB°, 1,000]™100c-Se | -4 NL 4 BY EY < |TRIBUTARY =z bd 7 w - oc 4 fag << "Ww 4 ray aoOOo <<its Le e "4 2 bn}o 7)} a 'a EL 100.E to'kb 4 =4 .Wl 4 Ww 4 =,=4 10 T I T T T T T !T T T T T T 1 ite]20 30 40.50 60 7Oo 80 $0.20 30 40 590 60 70 80 MAINSTEM DISCHARGE AT SUNSHINE (cfs:X 10°)MAINSTEM DISCHARGE AT SUNSHINE (cfs X 10°) PREPARED BY:PREPARED FOR:SURFACE AREA RESPONSES TO MAINSTEM DISCHARGE FIGURE 3.3SSM.EWT&A IN THE.LOWER SUSITNA RIVER: |HARZA:EBASGO R&S&M CONSULTANTS,INC.&WOUND RINE Y &ASNUNEATES . orovoeiars yonoioaiere sunvevons GOOSE CREEK AND MONTANA CREEK SUSITNAJOINTVENTURE SUNSHINE SLOUGH po,000]SUNSHINE SLOUGH (SC I-5) 7 ACE__AREATEDSURF 10,000.CHANNEL 1,000_] Tun KWay>4 Ep . ;-sipE__/SLOUGH - ro o oo7 nN kK kL -_ 100_]<4 wes TRIB MOrr <|UTARY UTH w. oO 4 <4i fv >4 o Q uw kK K Ww = 10.4 1 & :lykK 4 Ny,RY 7 & vyy af q © 1.0 T T t T T T 10 20 30 40 50.60 70 MAINSTEM DISCHARGE AT SUNSHINE (X 10°,cfs)FIGURE 3.4 nilealatlg By:SURFACE AREA RESPONSES TO MAINSTEM DISCHARGE PREPARED FOR: SISM iN THE LOWER SUSITNA RIVER: REM CONSULTANTS,INC.RHARZA>EBASCOwnemenneeceleeersmvonccewersecavavoceSUSITNAJOINTVENTURE -21- R23/1 28 Birch Creek Slough Birch Creek Slough is a long,narrow,and meandering single, isolated channel,fed by Birch Creek and groundwater inflow.It flows through a vegetated area for its entire length with vegetation extending down to and overhanging much of the bank.The combination of the narrow channel,overhanging vegetation,and shadows in the photography made detection of water's edge and the edge of vegetation very difficult.For this reason,delineation and digitizing of habitat type surface areas was not done on Birch Creek Slough.However,a verbal description of the slough and _its responses to the mainstem stage that were noted during the helicopter overflights are discussed below. The head of Birch Creek Slough becomes dewatered between mainstem discharges of 59,100 and 36,600 cfs.A road crosses the slough approximately 1,000 feet downstream from the head of the slough. Road construction in 1984 apparently caused the culvert to be blocked,thus preventing overtopping mainstem inflow.The upper portion of the slough contains numerous beaver dams which form a series of impounded pools.These do not appear to have significant flow through them as evidenced by stagnant-appearing water,and early ice formation.During reconnaissance surveys,no evidence of spawning was seen in these upper areas in contrast to the lower reaches of the slough where salmon spawning was observed on August 31,1984 and carcasses were seen on October 10,1984.The lower reaches of the slough are characterized by a pool-riffle type of habitat which appears to provide suitable habitat for spawning.The beaver dams appear to provide a barrier to upstream movement of salmon in the slough and limit fish utilization to the downstream areas. R23/1 29 3.5 Discussion Definitions for aquatic habitat types used in this study represent a set of visually recognizable,streamflow-dependent physical characteristics that are not limited to fixed geographic locations.An example of the flow-dependent nature of these definitions.are the formation of side slough,clearwater area,turbid backwater and side channel habitats.The berms at the heads of side channels may become dewatered as the mainstem discharge decreases,forming a turbid backwater habitat.As the discharge continues to decrease the turbid backwater may remain a turbid backwater or become a clearwater area or a side slough depending on the local influence of upwelling,channel length and:channel slope. Clearwater areas form after the berm becomes dewatered.These areas clear due to settling out of suspended particles or by displacement of turbid water by flushing with clearwater originating from groundwater sources.They eventually dewater completely.Side sloughs are clear water habitats in which the flow is maintained by upwelling and surface water runoff at 13,900 cfs or lower.When mainstem discharge increases and river stage rises,the berm at the head of the side channel is overtopped.Turbid mainstem water flows into the overflow channel and replaces the former clearwater habitat with deeper,faster-flowing,turbid water.The aquatic habitat type at this location then fits the definition of side channel habitat. The surface area response curves for the representative areas in the lower river appear at first very complex without clear trends.This is a function of the complexity of many of these representative areas each containing numerous individual channels.Within a side channel complex, for example,various channels or groups of channels have different breaching discharges.A typical sequence for a channel is to transform from a secondary side channel to a turbid backwater then become a clear water area and finally dewater.Another sequence may show a secondary side channel becoming a side slough,or remaining a secondary side channel throughout the flow range.In combination,the loss of a given -22- R23/1 30 habitat type in one channel may be replaced by the gain of that or another habitat type in another channel. The upstream boundary of tributary mouth habitat is defined as the end of the backwater zone caused by mainstem flows.Field identification of the boundary was difficult for steeper gradient streams such as_Willow, Montana and Goose Creeks and was more difficult and is subject to interpretation for flatter gradient streams such as Caswell,Sheep and Sunshine Creeks. Surface area responses are a function of streamflow and channel geometry. Previous work by Klinger and Trihey (1984)has shown the repeatability and usefulness of wetted surface area mapping on the Susitna River from RM 101 to RM 149,a single channel and split channel river.The ability to replicate surface area measurements for comparative purposes.is dependent on stable channel geometry,which is not the case for braided rivers such as the mainstem.Consequently this study limits its analysis to the side channel complexes.The next section addresses the stability of the side channel complexes. Differences in channel morphology were noted between the 1983 aerial photographs and the river in 1984.This difference was first observed during the helicopter overflight on July 24,1984 at a flow rate (55,200 cfs)less than the flow rate of the aerial photography (59,100 cfs).After field mapping the wetted surface area for the 59,100 cfs photography,the delineations were field checked on August 22,1984,at 56,300 cfs. Between the dates of original mapping and checking,a peak flow of 82,000 cfs occurred.By the time of the later field checking,some of the gravel bars had increased in size and changed location. Even though channels within side channel complexes display gravel bar shifting on a relatively short time scale as a result of moderately high flow events,the wetted surface area response to discharge is generally repeatable.This is because of the apparent dynamic equilibrium of the R23/1 31 river as a whole.The net effort being that habitat lost (or gained)within a given reach is replaced (or lost)elsewhere (Glova and Duncan,1985). -23- R23/1 32 4.0 MORPHOLOGIC RESPONSE OF SIDE CHANNEL COMPLEXES 4.1 General Braided rivers are dynamic systems whose channel shapes change significantly with only moderately high flow events.As the river channel shifts across the floodplain,some gravel bars form,become vegetated and increase in size while other bars and/or islands erode.The purpose of this assessment is to quantify the natural change in vegetated island shapes in the representative areas studied in Section 3.0. The rate of change or shifts in thalweg position or in erosional changes is very difficult to determine between successive sets of photography. Changes could occur at a constant,uniform rate or they could be the result of sudden,brief episodes occurring at a given time somewhere between the photo dates. Establishment and growth of vegetation on gravel bars provides some indication of a period of relative stability.However,due to the time period between photo dates,periods of stability with vegetation growth may be interspersed with periods of high erosion.Therefore,it is difficult to interpert channel stability from photos when an obvious trend is not evident... In some reaches of the river the main low water channels have been shifting from the west side of the floodplain to the east side;in other reaches the low water channels are shifting from east side to west side. In some areas,the low water channel has been shifting from a single low water to a split low water channel.As the channel meander moves down valley,areas which have been stable for a relatively long time (islands with tall cottonwoods)are being eroded away. During the.photo analysis it was noted that most of the channel changes. occurred outside of the study areas but that some of these changes R23/1 33 affected the study areas.A significant change that occured in the side channels was log jams.As relatively stable islands are eroded the trees fall into the river and are swept downstream.Jams may form at the heads of a side channel creating a low velocity area where sand and silts deposit.Over time these areas may aggrade thereby raising the elevation of the berm at the head of the side channel and increasing the discharge required to overtop it. 4.2 Methods There are eleven complete sets of aerial photos of the lower river.For evaluating the morphologic change,four sets of photography spaning the years from.1951 to 1983 were selected.Photography was obtained for the following dates:July 3,1951,1962,and 1963,August 24,1980,August 27 and September 16,1983.The 1962 and 1963 photography covered different portions of the river,therefore only one date was used on any particular portion of the river. The photographs were taken at different flows,therefore only relatively large morphologic changes such as large scale deposition or erosion of vegetated islands and the relative position of major channels were compared.Detailed changes in channel cross-sectional shape,breaching discharges or debris jam _position could not be discerned from the ._photographs. Since the photography was taken at different scales,changes were normalized by scaling stable features in the photographs.The level of precision of this method was sufficient for studying relative morphologic changes..-Changes were .delineated .on the September 16,1983 photography.Caswell Creek and Sheep Creek were delineated on the August 27,1983 photography because they were not covered in the- September 16th photography.The August 24,1980 photography was used -to evaluate trends and shifts in trends but was not included in the figures 24- R23/1 34 because of the slight differences from the September 16,1983 photography. 4.3 Site Specific Descriptions SC IV-4 Between 1964 and 1980,the west mainstem low water channel shifted towards the west bank.The east mainstem low water channel between 1980 and 1983 started eroding gravel bars on the west side of the side channel complex downstream of Hooligan Side Channel (Figure 4.1).The bar at the head of Hooligan Side Channel has grown since 1951.Within the side channel complex itself,major changes are an increase in size and vegetation of small gravel bars.Since 1951 a small island downstream of the ADF&G Eagles Nest study site has eroded away., Willow Creek (SC 111-1) The width of the main channel through the study area has decreased from 1951 to 1983.Gravel bars in the channel are increasing in size and becoming vegetated (Island A,Figure 4.2).The gravel bars in the northwest corner of the study site are becoming more stable and vegetated.The entrance to the side channel complex from the east mainstem channel increased in size from 1962 to 1980.The channel at the mouth of Willow Creek has remained relatively stable since 1951. Caswell Creek Caswell Creek channel has been relatively stable from 1951 to 1983 (Figure 4.3).Since 1951 the side channel at the mouth of Caswell Creek has been shifting to the west away from Caswell Creek.This has caused an increase in the length of the low water channel from the creek mouth to the side channel. *,ty3as”_PeteOk.oeéjRigRCI Sh tie! En Si os eeea8&,Leal a:4 Pei aRehMaesRE FT has at,; ted pas "ce,>%Pe ye vceoa "iz 4ayFSARs aaaeatens LEGEND VEGETATED BANKS:- 195%.DATE OF PHOTOGRAPHY:9/16/83 . 1962 rrr TTT .00 500 9 1000 : .GRAPHIC SCALE:P=dt FT PREPARED FOR:PREPARED BY:| FIGURE 4.42MEWT&A COMPARISON OF VEGETATED RIVERBANKS MARZ /A°EBASCOR&M CONSULTANTS,INC.SRNR eT eesTreTs --AND ISLANDS 1951,1962 and 1983:SUSITNAJOINTVENTUREENGINEEASGECLOGISTSMYDROLOOISTSBUAVEYORS .Sc IV-4 ; -S PREPARED BY: _=2YSM EWT&A R&M CONSULTANTS,INC. ENGINESAS GEOLOGISTS HYDAOCLOGISTS SURVEYORS 8 WOUDD FHINEY &sent lates -LEGEND VEGETATED BANKS: 1951 1962 rrrTT TASES oe FIGURE-4.2 PREPARED FOR: DATE OF PHOTOGRAPHY:9/16/83 HARZAs EBASGO =ee $ed SUSITNA JOINT VENTUREGRAPHICSCALE:eeeee ET 8/27/88 $00en eee err PREPARED FOR -DATE OF PHOTOGRAPHY: tintLePeat:Pit ReesSahe hires Aue POG eines, Soe 4 Tee Yenhaveeae 5 SHEEP CREEK CASWELL CREEK.3F e Cmt nSoS. Lax . . GRAPHIC SCALE FIGURE 4.3 HARZAEBASGO SUSITNA JOINT VENTURESHEEPCREEKANDCASWELLCREEK COMPARISON OF VEGETATED RIVERBANKS AND ISLANDS 1957,1962 and 1983EWT&A #WOULT TRIMEY &ASM EaEES > R&M CONSULTANTS,INC. ENGINEERS GEOLOGIGTS HYDROLOGIETS SURVEYORS| PREPARED BY: R23/1 35 Sheep Creek In 1951 the majority of the flow was on the east side of river flood- plain.From 1980 to 1983 the majority of flow shifted from the east side of the river to the west side of the river away from the mouth of Sheep Creek.Sheep Creek is now flowing into a side channel of the mainstem which may continue decreasing in size under natural con- ditions (Figure 4.3). Goose Creek (SC 11-4) The main mainstem channel has been shifting to the west since 1951. Erosion is limited,with the dominant process being deposition on and around gravel bars and islands,with vegetation covering these newly stable areas.Island A (Figure 4.4)was a.slightly vegetated gravel bar in 1951 with the extent of vegetation increasing as the bar became more stable.In 1951 the head of side channel B was a diverse set-of gravel bars (Figure 4.4).Since 1951 the head of the side channel has become more stable and decreased the amount of water that could enter this channel.Between 1963 and 1980 a debris jam formed near the mouth of Goose Creek diverting a portion of the creek flow into side channel C (Figure 4.4). . Montana Creek (sc J1-1) The side channel complex has aggraded since 1951,especially near the creek mouth (Figure 4:5).The mouth of Montana Creek shifted in the upstream direction between the 1951 and 1962 photographs, shifted downstream between 1962 to 1980 and upstream again between 1980 to 1983 (Figure 4.5}.The island near the upstreamend of the east side channel has become more vegetated since 1951.The interior of the side channel complex is relatively stable with limited aggradation and vegetation growth. -28- R23/1 36 Sunshine Slough (SC I-5) Sucker Side Channel has become narrower with vegetation encroaching on the channel (Figure 4.6).The islands near the ADF&G Sunrise and Sunset study sites have become more stable,transitioning from gravel bars to vegetated islands from 1951 to 1984 (Figure 4,6).The head of Beaver Dam Slough has become more stable.The main channel has shifted slightly east so it impinges on the side channel complex and has caused relatively rapid erosion at point A (Figure 4.6).Debris jams within the side channel complex are causing areas of aggradation,increasing the stability of the gravel bars. Birch Creek The upstream end of Birch Creek Slough is on the outside of a thalweg meander in a relatively stable area.The slough itself is stable,with little or no change since 1951.The downstream end of the slough is on the inside of a thalweg meander.Islands at the slough mouth have eroded away between 1951 and 1962 (Figure 4.7). Since 1962 the slough confluence with the mainstem has been into a side channel.The frequency of flushing flows through the slough is affected by a road across the slough to access a timber sale area (Figure 4.7). 4.4 Results and Discussion In general the representative areas evaluated in this report are stable. Individual bars and islands along the perimeter of each representative area may be eroding or aggrading as the mainstem channels shift location. However,the central portion of the side channel complexes are stable. Dramatic changes in channel position and form may occur whenever the river reaches bankfull stage.At bankfull stage,gravel in the active S Wee f EY J i Be -a yas ep Riccar aE SeLEGENDSeRES,MS ens:ro Aa TE anc ReROE SS sda RRS tions eek Na VEGETATED BANKS:DATE OF PHOTOGRAPHY:9/16/83 19962 eras GRAPHIC SCALE:ag RR PREPARED BY:}" .PREPARED FOR: :COMPARISON OF VEGETATED RIVERBANKS __Ficune 4.4CcS::[a )Soa WTA AND ISLANDS 1951,1962 and 1983:HARZA*EBASCO RSM CONSULTANTS,INC. RNGINESRS GEGLOOGISTS HYDACLOGISTS SURVEYORS GOOSE CREEK 1 of 2 "SUSITNA JOINT VENTURE a - 2 CHAN geek 8:tee Wes we as iene LEGEND Spescal ee CHATS WS Pint fiycawSA 3 VEGETATED BANKS:. . DATE OF PHOTOGRAPHY:9/16/83 tee2 sree .GRAPHIC SCALE:TN aeeeoe COMPARISON OF VEGETATED RIVERBANKS |Fisure4-4 |PREPARED FOR: |SYN,oe c 7 :oaMnm|LWT RA AND ISLANDS 1951,1962 and 1983:HARZA*EBASGO wac.oomre wy te euavavona : .;GOOSE CREEK 2 of2 SUSITNA JOINT VENTURE LEGEND VEGETATED BANKS: 1951 t 1962 rrr PREPARED BY: DATE OF PHOTOGRAPHY:9/16/83 tooo $00 °O00GRAPHICSCALE;NNeSET ISM R&M CONSULTANTS,INC. ENGINEERS BECLOTGIGTS HYDROLOGISTS SURVEYORB EWT&A =------ &WOUDY TRIMS &ADnemrateN COMPARISON OF VEGETATED RIVERBANKS _AND ISLANDS 1951,1962 and 1983: MONTANA CREEK FIGURE 4.5:PREPARED FOR:; HARZAcEBASGO SUSITNA JOINT VENTURE LEGEND VEGETATED BANKS: 1951 1962 rrr TTT PREPARED BY:FIGURE 4.6.PREPARED FOR: isu EWT&A COMPARISON OF VEGETATED RIVERBANKS : SUG Na?«[===ee}«0-C("-:”*«*SANND:ISLANDS 1951,1962 and 1983:|HARZA*EBASGO aroLoowre wyonoLoawere suavevons SUNSHINE SLOUGH 1 of 2 SUSITNAJOINTVENTURE LEGEND VEGETATED BANKS: 4951 1962 on odie wie ie le ie =DATE.OFPHOTOGRAPHY:9/16/8310003001000SFT.GRAPHICSCALEPREPARED BY: _2IsM EWT&A R&M CONSULTANTS,INC. SNGINEERS DECLOGISTS HYOROLOO!ISTS SUAVEVYORS &WOULD TRIKEY &ASM DATES COMPARISON OF VEGETATED RIVERBANKS AND ISLANDS 1951,1962 and 1983:SUNSHINE SLOUGH 2 of 2 FIGURE 4.6 PREPARED FOR: RHARZA"EBASGCO SUSITNA JOINT VENTURE LEGEND VEGETATED BANKS: 1951 1962 rrr DATE OF PHOTOGRAPHY:8/27/83 GRAPHIC SCALE:a PREPARED BY:a PREPARED FOR:COMPARISON OF VEGETATED BANKS FIGURE 4.7=EWT&A RIVER R&MCONSULTANTS,INC. onrou!Te HY TS SURVEYORS #BOUNTY TREETY &Ape neits _AND ISLANDS 1951,1962 and 1983:BIRCH CREEK SLOUGH 1of 2 HARZA*EBASGCO SUSITNA JOINT VENTURE gasreisB73i,ee a?BIRCH CREEK SLOUGH 2 of 2 ee > Geer ase ee LEGEND :; VEGETATED BANKS:DATE OF PHOTOGRAPHY:8/27/83 1902 rrr ;GRAPHIC SCALE:ee PREPARED BY:PREPARED FOR: |COMPARISON OF VEGETATED RIVERBANKS FIGURE 4.7SMEWT&A |27 [Al °(E[8SSTNe|e -AND ISLANDS 1951,1962 and 1983:ARZA?EBASGO SUSITNA JOINT VENTURE R23/1 37 floodplain scours and fills as bed material is moved down valley.The main channel may change its location dramatically,intercepting other channels at different locations causing them to readjust.In general,the channel geometry of the main channel remains uniform as it changes location within the floodplain.Minor channels respond to processes such as main channel and major side channel changes of location,debris jam formation and local sediment movement. Debris jams influence the meandering pattern of major subchannels,while they may control the overtopping discharge of side channels.Debris jams form,increase and decrease in size during floods approaching bankfull stage.When the debris jams increase in size they can increase the overtopping discharge for a side channel. -36- R23/1 38 5.0 COMBINED EVALUATION OF LOWER RIVER SIDE CHANNEL COMPLEXES 5.1 General The response of wetted surface areas are affected by factors other than discharge,including:channel cross-sectional shape,channel gradient, stability of 'the channel bed,and whether the wetted surface area was delineated on the rising or falling limb of the hydrograph.The response of individual channels within a side channel complex is similar for both the middle river and lower river.However,the response of an entire side channel complex in the lower river will be different than for a given section of the middle river.The difference is due to the combination of major,intermediate and minor channels providing replacement wetted surface areas as the mainstem discharge decreases.The influence of each of these factors is detailed below. 5.2.Channel Hydraulic Parameters The morphology of channels within side channel complexes (e.g.the cross-sectional shape,gradient of the channel and bed material)controls the manner in which the channels respond to changes in discharge.For example,the rate of change of wetted surface area for decreasing- discharge will be greater for a wide shallow channel than for a narrow deep channel.In a plot of discharge vs.wetted surface area,a steep line will generally indicate a side channel complex with more numerous gravel bars and fewer narrow deep channels than does a line with a flatter slope. An exception occurs when the mean streambed elevation of the channels of a particular side channel complex are high relative to other side channel complexes.These complexes dewater at a higher discharge,such as at SC I1-9 (Figure 2.3). Goose Creek Side Channel Complex (SC II-5)contains predominately wide shallow minor channels,some of which dewater at 59,100 cfs.The. R23/1 39 intermediate side channels transform to turbid backwaters and side sloughs at 36,600 cfs and dry up at 21,100 cfs.In contrast,SC IV-4 is an example of a side channel complex with many relatively narrow deep channels which predominately start dewatering below 36,600 cfs. These two side channel complexes have approximately the same total wetted surface area at 75,200 cfs -16.07 million square feet for SC IV-4 as compared to 16.93 million square feet for Goose Creek (Table 3.3). However,at 36,600 cfs the total wetted surface area for Goose Creek is 9.66 million square feet,whereas SC !IV-4 has 12.34 million square feet. Side channel gradient controls the rate at which a channel may make the transformation from a turbid backwater to a clear water area.Given the same upstream berm elevation,channel length and relative position in a side channel complex,a channel with a steeper gradient may have more water in the lower portions of channel than would a flatter gradient channel.This is due to the backwater effect of the mainstem on the downstream end of the channel. 5.3 Aerial Photography Air photo.interpretation is highly dependent on the quality of the photography..Although each set of photographs used in this study were generally of high resolution,the time of day,date,and prevailing weather | conditions at the time the aerial photographic missions were flown affected the extent to which detailed riverine features were visible.The 13,900 cfs photographs,obtained on October 25,1983,were taken after ice had begun to form along the river and a light snowfall had covered the ground.This made determination of the water's edge more difficult. The remainder of the photography was obtained in late August through mid-September.At this time of the year combination of sun angle and well-developed deciduous'foliation resulted in extensive shadows along the south shorelines.These shadows sometimes obscured the water's edge and -37- R23/1 40 made surface area delineations difficult.This was the reason Birch Creek Slough was dropped from our analysis.The shadows made it impossible to accurately delineate the change in wetted surface area with discharge. There were problems encountered using aerial photography from two different years and in delineating the 1983 photography using ground truthing obtained in 1984.Most of the problems dealt with 1984 observations of gravel bars of larger sizes and in different locations than in the 1983 photography. Whether the photographs were taken on a rising,falling,or steady stage influences the habitat type,specifically whether a channel is classified a clearwater area or turbid backwater.On a rising stage an intermediate side channel could be a clearwater area or side slough if there has been sufficient time between periods of overtopping flow for the channel water to clear up.On a falling limb,an intermediate side channel could be a turbid backwater if the aerial photography were taken immediately after the berm dewatered.If the channel was influenced by upwelling then as the discharge continued to drop,the turbid backwater would transform to a side slough.If upwelling was not present,the channel would remain a turbid backwater until the water cleared by settling of the sediment.This was noticed at SC IV-4 between the 36,600 cfs and 21,100 cfs photographs. The following is a description of the flow regimes when the aerial photographs were taken. Discharge (cfs) Date at Sunshine Flow Regime 08/27/84 75,200 a rapidly falling stage 08/27/83 59,100 at or near a peak stage 09/06/83.36,600 a slowly falling stage 09/16/83 21,100 a slowly falling stage near base flow 10/25/83 13,900 a slowly falling stage near base flow,some local ice effects R23/1 41 5.4 Summary In general,the habitat surface area response curves for the lower river study areas appear different than those for the middle river (as presented in Klinger and Trihey,1984 and Klinger-Kingsley,1985).Differences and certain similarities exist between the lower river and the middle river which help explain the surface area responses.The middle river is a single or split channel river whereas the lower river is a braided channel with many more channels present in a given length of the river than for the same length in the middle river.This results in a greater buffering or dampening effect on the habitat type surface area response for the lower river than for the middle river.The net loss or gain of a given habitat type within the lower river viewed as a whole may be minor.In contrast,with fewer channels in a given length of the middle river,this buffering effect is less pronouced,and the surface area response curves are more directly linked to changes in discharge.Looking at isolated channels within lower river side channel complexes reveals similar processes occurring as in middle river channels. The concept of braided rivers providing a relatively stable amount of low velocity wetted surface area for a range of discharges is supported by detailed studies of New Zealand braided rivers (Mosley,1982,Glova and Duncan,1985).Mosley (1982)found for braided rivers in New Zealand that the surface area associated with shallow,slow water remained relatively constant over a wide range of flows,even though the physical location changed.-This is because braided rivers are composed of numerous channels with a range in sizes and overtopping discharges,thus providing a more stable wetted surface area response to changes in discharge than a single-thread channel. -38- R23/1 42 REFERENCES Glova,G.J.and M.J.Duncan.1985.Potential Effects of Reduced Flows on Fish Habitats in a Large Braided River,New Zealand. Transactions of the American Fisheries Society.Vol.114.Pages 165-181. Klinger-Kingsley,S.A.1985.Response of Aquatic Habitat Surface Areas to Mainstem Discharge in the Talkeetna-to-Devil Canyon Reach of the Susitna River,Alaska.E.Woody Trihey and Associates.Draft Report for Alaska Power Authority,Susitna Hydroelectric Project, Anchorage,Alaska. Klinger,S.and E.W.Trihey.1984.Response of Aquatic Habitat Surface Areas to Mainstem Discharge in the Talkeetna to Devil Canyon Reach of the Susitna River,Alaska.E.Woody Trihey and Associates. Report for Alaska Power Authority,Susitna Hydroelectric Project, Anchorage,Alaska.Document No.1693.1 Volume. Mosley,M.P.1982.Analysis of the Effect of Changing Discharge on Channel Morphology and Instream Uses in a Braided River,Ohau River,New Zealand.Water Resources Research.Vol.18,No.4 Pages 800-812. R23/1 43 EXHIBIT A Aerial Photography Showing Mainstem and Side Channel Classifications of the Lower Susitna River. DATE OF PHOTOGRAPHY:SEPTEMBER 16,1983 LOWER SUSITNA RIVER DISCHARGE AT SUNSHINE:21,100 cfs 2000 1000 °2000 4000 SCALE IN FEET PREPARED BY: BYSINW EWT&A |.FIGURE A=-14 MAINSTEM AND SIDE CHANNEL MORPHOLOGIC CLASSIFICATION R&M CONSULTANTS,INC.&WUT TRENT &ASM EATEN RIVER MILE PREPARED FOR: HARZA*EBASGO SUSITNA JOINT VENTURE TEE AS;See PaisRW RES Ns 2000 1000 [e)2000 4000 LOWER SUSITNA RIVER a aDATEOFPHOTOGRAPHY:SEPTEMBER16,1983 DISCHARGE AT SUNSHINE:21,100 cfs SCALE IN FEET PREPARED BY: 7 . : .| FIGURE A o PREPARED FOR: =SM EWT&A MAINSTEM AND SIDE CHANNEL MORPHOLOGIC CLASSIFICATION IZMIR 72 /A\2 EBASCO R&M CONSULTANTS,INC. o2o0t'Te HY Te BURVEYORG t BOUDY TRINES &ASSULLATES RIVER MILE 90 TO 95 SUSITNA JOINT VENTURE Berkeeeeey,Yaar ¥, sy inure SEG aESRSS AMET ee 5 ”.wage he:el eB ei B:*BeetBeneNT dor SAGAR EE REE SENAS Shp Z AS Soe ii es SS RaSh ae LID EA Ao REE TAS oF Bice SEM ee ROE mee ere Ae soe=f SENSE REN rapes e ;of >Sa Se ari %Sy NG ;,*Pais:-3 ne Pas Gee Nays woes %an uses ;BS = 2000 1000 °2000 4000 LOWER SUSITNA RIVER |nee ----a -----ness DATE OF PHOTOGRAPHY:SEPTEMBER 16,1983 DISCHARGE AT SUNSHINE:21,100 cfs SCALE IN FEET PREPARED BY:FIGURE A-3 PREPARED FOR: SM EWT&A MAINSTEM AND.SIDE CHANNEL MORPHOLOGIC CLASSIFICATION .AARZAsEBASCO R&M CONSULTANTS,INC,|!"RIVER MILE 84 .-TO 89 SUSITNAJOINTVENTUREaeoL!Te HY:Te SURVEYORS ah kene2a. 4000202000 s. ,100 cfs LOWER SUSITNA RIVER IN FEETSCALE21DISCHARGEATSUNSHINE1983SEPTEMBER16,DATE OF PHOTOGRAPHY BASGO GEOL LuCc>omZz{au}(u]>bez2'e)2saBe&op) q@aalaua©o5+i<Wwct=)9[rs 2°iPdoue7)0<olOoooOoagoOozrafengoo=0a2(«za<=oOFG 'woo> oe=?)Qa=<=Ww-79)z<=aieI:Bil:faUy23 "Le W)2ksakeJ053:>wsi)220w>|0o-4aihewedea.|OL)¢ stbe 4 PISSi}BNA enSAx eeve 0004202000 LOWER SUSITNA RIVER IN FEETSCALE21,100 cfsDISCHARGEATSUNSHINE1983|SEPTEMBER 16,DATE OF PHOTOGRAPHY BASCO uwlon5|zuy{u]>oD @w_-re)2<@so[N]2WWE«(0G3ailawioceoit9)1<iwfc=)4i z4rm<9L7”Pd ir (3)CoSo0°ae)=Fa«Ooww=onrrzwWza<28wu>Qcrra2<=-li77]z=<=Rif5U02uk2<oad.|2oo2a020o=¢ayeawt,)a=00 TS BURVEYORSTeHV®&ono. LOWER SUSITNA RIVER bond Porahe”De 6 ee canA=Vw oR 4 2000 $000 is)2000 4000 DATE OF PHOTOGRAPHY:SEPTEMBER 16,1983 DISCHARGE AT SUNSHINE:21,100 cfs SCALE IN FEET PREPARED BY: : ) . FIGURE A-6 PREPARED FOR: Sem EWT&A MAINSTEM AND SIDE CHANNEL MORPHOLOGIC CLASSIFICATION IAAI ZZ/\2 EBASGO R&M CONSULTANTS,INC, TS SUAVSYORS@eoLTsHY B WNT FINE &ANDOU EARES RIVER MILE 7 14 TO 76 SUSITNA JOINT VENTURE eats:: :eleyayitedRePiro DATE OF PHOTOGRAPHY:SEPTEMBER 16,1983 2000 1000 °2000 4000 LOWER SUSITNA RIVER DISCHARGE AT SUNSHINE:21,100 cfs SCALE IN FEET PREPARED BY: _SisM EWT&A R&M CONSULTANTS,INC. @rOL Te HY TS GUAVEYOR®S e ROOOY TIME &Se TATE PREPARED FOR:. HARZA-EBASGO SUSITNA JOINT VENTURE . ;FIGURE A-7 MAINSTEM AND.SIDE CHANNEL MORPHOLOGIC CLASSIFICATION RIVER-MILE 67 TO 72 aes Se .BS A Sr LOWER SUSITNA RIVER >mat,oAeye 2000 1000 (°]2000 4000 SCALE IN FEETDATEOFPHOTOGRAPHY:SEPTEMBER 16,1983 . . DISCHARGE AT SUNSHINE:21,100 cfs PREPARED BY: SSN)EWT&A |MAINSTEM AND.SIDE CHANNEL MORPHOLOGIC CLASSIFICATION RSM CONSULTANTS,INC.7 Bowen mines e somuneanes RIVER MILE 63 TO 62 OBO.Te HY TS SUAVEYORS FIGURE A-s PREPARED FOR: HARZAEBASGCO SUSITNA JOINT VENTURE Rg tate oe xENS '"A os a me a-Spooks 5 l Pte eiRteAprey KASHWITNA RIVER 2000 1000 °'2000 4000 LOWER SUSITNA RIVER DATE OF PHOTOGRAPHY:SEPTEMBER 16,1983 DISCHARGE AT SUNSHINE:21,100 cfs SCALE IN FEET PREPARED BY:FIGURE A-9 PREPARED FOR:- =I EWT&A MAINSTEM AND SIDE CHANNEL MORPHOLOGIC CLASSIFICATION HARZA°EBASCO RSM CONSULTANTS,INC.b BWUUDY TRENDY&ASD EATES RIVER MILE 5 9 To 65 . SUSITNA JOINT VENTURESRBGEOLTeHYTSSURVEYORS Spr Wag>, ENOINESRD GHEOLOOIBTS HYDROLOGISTS BURVEYORS 2000 1000 (°)2000 ..4000 LOWER SUSITNA RIVER le|DATE OF PHOTOGRAPHY:SEPTEMBER 16,1983 DISCHARGE AT SUNSHINE:21,100 cfs SCALE IN FEET PREPARED BY: |FIGURE A-10 PREPARED FOR: =I EWT&A MAINSTEM AND SIDE CHANNEL MORPHOLOGIC CLASSIFICATION AI/ARZ/A\2 EBASGOR&M CONSULTANTS,INC.-_RIVER MILE 56 TO 59 .SUSITNA JOINT VENTURE 1h:eia 400020)2000 LOWER SUSITNA RIVER DISCHARGE AT SUNSHINE IN FEETSCALE PREPARED FOR 21,100 cfsDATEOFPHOTOGRAPHY:SEPTEMBER 16,1983 -11FIGUREA ="EBASGORAIRZAMAINSTEMANDSIDECHANNELMORPHOLOGICCLASSIFICATION SUSITNA JOINT VENTURETO5754RIVERMILE EWTS&A ©WOLD TRINES &ASKER TAHES PREPARED BY: aS R&M CONSULTANTS,INC. ENQGINGERS GECLOOISTS HYPACLOGISTS SURVEYORS onREE?é oR ,2000 1000 )2000 4000 LOWER SUSITNA RIVER sn memee DATE OF PHOTOGRAPHY:SEPTEMBER 16,1983 DISCHARGE AT SUNSHINE:21,100 cfs SCALE IN FEET PREPARED BY: ,|| FIGURE A-12 PREPARED FOR: =SIV EWT&A |MAINSTEM AND SIDE CHANNEL MORPHOLOGIC CLASSIFICATION RARZAcEBASCOR&mM CONSULTANTS,INC.-_-_-_-_-_-.RIVER MILE 51 TO 53 SUSITNA JOINT VENTURE 00040002 LOWER SUSITNA RIVER SCALE21,100 cfs .DISCHARGE AT SUNSHINESEPTEMBER16,1983DATEOFPHOTOGRAPHY IN FEET EBASGO uwCcD>kFzLJ>omz0,2OeasoN2«(053aalawla©OS©-{<Wwa24rey 4°-<3)us””<po]Oo©6Oowwgo«COzsFa,fendoo=«<a2Wwza<2oF-Wwy>og”)Qz<=WwWK-”zC-¢=Gilioe2sa)2u)kK2<.|2>C)22OwSiu<qaRyleaw (a7=(04 TS SURVEYORSTesHYao. 4 ; n ts'S Oe yar hakaeeR hg 4 TT AA en. f fe bod ond ce weCM E TEE SR SPAS x . 5ae'e! 4 ; " See op ee iy. < Bo ttt a mete . yo Srocmtii 40002000 IN FEET SUSITNA JOINT VENTURE SCALE PREPARED FOR: HARZA*EBASCO 2000 1000 FIGURE A 14 TO 47 DISCHARGE AT SUNSHINE:21,100 cfs RIVER MILE 45 LOWER SUSITNA RIVER MAINSTEM AND SIDE CHANNEL MORPHOLOGIC CLASSIFICATIONEWT&A ©BOUOT FRINEY &ASK EATS TS SUAVEVYORSTeWYReGEOL R&M CONSULTANTS,INC. PREPARED BY: te Y_ DATE OF PHOTOGRAPHY:SEPTEMBER 16,1983 ns. weg '$a "sib: wf tee eeni Hesetanl ayaah cane inprrg ts ; ' ; Eng Bipat ee Ae eygetee SSPE SESGA Aa@ FLAS Bath ero Sane Ried Nh oe . ia TRROS ay St Rex CSayer 0004200020001000LOWERSUSITNARIVER IN FEETSCALE PREPARED FOR 21,100 cfsDISCHARGEATSUNSHINESEPTEMBER16,1983DATEOFPHOTOGRAPHY -15FIGUREA HARZA*EBASGOMAINSTEMANDSIDECHANNELMORPHOLOGICCLASSIFICATION RIVER MILE 43 SUSITNA JOINT VENTURETO44 EWT&A F WOUNT TRINEY &ASNOLIATES PREPARED BY: eSVAR&M CONSULTANTS,INC. Ta SUAVEVORSTe#YEOL oe Wr NNR ae ae LOWER SUSITNA RIVER cehit,AgadeLag sSAASe 2000 1000 ie]2000 4000 SaarDATE OF PHOTOGRAPHY:SEPTEMBER 16,1983 DISCHARGE AT SUNSHINE:21,100 cfs SCALE IN FEET PREPARED BY:.FIGURE A-16 PREPARED FOR: SIS MW EWT&A MAINSTEM AND.SIDE CHANNEL MORPHOLOGIC CLASSIFICATION AARZA2 EBASCOREMCONSULTANTS,INc.b BUUDY FMINE?&ASR EATEN RIVER MILE 3 9 TO 44aReGBOLTeMYiTSSUAVEYORS. SUSITNA JOINT VENTURE PLE Set °2000 1000 fe)2000 4000 LOWER.SUSITNA RIVER es cer ce DATE OF PHOTOGRAPHY:SEPTEMBER 16,1983 DISCHARGE AT SUNSHINE:21,100 cts :SCALE IN FEET PREPARED BY: _.FIGURE A-17 PREPARED FOR:. 2ISIM |EWTS&A |a MAINSTEM AND.SIDE CHANNEL MORPHOLOGIC CLASSIFICATION bead REM CONSULTANTS,INC.e "eom TRAMEY &ASNEM EATEN . ..VAR Z/N EBASG RIVER MILE 36 TO 41 ;_SUSITNA JOINT VENTURE ogo.Ts HY TS SURVEYORS PRRaN PD Tt Be eTsreeffFoeKaianes Rie .petgety7ern£8\batDATE OF PHOTOGRAPHY:SEPTEMBER 16,1983 PREPARED BY: LOWER SUSITNA RIVER ISM DISCHARGE AT SUNSHINE:21,100 cfs aR GEOL EWT&A REMCONSULTANTS,INC. 2000 4000 it } SCALE IN FEET PREPARED FOR: HARZAEBASGCO _ SUSITNA JOINT VENTUREFBUGOYTAIMEY&ASNUOLEATESN Te Hy TS BUAVEVORS MAINSTEM AND SIDE CHANNEL MORPHOLOGIC CLASSIFICATION FIGURE A-18 RIVER MILE 34 To 37 Ihs x "+4 u c ee RAD oe”he Mw,.Shy sm Rieeeaeete , 2000 1000 0 ;2000 4000 LOWER SUSITNA RIVER DATE OF PHOTOGRAPHY:SEPTEMBER 16,1983 DISCHARGE AT SUNSHINE:21,100 cfs *SCALE IN FEET PREPARED BY:FIGURE PREPARED FOR: A-19ISM R&M CONSULTANTS,INC. TS SUAVEYORSGEOLTeHY EWT&A ©ROUDY TRINEY &ASM EATEN MAINSTEM AND SIDE CHANNEL MORPHOLOGIC CLASSIFICATION RIVER MILE 29 TO 3 5 AARZA*EBASGO SUSITNA JOINT VENTURE EXHIBIT B Aerial Photography for Selected Representative Areas Showing Habitat Types at Selected Mainstem Discharges. LEGEND CW CLEARWATER AREA MS MAINSTEM SS SIDE SLOUGH PSC PRIMARY SIDE CHANNEL T™TRIBUTARY MOUTH SSC SECONDARY SIDE CHANNEL T TRIBUTARY DATE OF PHOTOGRAPHY:8/27/84 .1000 500 °1000 TB TURBID BACKWATER .RIVER MILE GRAPHIC SCALE:ee eee FT PREPARED BY:SC IV A FIGURE B-1 PREPARED FOR: _aay EWT&A R&M CONSULTANTS,INC. BNOINEERG oucLogiste AYODROLOGISTS BUAVEYORS 8 WUT CRIMEY &ADNOLIATES DISCHARGE AT.SUNSHINE:75,200 cfs HARZA?EBASGCO SUSITNA JOINT VENTURE LEGEND CW CLEARWATER AREA MS MAINSTEM SS SIDE SLOUGH PSC PRIMARY SIDE CHANNEL TM TRIBUTARY MOUTH DATE OF PHOTOGRAPHY:8/27/83 SSC SECONDARY SIDE CHANNEL T TRIBUTARY 1000 500 i)100 TB TURBID BACKWATER ¢RIVER MILE GRAPHIC SCALE;-MDM®,ee FT PREPARED BY: SC Iv-4 FIGURE B-2 PREPARED FOR: Cc =__SSM EWT&A if HARZAsEBASGCO REM CONSULTANTS,ING.-DISCHARGE AT SUNSHINE:59,100 cfs GEOL Ts HY TS SUAVEYORS SUSITNA JOINT VENTURE NaratteYeta,re 74,besheresRE eaEEL,egi54"ea ATDOEPONE ae LEGEND CW CLEARWATER AREA MS MAINSTEM $$SIDE SLOUGH PSC PRIMARY SIDE CHANNEL TM TRIBUTARY MOUTH SSC SECONDARY SIDE CHANNEL T TRIBUTARY TB TURBID BACKWATER ¢ RIEVER MILE bi EgeRoeaynase ;f pugs:an ge ae SAeSROTALSadERD pond ¥eZ .- aErY ik aot."to ity ' "€©Pa. 3:32% ODE3! *find FSTN(o442)a pea Dy Neices DATE OF PHOTOGRAPHY:9/6/83 1000 §00 fe]1000.GRAPHIC SCALE:NeET PREPARED BY: isi EWT&A R&M CONSULTANTS,INC.F WOUDT CHIMEy &ASDOCTALES SNGINERRS GEQLOGISTS HMYDAOCLOOISTS SUAVEYOARS PREPARED FOR: AARZA*EBASGO SUSITNA JOINT VENTURE FIGURE B-3SCIV-4 DISCHARGE AT SUNSHINE:36,600 cfs LEGEND CW CLEARWATER AREA MS MAINSTEM SS SIDE SLOUGH OF P -; - PSC PRIMARY SIDE CHANNEL JM TRIBUTARY MOUTH DATE HOTOGRAPHY:9/16/83 SSC SECONDARY SIDE CHANNEL T TRIBUTARY 1000 500 ke]1000 TB TURBID BACKWATER *'RIVER MILE GRAPHIC SCALE: _FT PREPARED BY: SC IV-4 FIGURE B-4 PREPARED FOR: _SsM EWT&A :AARZA*EBASGO R&S&M CONSULTANTS,INC.e BVO Mee.&Asnamastes &. OROL:T®HYDROLOGISTS BSUAVEYORS DISCHARGE AT SUNSHINE:21,100 cfs SUSITNA JOINT VENTURE LEGEND cw CLEARWATER AREA MS MAINSTEM $$SIDE SLOUGH ,;, PSC PRIMARY SIDE CHANNEL TM TRIBUTARY MOUTH DATE OF PHOTOGRAPHY:10/25/83 . SSC SECONDARY SIDE CHANNEL T TRIBUTARY 1000 500 °1000 TB TURBID BACKWATER +RIVER MILE GRAPHIC SCALE:ee FT SM EWT&A R&S&M CONSULTANTS,INC. ENGINEERS GEOLOGIETS HYDAGLOGISTS BSUAVEVYORS &WUUDT PRIMEY &ANNOL LATED DISCHARGE AT SUNSHINE:13,900 cfs AHARZA:EBASCO SUSITNA JOINT VENTURE Bote ees PREPARED BY: SV EWT&A | R&E&M CONSULTANTS,INC. ENGINEERS GEOLOGISTS HYDROLOOISTS SUAVEYORG WET TMIN &ASM deers MS Psc ssc TB MAINSTEM PRIMARY SIDE CHANNEL SECONDARY SIDE CHANNEL TURBID BACKWATER CLEARWATER AREA SIOE SLOUGH TRIBUTARY MOUTH TRIBUTARY RIVER MILE oN oeaistasaeMS, EERETTie we HARZA*EBASGCO woo 500 °1000GRAPHiCSCALE;See my |SUSITNA JOINT VENTURE DATE OF PHOTOGRAPHY:8/27/84 PREPARED BY: _ism EWT&A R&S&M CONSULTANTS,INC. ANGINERRS GEOLOGISTS HYDAROLOGISTS SUAVEVOR® ©RODD TRIED &ASSENT ATES MS Psc ssc TB MAINSTEM ss PRIMARY SIDE CHANNEL ™ SECONDARY SIDE CHANNEL T TURBIO BACKWATER e CLEARWATER AREA SIDE SLOUGH TRIBUTARY MOUTH TRIBUTARY RIVER MILE POEGoSapagta,FIGURE B 7- ._DATE OF PHOTOGRAPHY:8/27/83 AARZAsEBASGO 1000 500 °wooGRAPHICscaLE:CE _ee CSUSITNA JOINT VENTURE TaNLS iade xh Ipateavesy 4::osVeHEYENiehoa ewe='«ieee, PREPARED FOR Sry bane¥..a -3FIGUREB 9/6/83 EBASGOoDATEOFPHOTOGRAPHYRAIRZA SUSITNA JOINT VENTURE 1000 FT 500}OOo GRAPHIC SCALE Cw CLEARWATER AREA Ss SIDE SLOUGHSsMAINSTEMSs PSC PRIMARY SIDE CHANNEL M TRIBUTARY MOUTH TRIBUTARY RIVER MILE ™ T °TURBID BACKWATER SSC SECONDARY SIDE CHANNEL 8T PREPARED BY: EWT&A 6 WOUDT FRIMPY &aesuelesINC. BNGINESAS GEOLOGIATR MYDAOCLOCOISTS SURVEYORS R&S&M CONSULTANTS PREPARED BY: 2eM-1 EWT&A R&M CONSULTANTS,INC. SNGINGEARS GECLOGISTS MYDROLOOISTS BURVEYORS b WOODY DHEY &Asm Estes MAINSTEM PRIMARY SIDE CHANNEL SECONDARY SIDE CHANNEL T TURBID BACKWATER ° CLEARWATER AREA SIDE SLOUGH TRIBUTARY MOUTH TRIBUTARY RIVER MILE FIGUREB- -9 DATE OF PHOTOGRAPHY:9/16/83 1000 500 to)1000GRAPHICSCALE:FREERELees 4 FT oy PREPARED FOR: HARZAsEBASCO SUSITNA JOINT VENTURE |-.gain ce:fe =ae fon :5 ae &:z =tN :nt :='y : ae Ant SH oeMoaeete? '."$*:=$ 'a B ': r,i > CLEARWATER AREA : .PREPARED FOR: SQV,MS MAINSTEM $$SIDE SLOUGH .eS VA EWT&A PSC PRIMARY SIDE CHANNEL TM TRIBUTARY MOUTH DATE OF PHOTOGRAPHY:10/25/83 AAR ZAs EBASCO , REM CONSULTANTS,INC.F Mamany pater ys ©apni nates SSC SECONDARY SIDE CHANNEL T TRIBUTARY ¥000 500 Co)1000 ENGINEERS GROLOGISTE HYDAOLOGISTS BUAVEYORS -TB TURBID BACKWATER e RIVER MILE .GRAPHIC SCALE:a FT SUSITNA JOINT VENTURE PREPARED BY:LEGEND cw 5 Seenpes oe oe cngen tyESSeesan7SaoeSeeay oe Fhe43ea =te gee et i gleMYSATEeaaBANesPeBN SeeSieeelclaeahKretaldeeeee3.5 et Che:*SERCHTE Se E AREA FOR 59,100 cfs WEVA aeLEGEND"GW CLEARWATER AREA is Rot MS MAINSTEM SS SIDE SLOUGH . . PSC PRIMARY SIDE CHANNEL TM TRIBUTARY MOUTH FACE AREA DATE OF PHOTOGRAPHY:8/27/83 "$SC SECONDARY SIDE CHANNEL T TRIBUTARY DATE OF PHOTOGRAPHY:8/27/84 1000 500 °1000 TB TURBID BACKWATER -'=__-sRIVER MILE oe oo re _.;GRAPHIC SCALE:P™™™"*"*ee FT PREPARED BY:; .FIGURE B -117.PREPARED FOR:aN ewrea] -§CASWELL CREEK ©NES''_-HARZA=EBASCORSMCONSULTANTS,INC.La”*MOUDY TRIMEY &senactetys -_ SUSIFNAJOINEVENTURES =>"T=>SNGINERAS..08OLOGISTS -MYDROLODISTS SUAVEVORS |*:coaiienienanl Bore ES .3: yipbg seePtpenta Betsos araSwiee Bae paaee =£2esAAeE ' Ri9 TER cephen WETTED SURFACE AREA FOR 13,900WETTEDSURFACEAREAFOR21,100 DATE OF PHOTOGRAPHY:8/27/83 v000 500 °1000 eee FT PREPARED FOR GRAPHIC SCALE FIGURE.B-12:CASWELL CREEK HARZA:EBASGCO RADab -Sentmtet iNT ot EWT&A D WEY PRIMED @ Asma Pates LEGEND CW CLEARWATER AREA SIDE SLOUGH TM TRIBUTARY MOUTH ssMAINSTEMMs PSC PRIMARY SIDE CHANNEL TRIBUTARY RIVER MILE SSC SECONDARY SIDE CHANNEL T TURBIO BACKWATERTs PREPARED BY S R&M CONSULTANTS,INC. TS BURVEYORS -Te HV-omc. Aah ed: Be 7 oy "i ¥fdSahatBRR ae oy ha :aot tBx.RES WAAR:"ae xms 8)AP , R&M CONSULTANTS,INC. BNOINEERS GEOLOGISTS HYDACLOGISTS SURVEYORS - ©WOUDY TIMED &ASR ALES DISCHARGE AT.SUNSHINE:75,200 cfs LEGEND CW CLEARWATER AREA MS MAINSTEM $$SIDE SLOUGH : PSC PRIMARY SIDE CHANNEL TM TRIBUTARY MOUTH DATE OF PHOTOGRAPHY:8/27/84 SSC SECONDARY SIDE CHANNEL YT TRIBUTARY 1000 500 °1000 TB TURBID BACKWATER °RIVER MILE GRAPHIC SCALE: _FT Y::ining B EWT SHEEP CREEK FIGURE B-13 PREPARED FOR _2isM &A HARZA*EBASGO LEGEND CW CLEARWATER AREA MS MAINSTEM SS SIDE SLOUGH PSC PRIMARY SIDE CHANNEL TM TRIBUTARY MOUTH SSC SECONDARY SIDE CHANNEL T TRIBUTARY TB TURBID BACKWATER °RIVER MILE WET TED SURFACE AREA FOR 36,60 reiS <p b Ties YCpa ;5 ae eit oP r+ ee 3 io . .2 ¥ ' ' j e ssWETTEDSURFACE AREA FOR 59,100 cfs ey Ei tes: fee ces . F iy 4 - crn e re,Z : 2 BisseBMEaAT Eo 5 J oro = '3 Fey es .Sor : 3 are 'ays : Ps 34 es aS Sek agin <we =:ne § x De penaray CF ot et SS ee hs Brees Bans apace Se PeEPTSL:A ane Set yg:36 5 eek z ? Ni.¥qjWeeOost,".Se 7 :¥; Ae >Lb,ae oY pias x oo iS ' nh oe, 2Y: OE ti Me Ss Cer ;"ee cfs pay hives oY. F- =ps, "ook at st: 2 es tes ca SOR.x =< (x B G te 43eit!%mh Sears 'a SS <=a = as qi rq - ah ss ex ers oe z, bs 3 ad x = aS < p Sigel 4 re ae 5 -; ow ia i & seit 4 et Serna? SAS eet rs DATE OF PHOTOGRAPHY:8/27/83 1000 500 C)1000GRAPHICSCALE:=_eee |FT PREPARED BY: _BISM EWT&A | R&M CONSULTANTS,INC. @szo0LU Te HY OGIeTsS SUAVEVYORS ©WON FmIEy &ASN DALES SHEEP CREEK FIGURE B-14 PREPARED FOR: HARZA*EBASGO SUSITNA JOINT VENTURE SPRoy LEGEND CW CLEARWATER AREA MS MAINSTEM $S SIDE SLOUGH PSC PRIMARY SIDE CHANNEL TM.TRIBUTARY MOUTH SSC SECONDARY SIDE CHANNEL T TRIBUTARY TB TURBID BACKWATER ¢RIVER MILE nancapeitynes4aa)wyWyatet*833,fH ay 3 Nee RAIL ote "BSiresBigetsaSPTCYope4x ; aera SEEN BdpoeSEO LAME PAsWETTED.SURFACE AREA FOR 21,1.Aes cis 5ce4 cf ts 'Ae hier ee @ at reSeiS730 Fé 3 es ag EF +, -aa oa ? = ny A ari ” 3 id Ot Sp $3 ¥,ve ns 4 2)ae rs ; a f x t Z : : 3 Bee Sec aiefree !PEER EN ms 'a upeaePoyers7; os aH Pe Ket oeee ast airs ;seek & :me,4g '"ass iP yt WETTED SURFACE AREA FOR 13,900 cfs ef Se :"A sheaPROTEASENOodwae3raaieSo aeRAhaeyai.%,AN.ot te a -e Ee was Sea ee pee Z if pee ra.¢ on '.Le te 3 fre sk aie pein ss a ae wen Melee DATE OF PHOTOGRAPHY:8/27/83 woo 500 Le)1000 |GRAPHIC SCALE;nSee FT PREPARED BY: SM EWT&A R&&M CONSULTANTS,INC. onc.Te HY OGISTS BURVEVYORS ©WAmETy TUNED ANNU LATS SHEEP CREEK DISCHARGE AT SUNSHINE:59,100 cfs PREPARED FOR: HARZA:EBASGCO SUSITNA JOINT VENTURE FIGURE B-15. CWCLEARWATERAREASIDESLOUGHTRIBUTARYMOUTHTRIBUTARYss™MAINSTEMPSCPRIMARYSIDECHANNEL$SCSECONDARYSIDECHANNELTLEGENDTBRIVERMILE°TURBIDBACKWATERaAiheSEYRSeeeonOs:PREISbeak PesRRAergMOLataTReaee deatRS . pie ae araaeHiESse5wes a?i taen rvenigcee PTsaeeke SeAPHY:8/27/84 $000 $00 ()1000GRAPHICSCALE:P=)FT PREPARED BY: 2M-__LU EWT&A | R&M CONSULTANTS,INC. OEOL Te HY!Ts sSURVEeYORGe ©Ward Coioev @ encm bares. GOOSE CREEK 1 of 2 DISCHARGE AT SUNSHINE:75,200 cfs FIGURE B-16 PREPARED FOR: HARZAEBASCO SUSITNA JOINT VENTURE a =z wok x bo») <.$«oer222z3zattfzees<3.2 a4guaows@pepeze2Oner« =Coz Re a wu az=2°568<wa=522oresal2zoaZZoe 'fZi<eu 5 :fis.it eS me if % 6 seer '.DATE OF PHOTOGRAPHY: megege . A 00 |$00 oO 1000.GRAPHIC SCALE;NSeeET PREPARED BY:FIGURE B-16 PREPARED FOR:ey EWT&A GOOSE CREEK2 of 2 | HARZA°EBASCO REM CONSULTANTS,INC.= DISCHARGE AT SUNSHINE:75,200 cfs SUSITNA JOINT VENTURE CWCLEARWATERAREAssLEGENDSIDESLOUGHMAINSTEMMSx - > ° = >>Wwaed «<<xr >>mmwWzaae2 ere = rere ad sy aziwZrz [4<0 wxowoaxwoox2>o aad ><?x 2a<2soaFock<u>aor oO Oooanr 000 500 0 1000GRAPHICSCALE:NSeesFT PREPARED BY: EWT&A REM CONSULTANTS,INC. SAS GEOL TS HYDAOLOGISTS SUAVEYORS ©WOMMDT TREEDY &ARNEN ESTES GOOSE CREEK 1 of 2 DISCHARGE AT.SUNSHINE:59,100 cfs FIGURE B-17 PREPARED FOR: AARZA*EBASCO SUSITNA JOINT VENTURE CWCLEARWATERAREALEGENDMSSIDESLOUGHss™MAINSTEMTRIBUTARYMOUTHPSCPRIMARYSIDECHANNELTRIBUTARYRIVERMILETt°SSCSECONDARYSIDECHANNELTURBIOBACKWATERTB.>oS os tr DATE OF PHOTOGRAPHY:8/27/83 .1000 500 °1000GRAPHICSCALE;nnesET PREPARED BY: SSM EWT&A | R&M CONSULTANTS,INC. gre GBOL'Tes HY TS SUSVEYORS -WAM CRIMETD ann tates. GOOSE CREEK 2 of 2 DISCHARGE AT SUNSHINE:59,100 cfs FIGURE B-17 PREPARED FOR: HARZAs EBASCO SUSITNA JOINT VENTURE Hin eh i ei ie.'teACCESS5PellWisgoon*FC Re Ree an ane CwCLEARWATERAREASIDESLOUGHTMTRIBUTARYMOUTHT>TRIBUTARYRIVERMILEdere syzMiseeS'eeSENG MAINSTEMPSCPRIMARYSIDECHANNELLEGENDPd _Sid2ta z at =of wso% >Oo c< P aFe=ee 8 4,A u 5 :PEA FE ESN as ;SRR ER RSI LER =>;DATE OF PHOTOGRAPHY:9/6/83 ”o , aor -1000 500 0 1000GRAPHICSCALE:2 _eT PREPARED BY: 2M EWT&A -GOOSE CREEK 10f2 FIGURE B-18 YAIR IN SBA REM CONSULTANTS,INC.1 WOUDT TRINEY&ASSO LA tts .SCO ENGINERAS BDECLOBISTR HYDROLOO!STR BUAVEVYORS .DISCHARGE AT SUNSHINE:36,600 cfs SUSITNA JOINT VENTURE SIDESLOUGH™MTRIBUTARYMOUTHCWCLEARWATERAREAT®83MAINSTEMPSCPRIMARYSIDECHANNEL MS'Pens eSnBRSt.TRIBUTARYRIVERMILETURBIDBACKWATERDATE OF PHOTOGRAPHY:9/6/83. woo $00 °1000GRAPHICSCALE;2ees FT8$CSECONDARYSIDECHANNELTBPREPARED BY:-- SM EWT&A _GOOSE CREEK 2 of 2 FIGURE B-18 PREPARED FOR: RSM CONSULTANTS,INC.PF SOUDY tmiMEy@AssUnTATE HARZA EBASGO pEOLoasTs HYoROLOUISTe sUAVevoRS DISCHARGE AT SUNSHINE:36,600 cfs SUSITNA JOINT VENTURE LEGENDCWCLEARWATERAREASIDESLOUGHMAINSTEMPSCPRIMARYSIDECHANNELMsTMTRIBUTARYMOUTHT*TRIBUTARYRIVERMILESSCSECONDARYSIDECHANNELTURBIDBACKWATERTBPREPARED BY: «3=9 at!e i #000 S00 ce]4000GRAPHICSCALE;2S ee ee ET ISM EWT&A | R&M CONSULTANTS,INC. QNGINEERG GHROLOGIETS HYDADOLOOIOTS SURVEYORS #WOODY TRING &SoM FATES GOOSE CREEK 1.of 2 DISCHARGE AT SUNSHINE:21,100 cfs FIGURE B-19 PREPARED FOR: HARZA*EBASGO SUSITNA JOINT VENTURE CWCLEARWATERAREAssLEGENDSIDESLOUGHMAINSTEMTMTRIBUTARYMOUTHT°PSCPRIMARYSIDECHANNELTRIBUTARYRIVERMILE) w z z < x=og wko25>oO(a¢<n z 9°o tgs 28%gs BLEED OF oO o nae Se vangSiMotBOSE d's iaasETRE Fhe.frgeiay im.% Pty wean sa ae ies 'BRE nieSeeee Nsi; 'eSSS Lea we"one oe eek "0,eTnfSeu A ee DATE OF PHOTOGRAPHY:9/16/83 .1000 §00 o 1000GRAPHICSCALE;neee ET PREPARED BY: SSE EWT&A | R&M CONSULTANTS,INC. UNGINEERS GHEOLOGIETS HYDAOLOGISTS BURVEYORS d WDL Emeldy &SOME dares FIGURE B-19GOOSECREEK2of2 DISCHARGE AT SUNSHINE:21,100 cfs PREPARED FOR: HARZA*EBASCO SUSITNA JOINT VENTURE CWCLEARWATERAREAssTMTRIBUTARYMOUTHToSIDESLOUGHTRIBUTARYRIVERMILEafl w d zr<°%woa<wo =aEPESsa<Zs €::ty pane eal eeO|zz ne ete :<r ak >se z Z ='5 Peemgee BOR yo AEN ep eee Rin ee Tees a ENS ates Oo -DATE OF PHOTOGRAPHY:10/25/83 Wleanna oe wa Fao 1000 $00.°1000GRAPHICSCALE:=ae \FT PREPARED BY:' . .PREPARED FOR: 2S2M 7 EWT&A GOOSE CREEK 1 of 2 Figure poe _ R&M CONSULTANTS,INC. SADOT Heine sa aoman nates -HARZA*EBASGO ENOINSERE GZOLODIATS HYDROLOGIeTs SURVEYORS - DISCHARGE AT SUNSHINE:13,900 cfs SUSITNA JOINT VENTURE CwCLEARWATERAREALEGENDSIDESLOUGHTMTRIBUTARYMOUTHMAINSTEMPSCPRIMARYSIDECHANNELusSROs veanaernge TRIGUTARYRIVERMILEko a w z z =og wka% »oO ee «<a za on 'Bons :Reet ; 8s ee an PE iat st rot -_TT. oe DATE OF PHOTOGRAPHY:10/25/83 oo Qr woo 500 o 1000GRAPHICSCALE;2ee FT SSM EWT&A _GOOSE CREEK 2 of 2 FIGURE B20PREPAREDBY:PREPARED FOR: BOS ne ||WTA MARZA >EBASCO BNGINERRS GEGLOGISTS HYDACLOGISTS SURVEYOR!™DISCHARGE AT SUNSHINE:13,900 cfs SUSITNA JOINT VENTURE ,eect rene teodPare ry "8 wt OOS:tons 'wi ,,sett SERN RY ER NT "3,alOr '* @uoch Ts HV Ta SUAVEVORE DISCHARGE AT.SUNSHINE:75,200 cfs LEGEND CW CLEARWATER AREA MS MAINSTEM $$SIDE SLOUGH . PSC PRIMARY SIDE CHANNEL T™M TRIBUTARY MOUTH DATE OF PHOTOGRAPHY:9/27/84 SSC SECONDARY SIDE CHANNEL T TRIBUTARY 1000 500 °1000° TB TURBID BACKWATER .RIVER MILE GRAPHIC SCALE:ee FT PREPARED BY:.FIGURE Be-21 PREPARED FOR: , Sey EWT&A MONTANA CREEK AARZA'EBASGO REM CONSULTANTS,INC.bP WEY TIRED&ASN BADEN SUSITNA JOINT VENTURE Sve®SP eS AER aN Fere 'oe re oemrenhee LEGEND 'GW CLEARWATER AREA MS MAINSTEM SS SIDE SLOUGH ' : PSC PRIMARY SIDE CHANNEL ™™TRIBUTARY MOUTH DATE OF PHOTOGRAPHY:8/27/83 SSC SECONDARY SIDE CHANNEL T TRIBUTARY "1000 500 0 1000 TB TURBID SACKWATER °RIVER MILE GRAPHIC SCALE:ET PREPARED FOR:PREPARED BY: 2sM EWT&A | REM CONSULTANTS,INC. ENGINEERS GEOLOGISTS MYPROLOOISTS BSUAVEYORG b WOLDS FUEL &ASD DATES MONTANA CREEK DISCHARGE AT SUNSHINE:59,100 cfs FIGURE B-22 HARZA*EBASGO SUSITNA JOINT VENTURE LEGEND CW CLEARWATER AREA MS MAINSTEM SS SIDE SLOUGH PSC PRIMARY SIDE CHANNEL TM TRIBUTARY MOUTH SSC SECONDARY SIDE CHANNEL T TRIBUTARY T8 TURBID BACKWATER ry RIVER MILE Py eetSalienaeee? 8 see sie.ie.133are OS reaFieaE,is *ate:..On a vr <a ede) DATE OF PHOTOGRAPHY:9/6/83 to00 500 °1000GRAPHICSCALE:P=ET PREPARED BY: EWT&A_ R&M CONSULTANTS,INC. ENGINEERS GEOLOGISTS HYDROLOGISTS SURVEYORS t WOODT TRIMEY &ASNOL ESTES MONTANA CREEK | DISCHARGE AT SUNSHINE:36,600 cfs FIGURE B-23 PREPARED FOR: HARZA*EBASGO SUSITNA JOINT VENTURE LEGEND CW CLEARWATER AREA MS MAINSTEM 'SS SIDE SLOUGH PSC PRIMARY SIDE CHANNEL TM TRIBUTARY MOUTH DATE .OF PHOTOGRAPHY:9/16/83 SSC SECONDARY SIDE CHANNEL T TRIBUTARY 1000 500 ()1000 TB TURBID BACKWATER °RIVER MILE 'GRAPHIC SCALE:EU PREPARED BY:FIGURE B-24 PREPARED FOR:: 7 .Sem EWT&A |.MONTANA CREEK AARZA?EBASGCOR&M CONSULTANTS,INC.*7?Simms smmans DISCHARGE AT SUNSHINE:21,100 cfs . BRS GEOL!Ts Hy OQGisTsS SURVEYORS -a SUSITNA JOINT VENTURE MONTAN CRE LEGEND CW CLEARWATER AREA MS MAINSTEM SS SIDE SLOUGH DATE OF PHOTOGRAPHY:10/25/83PSCPRIMARYSIDECHANNELTMTRIBUTARYMOUTH SSC SECONDARY SIDE CHANNEL T TRISUTARY TB TURBID BACKWATER ¢RIVER MILE 1000 500 [e]1000 GRAPHIC SCALE:P="FT PREPARED BY:FIGUREB-25-PREPARED FOR: _2M EWT&A .MONTANA CREEK MARZAEBASCO R&S&M CONSULTANTS,INC.b WOUDT FREY &ASM EVTEN DISCHARGE AT.SUNSHINE:13,900 cfs SUSITNAJOINTVENTURESNGINSERSGEOLOGISTSHYDAQLOGISTSSUAVEYORE ne ORGS ateeece , PERE AY Aor LENS 3 B|000! Beoa Mek x8 rd =ee"21V9OSSIHdVED i ) 608 0001 ye/L7/8 *AHdVYOOLOHd AO ALVGSoePEAENEeats, 23 raeRee 2TIW UZAYA¥UVINSIUL HLNOW AUVINGINLHONOTWS 21S vauy YaLVMeVaTS YBLVMNOVE GigunL |@L JBNNVHS agls AYVONOO]S oss JANNVHSD 2GIS AUVAIYd OSd W3LSNIVN SWqnNada1 %a5egJemw-oSa[N}$ul KE z(0GaaeO65ve)N|[ee]Ww[omg2(v]row. " 5O68rRo5a|wo3AWw+z<=3”«z=<x52vy)a<jclfx)30%2%ueFs:éHe . J? > "it a| |221}3=U3a,Volei=(oaa(UL ae aN eatingNdi2 1000 :8/27/8410005000a_SFT PREPARED FOR DATE OF PHOTOGRAPHY GRAPHIC SCALE TOASATSPt JW YBAleAuVingiat HLNOW AYVIAGIULHONO1S 2als VauV YaLVMYVE19 UBLVMNOVE Giaynl aL SENNVHSD 3018 AUVONODRS OSS JINNVHS 3GIS AUYWIEd Sd , W3LSNIVW SINGN3931 FIGURE B-26 "EBASCORARZASUNSHINESLOUGH.2 of 2 SUSITNA JOINT VENTURE75,200 ctsDISCHARGEATSUNSHINE EWT&A Pd WEED PRIME &ADM DALES .PREPARED BY NC ENGINESRE GEGLOGISTS MYDROLOOITSA SUAVEYORS R&M CONSULTANTS,| CWCLEARWATERAREALEGENDSIDESLOUGHssTMT°MSMAINSTEMTRIBUTARYMOUTHTRIBUTARYPSCPRIMARYSIDECHANNELSSCSECONDARYSIDECHANNELRIVERMILETURBIDBACKWATERTBey 3 «if LPs2Sbeet Ea. Ld SqrFeeHotAN+a8/27/831900050001000eeeeeeT'DATEOFPHOTOGRAPHYGRAPHICSCALEets PREPARED BY: EWT&A | RSM CONSULTANTS,INC. BABS @HaL Te HY TS BURVEVYORS WOT PRIMED &WenLAre SUNSHINE SLOUGH 1 of2 DISCHARGE AT SUNSHINE:59,100 cfs PREPARED FOR:. HARZA>-EBASCO SUSITNA JOINT VENTURE FIGURE B-27 CWCLEARWATERAREALEGENDSIDESLOUGHT™'™TRIBUTARYMOUTHT°MAINSTEMPSCPRIMARYSIDECHANNELTRIBUTARYRIVERMILE$SCSECONDARYSIDECHANNELTURBIDBACKWATERTB8/27/831000500[e)1000ceaseOTarsemneemme|FTDATEOFPHOTOGRAPHYGRAPHICSCALEPREPARED BY: SisM EWT&A REM CONSULTANTS,INC. ENGINEERS GEOLOGISTS MYDROLOGISTS SURVEYORS e ROUDS FRIMEL ©Semmttes SUNSHINE SLOUGH2 of 2 DISCHARGE AT SUNSHINE:59,100 cfs FIGURE B-27 PREPARED FOR: HARZAEBASGO SUSITNA JOINT VENTURE CWCLEARWATERAREAss™T°LEGENDSIDESLOUGHTRIBUTARYMOUTHMAINSTEMPSCPRIMARYSIDECHANNELMSTRIBUTARYRIVERMILESSCSECONDARYSIDECHANNELTURBIDBACKWATERTB9/6/83$00DATEOFPHOTOGRAPHY1000GRAPHICSCALEFTPREPARED BY: _ism EWT&A R&M CONSULTANTS,INC. QNGINERAS GECLOGISTS HYOROLOGISTS SUAVEYORS DP Wamrtry Ewere &ADM Ite SUNSHINE SLOUGH 1 of 2 DISCHARGE AT SUNSHINE:36,600 cfs FIGURE B -28 PREPARED FOR: AARZA EBASGO SUSITNA JOINT VENTURE :93/6/83 °1000 NR DATE OF PHOTOGRAPHY GRAPHIC SCALE BTW UaAlYAUVINgIUL HLNOW AuVINGtuLHONOS Jars VauV yaLVMHVIT9 waLVMNOVA Giauynl GL JANNVHO 30IS AHYVQNOS3S O66 JANNVHO 301S ABVAIEd 3Sd WALSNIVH SWGN3931 BASGCO Wwfom>keZi)ea2easa[N]=wWE=GS3aSlBea5[+3]N1aiwape]oueNen”) -_- -°o.|lCU?°oN6352205=oO3WwFr2irT°OQO<<=52WYa<i;CalleSIJreuiFkRF.|d2> th)maz°0aOWale=Ce TS HYDROLOGISTS SuAVEYORS@BOL: 4 aaa LEGENDCWCLEARWATERAREASIDESLOUGHMSMAINSTEMTRIBUTARYMOUTH™T°PSCPRIMARYSIDECHANNELTRIBUTARYRIVERMILE$8CSECONDARYSIDECHANNELTURBIDBACKWATERT3setaeSs ARGTSDI WifeMe NCSaoarBe 9/16/831000500)1000aFT'DATEOFPHOTOGRAPHYGRAPHICSCALEPREPARED BY: _SteM EWT&A R&M CONSULTANTS,INC. ENGINEERE GEOLOGISTS HYDROLOOISTS SURVEYORS b WOUND TRIMNEY &ASM EATEN SUNSHINE SLOUGH 1 of 2 DISCHARGE AT SUNSHINE:21,100 cfs FIGURE B-29 PREPARED FOR:HARZA°EBASCO SUSITNA JOINT VENTURE CWCLEARWATERAREAssLEGENDMSSIDESLOUGHMAINSTEMTMTRIBUTARYMOUTHT°PSCPRIMARYSIDECHANNELTRIBUTARYRIVERMILE$SCSECONDARYSIOECHANNELTURBIOBACKWATERTBDATEOFPHOTOGRAPHY:9/16/831000$001000FTGRAPHICSCALEPREPARED BY: _aisM EWT&A | RSM CONSULTANTS,INC. ENGINEERS GEOLOGISTS HYOROLOOIST®BUAVEVORS b WOUDS FAHEY &Annieres SUNSHINE _DISCHARGE AT SLOUGH 2 of 2 SUNSHINE:21,100 cfs FIGURE B-29 PREPARED FOR: HARZA*EBASGO SUSITNA JOINT VENTURE GWCLEARWATERAREALEGENDSIDESLOUGHTMTRIBUTARYMOUTHMAINSTEMPSCPRIMARYSIDECHANNELTRIBUTARYRIVERMILETt°ee SSCSECONDARYSIDECHANNELTURBIDBACKWATERTs4gaaTE:oNpoe ahi oe erates 10/25/83$00DATEOFPHOTOGRAPHY1000FTGRAPHICSCALE:PREPARED BY: etsy EWT&A RSM CONSULTANTS,INC.&WUT PRINPD&Asm DATES ENGINERAS GECLOGIGTS HYDROLOGISTS SURVEYORS PREPARED FOR:SUNSHINE SLOUGH 1 of 2 FIGURE Bose MARZA°EBASCO DISCHARGE AT SUNSHINE:13,900 cfs SUSITNA JOINT VENTURE >10/25/83 Qo 1000 EEE ET PREPARED FOR OF PHOTOGRAPHY GRAPHIC SCALE AR BASGCO[E . * i) SUSITNA JOINT VENTURE AR ZZA -30FIGUREB « 13,900 cfsDISCHARGEATSUNSHINE SUNSHINE SLOUGH 2 of 2EWT&A b WUD Times &ann tates,INC. Te Hy:BAS GEOL JTW WSAlY e UBLYMNOVG Gieauni AL AYUVINGIUL 1 'ANNVHS 30'S AUYVGNODAS OSS HLNOW AuVInNeIyL WL TANNVHO JIS AUVWIud OSd HONOIS aaIsS) 8S W3LSNIVA SIN VauVv YsLVMHV3STID MS - "GNaDgT PREPARED BY R&M CONSULTANTS