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Home My WebLink AboutAPA2466]1 II I] 11 1J i_I SUSITNA HYDROELECTRIC PROJECT FISH MITIGATION PLAN Report by Woodward-Clyde Consultants Lawrence L.Moulton Larry A.Rundquist Stephen C.Crumley N.Elizabeth Bradley Under Contract to Harza-Ebasco Susitna Joint Venture Prepared for Alaska Power Authority Settlement Document November 1984 Document No.2466 Susitna File No.4.3.1.4 ~J "J J ""I. 1 l . ;1 i ",J I ~.l j J . J J J .J ~~,J. (,"""-.....::-. -J j II r ] I j ANY QUESTIONS OR COMMENTS CONCERNING THIS REPORT SHOULD BE.DIRECTED TO . THE ALASKA POWER AO'l'HORIfi SUS:IDA PROJECT OPF:ICE TABLE OF CONTENTS TITLE PAGE • . • • TABLE OF CONTENTS. LIST OF TABLES • • LIST OF FIGURES ••• EXECUTIVE SUMMARY • •a.1. ....ii .iii V •vii 1 -INTRODUCTION •'. 1.1 -Approach to Mitigation 1.2 -Scope .....o'•••••• 1.3 -Selection of Evaluation Species. 1.4 -Overview of Selected Evaluation Species in Mi.ddle Susitna River • . . . . • • . • • • • • • • 0 • • • •1 . . • . 1 . . • • •~• 2 • • • • • • • • • 3 the . 6 26 ·24 APPENDIX A Passage Reach Flow Evaluation •30 •35 • • • •36 ·. ..42 •79 •84 •84 • • • •85 •88 • • •88 ·89 ·89 . .89 91 APPENDIX B Fish Mitigation Plan 2 -DOWNSTREAM.. • • • • • . • • • • • • • • • .. • .10 2.1 -Mitigation Options -Historical Perspective...•••10 2.1.1 -Flow Release.• • •• ••••••10 2.1.2 -Habitat Modification •••••••••.••10 2.1.2.1 -Alaska.• • • • • • • • • • • • • •••11 2.1.2.2 -Canada.• • • • • • • • • • •••••••13 2.1.2.3 -Washington State • • • •• •15 2.2 -Development of Mitigation Plan • • • • • • • • • • •24 2.2.1 -Impact Assessment ••••..•••.••••••••24 2.2.1.1 Spawning Habitat Utilization in Sloughs and Side Channels • • • • • • • • • • . • • • • 2.2.1.2 -Project Related Physical Changes in Sloughs and Side Channels • • • • • • • • • • • • • • 2.2.1.3 -Relationship Between Physical Changes and Available Habitat in Sloughs and Side Channels • 2.2.2 -Mitigation Options....•••. 2.2.2.1 -Flow Release.• • • •••• 2.2.2.2 -Habitat Modification •••••••. 2.2.2.3 -Artificial Propagation.•••• 2.2.3 -Monitoring Studies ••••• 2.2.3.1 -Impact Monitoring of Salmon Populations •. 2.2.3.2 -Mitigation Monitoring ••••.••.••• 3 -IMPOUNDMENT • • • • • • • • • • 3.1 -Introduction and Background .•••• 3.2 -Mitigation Options 3.2.1 -Rainbow Trout 3.2.2 -Arctic grayling •. 4 -REFERENCES II I I ii .J I j ] J j J ] I I j J J J J J 1 J 1 III ' i I II iJ .J LIST OF TABLES Table 1.Summary of estimated costs for habitat modification measures in selected sloughs and side channels. Table 2.Susitna River average annual salmon escapement by sub-basin and species. Table 3.Chum salmon peak index counts by habitat type above RM 98.6, 1981-1983 Table 4.Chum salmon peak index counts in sloughs above RM 98.6, 1981-1983. Table 5.Second-run sockeye salmon peak survey counts in sloughs above RM 98.6,1981-1983 Table 6.Pink salmon total slough escapement above RM 98.6, 1981-1983. Table 7.Selected rivers with hydroelectric projects and associated mitigations for anadromous fish species. Table 8.Area spawned between passage reaches within Slough 8A for 1982,1983 and 1984.The ratio of the composite to the total area spawned for all years and percent distribution of spawning fish in 1984 are also shown. Table 9.Area spawned between passage reaches within Slough 9 for 1982,1983 and 1984.The ratio of the composite to the total area spawned for all years and percent distribution of spawning fish in 1984 are also shown. Table 10.Area spawned between passage reaches within Slough 9A for 1982,1983 and 1984.The ratio of the composite to the total area spawned for all years and percent distribution of spawning fish in 1984 are also shown. Table 11.Area spawned between passage reaches within Slough 11 for 1982,1983 and 1984.The ratio of the composite to the total area spawned for all years and percent distribution of spawning fish in 1984 are also shown. Table 12.Area spawned between passage reaches within Upper Side Channel 11 for 1982,1983 and 1984.The ratio of the composite to the total area spawned for all years and percent distribution of spawning fish in 1984 are also shown • Table 13.Area spawned between passage reaches within Slough 21 Complex for 1982,1983 and 1984.The ratio of the composite to the total area spawned for all years and percent distribution of spawning fish in 1984 are also shown. iii Ii I ) j ] j ] ] -] I j J J J J j J 1 II II I, I List of Tables (Continued) Table 14.Mean monthly discharges at Gold Creek for natural conditions. Table 15.Relationship between mitigation alternatives and the impacts for which they are applicable. Table 16.Condition which provides successful passage most frequently and approximate percent of time that passage is successful during the period 20 August -20 September at Slough 8A. Table 17.Condition which provides successful passage most frequently and approximate percent of time that passage is successful during the period 20 August -20 September at Slough 9. Table 18.Condition which provides successful passage most frequently and approximate percent of time that passage is successful during the period 20 August -20 September at Slough 9A. Table 19.Condition which provides successful passage most frequently and approximate percent of time that passage is successful during the period 20 August -20 September at Slough 11. Table 20.Condition which provides successful passage most frequently and approximate percent of time that passage is successful during the period 20 August -20 September at Upper Side Channel 11. Table 21.Condition which provides successful passage most frequently and approximate percent of time that passage is successful during the period 20 August -20 September at Slough 21. Table 22.Condition which provides successful passage most frequently and approximate 'percent of time that passage is successful during the period 20 August -20 September at Side Channel 21.. Table 23.Candidate sites for development of replacement spawning habitat. iv LIST OF FIGURES Mitigation plan development and implementation Predicted winter mainstem stages for natural and project flows near the head of Slough 9A Recurrence interval of the pink discharge at Gold Creek during August 20 -September 20 from 1950-1984. between Option Analysis Schematic diagram illustrating difference composite area and total area spawned Simulated minimum,maximum and mean monthly discharges for maximum power Case P-1 compared with minimum,maximum and mean monthly discharges for natural conditions Shore ice buildup without overtopping Predicted winter mainstem stages for natural and project flows near the head of Slough 11 Predicted winter mainstem stages for natural and project flows near the head of Slough 21 Predicted winter mainstem stages for natural and project flows near the head of Slough 9 Predicted winter mainstem stages for natural and project flows near the head of Slough 8A 1 I I I Figure 1- Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. Figure 9. Figure 10. Figure 11. Figure 12.Minimum and maximum weekly discharges for Case C flows compared with minimum,maximum and mean monthly discharges for natural conditions Figure 13.Minimum and maximum weekly discharges for Case EV flows compared with minimum,maximum and mean monthly discharges for natural conditions Figure 14.Minimum and maximum weekly discharges for Case EVI flows compared with minimum,maximum and mean monthly discharges for natural conditions i,I v 1 I j I ] ! I I 1 j . i I I j l 1 I I I LIST OF FIGURES (Continued) Figure 15.Simulated minimum,maximum and mean monthly discharges compared with minimum and maximum weekly discharges for Case EVI instream flow requirements Figure 16.Wing deflector Figure 17.Typical passage reach of slough along middle section of the Susitna River Figure 18.Rock gabion channel Fig~re 19.Channel barriers I Figure 20.Collector tank at Slough 9 I) 21.Thalweg profile of SloughFigure 9 Figure 22.Thalweg profile of Slough 11 Figure 23.Thalweg profile of Slough 21 Figure 24.Induced upwelling using tributary water supply Figure 25.Weir to increase spawning habitat Figure 26.Timber post weir Figure 27.Rock gab ion weir Figure 28.Rock weir Figure 29.Berm design to prevent overtopping of sloughs Figure 30.Locations of mitigation measures and percent distribution of spawning chum salmon during 1984 in Slough 8A Figure 31.Locations of mitigation measures and percent distribution of spawning chum salmon during 1984 in Slough 9 Figure 32.Locations of mitigation measures and percent distribution of spawning chum salmon during 1984 in Slough 9A Figure 33.Locations of mitigation measures and percent distribution of spawning chum salmon during 1984 in Slough 11 ?nd Upper Side Channel 11 Figure 34.Locations of mitigation measures and percent distribution of spawning chum salmon during 1984 in Lower Side Channel 21 vi 1 I l 1 1 ! I j -I !. 1 (. .j 1 .( 1 i J .,, EXECUTIVE SUMMARY The approach and the process that will be followed to develop an acceptable mitigation plan for potential impacts of the proposed Susitna Hydroelectric Proj ect are outlined.The goal of the Alaska Power Authority for the project fisheries mitigation is to maintain existing habitat or provide replacement habitat of sufficient quantity and quality to support the productivity of naturally reproducing populations (APA 1983).Two mitigation approaches are proposed to achieve this goal 1)'modifications to design,construction or operation of the project;and 2)resource management strategies.The first approach is proj ect specific and emphasizes the avoidance or minimization of adverse impacts.The second approach would employ measures to rectify,reduce or compensate for impacts that cannot be mitigated by the first approach.These approaches are applied to two geographica;I.areas that are expected to be impacted by the proj ect: downstream of the project and the impoundment zone. Three mitigation options,flow release,habitat modification and artificial propagation are proposed for downstream impacts.These options are directed at impacts to chum and sockeye spawning habitat in sloughs and side channels in the Talkeetna to Devil Canyon reach of the middle Susitna River.A summary discussion is provided on the first option,flow release,as the primary means of mitigating for impacts on chinook juvenile rearing. Flow releases designed to minimize impacts to chinook juvenile rearing (Case EVI),minimize impacts to chum spawning (Case C),and minimize impacts to both chinook rearing and chum spawning (Case EV),are analyzed for their mitigative potential for chum and sockeye spawning habitat in sloughs and side channels.A qualitative discussion of flow release as the primary option for mitigating impacts to chinook juvenile rearing habitat is presented.The flow releases evaluated partially mitigated for losses of spawning habitat in sloughs and side channels.Habitat modification is proposed to rectify residual impacts. vii Habitat modification techniques used in stream enhancement projects in Alaska,Canada and Washington State are evaluated and those with the greatest likelihood of success are applied to seven sloughs and side channels in the middle S.usitna River.The modification techniques selected and associated co~ts for each slough are summarized in Table 1.Artificial propagation in the form of streamside egg boxes is proposed as a mitigation option should higher priority options· prove ineffective. Monitoring studies are proposed to (1)monitor salmon population and production levels to ensure that the predicted level of impact is not being exceeded and (2)evaluate the effectiveness of the project mitigation plan. In the impoundment area,Arctic grayling is selected as the evaluation species for mitigation because of its abundance in the area,its sensitivity to impacts during all seasons and life stages,and its desirability as a sport fish.Measures to avoid,minimize,rectify or reduce the anticipated loss of spawning and Arctic grayling habitats are considered infeasible (APA 1983)•Therefore,measures to compensate for the loss of Arctic grayling habitat are ..the options considered for impoundment mitigation planning. viii J j I 1 I .J I J ) .I ..II.! I, I I II 1 -INTRODUCTION 1.1 -Approach to Mitigation The Alaska Power Authority's (APA)goal for Susitna Hydroelectric Project fisheries mitigation is to maintain the productivity of natural reproducing populations (APA 1982).This is consistent with the mitigation goals of the U.S.Fish and Wildlife Service (USFWS)and the Alaska Department of Fish and Game (ADF&G)(APA 1982,ADF&G 1982a, USFWS 1981).The APA plans to either maintain existing habitat or provide replacement habitat of sufficient quantity and quality to support this productivity.Where it is not feasible to achieve this goal,APA will compensate for the impact with propagation facilities. The'development of the fish mitigat;on plan will follow a logical step-by-step process.Figure 1 illustrates this process and identifies the major components (APA 1983).The options proposed to mitigate for impacts of the Susitna Hydroelectric Proj ect will be analyzed according to the hierarchical scheme shown in Figure 2. Mitigation options proposed are grouped into two broad categories based on different approaches: Modifications to design,construction,or operation of the project Resource management strategies The first approach is project specific and emphasizes measures that avoid or minimize adverse impacts according to the Fish and Wildlife Mitigation Policy established by the APA (1982)and coordinating agencies (ADF&G 1982a,USFWS 1981).These measures involve adjusting or adding project features during design and planning so that mitigation becomes a built-in component of project actions. 1 If impacts cannot be mitigated by the first approach,rectification, reduction or compensation measures will be implemented.This type of mitigation will involve management of the resource rather than adjust- ments to the project,and will require concurrence of resource manage- ment boards or agencies with jurisdiction over resources within the project area. Mitigation planning for the Susitna Hydroelectric Project has emphasized both approaches.The sequence of option analysis from avoidance through compensation has been applied to each impact issue. If full mitigation can be achieved at a high priority option,lower options may not be considered.In the development of mitigation plans,measures to avoid,minimize,or rectify potential impacts are treated in greatest detail. Monitoring and maintenance of mitigation features to reduce impacts over time are recognized as integral parts of the mitigation process. The monitoring program is being developed and will be applied to fishery resources and their habitat. 1.2 -Scope This report presents analyses of mitigation options that can be used in developing an acceptable mitigation plan for impacts resulting from ~l1.~PJ:()2()~~~_~~s;_~~?-l:l.l:II~_l:'<:l~!~~!=_l:'~<:~J::"<:lLe_~E·..gp_t~~ns._a:r e .J):r~sell_~~~for -----~-----impacts on.....-fish._resources__and_.nabitats-.in__tw:o __ar.eas_affected_by_the ._____.. project;1)downstream of proposed dams and 2)the impoundment zone. Downstream of the proposed project,impacts and mitigation measures for chum and sockeye salmon spawning habitat are evaluated.Several sloughs were select:ed.f()r detailed analylOliS i.n tb.il3_report;.however, the analyses are applicable to other sloughs and side channels in the middle Susitna River where physical impacts are .expected to be j I../ J I I i \similar.The selected sites (Sloughs 8A,9,9A,11,21,Upper Side Channel 11,and Side Channel 21)were the ones most heavily used during the 1981-1983 study period (Barrett et al.1984).Downstream impacts to chinook salmon rearing and associated mitigation options are qualitatively discussed.As quantified habitat-flow relationships become available for juvenile salmon rearing in 1985,detailed mitigation option analyses will be undertaken. This report presents alternative project flow regimes as the primary mitigative alternative for chinook juveniles and the partial mitigation for chum spawning.Additional chum salmon spawning mitigation follows one of the following strategies:(1)structural modification to presently utilized side sloughs to maintain production spawning habitat and (2)artificial propagation with stream-side egg boxes to compensate for losses.As stated in the License Application (APA 1983),mitigation can be achieved with either strategy.Final decisions on the strategy to be implemented will be made through discussions with resource managers. Preliminary mitigation options for impacts to Arctic grayling habitat in the impoundment zone are also presented.An "expanded version of mitigation approaches for this area will be prepared in 1985.The mitigation plans for other species/life stages,other project areas, and the applicability of proposed mitigation plans to other phases of the project are subjects of upcoming reports. 1.3 -Selection of Evaluation Species All three mitigation policies (APA,ADF&G and USFWS)imply that project impacts on the habitats of certain sensitive fish species will be of greater concern than changes in distribution and abundance of less sensitive species.Sensitivity can be related to high human use value as well as susceptibility to change because of project impacts. Statewide policies and management approaches of resource agencies suggest that concern for fish and wildlife species with commercial, 3 subsistence,and other consumpt,ive uses is greater than for species without such value.These species are often numerous,and utilize a wide range of habitats,as well as having high human use value.Such characteristics often result in these species being selected for careful evaluation when their habitats are subj ected to alternative uses.By avoiding or minimizing alterations to habitats utilized by these evaluation species,the impacts to other less sensitive species that utilize similar habitats may also be avoided or reduced. The evaluation species were selected after initial baseline studies and impact assessments had identified the important species and potential impacts on available habitats throughout the year. "Mitigation plans were then developed that will reduce impacts on habitat parameters that are expected to control populations of these species. Based on the aquatic studies baseline reports,impact assessments,and harvest contributions,five species 6f Pacific salmon (chum,sockeye, chinook,coho,and pink)were identified as evaluation species for the SusifnaRiver~downstteamfromDeviTCanyon·(fiPA r983)~ Since the greatest cganges in downstream habitats are expected in the reach between Devil Canyon and Talkeetna,fish using that portion of the river were considered to be the most sensitive to project effects. Because of differences in their seasonal habitat requirements,not all ~...~~~~.~.~....salmoI!~.p.E:!c::.~~w()J!lc:l.1:>gE:!q:tlgllyg:f:EE:!C::!;E:!cl1:>y!;l:lE:!pl."QPQf?E:!<i pl."Qjec!;.Of the five species,chum and sockeye salmon appear to be the most vulnerable in this reach,because of their dependence on slough habitats for spawning,incubation and early rearing.Of these two, chum salmon are the dominant species.Chinook and coho salmon are less likely to be impacted by the project because two critical life stages,spawning and incubation,occur in habitats that are not likely to be altered 'bY the project.w:I:1ilesome pink salmon spawn in slough habitats in the reach between Devil Canyon and Talkeetna,most of these fish utilize tributary habitats.The mitigation measures proposed to maintain chum salmon productivity should allow sockeye and pink salmon to be maintained as well.The chinook juveniles rear in 4 I I '"1 ,'I I the river up to two years and coho salmon juveniles up to 3 years prior to out-migration.Much of the coho rearing apparently occurs in clear water areas,such as in sloughs and tributary mouths,with chinook rearing in turbid side channels as well as clear water areas. Replacement habitat that may become available in the mainstem under project flows and the effect of the potential loss of rearing areas in sloughs is the subject of ongoing studies. The greatest change to resident fish will occur'in the impoundment zone.In the impoundment zone,Arctic grayling were selected as the evaluation species because of 'their abundance in the area,their sensitivity to impacts during all seasons and life stages,and their desirability as a sport fish. In summary,the evaluation species and life stages selected for the Susitna Hydroelectric Project are: (A)Devil Canyon to Cook Inlet Reach PRIMARY Chum Salmon Spawning adults Embryos and pre-emergent fry Chinook Salmon Rearing juveniles SECONDARY Chum Salmon Emergent fry Returning adults Out-migrant juveniles Chinook Salmon Emergent fry Returning adults Out-migrant juveniles 5 Sockeye Salmon Spawning adults Embryos and pre-emergent fry Emergent fry Rearing juveniles Returning adults Out-migrant juveniles Coho Salmon Emergent fry Rearing juveniles Returning adults Out-migrant juveniles Pink Salmon Spawning adults Embryos and pre-emergent fry Emergent fry -_Re_tu rning_l;'Ldu_l~st Out-migrant juveniles (B)Impoundment Zone Arctic Grayling -Spawning adults .... Rearing Overwintering 1.4 -Overview of Selected Evaluation Species in the Middle Susitna River Fishery resources in the Susitna River comprise a major portion of the Cook Inlet commercial salmon harvest and provide sport fishing for residents of Anchorage and the surrounding area.The Talkeetna-Devil 6 J I J ,I Canyon sub-basin provides habitat for annual escapements of approximately 24,100 chum;9,500 chinook;2,200 coho;54,800 even-year pink;4,400 odd-year pink;and 2,800 sockeye (Table 2). Most chum salmon above RM 98.6 spawn in either sloughs or tributaries (ADF&G 1981,1982a;Barrett et al.1984).About 93 percent of the 10,570 chum salmon counted during peak index surveys were observed in tributaries or sloughs;the remaining 7 percent were observed at mainstem spawning sites (Table 3).In 1983,chum salmon peak index counts in tributaries and sloughs were about equal,while in 1982 and 1981,counts were higher in sloughs (Table 3).Chum salmon peak index counts in middle Susitna River sloughs are presented in Table 4. Eleven of the 33 sloughs _surveyed in all three years supported chum salmon spawning in each year.Four of the eleven,Sloughs 8A,9,11 and 21,averaged over 200 fish'annually for the three years and accounted for about two-thirds of the total chum salmon counted in sloughs.Eighteen chum salmon mainstem spawning sites were identified during 1981-1983 surveys;seven sites were used in two or more of the three years (Barrett et al.1984).The peak of chum salmon spawning occurred during the last week of August in tributaries,the first week of September in sloughs,and the first two weeks of September at mainstem spawning sites in all three .years (ADF&G 1981,1982a,Barrett et al.1984). Juvenile chum salmon expend one to three months rearing.Most juvenile chum are distributed in side sloughs and tributaries,their natal areas.Outmigration is generally complete by mid-July (Schmidt et al.1984). Sockeye salmon escapements to the Susitna River system consist of two distinct runs.The first-run sockeye spawn primarily in the Talkeetna River drainage.Second-run sockeye are distributed system-wide.Most second-run sockeye salmon in the Talkeetna-Devil Canyon sub-basin spawn in slough habitat (ADF&G 1981,1982a,Barrett et al.1984). Approximately 99 percent of the 2,420 second-run sockeye counted during peak spawner counts were observed in sloughs.The remaining second-run sockeye salmon were in the mainstem and tributaries.One 7 main channel spawning site (RM 138.6-138.9)was identified during the 1981-1983 surveys (ADF&G 1981,1983,Barrett et al.1984).Six second-run sockeye were observed in tributaries during the 1981-1983 surveys.All six,however,were considered milling fish that did not spawn in streams (ADF&G 1981,1982a,Barrett et al.1984).During spawning surveys in 1981-1983,second-run sockeye were observed in 17 sloughs above RM 98.6 (Table 5).Only 3 of the 17 sloughs contained significant numbers of spawning second-run sockeye in all three years. Sloughs 8A,11 and 21 accounted for 89 percent of the total slough peak counts in 1981,95 percent in 1982 and 92 percent in 1983 (Table 5).The peak of spawning occurred between the last week of August and the end of September in all three years (Barrett et al. 1984). Juvenile sockeye generally rear in upland and side slough habitats. Tributaries and side channels are relatively important for rearing. Most juvenile sockeye leave the Talkeetna-Devil Canyon during their first year of life (Schmidt et al.1984). Most coho salmon in the Talkeetna-Devil Canyon sub-basin spawn in tributaries.During spawning ground peak surveys in 1981-1983,over 99 percent of the 1,336 coho salmon counted were observed"in tributaries.Only five coho salmon were observed spawning in mainstem and slough habitats (ADF&G 1982a). "Coho-juveniles-g-eneral1y -spend-one to two years-rearIng :I.Ii-Treshwater-. Most juveniles are distributed in tributary,upland slough,and side channel slough habitats (Schmidt et al.1984). Most "pink salmon in the Talkeetna-Devil Canyon "sub-basin "spaWn in tributaries (Barrett·et al.1984).Pink salmon we"re documented spawning in sloughs in"1981 and 1982 (ADF&G 1981,1982a).Total slough escapement of pink salmon above RM 98.6 in 1981 was 38 fish in Slough 8 (Table 6).However use of Slough 8 may have been due to Lane Creek flowing into the slough in 1981.Lane Creek changed its course subsequent to the 1981 season and pink salmon were not observed spawning in this slough in 1982 or 1983.In 1982,total pink salmon 8 J "\ I I f. ! r J escapement above RM 98.6 was about 297 fish in seven sloughs (Table 6).Two of the seven sloughs,11 and 20,accounted for over 80 percent of the pink salmon total escapement in sloughs in 1982.No pink salmon were observed spawning in sloughs in 1983;fish counted in slough habitat during spawning surveys in 1983 were considered milling fish (Barrett et ale 1984).In 1981,the peak of pink salmon spawning in Slough 8 occurred about the last week of August,while in 1982 the peak of pink salmon spawning in sloughs occurred during the first three weeks of August (Barrett et al.1984).No pink salmon were observed spawning in the mainstem of the Susitna River above RM 98.6 in 1981-1983 (Barrett et ale 1984). After emergence,juvenile pink move almost immediately downstream to sea with little if any freshwater rearing.Few juvenile pink salmon are observed after July in the middle Susitna River (Schmidt et al. 1984). Chinook salmon spawn exclusively in tributaries or tributary mouths above RM 98.6 (Barrett et al.1984).No chinook spawning has been observed in any mainstem,side channel or slough are~s. One to two months after emergence,many juvenile chinook move"from their natal tributaries to rearing and overwintering areas (mainstem, side channels,side sloughs,upland sloughs,and tributary mouths). Most juvenile chinook in the Talkeetna-Devil Canyon sub-basin spend one winter in freshwater before going to sea (Schmidt et ale 1984). 9 -I 1 ? ! .1 \ ~[ ! j f . r ,f -1 J t1 ! I I I I I \ I, I 2 -DOWNSTREAM MITIGATION 2.1 -Mitigation Options-Historical Perspective 2.1.1 -Flow Release Flow releases designed to meet instream flow requirements of fishery resources are mitigative measures that have recently been routinely incorporated in project operations. Historically,this was not always the case.As older projects are relicensed,flow-release restrictions are being instituted to protect downstream fish habitat.Instream flow requirements for anadromous species have generally focused on the spawning and incubation life stages as flow needs for these life stages are more easily assessed than for other stages.Minimum and target maximum flows are often required during the spawning season while minimum flows based on the spawning flow are implemented during the periods of incubation and emergence. Recently,ramping rate and amplitude restrictions have been placed in the flow release schedules of several proj ects to avoid stranding of fry and juveniles during flow fluctuations. A selection of rivers with anadromous fish populations and hydroelectric or flood control projects and associated flow release restrictions is presented in Table 7 to illustrate the evolution of instream flow requirements.Additional mitigation measures (e.g.hatcheries)are also indicated. 2.1.2 -Habitat Modification On-site habitat modification as a mitigation option for hydroelectric projects has rarely been employed.Habitat modifications as enhancement projects are more commonplace,and the various techniques employed are applicable to the slough and side channel areas of the Susitna River.Examples of mitigation and/or enhancement proj ects in Alaska,British Columbia and Washington State are presented below. 10 2.1.2.1 -Alaska (a)Chilkat River Salmon Enhancement Project In 1983,the Northern Southeast Regional Aquaculture Association (NSRAA)completed construction of a 1,SOO-foot spawning channel for chum salmon near Haines,Alaska (Bachen 1984).The channel was located in the floodplain of the Klehini River above the confluence with the Chilkat River.The existing channel had supported chum'spawning in previous years.In the construction process native material was excavated from the channel and sorted on site; particles in the size range of 3/4 to 3 inch were returned to the channel;Flow through the channel was supplied by 6"'7°C groundwater at a rate of approximately 2.7-S.~ds. The channel was divided into three level sections with six-inch drops between sections.Wooden check dams placed at the lower end of each section provided adequate depth for spawning upstream. During 1983,the first year of operation,461 chum salmon and 117 coho salmon returned to the channel.Approximately 700 chum salmon had used the channel in previous years. The lower than average utilization may be attributed to the ..........___..__._..w_e.aJs.__.e_s.c.ap~lllent __in__19B_3_..HQw.eyer_,--the-es_t.imat.e_d __egg:'.':':to:'.':':fry.._ ..--.-------.-.-.-.-------------.-----surviva-l-the~fo_l-lowing--spring-was-2-2-z4-percent,---2--3-times-----·----- greater than the estimated survival in unimproved natural system (Bachen 1984).In 1984,the second year of operation,approximat.ely 1,500 fish had returned to the channel by the end.of Octoher. The channel was designed to accommodate as many as 3000 females assuming uniform distribution of fish at a density of one female/11 square feet. 11 J t I The channel was constructed at a cost of $125,000 or approximately $37 per square yard.The only scheduled maintenance for the channel is weekly removal of carcasses during the spawning season to prevent increased oxygen demand resulting from decomposition. Application to Susitna River Mitigation Plan.Chum salmon escapement in the second year was at least 1500 fish, approximately twice its historical use,perhaps due to a large escapement or preferential use of the channel. Increased use of the channel should occur as the first returns arrive in the fourth year of operation.If egg-to-fry survival rate of 22-24 percent (about 2-3 times the estimated survival in unimproved channels)were repeated the second year,the net result would be a 400-600 percent increase in production over historical levels. These results indicate the potential production that can be attained with appropriate habitat modification techniques. (b)Tern Lake Enhancement Project The U.S.Forest Service completed a spawning enhancement project on Daves Creek immediately below the outlet of Tern Lake.Prior to construction,the channel geometry and substrate in this reach of the creek provided only marginal habitat for chinook and coho salmon spawning.The channel was restructured and substrate appropriate for chinook salmon spawning added.The pool-riffle sequence was establish/?d with notched logs.Following two years of operation,increased use by spawning chinook as well as coho salmon has been reported (Ralph Browning,USFWS,pers. comm.,1984).A two year project evaluation report will beiforthcomingbytheendof1984. 12 Application to Susitna River Mitigation Plan.The Tern Lake proj ect is a recent development and evaluations at this point are preliminary.It does appear that it has met its general objective of providing additional spawning habitat in an area that was only marginally usable earlier; however,overall assessment of the success of the project must await the returns from these spawning areas in 1986. The use of log barriers to establish pools and riffles is a technique that is proposed ,for various sloughs in the Susitna River. (c)Williwaw Creek near Portage Construction of a salmon enhancement proj ect by the U.S. Forest Service an.d Alaska Department of Transportation is currently underway at Portage Creek.A groundwater-fed spawning channel measuring approximately 3,000 feet in length and 20 feet in width has been designed principally for chum salmon but may be used by all five species of Pacific Salmon that occur in the area.In addition,4 rearing ponds totaling five acres have been planned. Expected completion date is fall 1985. 2.1.2.2 -Canada ---------.---.--.--.-----.-In---the---late-1-9-7-0sthe--Canadianc--Depar-tment--of---Eisher-ies--and---. Oceans initiated a program in southern British Columbia to increase chum salmon production by developing new spawning areas or improving existing ones (Lister et .a1.1980a).The areas selected for enhancement were located in overflow channels ..g~nEara:I,:I,y _s_~pal:."9:1:~(lfro!11.the ma,in.x:i,yer (;!~~EaP1:cluring flood conditions similar to sloughs and side channels of the middle Susitna River under project flows.The source of flow through these areas was generally groundwater. Among the techniques used to enhance these spawning areas were to 1)provide access into the channels by removing obstructions; 13 J ,I .'I '1 J i 2)lower the bed elevation of the channel to increase groundwater flow,depth,and area available for spawning; 3)install weirs to increase water depth and control gradient; and 4)add suitable spawning gravels where previously lacking. Chum salmon egg-to-fry survival for seven improved channels after the first year of operation averaged 16.3 percent, approximately twice the average (7.9 percent)documented at six natural spawning areas in British Columbia.Survival at two of the sites,33.5 and 20.7 percent,exceeded egg-to-fry survival previously reported for chum salmon under natural conditions, and compared favorably with the average (27 percent)achieved at a spawning channel with controlled flow at Big Qualicum River on Vancouver Island.Moreover,one channel that did not support a spawning population of chum salmon in the past received over 1,300 spawners in the first year of operation with a 20 percent egg-to-fry survival. In channels where sorted gravel was added,both high and low survivals were recorded.The removal of fine material may allow for greater egg deposition;however,the overall survival may have been reduced because of facilitated access to interstitial space by predators.The advantages of sorted gravel may also have been masked by other site specific biological and physical features that affect survival such as density of spawning fish and channel characteristics that determine the gradient and groundwater flow. Application to Susitna River Mitigation Plan.The Canadian enhancement projects demonstrated that through various habitat modification techniques the production from historical spawned areas can be improved by increasing the amount of suitable spawning habitat and thereby accommodating more spawning pairs and by attaining high egg-to-fry survival rates.As applied to the Susitna River,improvement of habitat quality in selected areas of the middle Susitna River may be used to mitigate for some spawning areas that will be lost. 14 2.1.2.3 -Washington State (a)Satsop River Chum Enhancement Projects In recent years the Washington State Department of Fisheries has undertaken instream chum enhancement projects along the Satsop River to restore chum salmon runs in this area to their historical levels (Dave King,Wash.Dept. Fisheries pers.comm.,1984).Three projects completed to date have involved modifications to old river channels that convey water only during high flow.In two of the channels the silt-sand substrate was excavated to a depth to intercept the water table and replaced with 1/4 to 3 inch leveled gravel.In the third channel,after excavation, the gravel in the channel appeared suitable for spawning and did not require replacement.The channels were graded to an approximate 2 percent gradient and.where necessary, diked off at the upper end to prevent overflow during flood ....'R.e r:i,9cl.§. Although the projects have been in operation only for 1 or 2 years,preliminary evaluations appear promising with egg-to-fry survival ranging from 38 to 78 percent.The highest survival was documented in the channel in which the ......-.--···-.---·----·--native--gravel·-was·--ret·ai:ned-;,-·---··Th±s-cha:p.nel-was--onIT--a·····-·····---- .---~.--~.-._--~-.~--_._--depres-sion befo're it was modified and had not been used by ,---------.- fish previously.Its dimensions were 7 feet by 500 feet. It received 52 fish its first year of operation.The low density (reduced likelihood of superimposition)and the protection against predation afforded by smaller gravels and.sand found in the·natural·substrate may.have contributed to the high survival rate.Dimensions of the remaining channels and densities of spawning fish were: 20 feet by 600 feet with 600 fish and 15 feet by 1,000 feet with 1,000 fish. 15 J l 1 J .l J I The Washington State costs associated with these projects were $15 per square yard for channels with replaced gravels and $11-12 per square yard without replacement.During the construction process some sand and silts were deposited over the replaced gravels and were removed with a gravel cleaning machine at cost of $2-4 per square yard. Application to Susitna River Mitigation Plan.The Satsop River projects were patterned after the pioneering work of the Canadians in British Golumbia and their application to the Susitna River"are similar.The egg-to-fry survival from the Washington projects indicates the potential production that can be attained"with appropriate habitat modification techniques. (b)Baker Lake Substitute Spawning Beach Historically,an estimated 95 percent of the sockeye salmon spawning in the Baker River,Washington system was confined to two beach spawning ~reas on Baker Lake.Completion of the second Baker Lake Dam resulted in the reservoir inundating the lake shore spawning beds to a depth of 60 feet.Periods of reservoir drawdown also coincided with hatching and fry emergence,with the result that any egg deposition within the elevation range of drawdown would be subject to dewatering or freezing.As a mitigation measure a substitute spawning beach was developed to perpetuate this stock of fish. Studies done before the dam was built indicated that the spawning areas were associated"with entry points of coldwater springs.At average lake levels the "temperature of these springs was independent of lake temperatures and varied only a few degrees from the time fish spawned until ...~ .,' 16 ..........."'~ / fry emerged.However,during fall floods when the lake level rose 5 feet or more,the temperature in the spawning areas approximated lake temperature,possibly indicating cessation of flow from the springs due to hydrostatic pressure.Fall reservoir conditions (60 feet of head at the spawning areas)would be likely to effect the same changes.One of the criteria for selecting a site for development of a substitute spawning beach was based on acquiring a water supply with temperature patterns 'and water chemistry similar to those present in the lake shore spawning grounds.Of the tributary streams entering Baker Lake,only one possessed similar water quality while the others differed markedly.Moreover,this stream did support a small number of spawning sockeye. Preliminary testing involved a 1,000 square feet beach in which water diverted from the selected stream provided upwelling through the area by means of a timber gridwork. Following the success of the test beach,two 15,000 square feet earthen beach ponds were added.Each accommodates approximately 1,500 adult fish.The source water is supplied through a diffusion system consisting of two, 14-inch supply mains drawing water from a diversion dam, with each main connected to 50 four-inch pipes stationed three feet apart.Water exits each set of 50 pipes through 3/16 inch holes drilled 8 inches apart.The network is covered with 1/4 to 3/4 inch gravel and supplies the entire area with upwelling water.The total flow required for the system is approximately 3.75 cfs.The head differential between the headworks of the dam and the spawning pools is about 3 feet. The system has operated successfully for many years with excellent egg deposition efficiency and egg-to-fry survival ranging from a low of 35 percent to a high of 89 percent of potential egg deposition. 17 The success of this project may have been due in large part to selecting a source of water with water quality characteristics similar to those present in the historical spawning grounds. Application to Susitna River Mitigation Plan.Mitigative measures for the middle Susitna River which propose the use of supplemented water supply will include'evaluations of the water quality and temperature profile to insure satisfactory results.The Baker River beach spawning upwelling system described in detail above demonstrates that such a system could be used for those species on the Susitna River,i.e.chum and sockeye salmon,that appear to depend on upwelling for spawning. (c)Columbia River Spawning Channels Construction of dams on the Columbia River has been '--'-----J:;.esponsiblefor ,the-inundation ,and subsequent-lossof--the--, historic mains tern spawning grounds for fall chinook.The natural habitat for salmon above Bonneville,the dam farthest downstream,has deteriorated as a result of increased water temperatures,pollution,predation and decreased velocities (Meekin,T.K.1967).Although these ·-···-·'-··-_~_··_-·"---------eiivi~ronmentaIcoria"!t :[6iis-n:a:v-e----a:f-f ec tea--several--l-ife--s·t-ages'--;-.----"..--..--~-...-.. loss of for spawning has been the principal concern. The Washington Department of Fisheries,faced with the decisiouofhowto perpe.t:tia.t:e'EheColtiillbiiiRiver runs, considered two-alternatives.Thef:Crst was to develop fish hatchery programs and the second was to construct artificial spawning channels simulating natural conditions. The Department opted for the second alternative and in 1954 18 J 1 ,I 1 .1 \. I IIi initiated a program to evaluate the physical habitat requirements for spawning chinook salmon so that artificial spawning channels could be constructed to mitigate for the loss of mainstem spawning areas.This resulted in the construction of the McNary Supplemental Spawning Channel in 1957,the first of its kind for the propogation of chinook salmon.The Canadian Department of Fisheries and Oceans had experimented with artificial spawning channels for pink salmon in British Columbia since 1954 and had reported good egg-to-fry survival (Houston and Mackinnon 1957). The spawning channel program expanded with the completion of five hydroelectric proj ects above McNary Dam;Chief Joseph Dam in 1957,Priest Rapids in 1960,Rocky Reach in 1961,Wanapum in 1967 and Wells in 1967.Each of these dams incorporated fish passage facilities,except for Chief Joseph Dam which marked the endpoint for upstream migration of anadromous fish.As mitigation for the inundated spawning grounds,spawning channels were also developed at Priest Rapids,Rocky Reach,and Wells Dams. Evaluations of the performance of each of these channels in maintaining the mainstem chinook stocks were conducted during each year of operation.The results are summarized below. (i)McNary The McNary spawning channel consisted of 12 spawning runs measuring 22 by 175 feet with each run separated by a pool.Gravel size ranged from 0.5 to 3 inches.Flow through the channel was 92 cfs.As this was the first spawning channel completed, several important conclusions were derived that were of use in development of subsequent channels (Meekin 1967). 19 1)It was demonstrated that chinook salmon would voluntarily enter a channel with physical conditions resembling natural ones and spawn. 2)The poor return of marked fish indicated that a self-perpetuating run had not been established. 3)The allocated area of 55 square feet per female was insufficient to support spawning and at least 165 square feet was required. 4)Low egg-to-fry survival resulted from high water temperatures,silt deposition,and superimposition. 5)Attempts to transplant fall chinook indigenous to the upper reaches of the river resulted in excessive pre-spawning mortality. (ii)Rocky Reach The Rocky Reach Spawning Channel was constructed as a mitigation facility for loss of chinook salmon spawning grounds resulting from the construction of "'Rt:fcky'Reach 'Dam~'"...The'l;OOO';;'focft ·····lofig-15y-32 ·fcHft··,··· wide spawning channel was designed to accommodate 330 pairs of chinook salmon -the number of fish estimated to spawn historically in the reach inundated bY.the'reservoir.The results of seven yearEf of operation were : 1)High prespawning mortality of adults. 2)Low numbers and small fry production with correspondingly small size and few juveniles released. 20 'J 'j I \ I / 3)Extremely low adult returns. 4)High operational costs. Prespawning mortality resulted from excessive handling combined with high temperatures,which increased the susceptibility to disease. Egg-to-migrant survivals were quite variable over the seven years of operation with three years greater than 40 percent and the other four years less than 10 percent.Factors thought responsible for the low survival included superimposition, predation by juvenile coho,and nitrogen supersaturation (Meekin et al.1971). The poor returns of adult fish may have been attributable to low survival during outmigration or perhaps straying of adults,since the channel water was pumped directly from the Columbia;however, significant numbers of marked adults were not observed at upstream dam fish ladders. In summary,the channel did not fulfill its intended purpose of maintaining a viable run of chinook salmon that historically spawned in the Rocky Reach section of the Columbia. The channel is presently being used as a coho egg incubation channel and rearing station. (iii)Priest Rapids The Priest Rapids Spawning Channel was completed in 1963 as a mitigation measure for the loss of chinook salmon spawning grounds following the construction 21 of Priest Rapids and Wanapum Dams on the Columbia River.The channel was approximately 6,000 ft and designed to accommodate 2,500 pairs of chinook spawners. The period of channel operation from 1963 to 1967 was characterized by substantial prespawning mortality and poor juvenile production ranging between 5 and 14 yercent of the potential egg deposition.The 1967-68 season marked a transition point in the channel operation.For three seasons, production in the channel was consistent,and was greater than 50 percent of egg deposition (Allen 1968).The increased production of the later years was attributed to: 1)Decreased superimposition resulting from reduced number of adults in the channel and their forced dispersion. 2)Lower incidence.of disease and elimination of treatments. 3)Maintenance o~adequate flows through the entire ........._.___.._._.....__..incubatiou_.periods.•._. 4)Negligible introduction of wind-blown sand deposits into the spawning channel. However,this channel,like the others,suffered from the lack of .significant adult ..return to the facility apparently due to the poor seaward survival of outmigrants ·and a high rate of straying for returning adults. 22 I I ,) I [I I] I j 11 [ 1 I] II 11 u (iv)Wells Spawning Channel The Wells Spawning Channel was designed to accommodate 3,000 female spawners.The spawning channel,measuring 6,000 feet,began operation in 1967.For the first five years of operation,fry production ranged from 48 to 66 percent of egg deposition.Moreover,prespawning mortality was less prevalent in this channel than in some of the older ones.However,this channel,like those that preceded it,was unable to produce fry of a size that would enable them to survive the downstream passage through numerous dams and predator-infested waters.The net result was that self perpetuating runs could not be maintained.In time the facilities were converted to rearing areas for hatchery produced fry. The overall failure of the Columbia River Spawning Channel program was largely attributable to environmental conditions unique to that system. Several of the channels,particularly Wells,were successful in producing fry from naturally spawning adults.Extraneous factors such as low survival of outmigrants and possible straying of returning adults,however,contributed to the program's eventual demise. Application to Susitna River Mitigation Plan.The Columbia River Spawning Channels provide evidence that chinook salmon would 'voluntarily enter and successfully spawn and incubate in an artificially constructed channel if conditions resembling.the natural environment were simulated.In addition, the eventual failure of the channels and replacement 23 with artificial incubation facilities ponds emphasize the importance in alternative mitigation optio~s should higher priority measures occur. 2.2 -Development of Mitigation Plan and rearing developing failure of It is expected that the distribution and abundance of fish species downstream ot the proposed Susitna Hydroelectric Project will change as a result of project operation.The impact assessments presented in this report were developed for the maximum power flows (Case P-l) which includes no minimum instream flow requirements,and three proposed proj ect flows (Case C,Case EV,and Case EVI),each with different environmental flow constraints.Case C is designed to provide mitigation for chum spawning in sloughs.Case EV is designed to mitigate fpr both rearing and spawning habitats.Finally,Case EVI is designed to minimize impacts to rearing habitats.The development of these flow regimes is discussed in Harza-Ebasco (l984b).The general impacts related to all flow regimes are discussed in the -~foLTowinlrEiE:fc-t-ionrsp eci-f"icaTfferences--irl-tne degreeof~impacf--am6ng- the various flow regimes are discussed in subsequent sections.The impact assessments link predicted physical changes with habitat utilization to provide a qualitative statement of impacts likely to result from the Susitna Hydroelectric Proj ect.Impact issues have been identified and ranked by procedures established by the Susitna ______~~_Hydroelectric Project Fish and Wildlife Mitigation Policy"_(APA 1982).~_ 2.2.1 -Impact Assessment 2.2.1.1 Spawning Habitat Utilization in Sloughs and Side ...---.._.._.,. Channels The area of spawning habitat utilized within selected sloughs and side channels was estimated by digitizing the actual areas 24 -j I J r I I I II II II [) 11 I J 11 u spawned during the 1982,1983,and 1984 spawning seasons as outlined by ADF&G (unpublished maps of spawning areas).The 1981 data were not used because the high flows and poor visibility during the spawning season precluded definition of spawning areas.The areas outlined by ADF&G indicate general areas of spawning,not the area actually excavated by spawning fish.For example,a circumscribed area of 10,000 square feet may have had 50 spawning pairs of fish widely distributed,while a similar area elsewhere may have accommodated several hundred spawning fish over the course'of the season.The areas spawned .for all three years were classified as composite or total areas. Composite areas were obtained by superimposing maps of spawned areas for each year and measuring the area spawned one or more times.Total area was the sum of the area spawned in each of the three years.Figure 3 illustrates the difference between composite area and total area.The ratio of the composite areas spawned to the total area used over the three years is presented in Tables 8 through 13 for Sloughs 8A,9,9A,11 and 21 and Side Channel 21 and Upper Side Channel 11.The ratio of the composite area to total area serves as an index of the amount of area repeatedly spawned during the three years.If the same area were used each of the three years the ratio would be .33. Greater values indicate less repeated use of spawning habitat. A value of 1.0 indicates different areas w~re used in each of the three years. The composite areas spawned can be considered representative of the potential spawning habitat within the sloughs and side channels evaluated if the following conditions are satisfied: II 1)Sufficient numbers of fish annually escaped to the sloughs and side channels to occupy generalized areas of available spawning habitat. 25 2)-Flows during the 1982, 1983,and 1984 spawning periods provided average access and passage conditions to spawning habitat that were representative of the conditions the long term flow record has provided. 3)The periods in which access and passage conditions were provided by the 1982-1984 flows coincided with the availability of spawning fish. Further evaluation of the above conditions will be undertaken when the flow and escapement records for the 1984 season become available.The fortuitous occurrence of a high 1984 escapement and a period of high flow coincident with the historical beginning of the peak spawning period during the 1984 season should provide a valuable data base for evaluation of conditions that allowed access to and utilization of most of the potential slough and side channel spawning habitat in the middle Susitna River. 2.2.1.2 Project Related Physical Changes in Sloughs and Side Channels Operation of the Susitna Hydroelectric Project would modify the annual flow and temperature regime of the Susitna River,thus ---------------------------causing-:physic-al----changes-in -sloughs-and--s±de---chann-els---in-the--- -----------------------Iniddle reach .-Tri-genlirai ,ilows-<furIng-proj-ect--operation would------~---- .be less than natural flows during June,July,August,and September and higher than natural flows in the remaining months as the reservoir is drawn down.Project flows would be relatively constant throughout the year as compared with the -natural vari:ability -offlbws~Thej:5roject-flow::regime-_would cause the following physical changes in sloughs and side channels of the middle Susitna River: Reduced backwater effects during summer Reduced frequency of breaching during summer 26 ] ] I J- I 11 r ] II I I II II II I] Reduced groundwater upwelling during summer and in winter upstream of the ice cover Increased frequency of winter overtopping in ice-covered areas Susitna River discharges 'presented in this report are flows at the Gold Creek gage maintained by the USGS. (a)Backwater A backwater area forms at the mouth of a slough or side channel if the stage in the mainstem is greater than the stage of the flow in the slough or side channel at its mouth.If the mainstem stage rises with no change in flow in the slough or side channel,the level of the backwater increases and the aerial extent of backwater influence moves upstream in the slough or side channel.If the mainstem stage drops,then the backwater level also drops and its length is shortened.The drop in mainstem stage can be sufficient to eliminate the backwater completely; the stage and corresponding mainstem discharge at which this occurs varies from site to site.The stage of the backwater may be defined by the mainstem discharge that forms the backwater.Proj ect operation would generally cause a decrease in backwater area and,stage during June through September. u IJ (b)Breaching A slough or side channel breaches when the mainstem flow overtops the upstream end,or head,of the channel. Breaching is directly related to mainstem discharges;as the discharge increases,the stage increases and when stage exceeds the elevation of the top of the berm at the head of the slough or side channel,flow is diverted through the channel.Further increase in stage will cause additional 27 flow to pass through the slough or side channel.Project operation would generally cause a substantial decrease in the amount of time that a slough or side channel would be breached. (c)Groundwater Upwelling Groundwater flows out of (upwells from)the bed of a slough or side channel when the elevation of the bed is lesSi than that of the local groundwater level.Studies have been conducted to relate the flow and temperature of the mainstem to upwelling quantity and temperature in sloughs and side channels (APA 1984).Although a complete evaluation of the sources of groundwater was not conducted, the apparent groundwater upwelling component of slough flow was isolated from the surface inflow component and related to mainstem discharge at Sloughs 8A,9,and 11. Relationships were developed in the form of regression equations for inferred upwelling component as a function of mainstem flows;these were used in a preliminary analysis of proj ect related changes in the groundwater upwelling component of slough discharge as described in Appendix A• .....___.._...~h~._~~_lIlPC?~I:3:_t:.tl:.:r_~_2.~..~h~_Rl:"<:l!1!l:<:ly.r_~1:~!:"..tl:.P't\7~l:I.:i:!l:g._~EP_~Cl.E~~<:l_ .-..-.---.--.-----------...-~--...···-:r'emai-n.-'};'eJ.at-:i..veJ.yGQnstant-....at-a~vaJ.ue-appr.ox.imately-equal------....----... to the mean annual river temperature (APA 1984).A mean annual temperatu~e increase resulting from project operation will probably be reflected as a slight increase in the temperature of groundwater up't\7elling flow (APA ...1984)• Winter flow and ice regimes ...affec·t upwelling in the sloughs.As the mainstem forms an ice cover,the stage increases because of backwater effects from frazil ice particles and pans jamming in constricted areas or building 28 ]i up on downstream jams.Thus river stage with an ice covel at low flow may approximate the stage of a much larger flow in the open channel conditions of summer flows,thus changing the hydraulic head that controls groundwater from the river.I The higher proj ect flows in conjunction with increased water temperatures would change the ice processes,and thus ~--------upwelling,in the middle Susitna River.Under'\project operation,the upstream edge of the ice cover would vary from RM 125 to RM 142 depending on meteorologic conditions and the depth (and thus temperature)from which water is withdrawn from the reservoir (Harza-Ebasco 1984b). Upstream of-the backwater effects of an ice cover,the stage in the river would decrease relative to the stage experienced under an ice cover formed under natural conditions.According to preliminary upwelling studies, this would result in decreased groundwater upwelling in 11 1·1IJ II 11II sloughs and side channels throughout the .winter. II IIJ 11 I I j Downstream of the ice front the increased staging would result in upwelling rates greater than those under natural conditions. (d)Winter Overtopping The stage increase during ice cover formation (winter staging)was described briefly in the previous section in relation to the reduced upwelling at locations upstream from the ice front.With project flows higher than natural flows during winter,the staging effect would be higher during proj ect operation downstream from the ice front. Thus,the probability of breaching caused by ice staging at and downstream from the ice front would also be greater. Under natural conditions,the staging effects occasionally cause slough I and·side channel overtopping.When an ice cover forms,shore ice develops causing flow restrictions (R&M Consultants,Inc.1983).The shore ice may act as a 29 barrier to contain the flow and prevent the mainstem from overtopping the slough berms (Figure 4).However,under higher mainstem discharges,the probability of overtopping would increase.Figures 5 through 9,derived from ice cover prediction modeling (Harza-Ebasco 1984a),may be used to predict possible overtopping events under natural and proj ect winter flow regimes at Sloughs 8A,9,9A,11 and 21.They do not,however,identify the probability or duration of actual events which are dependent on other factors besides mainstem stage. 2.2.1.3 Relationship Between'Physical Changes and Available Habitat in,Sloughs and Side Channels The physical changes associated with project flows as discussed in Section 2.2.1.2 would either 1)directly affect the quantity and quality of spawning and incubation habitat by reducing the area that satisfies the physical requirements of these life ......"_"__,,,,,stggEa.J?,...Q!",.2.L,:i,.'I:1._cl:i,.:t::'g,~t,l>rg,::t::[ect:..t:11g,...gyg:!'lgb,;i.J..:i,.,ty Q.f .s:Rgwn:!,ng habitat by restricting access to those areas. (a)Direct Effects J J (i)Reduced Backwater BackwaEereffects iti-the area--~thesIo\lgh-mouth'-' under natural conditions provide greater depths in the affected zone than would be provided by local slough flow.Project flows would substantially reduce the backwater zone in some sloughs resulting 'i'n ..a-dect'easefiLthesurfaceareawith suitable spawning depths and a loss of spawning habitat at the slough mouth.The degree of loss would be dependent on the relative spatial distribution of available spawning habitat under natural and project conditions. 30 (ii)Reduced Frequency of Breaching Flows Breaching flows also provide additional spawning habitat within the slough and side channels by increasing the amount of area with suitable spawning depths.Proj ect flows would·substantially reduce the frequency of breaching flows and thus decrease the potential spawning habitat.The amount of II habitat lost would be dependent on the site specific frequency of breaching flows under natural conditions.Spawning habitat provided at breached conditions in sites with relatively high breaching discharges (low frequency of occurrence)is generally of insufficient duration for fish to effectively utilize;if such habitat were used,it would likely result in dewatering and freezing of the embryo.Spawning habitat provided under breached conditions in channels with relatively low breaching discharges (high frequency of occurrence) can be effectively utilized;embryos have a higher probability of remaining wetted and unfrozen at such sites.The infrequent breached conditions under I I IJ project flows would result in a loss of this spawning habitat.The quantity of habitat loss would depend on the relative spatial distribution of available spawning habitat under natural and project conditions. (iii)Reduced Upwelling Reduced mainstem flows during the spawning season would also decrease the amount of upwelling in the slough.Chum salmon prefer to spawn in areas with upwelling flow (Vincent-Lang 1984).The reduction in the rate of upwelling would reduce the quality and quantity of available spawning habitat.Winter 31 flows,although higher than natural,would result in reduced upwelling in sloughs upstream of the ice cover because the s.taging effects during ice formation would no longer occur.A decrease in the rate of upwelling in winter may decrease the quality of incubation habitat. (iv)Increased Frequency of Winter Overtopping Proj ect winter flows would be higher than flows under natural conditions.Thus,the probability of breaching caused by ice staging at,and downstream from,the ice front would also be greater.Under natural conditions,the staging effects occasionally cause slough overtopping. For those sloughs which are overtopped,the influx of near freezing water and subsequent ice formation WQ_~l<:lI:'~l?!!lt:i.n I:'~t<:l.r<:l~<:l<:l~:y~lQP.JIl~n:t~f ~_mbt'Y'Qs an<:l_. delayed emergence timing (ADF&G 1983b). (b)Indirect Effects I I i -I Project mainstem discharges during the August-September .--------'---------------spawning-seasonwould··reducethechanneldepths''insloughs .-."....---...-J .---------------------------.--..and side channels.The depth at any location-lii-"'a---slough--------------. or side channel is-a function of the cumulative effect of backwater,breaching,and local flow in the channel.Local flow is generated by surface inflow (surface runoff and tributary inflow)and groundwater upwelling. The influence of mainstem discharge on backwater, breaching,and groundwater upweiiing was introduced previously.Variations in surface inflow are not dependent on the mainstem discharge directly,even though there is some correlation through their mutual dependence on 32 I iII IIIJ precipitation.The shallow depths at various locations in sloughs and side channels would result in restricted passage of adult fish and a loss of otherwise available spawning habitat.Criteria that have been developed for evaluation of fish passage are a function of flow depth and length over which the depth remains shallow.Reaches within sloughs and side channels that have inadequate depth for successful passage are referred to as passage reaches (Sautner et al.1984). Decrease in slough or side channel depth resulting from project operation is also dependent on the location within the slough or side channel.Relative changes in depth generally decrease in the downstream direction for a given channel configuration as surface inflow and groundwater upwelling accumulate through the site. Assessment of the relative impacts of project operation on passage conditions can be accomplished by identifying how often a certain depth occurs under natural and proj ect conditions.For example,specified depth for successful passage at a passage reach located near the mouth of a slough may be reached or exceeded 80 percent of the time due to backwater only,20 percent of the time due to breaching only,and 40 percent of the time if an average groundwater flow were supplemented by surface inflow. Since backwater,breaching,and groundwater upwelling are functions of mainstem discharge,the frequency of a certain depth being equalled or exceeded can be obtained from the flow duration curve for the period of interest.An approximation of the frequency of surface flow can be obtained from a precipitation duration curve,which is related to the surface flow through a runoff coefficient. If it is assumed,to be conservative,that the backwater, breaching,and precipitation events are coincident,then in the example above,the frequency that the specified depth 33 is equalled or exceeded is 80 percent,corresponding with the frequency due to backwater.The evaluations of project effects can address the frequencies corresponding to project operation,which may be 0 percent of the time due to backwater only,0 percent of the time due to breaching only,and 35 percent of the time if average groundwater , were supplemented by the unaffected surface inflow.Thus, the effects of the proj ect for the passage reach in this example is reduction in the percent of time that a specified depth for successful passage is equalled or exceeded from 80 percent to 35 percent.This relative change is fairly typical of the change that may occur to a passage reach near the mouth of a slough or side channel, while a change from 10 percent to 8 percent may be more typical of a passage reach located farther upstream in the site. A recurrence interval curve for the peak flow during the §':R~'tV1:l.j,l1,g §.galiQI1 (A1:Lg:t1J31:2Q -SgpJ;~~1l!1:>l:lt:2Q)WI:l.§l<:ll:lYl:l;!.QPed1:Q assess the importance of high flow events in providing suitable passage conditions (Figure 10).For example,the exceedance p'robability of a flow of 19,000 ds is 29 percen~on a flow duration curve,yet the recurrence of that flow during the spawning season is approximately ......-------.-.three-out-'~of'-four--years-;--""The····occurrence--·of--a ..highf'low' _._..~..__.__._-~-~_._-----_.~~-----_._-coincident -with peak escapement timing to sloughs----··wo-uld-~--·-----~·---- produce maximum passage benefits.Peak 'flows during the August 20 -September 20 period generally clustered around the first part of the period,August historically having ......."'higher f·lows.Peak escapements'to sloughs also have occurred during the early •part oftheperibd for the 1981-1983 seasons.Recurrence interval analysis will be refined in upcoming reports following a detailed examination of fish wheel catches,flow records,and escapement timing to sloughs for the 1981-1984 seasons. 34 J .J .( j I I Analyses in Appendix A provide results indicating pro]\::._ influence on passage reaches in selected sloughs and side channels of the middle Susitna River. 2.2.2 -Mitigation Options For the middle section of the Susitna River,altered flows would affect the fish populations.Under natural conditions,mainstem discharges are high in late May,June,July,August,and early September and decrease during September and October to low flows throughout the winter (Figure 11).Hydroelectric power is desired primarily during winter and water is retained during summer to fill the reservoir.Flows under proj ect operation II II II would be much more uniform throughout the year and thus would necessarily be higher in the winter and lower in the summer than natural flows. Three levels of mitigation ·options are proposed for potential impacts on fish populations in the middle Susitna River resulting from project operation;these are flow release, habitat modification,and artificial propagation.The purpose of flow release is to avoid or minimize the impacts by maintaining an acceptable amount of suitable habitat for limiting species/life stages which cannot be economically maintained using other techniques.The purpose of habitat modification is to rectify or reduce the impacts remaining after implementation of the flow release mitigation.This will be accomplished through modification of existing habitats to maintain or The purpose losses which enhance the natural productivity of the habitat. of artificial propagation is to compensate for cannot be economically mitigated for by flow release and habitat modification. 35 2.2.2.1 -Flow Release (a)Impact Issue The proposed hydroelectric development on the Susitna River is for power production.To maximize power and energy benefits,the discharge downstream of the dams would follow Case P-l (Harza-Ebasco 1984a).This schedule of flows varies greatly from the natural mean monthly flows recorded at Gold Creek (Figure 11,Table 14). Case P-l flows average 9,700 cfs during both the winter (October through April)and summer (May through September) periods (Harza-Ebasco 1984a).During winter,mean flows will gradually increase to a maximum of approximately 12,000 cfs in December,followed by a gradual decrease through the rest of the winter.Mean December flow can be as high as 14,000 cfs in some years.Minimum monthly mean flows would rarely be less than 7,000 cfs during the winter ---periba····{Harzl:t:;;;E15a-sco ··t98lfa:}~ Summer flows would exhibit more variability around the mean of 9,700 cfs.During high flow years,mean flow in May, June,and July could approach 20,000 cfs while mean flow in August and September could be greater than 20,000 cfs _.._.-..--~._._..--_._-_."-_._~----_.~...•--~-_..,---_._-----,------_.•.._~.__._--._•.._._-.-_.__._--_._----_.~..•._._..-_.._.._----_.._._._--_.-._-------,~-.-...-._.__•.•...._-_.__._-_._._-, (Harza",:,Ebasco 1984a).In low flow years L the flow couldbe _ 4,500 cfs for extended periods.Summer flow would be less than 7,000 cfs about 30 percent of the time (Harza-Ebasco 1984a). The comparatively low flows during August and September would r-estdct -movement ofadtilf salmon info and within sloughs.At a mainstem discharge of 6,000 cfs under Case P-l,backwater effects at the slough mouths would be negligible,breaching of the sloughs would rarely occur, and the upwelling component of local flow would be less 36 I J j' 1 I I I j i I II II than that at natural flows.Proj ect flows would also reduce the spawning habitat available due to reduced backwater,breaching,and groundwater upwelling effects. Project flow in the mainstem during winter can cause reduced upwelling upstream of the ice front and increased potential for overtopping downs'tream of the ice front. Juvenile salmon rearing habitat would be reduced under Case P-l flows during both summer and winter months.Flows of 4,500 cfs in summer months would result in a substantial loss of the mainstem and side-channel rearing habitat presently used by chinook juveniles (Harza-Ebasco 1984a). Juvenile overwintering habitat may also be adversely affected under Case P-l flows;the increased winter main- stem stage would overtop the sloughs mor~frequently in ice-covered areas and may result in displacement or mortal- ity of juveniles.On-going instream flow-juvenile rearing habitat studies will allow for a quantitative assessment of potential flow-related impacts to these habitats. (b)Mitigation Of the project flow schedules which have been identified (Harza-Ebasco 1984a),three mitigation flow schedules are discussed to reduce the adverse impacts of Case P-l.Case C,previously selected as the primary environmental flow case presented in the License Application,is intended to partially mitigate impacts to spawning adult salmon.Case EV is designed to reduce both spawning and rearing habitat impacts.The Alaska Power Authority's designated flow case,Case EVI,is selected primarily to reduce loss of chinook rearing habitat (Harza-Ebasco 1984a). (i)Case C The environmental flow components of Case Care designed to maintain suitable conditions for the 37 upstream migration of adult salmon during the summer and to increase access to side sloughs by chum salmon for spawning during August and September as compared to Case P-1 (Harza-Ebasco 1984a).Mainstem flows in August and September are constrained to provide a minimum of 12,000 cfs (Figure 12).No maximum flow constraints throughout the year are established. In comparison to Case P-1 flows,Case C will improve the frequency of salmon passage into sloughs and side channels in August and September.A mainstem discharge of 12,000 cfs under the Case C flow schedule will increase the backwater effects in slough mouths.Breaching of some side channels would occur at this flow.The local flow in side sloughs would also increase due to upwelling related to mainstem discharge. However,the lack of a constraining maximum flow adversely affects rearing and overwintering habitat as well as incubating conditions.The low mainstem flows of 6,000 cfs in summer months prior to August under Case C would result in the loss of most of the ..-----··.·.-··-·---.-··-····-····-·--·-exi:sting..chinook-·-juveni-le--habitat·-currently-·in-·use··. (Harza-Ebasco 1984a)•The potential magnitude of -------. these adverse impacts prompted the identification of more detailed and refined environmental flow schedules (Harza-Ebasco 1984a). Case EV flow constraints are designed to minimize the losses of the existing chum salmon slough 38 1 l' I I ;~l .J I I passage in channels. channels. required to majority ()fIi i ) I.'J spawning habitat and chinook salmon side channel rearing habitat. Spawning habitat will be partially preserved by mainstem flows which are constrained to a minimum of 12,000 cfs during August and early September when chum salmon are migrating and spawning in sloughs of the middle Susitna River (Figure 13).Case P-l flows are proj ected to approach 6,000 cf s during this time.A mainstem discharge of 12,000 cfs will create backwater effects increasing the frequency of the mouths of some sloughs and side Breaching would occur in some side However,greater mainstem flows are breach the sloughs containing the the spawning ,habitat in the middle Susitna River (Sloughs 8A,9,9A,11 and 21). Local slough flows are anticipated to increase for Case EV in comparison to local flows under Case P-l. Based on current information (APA 1984),it is estimated that Case EV flows would increase slough flows by 0.5 cfs in Sloughs 8A,9 and 11 and by 4 cfs in Slough 21.However,local flows would be less than local flows under natural conditions. Case EV scheduled flows include a two-day period in August when the mainstem discharge will approach 18,000 cfs in order to improve access to chum salmon spawning habitat;the higher flow will increase breaching in some sloughs and backwater effects in most.At 18,000 cfs,breaching will not substantially ameliorate salmon passage in the sloughs of primary spawning importance (Sloughs 8A, 9,9A,11 and 21).Backwater effects may provide passage through an additional passage reach upstream 39 of the reaches passable due to backwater effects at 12,000 ds. Local flow during the fall spiking flow of 18,000 cfs is anticipated to remain approximately at the levels of the local slough flow at a mainstem discharge of 12,000 ds.The short duration of the higher flow and the probable unsaturated condition of the substrate above the 12,000 cfs mainstem stage may result in delayed and damped response of the local flow to the mainstem discharge increase. The Case EV minimum mainstem discharge of 9,000 cfs (Harza-Ebasco 1984a)would maintain much of the rearing habitat currently in use by chinook juveniles during the summer months.The minimum discharge would occur 55 percent of the time, although the predicted average flow during the ~~__~~~~_~~___--~---~~~__~~~summer __period_wouldbe~-LL,-4OO-cfs--(Harza""Ebasco 1984a).The spiking flows may cause displacement of chinook juveniles;however,the increased mainstem flow stability may improve .the overall quality of the remaining rearing habitat under Case EV (Harza-Ebasco 1984a). Winter flows under Case EV,in comparison to Case P-1,would decrease the frequency of breaching flows downstream of the ice cover and reduce the amount of upwelling upstream of the ice cover.The maximum wirtter discharges of 16 ,000c~fs would assist in maintaining-vIable-incubatIon-hab i tat within the sloughs;winter overtopping under Case EV will occur more frequently than under natural conditions downstream of the ice front.Upstream of the ice front under Case EV,the decreased inainstem stage from Case P-1 may result in reduced upwelling.Both 40 J .1 .( I j j .~ 1 I I I j cases will result in decreased upwelling upstream 0\ the ice front as compared to natural conditions. Case EV flows are designed to minimize loss of chum spawning habitat and chinook rearing habitat; however,additional measures would be necessary to mitigate for residual impacts.Additional mitigation also would be necessary for Case EV winter flows. (iii)Case EVI Case EVI is designed to minimize loss of existing chinook salmon side channel rearing habitat in all rs except low f '(Harza-Ebasco 1984a). Spawning habitat is not specifically considered in the establishment of minimum and maximum mainstem discharge constraints.The minimum discharge constraint for Case EVI is greater than natural discharges in the winter months and less than natural discharges in the summer months (Figure 14). The maximum constrained discharge is greater than the mean monthly natural discharge throughout the year (Figure 16).The simulated mean monthly discharges for Case EVI (Figure 15)are considerably greater than the minimum constrained discharge.The constraining bounds represent discharges which could be reached during low or high flow years. Under Case EVI,minimum flows during the critical period of chum salmon migration and spawning in August and September will be increased above the Case P-l projected flows of 6,000 cfs to 9,000 cfs. For Sloughs 9 and 11,a mainstem discharge increase from 6,000 cfs to 9,000 cfs is estimated to increase slough flow by 1 cfs over the former,based on 41 /. -/ ;/currently available analyses (APA 1984).In Sloughs 8A,9A and 21 the Case EVI flows are anticipated to also increase the local flow slightly. The higher mainstem flows will increase the discharge in the sloughs through increased groundwater contributions to local flow.This will' increase fish passage efficiency.The local flOWS) will be lower than local flows under natural ~ conditions in the August to September period.The frequency of passage will become less than the natural frequency of passage.The higher Case EVI flows will have a negligible effect on the backwater at the slough mouths ~nd the flows will not be high enough to breach the sloughs of primary importance to fish production (Sloughs 8A,9,9A,11 and 21). J ! Case EVI mainstem discharges are less than the nat.m:;·al dis eha·r-ges--du·:ring--t.hesumme:r-.and-·f.aJ.-J..··-..'the l~ck of breaching flows and backwater effects will still lower the efficiency of fish passage in sloughs.Local flow in the sloughs will also be lower than natural conditions.Case EVI will partially mitigate for impacts on chum salmon and .---.---------...----···wllr-m:[iiJ:mfze···-impacts-on·cfa:nook:-rearlng---na£IEat;_._...._.--.._...--.. ..._-_._---"--'--~-_.__.~_..----~----_._--"_._-_._._----_..__•.._-•.•..__.•.-.----~_._-_."----"_...__.._--~---_._"-_._--._-----_._._,----_._._,---------_..•......_.__._---_...._...._-.---._._------_._-------_.------- nevertheless,adverse impacts on side slough spawning and incubation will occur.Mitigation in addition to flow release will be necessary for the late summer,fall,and winter. (a)Impact Issue Residual impacts to the amount of spawning and incubation habitat available to chum salmon in sloughs and side 42 channels of the middle Susitna River will persist after implementation of the Case EVI or Case EV flow release. Case C flow releases during the spawning season are similar to the base flows of Case EV and will not be discussed to avoid redundancy.Partial or complete loss of these habitats,when compared with natural conditions,will result from: o Reduced backwater effects o Reduced frequency of breaching flows o Reduced upwelling during spawning and incubation •Passage restriction Increased frequency of winter overtopping in ice-covered areas (b)Mitigation Measures A number of mitigation measures are presented in this section that can be used singly or in combination to minimize identified impacts.Table 15 shows the relationship between the mitigation measures and the impact for which they are designed. (i)Channel Width Modifications Channeling slough flow will improve fish access through passage reaches by contracting the width of the channel and deepening the channel.This technique is especially useful in modifying short, wide passage reaches.Wing deflectors extending out from the channel bank or rock gab ions restructuring .1 the cross section of the natural channel may be used to contract the flow width (Bell 1973). In determining the modified width for the channel,a i maximum velocity criteria of 8 fps was used to !.'permit fish access through the reach (Bell 1973). 43 / -J -Wing Defl~ctors Wing deflectors are used to divert the flow in a ) ehannel.Two wing deflectors placed on OPPosite) banks will funnel the flow from to a narrower cross section as shown i Figure narrowed channel is designed to provide fish passage at the minimum flow.At higher flows,the wing deflectors are inundated;fill between the banks and the wing deflector walls is sized to prevent scouring at higher discharges.Fill will typically be composed of large cobbles available at the sloughs. Wing deflector walls are constructed either of rock or gabions formed of wire mesh and filled with cobbles.Another alternative is the use of 12-inch-diameter timbers,anchored to the banks and channel bed.A wing deflector costs $31,000 when constructed of rock,ap~roximately $24,000 ..when constructed with gabions,ang $22,000 if timber logs available on site are used.For sites where timber is not available,a log wing deflector would cost $23,000.Estimates are based ..C'pa.:t:Y.P:i,c:,li],..Pe:t.s§lig~reach ofliPP.!'():lf:i,lllli.:t:.~J:Y t .-----.---.-----------.-..------·-·--·----·--200-£.eet-£.o't'a-s±oug·h-on--the-mi-dd-le-Sus4:-tna-R4:-ve-l'------------ (Figure 17). -Rock Gabion Channel the original.Cross section of the channel with rock gabions is an alternative method of channelizing the slough flow.The channel is excavated and gabions are used to establish the new configuration.The new channel shape is designed to maximize depth at minimum flows;at higher discharges,the gabions prevent scouring of 44 J I .! l i I J -Wing Deflectors 1Wingdeflectorsareusedtodiverthe flow in a channel.Two wing deflecto~sp~ced on opposite banks will funnel the flow rom a wider to a narrower cross section as sh,wn in Figure 18.The narrowed channel is designed to provide fish passage at the minimum f~.At higher flows,the wing deflectors are ii:.ndated;fill between the banks and the wing rflector walls is sized to prevent scouring at~igher discharges.Fill will typically be czmpoed of large cobbles available at the sloughs. Wing deflecto walls are constructed either of rock or~gbi ~s formed of wire mesh and filled with cobble.Another alternative is the use of 12-inch-di meter timbers,anchored to the banks and chanJel bed.A wing deflector costs $31,000 when cistructed of rock,approximately $24,000 when ;t~nstructed with gabions,and $22,000 if timbjF logs available on site are used.For sites whe;e timber is not available,a log wing derector would cost $23,000.Estimates are based o~a typical passage reach of approximately ~O feet for a slough on the middle Susitna River (Figure 17). -Rock Gabion Channel Reshaping the original cross section of the channel with rock gab ions is an alternative method of channelizing the slough flow.The channel is excavated and gab ions are used to establish the new configuration.The new channel shape is designed to maximize depth at minimum flows;at higher discharges,the gabions prevent scouring of 44 the channel banks.Figure 18 illustrates a typical cross section for a reshaped passage reach.For long passage reaches,resting areas are created by widening the channel between the rock gabions forming the minimum discharge channel.The gabions are provided throughout the length of the passage reach and protected upstream by riprap or wing wall gabions.The gabion banks extend higher than the height of the maximum slough discharge to prevent collapse from erosion. The gabions composing the channel banks prevent scouring of the banks;the channel will be more stable than a similar channel modified by wing deflectors.For passage reaches with greatly varying discharges,the added stability of the rock gabion channel is an advantage.The cost of constructing the gabion channel is approximately $6.0,OQQ f9r aty.picalpassage reach.200.feet in length. (ii)Channel Barriers Fish access through passage reaches is also improved by-creat ing-a--serres·-of-··pools·.···_··Ba:f'f'ie:ts····a:f'e·····p laced to ,steep passage reaches and create pools between obstacles.Fish passage over the obstacles is accomplished if sufficient steps of decreased barrier height are provided to permit surmounting the original barrier (Bell 1973). Channel barriers are used on long slopes to create fish resting pools,as shown in Figure 19.These barriers with heights of 10 inches to 14 inches act as weirs,with a section of decreased height to improve fish passage between pools.The barriers are constructed of various materials.Concrete 45 I r highway curbs anchored to the bed with rebar (Figure 19)or cobbles and boulders placed to create a sill may be used.Logs may also be attached to the banks and anchored securely to the bed to prevent movement at high discharges.Gabions shaped as shown in Figure 19 may also be used (Lister et ala 1980b). Channels are constrained in width to form effective pools.For a wide channel,channel widths are modified where a pool and weir structure is desired. Estimates of costs per barrier on the basis of a two barrier system are listed below.Each slope will require more than one barrier to create a series of pools.As more barriers are built on a site,the cost per barrier will decrease because of the economies of scale;the major cost involved in the construction of the barrier is the cost of transporting the equipment needed. Barrier Concrete highway curbs Rock sill Gabions Anchored logs available on site Anchored logs not available on site Cost/Barrier $12,000 $16,000 $12,000 $11 ,000 $12,000 (iii)Passage Provided by Flow Augmentation With lower mainstem discharges,less groundwater may percolate into the sloughs,resulting in decreased slough discharge (APA 1984).Passage reaches negotiable at natural flows might become impassable under project conditions.In order to augment the slough flow,a piping system can be designed to 46 transport water from the mainstem or other sources to affected passage reaches. The sloughs of primary interest,including 8A,9, 9A,11,and 21,were considered in evaluating the feasibility of a piping system at a mainstem discharge of 9,000 cf s.This corresponds to the minimum spawning period mainstem discharge for Case EVI flows.The system feasibility was also considered at a mainstem discharge of 12,000 cfs corresponding to the minimum discharge for Case EV during the August to September period. For Sloughs8A and 9A,the mainstem elevations at 9,000 and 12,000 cfs would pr~duce insufficient head between the mainstem stage and the critical passage reaches to provide sufficient flow to provide passage.Flows corresponding to the site-specific ..----·overtopping-discha~ges-are·necessa:t'y-top:t'oducethe required head for the required flow. At Slough 9,a 9,000 cfs mainstem discharge would provide sufficient head for 1 cfs through a piped system.A collection tank (Figure ~O)20 feet from .----.---...·······themain--c1iannerwould···c6Tlect-·maIiiste1IJ.water~·.'the'· ...._--_-_.. collector was to be located 20 feet from the mainstemin order to provide erosion protection and a filtration system for the water.A I-foot- diameter corrugated metal pipe would deliver the wafer 2;800fe·ef·t6 the·upstream end of Passage .~R.eaCh (PR)'V,as·showli inFigure~21..At·a mainstem discharge of 17,000 cfs,the system would p'rovide approximately 1.5 cfs.The system would provide a maximum of 3 cfs prior to berm overtopping.The amount of flow provided by the system seems to be uneconomical when the alternative options available 47 l J 1 ,/ !~at Slough 9 are considered.The installation ( piping system is not recommended due to the cost of the system and the large number of mitigative measures feasible. For Slough 11,mainstem discharges of 9,000 cfs or ~12,000 cfs could provide sufficient head for a flow .~"./of ~__c=.s__fr~~_~__COll~ctor through a I-foot-diameter~~e for delivery t~a distance of 3,200 feet from the slough head (Figure 22).The installation of a piping system into Slough 11 is not recommended;the quantity of water supplied is low. Alternative mitigation options exist which could accomplish a similar reduction in negative impacts with reduced monetary costs. A mainstem discharge of 9,000 cfs would be necessary at Slough 21 for a local flow of 1 cfs from a similar sized collector through aI,700-foot-long, 0.75-foot-diameter pipe (Figure 23).A mainstem discharge of 12,000 cfs will not significantly increase the flow through the system.A maximum of 2 cfs would flow through the system just prior to overtopping.The shorter distance from the mainstem to the pipe outlet and the smaller pipe required in the system increase desirability of the installation of such a system.Although the addition of local flow would increase the frequency of passage and improve spawning habitat throughout Slough 21 and Side Channel 21,alternative mitigative measures accomplishing the same goal are more cost-effective. Estimated construction costs total $120,000 for the backhoe installation of the collector and piping system in Slough 9,$120,000 for the system in Slough 11 and $134,000 for the system in Slough 21. 48 (iv)Gated Water Supply System In the absence of large flows in sloughs and side channels,debris buildup,siltation,and algal growth may create passage restrictions and decrease available spawning habitat.Side sloughs and side channels are breached under natural conditions with a frequency from 1 to 4 years.The large breaching flows remove obstacles caused by debris and scour the channel bed.Flows of 50 cfs or greater may be required for the removal of debris and channel scouring.Under proj ect conditions,breaching of the sloughs and side channels will occur less frequently in spring and summer months and may not provide sufficient flllshing of the channel.A gated pipeline extending under the berm at the head of a slough or side channel could provide large quantities of flow under unbreached conditions. ,[ The gated water supply system consists of a 3 ft diameter corrugated pipe with a gate valve structure.The pipe intake is protected by a riprap cover to prevent the entrainment of fish and debris. The riprap will stabilize the bank of the berm at ------------------~---------the__intake_by_prev:enting--scour-.--.--Largeriprap---at-the ..------"-- out-]:-et-wi-l-l-cre-at"e-turoul-etrt-CCJlld:i:"t"i:"C>!fs-f-c>r-i:"1fiVrove-d------- air entrainment and the dissipation of energy to prevent excessive channel bed erosion.The gate valve structure will""enable the manual opening of -the pipe_to-allow.la.rge ..flows.into the channel.In order to-pr.()'V~ic1.e -tll~-st1~~ested 50 cfs of -sl()t1~ll flow,the pipe system will be operated at a high mainstem discharge.To prevent the influx of turbid water during chum spawning or near-freezing water 49 J ! during incubation,the pipe gate valve will remain closed during the fall and winter months. A gated water supply system to provide a minimum of 50 cfs is feasible at a given mainstem discharge if the head difference between the mainstem elevation and the slough bed is large enough to drive water through the required pipe length.A 3 ft head difference will deliver 50 cfs through a 4500 ft or less pipe length.A 1 ft head difference requires a pipe length of less than 1300 ft.Given the head difference and pipe length requirements,a gated water supply system is feasible at Sloughs 9,11, and 21.The estimated cost of a system with a pipe length of 2500 ft is $100,000. (v)Upwelling Augmentation A system providing supplementary upwelling would maintain or increase spawning habitat in the sloughs during low mainstem discharges.The mainstem and nearby tributaries were evaluated as possible sources of upwelling water.The mainstem as an upwelling water source could not be used at numerous sites because of the low hydraulic head at low mainstem flows. For sloughs with tributaries,the tributary could provide the water and the hydraulic head for an upwelling system,as shown in Figure 24.The critical period for induced upwelling would be during the project's projected low mainstem discharge period in August and September.Under natural conditions,it is assumed,based on the relationships provided in APA (1984),that upwelling increases during this period because of the high 50 mainstem discharges.Selection of spawning sites has been shown to be related to the presence of upwelling at a site;therefore,upwelling needs to be maintained under project flows to maintain spawning habitat. Under natural conditions,the mainstem stage and upwelling decrease from September until ice formation in November to December.Similarly,a tributary supplied upwelling system would also have decreasing discharges during this period.Reduction in a piped water supply would not become substantial until mid-October,when project discharges increase. Upwelling under proj ect operation is likely to be greater than upwelling -under natural conditions from September to December. Upwelling dur~ng winter (December to March)will decrease for sloughs upstream of the ice cover and increase sloughs doWnstream of the ice :front, relative to the natural conditions.,The upwelling provided by a tributary driven system may prove inadequate during this period upstream of the ice front. -.In-the-.spring-,-tributary--f.lows-increase.-with-the.....-- melting of snow and ice.By April,the tributary flows would be sufficient to provide upwelling from the piping system.Upwelling thus would be provided continuously throughout the year.Under natural <::onditionf3,upwelling i.s greatest from June through September and December through April. Temperatures of the upwelling flows from the piped system would correspond to the temperatures of the tributary flows.Water will flow through the system 51 [ [ I.~ ,J 1 I as long as .the water temperatures are above O°C. Freezing water will not be released in the spawning gravels,as flow will cease in the system at freezing temperatures. Estimated cost of the system is $210,000 for a 300-foot main pipe and 200-foot reaches of cross pipe,spaced at 5-foot intervals for upwelling.A system with a longer main pipe could be built to tap Gold Creek water for Slough 11.Until more refined values are available quantifying the extent of the reduction in upwelling,the system will not be recommended for installation in any slough. (v)Slough Excavation I \ I Mechanical excavation of certain reaches of sloughs would improve fish passage and fish habitat within the sloughs.At slough mouths,excavation would provide fish access when backwaters are negligible during low mainstem discharges.Mechanical excavation can be used to facilitate passage within sloughs by channelizing the flow or deepening the thalweg profile at the passage reach. On a larger scale,mechanical excavation to lower the profile of the entire slough could increase the amount of upwelling in the slough.A greater head between the mainstem and the slough bed would result in additional local flow in the slough. An additional benefit of the excavation process would be the opportunity to improve the substrate in the'slough.Replacement of poor substrate with suitable spawning gravels would provide additional spawning habitat.Sorting of the existing substrate 52 (vi) will be undertaken to remove unsuitable particle sizes.The excavation process would be designed to develop additional spawning and rearing habitat. An estimate of the cost to excavate a typical slough mouth in the middle portion of the Susitna River is $26,000.An estimate of the cost to lower a typical slough profile by 2 feet for a length of 2,000 feet in the middle section of the Susitna River is $34,000. Development of New Spawning Habitat In order to provide the conditions that chum salmon prefer for spawning,existing pools in sloughs would be modified.Chum salmon prefer to spawn at upwelling sites (ADF&G 1983a).A weir structure that is permeable at the base and impermeable l:l:J.~E:~1:lere ~-')llld 1:>E:.~:r_E:cted i.I1~p.ool_to p]:()d.l,lce ~ head difference between the upstream and downstream sides.Such a weir would cause water to flow through the spawning gravels placed at the base of the structure (Figure 25). A-notch in the top of the structure facilitates fish passage between pools.-The notchis--designea-for-8.--------- minimum slough discharge of 2 cfs;this discharge corresponds to a typical low discharge in the sloughs along the middle section of the Susitna River. The structure is securely embedded,anchored to the channel walls a.n.d bed,and riprapped to prevent erosion during high flows. 53 I ! ! J J 1 [ J ;\ \ 1 \ .1 \ i) ) The weir can be constructed of timber posts 10 inches in diameter,reinforced with 2 x 4 inch cross bracing and faced with impermeable ma~erial, as in Figure 26.Gravel materials are piled on each side of the weir;the gravel provides stability to the structure in addition to providing spawning habitat.Only fine silts present in the gravel base will be eroded by the 2 fps water velocities over the weir.The spawning gravels would have a maximum angle of 10°with the channel bed to prevent .downstream.displacement caused by females digging redds during spawning. Rock gabions can also be used to construct the weir shown in Figure 27.Sheets·of plywood in the center of the structure impede flow through the gabions. Spawning gravels provide habitat at the base of the structure.A notch is provided for fish passage at low flows. A rock structure with an impermeable core can be built as in Figure 28.Plywood sheets anchored with reinforcing rebars are adequate for use as a core. The decision as to the materials used for the weir structure will be made during the design phase of the project based on the cost,durability,and aesthetics of the various structures. The cost estimate of the three structures is based on a 20-foot channel width and a 3-foot natural pool depth.Economies of scale are considerable if more than one structure is built at a site. 54 J 1 -j I I '':"1' ...I \.I I I .J Cost/Weir $32,000 $32,000 $45,000 from $24,000 to slough need berm range on the Structure Timber pile weir Rock gab ion weir Rock weir Cost estimates per $161,000 depending configurations. An influx of cold mainstem water into the incubating area of the Slough 8A in 1982 caused adverse impacts (ADF&G 1983b).To prevent overtopping,the height slough berms is increased as shown in Figure (vii)Prevention of Slough Overtopping Project flows are higher than natural discharges in the winter.Ice'staging at these discharges will result in an increase in mainstem stage and increase the probability of overtopping of sloughs downstream of the ice cover front. S-i te-sp eC1f"ic:-n:a151 tat ··---------moaJ.-fl.ca t ion measures--------iif-e---j?roposea-.-------------- for Sloughs 8A,9,9A,11 and 21 and Upper Side Channel 11 and Side Channel 21.Collectively,the mean peak spawning counts to these sites comprised 72 percent of the mean total peak counts to sloughs for 1981, 1982,and 1983 -,(ADF&G1984Ci)."-The lllocl:i.;fi..g,Cit:i.:Oll.t:~Glm:i;q:Qes.Jmggest~cl for these selected sites are applicable to the remaining sloughs and side'cha.nnels·supporting 'spawning chum salmon in'the middle Susitna River.The proposed measures would be similar given a Case EVI or Case EV flow scenario.Cost estimates for these sites are summarized in Table 1. (c)Site Specific Impacts and Mitigations 55 ) )1 (i)Slough 8A -Relative Utilization During the 1981-1983 studies,the mean peak counts of chum salmon and sockeye salmon in Slough 8A were 331 (range:37-620)and 104 (range:67-177).The mean estimated total escapements to the slough were 553 chum (range:112-1062)and 152 sockeye (range: 131-195)(ADF&G 1984a).Slough 8A mean chum escapements comprised 15.7 percent of the total escapement to sloughs in the middle Susitna River. The approximate percentage distribution of chum salmon during the 1984 spawning season is shown in Figure 30 (Seagren 1984 memo). -Impact Mechanism •Backwater Spawning habitat that is dependent on backwater effects for providing suitable spawning depths would be lost because of proj ect effects.An estimated spawning area of 103,000 square feet is affected by.the backwater zone of.natural flows.The portion of this area would become unsuitable for spawning at Case EVI project flows would be greater than that of the Case EV flows. •Breaching The exceedence probabilities associated with natural breaching flows 27,000 and 33,000 cfs are 7 percent for the northwest channel and 2 percent for the northeast.channel (Sautner et al.1984).The recurrence intervals for flows 56 sufficient to breach the respective channels are approximately 2.1 and 7 years (Figure 10). These relatively low exceedance probabilities indicate.that the importance of breaching lies in providing successful passage rather than increasing the potential spawning habitat by increasing the area with suitable spawning depths.Neither the Case EVI or Case EV minimum project flows would be of sufficient magnitude to provide breaching conditions. •Groundwater Upwelling Groundwater reductions at the various passage reaches under Case EVI would range from 60 to 62 percent during the spawning season.Case EV reductions would range from 29 to 50 percent (Appendix A,Tables A5-A13). Overtopping of Slough 8A is predicted for several combinations of year specific climatologic data,operational regimes,and demand schedules (Harza-Ebasco 1984b). '". •Passage Restrictions Under Case EVI flows,the frequency of success- .ful passage conditions will decrease at passage reaches (PR's)I and II from natural levels of 79 and 48 percent to project levels of 25 and 16 percent.ForPR 'sIIIto IX the decrease will range from 1 to 3 percent (Table 16).Case EV flows would increase the frequency of successful passage above natural conditions to 100 percent in PR I.At PR II a decrease will occur from 48 57 IJ I:) ') ,) \} I I'f I \ I I) L , to 18 percent.At the remaining PRls,decreases would be 1 or 2 percent.The 18,000 cfs spike proposed for Case EV would temporarily provide frequencies of successful passage greater than those under natural conditions.These decreases in frequencies of successful passage may,over time,result in a loss of potential spawning habitat.Historically spawned areas are presented in Table 8. -Mitigation Passage through PR I s I and II is provided under natural conditions by backwater effects from a high mainstem discharge •With Case EVI flows, access through these passage reaches will be provided in an alternative manner to maintain the 103,000 square feet of fish habitat available within the slough.Benefits that may accrue from the Case EV 18,000 cfs spike would depend on its occurrence relative to escapement timing and other factor's contributIng to frequency of passage. The maximum channel bed elevation of the PR I will be reduced to ease fish passage into the slough. Flow in PR II will be channeled to increase the depth at the expected lower slough flow.Adding wing deflectors to narrow the channel and remove boulders from the channel will improve passage through PR II.Other passage reaches may be ) improved by excavating a deeper channel through the reach.Passage and improvement of spawning habitat in the west channel will be evaluated as 1984 data become available.Slough 8A passage evaluations are complicated by the presence of several beaver dams.Measures to provide passage through these structures will be undertaken with 58 'I the approval of appropriate Fish and Game management agencies. ,) Winter overtopping sometimes occurs at Slough 8A under natural conditions (R&M Consultants 1983). Under Case EVI,the frequency of winter overtopping is predicted to increase (Harza-Ebasco 1984b).Increasing the elevation of the berm at the head of each fork of the slough will prevent overtopping by near-freezing waters.The height of the northeast fork berm will be increased by 9 feet;approximately 250 feet of berm is required.The northwest fork berm will be increased four feet for a length of 250 feet. .1 11 /I /j Annual Operating & Maint.Costs Capital Costs Number ProposedMitigationMeasure The capital costs associated with each of the mitigation measures and the annual operating and maintenance costs based on semi-annual inspections and periodic repairs of mitigation measures for sA are shown below ancl.iil.Figure 3l:r: Slough mouth excavation -.------------------------.__Excav.ate __passage reaches._6_ Protective slough berms 2 26,000 5,000 -24,000 .1,500 _.lO_,OO.O._.._...._2,.0.0.0_ 61,000 15,000 Total $121,000 $4,00 (ii)Slough 9 -Relative Utilization During the 1981-1983 studies,the mean peak counts of chum salmon and sockeye salmon in Slough 9 (including 9B)were 295 (range:175-358)and 33 (range:2-91).The mean estimated total escapements '59 1 I/. I I 1, I'1 to the slough were 563 chum (range:430-645)and 81 sockeye (range:0-230)(ADF&G 1984a).Slough 9 mean chum escapements comprised 11.6 percent of the total mean escapement to sloughs in the middle Susitna River.The approximate percentage distribution of chum salmon during the 1984 spawning season is shown in Figure 31 (Seagren 1984,memo). -Impact Mechanism •Backwater Backwater effects provided potential spawning area during the study period 1982-1984 and a small portion of that area was spawned only in 1983.The lower portion of this slough has since silted in and the channel has changed its course,thus precluding spawning in this area. •Breaching The exceedance probability associated with breaching discharges of.19,000 cfs during the spawning period is 29 percent (Sautner et al. 1984).The recurrence interval for 19,000 cfs is about 1.3 years (Figure 10).It is probable that the breaching flows are providing the depth required for spawning in some areas and that these areas would become unspawnable at project flows.However,the extent of these areas appear minimal when the wetted perimeter bound- aries at a flow of 9,000 cfs are overlaid on outlines of spawned areas from 1982-1984. Neither Case EVI nor Case V project flows would be of sufficient magnitude to provide breaching conditions. 60 •Reduced Groundwater Upwelling Case EVI would reduce groundwater upwelling at each of the passage reaches by approximately 40 percent during the spawning season.Case EV reductions would amount to approximately 20 percent (Appendix A,Tables AI4-AI8). •Winter Flows The upstream extent of the ice cover is projected to progress beyond Slough 9 for several combinations of selected meteorologic data,operation regimes,and demand schedules. Based on thesimula:ti6ns completed to date, there is a moderate probability of annual overtopping of the slough (Harza-Ebasco 1984b). •Passage Restrictions Based on mainstem discharge-groundwater relationships and slough flow analysis,Case EVI flows will result in reductions in the frequency of successful passage conditions at PR's I,III, IV a.D,c:L V.Successful pa.Slsag~Cl.t P~I "to10u1d be ------------reduced--:from lOO-Eo-47 pet'Gent;-._.At-FR-'-s-III-and- IV,passage under natural conditions occurs 18· and 17 percent of the time as compared to 15 percent and 14 percent under project flows (Table 17).At PR V,natural occurrences of 29 percent will change ..to 0 percent passa.ge under proj ect flows.The reduction in opportunities of passage at PR's III and IV may also result in loss of some spawning habitat.Case EV flows would result in decreases of successful PR III and IV of only 1 to 2 percent and decreases from 29 to no passage at PR V.The general area of 61 I f spawning above PR V that would become inaccess- ible at Case EVI and Case EV flows amounts to approximately 5,300 square feet (Table 9). -Mitigation Passage through the downstream section of Slough 9 is currently difficult because of silt deposited during the 1983-1984 season.Removal of this silt· will expose the spawning gravels and increase the habitat·in the downstream region of the slough. The slough mouth would be excavated to increase the frequency of passage through PR I under the Case EVI flow regime. Based on the relationship between mainstem flow and·slough flow·presented in APA (1984),PR's III .and IV are greatly affected by a reduction in natural discharges.At discharges corresponding to Case EVI the frequency of passage through these reaches will be increased by excavating a deeper channel and channelizing the available local flow. Larger cobbles and boulders will be removed from the channel to improve the spawning habitat. Other efforts to improve spawning habitat in the pool region between PR's IV and V include construction of a rock weir to increase available spawning habitat. Upstream from PR V,spawning habitat is available under natural conditions.Under proj ect condi- tions,based on the currently available slough flow analysis,fish would not be able to reach this habitat.A pool and weir structure will be constructed to enable fish to access the natural pool habitat available upstream of PR V.A series 62 of 20 weirs composed of anchored logs will allow salmon to access an additional 1,000 ft of Slough 9. Slough 9 is expected to be overtopped more frequently in winter by the increased ice stage caused by project flows (Harza-Ebasco 1984a).An overtopping-prevention berm 8 feet high and 375 feet long will be placed at the head of the slough to maintain the suitability of incubation habitat within the slough.In addition,the berm would prevent the deposition of sands and silts as it currently occurs. The capital costs associated with each of·the mitigation measures the estimated annual operating and maintenance costs for all measures based on semi-annual inspections and periodic repair of mitigation measures for Slough 9 are shown below .. and in Figure 31: 1I J\·1 Mitigation Measure Number Proposed Capital Costs Annual Operating & Maint.Costs Slough mouth excavation Rock wei r .1 ·------..·..Protecti-ve-slough··berm---l Log barriers 20 Passage reach excavation 2 Total (iii)Slough 9A .."RelativeUtilization 26,000 ·59,000· 30,000 7,000 $250,000 $4,000 During the 1981-1983 studies,the mean peak count of chum salmon in Slough 9A was 135 (range:l05-182) while the mean estimated total escapement to the slough was 152 chum (range 86-231)(Barrett et a1. 63 .) [I 1984).Slough 9A mean chum escapement comprised 6.4 percent of the total escapement to sloughs in the middle Susitna River.The approximate percent- age distribution of chum salmon during the 1984 spawning season is shown in Figure 32 (Seagren 1984,memo). -Impact Mechanism The breaching discharge for Slough 9A has not been established but appears to be around 12,000 cfs with an exceedance probability of 71 percent (Sautner et al.1984).The recurrence interval for 12,000 cfs is approximately 1.05 years.Field observations during September 1984 indicated that the gravel surface of some areas spawned earlier in the season under breached conditions were dewatered.Survival from these areas is unknown.Estimates of the spawning area lost under Case EVI will be obtained by overlaying the boundaries of the wetted surface area at 9,000 cfs onto the spawned areas delineated for the 1982-1984 seasons.The base flow of 12,000 cfs for Case EV may provide breaching flows and a flow spike of 18,000 cf s most certainly would. [] II II IJ [, I j I II 1 IJ IJ IJ •Backwater Evaluation of backwater applicable to this slough conditions prevail for the spawning season. •Breaching effects are not because breaching majority of the 64 •Groundwater Upwelling Groundwater upwelling reductions at the various passage reaches in Slough 9A under Case EVI would range from 30-48 percent for the various passage reaches during the spawning season. Case EV reductions would range from 13-24 percent (Appendix A,Table A19-A28). •Winter Flows Simulation of the upstream extent of ice cover for several combinations of operating regimes, demand schedules and meteorologic conditions for selected years indicated that there is a probability of the slough overtopping on an annual basis (Harza-Ebasco 1984b). •Passage Restrictions Under natural conditions,PR's I-IX can be successfully negotiated by chum salmon 100 percent of the time (Table 18).Five out of these nine passage reaches are anticipated to .._provide.successfulpassagecondition.3 .to .32 -··--percent ·o-{--the--time--under··Case-EV-I--H:ows.·_···0f--·· the five passage reaches,PR III is considered to be of greatest concern since access to substantial amounts of historically spawned areas .can be achieved if passage through this reach is facilitated (Table 10).Breaching conditions resulting from Case EV flows would provide passage 100 percent of the time. 65 ] I j 1 J I ·1 1 1 ] [I II I] II II !J I j IIL.. -Mitigation Spawning habitat in Slough 9A is primarily accessed during breaching flows under natural conditions.Under Case EVI scheduled discharges, the habitat will be retained by lowering the slough profile until depths suitable for spawning are obtained. .While the slough profile is being excavated,the large cobbles and boulders will be removed to improve access between the series of pools that exist along the thalweg.Removal of the large cobbles and boulders will provide additional spawning habitat to that presently existing within the side channels. Slough 9A breaches at a relatively low natural mainstem discharge and protection from winter overtopping under project conditions will be supplied.The berm at the head of the slough will be heightened 10 feet for a length of 150 feet to prevent winter overtopping if the ice front is predicted to extend upstream of this slough more fr~quently than once every ten years. The capital costs associated with each of the mitigation measures and the estimated annual operating and maintenance costs for all measures based on semi-annual inspections and periodic repairs for Slough 9A are shown below and in Figure 32: Mitigation Measure Protective slough berm Excavation of slough Total 66 Number Proposed Capital Costs $42,000 76,000 $118,000 Annual Operating & Maint.Costs $4,000 (iv)Slough 11 -Relative Utilization During the 1981-1983 studies,the mean peak counts of chum salmon and sockeye salmon in·Slough 11 and Upper Side Channel 11 were 369 (range:238-459)and 532 (range:248-893).The mean estimated total escapements to the slough were 957 chum (range: 674-1,119)and 1,128 .sockeye (range:564-1,620) (Barrett et ale 1984a).Slough 11 and Upper Side Channel 11 mean chum escapement comprised 17.6 percent of the total escapement to sloughs in the middle Susitna River.The approximate percentage distribution of chum salmon during the 1984 spawning season for Slough 11 and Upper Side Channel 11 is shown in Figure 33 (Seagren 1984,memo). -Impact Mechanism •Backwater The backwater at the slough mouth affects approximately 50,000 square feet of area that ...__.h~l?1:IE!E!!l:~E~~_E!<!_i.!l:~l:1E!£Cll;~·.<'>\TE!r:~:Y'i.Il:~the -----.-.-.---.--.--------~-~-~--~--~~-~-....------.-----bounda-r-ies----o·f---------the----we.t-ted-------sur.f.ace area .a.t "". 9,000 cfs indicates that approximately 20 percent of that spawned area would be dewatered during Case EVI operations.Less habitat would be lost under Case EV flows.For purposes of mitigation,tnisdewatered area will be considered lost habitat..Additional habitat with the wetted perimeter at 9,000 cfs may be unsuitable for spawning due to.insufficient depth and would also be considered lost habitat. 67 I I II !1 •Breaching The exceedance probabilities associated with natural breaching discharges of 42,000 cfs is one percent (Sautner et al.1984).The recur- rence interval for this flow is about once every eleven years (Figure 10).Based on this low frequency of occurrence,the contribution of breaching conditions in providing access and passage or in increasing the spawnable area within the slough is negligible.Neither Case EVI,Case C or Case EV would provide breaching flows. •Groundwater Upwelling Groundwater reductions at the passage reaches in Slough 11 under Case EVI would range from 20-25 II II percent during the spawning season. j I Corresponding reductions for Case EV range from 13~19 percent (Appendix A,,Tables A29-A33). •Winter Flows Simulations of ice cover progressing have indicated that the front will proceed as far as Slough 11 generally in the coldest years (Harza-Ebasco 1984b).The probability of the slough overtopping on a yearly basis is therefore low. •Restricted Access Under natural conditions,PRls I-III provide successful passage 70,43 and 12 percent of the time,principally through the groundwater contribution to local slough flow (Table 19). 68 Passage reaches IV and V provide adequate passage conditions only during infrequent breaching conditions,which occur one percent of the time.Based on currently available information,project flows of 9,000 cfs will reduce the groundwater input to the extent that passage will be restricted across all passage reaches (APA 1984).Case V flows will provide additional groundwater to the slough and result in frequencies of passage for PR I,II and III of 60,20,and 5 percent.The Case EV spike would be of such short duration that contributions to groundwater·would be minimal. The spawning areas that will be affected are shown-in Table -Mitigation The passage reaches in Slough 11 will require ....-..-..._~.~-.-----~..-~·-~---cliannellzatioil-lii--or~der toincreaseflie deptli-of flow in the reaches and provide passage. A channel will be exc.avated through the silty materials at the slough mouth and the banks of the channel stabilized with rock gab ions •The .-----...---------.....-.-.-.-_.__...~.__.__.__~~s.tabilize_d_channe_LRil_L.e.:'8:~tendl,200__f eet....!!'R stream~_~_ in the slough and modify PR's I and II.Passage through 300 feet of PR III will be facilitated by construction of wing deflectors made from rock gabions. A channel will be excavated at PR IV.A pool and weir structure will be constructed in the excavated channel which will improve fish passage upstream.Ten weirs will be needed for 500 feet of slough channel. 69 j j I 1 J I ·01 I .1 !I Ii Under natural flows,backwater effects provide 50,000 square feet of fish spawning habitat at the slough mouth.Under project conditions,this spawning area will be partially replaced with rock weirs placed in pools between PR's II and III and PR's III and IV. Under project conditions the slough may experience winter overtopping.Current analysis or ice processes indicates a low frequency of ov~r topping;however should refined analysis show a higher probability,the berm at the head of the slough will be heightened five feet for a length of 250 feet to prevent this occurrence. The capital costs associated with each of the mitigation measures and the estimated annual operating and maintenance costs for all measures based on semi-annual inspections and periodic maintenance for Slough 11 are shown below and in Figure 33: i AnnualINumberCapitalOperating &~J Mitigation Measure Proposed Costs Maint.Costs Wing deflector 1 24,000 Weirs 2 61,000 Bank stabilization 1 25,000 Slough excavation 1 26,000 Log barriers 15 24,000 Protective berm 1 150,000 Total $310,000 $4,000 (v)Upper Side Channel 11 -Relative Utilization (see Slough 11) 70 -Impact Mechamism •Backwater Effects The backwater at the side channel mouth affects a large portion of the area that has been spawned in the past.Overlaying the boundaries of the wetted surface area at 9,000 cfs indicate that dewatering of spawned area would be minimal.However,the depths at 9,000 cfs may be unsuitable for spawning •. •Breaching The exceedance probabilit{'associated with the controlling breaching discharge of 16,000 cfs is 45 percent (Sautner et al.1984).The recurrence interval for this breaching discharge is 1.06 years (Figure 10).This relatively high ----I"requen-cy--oroccurrence-iuclicatesfliaf--oreacning flows are instrumental in providing access and passage and increasing the spawnable area in the side channel. _u •••••_._m"__Groundwater UP'tV~~l~_ng _____________••__m •·•__ Mainstem discharge groundwater upwelling relationship have not been developed for this side channel. •Winter Flows Similar to Slough 11 the probability of the side channel overtopping on a yearly basis is low to moderate. I 1 J -j I .j J II 11,I IIIJ I I .J IJ •Restricted Access Under natural conditions PRls I-III provide successful passage 100,45 and 45 percent of the time.Case EVI and EV would eliminate successful passage conditions at all the PRs, principally through reduction in breaching flows (Table 20).Historically spawned area that would be lost are shown in Table 12. -Mitigation The maj ority of the spawning area in this side channel occurs below PR II and much of this could be retained under Case EVI or EV flows.Access to spawning areas above PR II will require excavation of the channel.The measure,accompanied with replacement of spawning gravels would provide more spawning habitat than currently exists. Prevention of overtopping in the winter and during spring runoff will be accomplished by constructing a berm at the head of the side channel parallel to the flow.The berm would be 10 feet high and 1,000 feet in length. The capitals costs associated with each of the mitigation measures and the estimated annual operating and maintenance costs based on semi-annual-inspections and periodic repair of the meausres for Upper Side Channel 11 are shown below and in Figure 33: Mitigation Measure Channel excavation Protective slough berm Total 72 Number Proposed Capital Costs $26,000 161,000 $187,000 Annual Operating & Maint.Costs $4,000 (vi)Slough 21 -Relative Utilization During the'1981-1983 studies,the mean peak counts of chum salmon and sockeye salmon in Slough 21 and Side Channel 21 were 443 (range:274-736)and 96 (range 38-197).The mean estimated total escapements to the slough were 958 chum (range: 481-1737)and 148 sockeye (range:63-294)(Barrett et ale 1984).Slough 21 and Side Channel 21 mean chum escapements comprised 21.1 percent of the total escapement to sloughs in the middle Susitna River.The approximate percentage distribution of chum salmon during the 1984 spawning season for Slough 21 and Side Channel 21 is shown in Figure 34 (Seagren 1984,memo). -Impact Mechanism •Backwater Spawning areas in the mouth of the slough do not appear to be dependent on backwater.Areas that were spawned under natural flows should remain .................................................................... ...__._~.._..~_.._~_..__..!'l.l'awnable~nder Cas~EV:J:.aIl ..<i...~y..... •Breaching The exceedance probabability associated with the controlling breaching discharge of 25,000 cfs for the left channel is 10'percent (Sautner al.1984).The recurrence interval for breaching flows through the left channel is 1.7 years (Figure 10).Breaching provides access and passage within the slough,but does not 73 .J 'J 1 I l I 1 I appreciably increase spawnable area.Neither Case EVI nor Case EV would provide breaching conditions. •Groundwater Upwelling Case EVI would reduce groundwater upwelling at the various passage reaches by approximately 77 percent during the spawning season.Case EV reductions would be approximately 38 percent (Appendix A,Tables A31-A39). •Winter Flows The ice front is predicted as far upstream as Slough 21 only during the coldest of years (Harza-Ebasco 1984b).The probability of the slough overtopping .is very low. •Restricted Access PR I s I,IlL,and IIR provide suitable passage conditions 100,25 and 20 percent of the time under natural flow.Case EVI flows will reduce the frequency at PR I s I,IlL and IIR to 6,0, and 1 percent,primarily as a result of reduced groundwater flow (Table 21).The frequency of passage for Case EV and Case EVI flows would be 100,0,and 2 percent for PRls I,IlL and IIR. The restriction at PR IlL will eliminate the spawnable area above this point (Table 13).If passage were facilitated,much of the historically spawned area will not be of sufficient depth for use under project flows. 74 -Mitigation Passage through Side Channel 21 is necessary prior to entry into Slough 21.Modification of passages reaches within Side Channel 21 is needed to permit fish access to the habitat in Slough 21. After the large cobbles and boulders in the upper portion of the slough are removed,sorted gravel would be provided to increase the available spawning habitat. The capital cost associated with the mitigation measure and the annual operating and maintenance costs based on semi-annual inspections and periodic repair for Slough 21 are shown below and in Figure 34: 1 I j I j J ~.~°"'1 .J J ] l I 1 j I Annual Operating & Maint.Costs $4,000 $34,000 $34,000 Capital Costs Number Proposed ·Total Excavation of slough Mitigation Measure Passage through Slough 21 will be ameliorated by the excavation of the channel profile.A 2 foot drop in the elevation of the profile corresponds to the mainstem stage reduction from natural conditions to Case EVI conditions.Large cobbles and boulders will be removed and used to stabilize the banks and channelize the flow. (vii)Side Channel 21 -Relative Utilization (see Slough 21) 75 I 1 I IiJ -Impact Mechanism •Backwater Evaluation of backwater effects on availability of spawning habitat are not applicable in light of the low breaching discharges. •Breaching A series of channels enter Side Channel 21 (SC2l)along its length and each breaches at a different mainstem discharge (Figure 34).The uppermost channel,A6,has a breaching discharge of 24,000 cfs with an associated frequency of occurrence of 12 percent (Sautner et al.1984). The recurrence interval for 24,000 cf s is 1.65 years (Figure 10.Spawning areas between the entry point of this channel into SC21 and next downstream channel,A5,are limited primarily by the depth provided by local flow and not breaching. The exceedance probability of 71 percent and recurrence interval of 1.05 years associated with breaching discharges of 12,000 cfs at the AS channel indicates that mainstem overflow into the side channel provided the required depths for much of the spawned area downstream from this p~int during the 1982-1984 seasons.This was confirmed by field observations of the channel at unbreached conditions in September, 1984 when areas spawned previously in the season were observed to be dewatered.Case EVI would not provide proposed breaching conditions while the 12,000 cfs provided by Case EV may cause the lower entry channel to breach. 76 •Groundwater Upwelling Reductions in groundwater upwelling for Case EVI and Case EV would be 77 and 38 percent for the various passage reaches in Side Channel 21 (Appendix A,Tables A40-A49). •Winter Flows Similar to Slough 21,the ice front is only projected to reach Side Channel 21 in the coldest years.The probability of overtopping, is low,although the side channel would overtop before the slough. •Restricted Access Under natural conditions,the frequencies of suitable passage conditions range from 71-100 percent for PR's I-X (Table 22).Under Case EVI conditions,successful passage conditions will ,be available about 30 percent of the time at PR's I-IV and one percent or less at PR's V-IX, based on current analysis.The majority of the spawning occurs,above.PR V'andthese,areaswould "have-restri'cte'd'-'-a'cce'ss (Tab-le--1-3-h-,,-ease-EY--- should provide passage through all reaches 100 percent of the time. -Mitigation At project flows,the lack of breaching flows will impact fish passage within Side Channel 21.The frequency of fish passage will be increased by channelizing the local flow. 77 ,I 1 rj ,( 1 I I j l I I ) I I I j I ( ,j I I I I ") I Passage reaches I-V will be improved by excavating a channel through the most restrictive sections of each passage reach. Passage reaches upstream of PR V will be channelized with rock wing deflectors at the passage reaches.The flow through 2,500 feet of channel will be channelized with wing deflectors. Large cobbles and boulders will be removed to improve the frequency of fish passage through the reaches.Marginal spawning substrate in the upstream side channels will be replaced with sorted gravels to increase the available spawning habitat. Winter overtopping of the berms along the length of Side Channel 21 is not anticipated since the ice front on the Sus tina River is estimated to be downstream (Harza-Ebasco 1984b). The capital costs associated with each of the mitigation measures and the annual operating and 'maintenance costs based on semi-annual inspections and periodic repair for Side Channel 21 are shown below and in Figure 34: lJ Mitigation Measure Excavation of channel Wing deflectors for bank stabilization Total Number' Proposed 6 Capital Costs $45,000 240,000 $285,000 Annual Operating & Maint.Costs $5,000 (d)Development of New Spawning Areas Case EVI and EV flows during the spawning season will reduce the mainstem flows from a median level of 15,000 cfs 78 for the August 20-September 20 period to minimum required flows of 9,000 and 12,000 cfs.This reduction will result in the transformation of many side channels to sloughs. Areas in which spawning was limited·by high velocity under natural conditions may become suitable for spawning assuming other physical habitat requirements are satisfied. Habitat modifications to these new areas may prove more cost-effective than the measures required to maintain the production in some of the existing sloughs and side channels. Substrate may be unsatisfactory either because the particle size distribution is outside the preferred range for spawning or the substrate is of appropriate size but has become embedded with sands and silts under the natural flow regimes.Modification measures that would be taken to remedy these conditions would be replacement of !~~ppropriate substrate with suitable spawning gravel and scarifying the embedded substrate particles to remove the sand and silts. Preliminary screening of candidate mainstem and side channel si.tes is currently underway.Site selection and monitoring .of physical variables are criticaL..steps in assessTng ···tne-potent:i.al·····suc..ces·s··c)f..prop·o·sed..·rep·la·cement------·- spawning areas.A list of mainstem and side channel sites at which physical variables are presently being monitored is presented in Table 23.Evaluations of the potential of these sites to provide additional spawning habitat will be made as data become available. 2"2.2.3 -Artificial Propagation .j j ·r ] An alternative means to maintaining chum salmon achieve the production is 79 mitigation goal of through artificial I il I I propagation.Mitigation by artit1c1aypropagat1on '"',ou. considered if other mitigation measu~s are ineffectiv • artificial propagation method selecte~for mitigation for salmon spawning habitat losses in the"'midd.l.e-B.uS-i:na RivbJ.J.O stream-side egg incubation boxes.The emergent fry would be returned to the sloughs for rearing and/or migration.Egg boxes with gravity fed water systems are well suited for remote-site installation because they are cost effective and require little maintenance. (a)Design and Operation of Egg Box A stream-side egg incubation box similar to that used extensively on the Gulkana River in Alaska for artificial propagation of sockeye salmon would be used.The egg box is a 4 ft x 4 ft x 8 ft gravel-filled upwelling box capable of incubating 500,000 eggs.The box would be insulated to protect against freezing. In each egg box 500,000 green eggs (those just-fertilized) are placed on the gravel surface and incubated.At hatching the alevins fall or migrate into gravel interstitial spaces and reside there until the yolk-sac has been absorbed,at which time they emerge from the gravel and leave the box.Survival from green egg to emergent fry has averaged 85 percent (Roberson ADF&G,pers.comm., 1984). (b)Site Selection Criteria The primary concern in siting the egg boxes is the availability of a dependable water source.The water should be sediment free,meet water quality standards and be gravity-fed to the egg boxes.The latter is of primary concern due to the low reliability and high cost of pumping water.Other criteria are access to the site and proximity 80 / to a slough for juvenile release and adult return.Curry Station (RM 120)appears to satisfy the above criteria for site location. (i)Water Supply Curry Station has an existing gravity-fed surface water system.Using an existing system is more economical than developing a new one.The system at Curry was built in the 1930's as a water supply for the railway construction camp.It consists of an impoundment structure and pipeline which draws water year round.Before an egg box prog.ram is implemented,detailed flow rates,temperature and water quality data would needt()be obtained. Information on the seasonal temperature variation of the water source will be used to predict the emergence timing of fry and to select the proper brood stock. (ii)Slough Proximity Another aspect of site location is the proximity to a slough.The slough will be utilized in two ways. __¥_:tt:·§J:L~Dl~rg~_n.1:_Jl"Y:fl"()IJl t]:le .~gg boxes will be ·-----~---------l'e±eased-d_i_l'ec-t_1_y--i-nto--the-s±ough -E-or-add_i_t-iona±-----------· rearing and/or migration.Second,the slough will serve as an adult return area and will facilitate procurement of the brood stock.Curry Slough is approximately 4,000 feet downstream from Curry Station and can be utilized,-·altnough it may need some modifications to make it suitable. (iii)Site Access Curry Station is easily accessible by helicopter and rail.The close proximity of the railway will ·81 I -t j I I J I t \ I I I I I j I I,j 1 I \ 1 II I I I I (b) facilitate movement of materials and equipment to the site. Brood Stock The initial selection of brood stock will depend on the temperature profile of the water source.It appears that the existing water source is colder than intergravel temperatures to which incubating eggs are exposed.This may cause the fry produced from egg box to emerge later than native fry.If this delay exceeds the natural variation in emergence timing for native fry,the tributary spawning chum in the middle Susitna River,or another stock of earlier-spawning chum,will ·be selected to allow the egg box fish to emerge at the estimated escapement to the sloughs in the Talkeetna to Devil Canyon reach of the Susitna River,approximately the same time as native fry. The donor stock will be utilized for the first five years of the project since Susitna chum predominantly return at 4 and 5 years of age.After the initial 5 year introduction period the returning adults will serve as the brood stock. To mitigate for the loss of 4,200 chum,approximately 700,000 eggs (250 females)will be needed for egg box incubation.This figure is based on maintaining the 4,200 chum escapement using the.following assumptions:1.1:1 male to female ratio (Barrett et ale 1984),a 15 percent egg-to-fry survival (Schmidt et ale 1984),a fecundity of 2,850 eggs per female,and a 0.7 percent fry to adult return (including harvest)(Barrick et ale 1983).Excess returns to the egg box facility will be allowed to spawn naturally in adjacent sloughs.To insure genetic diversity of the artificially propagated stock,eggs from each femal~ will be fertilized with the gametes of several males. 82 (c)Alternatives for Development Ther.e are two alternatives for the Curry Station egg box site.The first is a plan to establish the egg box site at Curry Slough and the second is a plan for development of the egg box site at Curry Station. (i)Curry Slough Development Establishing the egg box site at Curry Slough will require the water source presently at Curry Station (approximately 4,000 feet upstream)to be piped to Curry Slough.This will entail burying (to safeguard against freezing and physical damage) approximately 4 ,000 feet of 6-iiic1:l.diameter pipe. The egg boxes will be set up near the downstream end of Curry Slough and emergent fry will be released directly into the slough from the egg boxes.The slough will be appropriately sloped to facilitate downstream migration of fry and to ensure that returning adults have access to the slough.The I I I I I ,\ advantage of locating the boxes adj acent to the slough,is that the emergent fry can be releasedl without being handled.Fry will be released into ......--the-slough toallow-for-acclimation ..and/or r.earing._-j .------b~e-f-o·r_e-s·e·award--m±gra:t±on-.-Re-re-a·s·ing-n~wly---emerged------------_· fry directly into the mainstem would not allow -for acclimation and orientation.The costs for this option are outlined in Appendix B and summarized below: .Nl!ml:l~r Mitigation Measure Proposed Artificial propagation 2 Total 83 Capital Costs $450,000 $450,000 Annual Operating & Maint.Costs $50,000 $50,000 I ( Ij II I II, (ii)Curry Station Development The Curry Station development consists of installing the egg boxes near the outfall of the existing water system.This will require a minimal amount of pipe, which can be installed above ground if insulated pipe is used.Newly emergent fry will be collected in two 18-foot-diameter x 4 foot deep above-ground rearing ponds.Fry will be transported daily to Curry Slough and released.This installation has the disadvantage of extensive handling of fry.The costs for this option are outlined in Appendix Band summarized below: Annual Number Capital Operating & Mitigation Measure Proposed Costs Maint.Costs Artificial propagation 2 $81,000 $35,000 Total $81,000 $35,000 2.2.3 -Monitoring Studies Monitoring studies are recognized as an essential projects. mitigation feature that provides for a reduction of impacts over time (APA 1982).Operational monitoring will be conducted to (1)monitor salmon population and production levels to ensure that the predicted level of impact is not being exceeded,and (2)evaluate the effectiveness of the project mitigation plan. 2.2.3.1 -Impact Monitoring of Salmon Populations Salmon populations in the Devil Canyon to Talkeetna reach will be monitored to assess whether populations maintain historical levels during the operation phase.Monitoring will consist of enumerating returning adults that pass Sunshine and Curry Stations a~d monitoring smolt out-migration from the reach. Adults will be enumerated using the fishwheel tag/recapture 84 program currently being used in the baseline studies.The smolt out-migration will be evaluated using a smolt trap program to the one conducted during the 1982 to 1984 baseline studies program. The results of these studies will be used to evaluate changes in the population size,species composition or changes in stream use patterns of the five Pacific salmon species.Results of the mitigation monitdring described in the following section will be used to assess the cause of changes. 2.2.3.2 -Mitigation Monitoring Mitigation features to be monitored for evaluation of the level df mitigation being achieved include: -Slough modification -Replacement habitats -Egg boxes The monitoring activity will include evaluating the operation and maintenance procedures to ensure that the facilities are operating effectively.If a mitigation feature is not meeting the intended level of effectiveness,modifications to the ............!!!:i"t:i"g~1:i.()!!..:f.~t:!1:u:t:~...~i.:I:L1:>~.1Il~<!~.....t_().!:rJ.C::E~Cls.~..!~.~....E!~fe:c::t:!~e:.l1e:.~l:l._._. (a)Monitoring Slough Modifications The various measures incorporated for slough habitat maintenance will be moriitored to assess whether they are meeting their intended fUIlction arid a~~()p~ratingp~operJ.Y.· .~.._.•.",..__._,._..~••......_.",..,....._.,_. Methods used to evaluate the slough mitigation features will be consistent with methods currently being used to assess baseline conditions of the parameters to be monitored. 85 ,r { '! ,I I III,. Mltlgatlon teatures aeslgnea to aLLOW aaULt saLmon pas sag into and within the sloughs will be annually inspectE::u after breakup to identify and conduct.needed repairs prior to the adult return.Annual monitoring of returning adults will allow identification of additional passage problems. Appropriate corrective actions will be taken. Modifications to sloughs designed to maintain spawning areas will be annually inspected prior to the spawning season to verify that the area contains suitable spawning conditions such as upwelling,amount of flow,depth of water,and suitable substrate.Areas that become overly silted will be cleaned.If slough flows diminish so that spawning is no longer possible,appropriate corrective actions will be taken The number of spawning adults returning to the sloughs will be monitored annually to meas?re changes in distribution to assess if the combination of minimum flow and slough modifications is maintaining natural production.This monitoring will also serve to assess whether the capacity of the modified areas is being exceeded.Appropriate remedial actions will be taken when spawning sites are inadequate. Fry production will be monitored annually incubation success.Fry monitoring will assessment of out-migration timing and success. to evaluate include an I The annual slough monitoring will include an evaluation of general slough conditions including vegetative encroachment,.beaver occupation,and general condition of the spawning and rearing areas.Appropriate remedial actions will be performed to maintain slough productivity. Representative sloughs will be monitored for temperature and slough flow.Monitoring of the physical processes will 86 / be continued until slough conditions stabilize under the regulated flow regime.This monitoring will be used in part to assess whether further modifications to the physical habitat must be made to maintain slough productivity. (b)Monitoring Replacement Habitats Replacement habitats which develop as a result of the lower and more stable project mainstem flows during the spawning season will be monitored to quantify use of these areas by adult salmon.Monitoring methodology will be similar to that currently used to evaluate spawning habitats and will include standard physical and chemical measurements as well as 1:>:iO+ogica,IClIla,lyses. (c)Monitoring of Artificial Propagation Stream-side egg boxes ,if utilized,will be monitored to --eva±uate--the4-r-ef-fec-ti-veness-in-pI'oduc-ing~-the··numher-of returning chum salmon for which they were designed. 87 I J ( Ii 3 -IMPOUNDMENT MITIGATION 3.1 -Introduction and Background The primary long-term impact associated with the filling of the Watana and Devil Canyon reservoirs is the loss of clear-water tributary habitat (AFA 1983).The tributary habitat that will be inundated currently supports a population of Arctic grayling,estimated in 1982 to be at least 16,300 fish.Aquatic habitats within the reservoirs are not expected to support a significant grayling population. In the impoundment area,Arctic grayling was selected as the evaluation species for mitigation because of its abundance in the area,its sensitivity to impacts during all seasons 'and life stages, and its desirability as a sport fish.Measures to avoid,minimize, rectify or reduce the anticipated loss of spawning and Arctic grayling habitats are considered infeasible (AFA 1983).Therefore,measures to compensate for the loss of Arctic'grayling habitat are the options being considered for impoundment mitigation planning. Impoundment mitigation options to compensate for lost Arctic grayling habitat were outlined in Exhibit E,Federal Energy Regulatory Commission License Application (AFA 1983)and included:(1)funding of research on Arctic grayling propagation technology;(2)hatchery propagation of Arctic grayling and the subsequent stocking of the reared fish (i.e.fingerling);(3)stocking of hatchery-reared rainbow trout if Arctic grayling propagation proved to be technically infeasible;and (4)the introduction of rainbow trout into the Devil Canyon reservoir.Agency comments on the hatchery-rearing of Arctic grayling were generally negative and concluded that grayling production in Alaska must be considered experimental and compensation must be judged as speculative (ADF&G 1983c).Reasons for this position were:(1)the lack of a reliable egg source;(2)low survival from the green egg to fry stage;(3)unsuccessful attempts to rear grayling fry to fingerling in hatcheries;and (4)the inability to evaluate survival of stocked fry because of their small size. 88 3.2 -Mitigation Options In the draft EIS,the FERC staff recommended that kokanee be considered for stocking in the impoundment reservoirs (FERC 1984). Stocked kokanee would:(1)provide sport fishing opportunities and (2)fill a niche in the reservoirs as a pelagic forage fish species. An evaluation_of this alternative will also be presented in the April 1985 report.Rainbow trout and Arctic grayling are evaluated below. 3.2.1 -Rainbow Trout Rainbow trout is the species being considered for primary compensation for lost Arctic grayling habitat.A rainbow trout propagation and a stocking program has documented success in Alaska and there is a high -demand for the species by sport anglers. It appears that Devil Canyon reservoir may be too turbid to successfully grow rainbow trout to a desired size.Turbidity levels in Devil reservoir are to -be in the range of 40-50 NTUs with light penetrating about one meter into the water column (T.Stewart,Harza-Ebasco,pers.comm.1984).Primary production in Devil Canyon reservoir is expected to be low as a result of the turbidity levels.Because the success of a stocking program of rainbow trout in Devil Canyon reservoir is uncertain,the reservoir's -l-imnology--·and--resident--fish populat-ions-·beforeini-t-iating--a-stocking- Sport fishing opportunities would be available to a larger number of people if fish were stocked near population centers.Additionally, stocking sites can be chosen that will have a higher probability of success than Devil Canyon reservoir ...Raiilbow tr()uthavebeensuccess- fully stocked in numerous lakes in the Matanuska-Susitna Valley area (L.Engel,ADF&G,Palmer,pers.comm.1984).Case histories,cost analyses and stocking areas for a rainbow trout stocking program will be discussed in the impoundment mitigation plan scheduled for 1985. 89 I i i 3.2.2 -Arctic Grayling Arctic grayling stocking is desirable because of "in-kind"replacement for lost spawning and rearing habitat.In 1984,significant progress was made in Arctic grayling propagation technology.About 100,000 grayling fingerling (approximately 50 to 60 mm)were reared at Clear Hatchery (D.Parks,ADF&GHatchery Manager,Clear,Alaska,pers.comm. 1984).Feeding 'experiments with various kinds of commercial feeds, automatic feeders,and increased light intensity are factors that were thought to be important in the successful rearing of grayling fingerling.The survival rate was about 70 percent from emergent sac-fry to 2 gram fingerling for one experimental group,which is about seven times greater than previous survival rates for emergent sac-fry to fingerling. Because significant progress in Arctic grayling propagation technology is being made and the desirability of "in-kind"replacement,grayling is still considered a primary candidate species for compensation.The impoundment mitigation plan scheduled for April 1985 will discuss propagation technology for Arctic grayling and examine areas that need further research,such as brood stock development,commercial feeds, vitamin deficiencies,disease problems,stocking evaluation,stocking areas. 90 I ] I [ 1 I II i I. I I I i 4 -REFERENCES Air Photo Tech,Incorporated.1983.Aerial Photographs on October 8, 1983. Alaska Department of Fish and Game.1981.Susitna Hydro Aquatic Studies Phase II Final Species /Subj ect Report:Adult anadromous fish study.Volume 2.Adult anadromous fish studies. Prepared for Acres American,Inc.Buffalo,NY. ADF&G.1982a.Susitna Hydro Aquatic Studies Aquatic Studies Program.Prepared for Incorporated,Buffalo,NY. Phase Acres I Report: American II i i ADF&G 1982b.Susitna Hydro Aquatic Studies -Phase I Final Draft Report:Aquatic Studies Program.Prepared for Acres American, Incorporated,Buffalo,NY. ADF&G 1983a. Report, 1982. Susitna Hydro Aquatic Studies -Phase II Basic Data Volume 4:Aquatic Habitat and Instream Flow Studies. j I III.) ADF&G 1983b.Susitna Hydro Aquatic Studies -Phase II Data Report. Winter aquatic studies (October 1982 -May 1983),Anchorage,AK. ADF&G 1983c.Review Comments Draft Exhibit E Susitna Hydroelectric Project.Prepared for Alaska Power Authority. ADF&G 1984.Susitna Hydro Aquatic Studies,Report No.3:Aquatic Habitat and Instream Flow Investigations,May -October 1983 (Review Draft).Chapter 1:Stage and discharge investigations. Prepared for Alaska Power Authority,Anchorage,AK.136 pp. Alaska Power Authority.1982.Susitna Hydroelectric Project:Fish and Wildlife Mitigation Policy.Alaska Power Authority.Anchorage, AK. Alaska Power Authority.1983.Application for license for project,Susitna Hydroelectric Project,before the Federal Regulatory Commission.Vol.6A.Exhibit E,Chaps.3. Power Authority.Susitna Hydroelectric Project. major Energy Alaska Alaska Power Authority.1984.Comments on the FERC Draft Environmental Impact Statement of.May 1984.Volume 9, Appendix VII -Slough Geohydrology Studies.Anchorage,AK. Allen,R.L.1968.Priest Rapids Fall Chinook Salmon Spawning Channel. Biological Investigations,1966-1967 season.Wash.Dept.Fish. Bachen,B.A.Development of salmonid spawning and rearing habitat with groundwater-fed channels.Presented at the Pacific Northwest Stream Habitat Management Workshop,October 10-11,1984. Humbolt,CA. 91 Barrett,B.M.,F.M.Thompson,and S.N.Wick.1984.Adult anadromous fish studies:May-October 1983.Alaska Department of Fish and Game Susitna Hydro Aquatic Studies Reprot No.1.Prepared for Alaska Power Authority.Anchorage,Alaska. Barrick,L.,B.Kepshire and G.Cunningham.1983.Upper Susitna River Salmon Enhancement Study (Draft)•Division of Fisheries Rehabilitation,Enhancement and Development,Alaska Dept.of Fish &Game.Anchorage,AK.15 pp. Bell,M.C.1973.Fisheries Handbook of Engineering Requirements and Biological Criteria (Revised 1980)•Prepared for Fisheries-Engineering Research Program,Corps of Engineers,North Pacific Division.Portland,Oregon. Browning,R.1984.Personal Communication.U.S.Fish and Wildlife Service. Butera,B.1984.Personal Communication.R&M Consultants. Engel,L.1984.Personal Communication.ADF&G Palmer,Alaska. Federal Energy Regulatory Commission.1984.Susitna Hydroelectric Project,Vol.Draft Environmental Impact Statement,FERC Project No.7114-Alaska. Harza-Ebasco Joint Venture.1984a. _ReqlJ.j.re1!L~Ilts.An~ho,):,1'!g~_,_AK. Evaluation of Alternative Flow '~ 'I Harza-Ebasco Joint Venture.1984b.Susitna Hydroelectric Project: Instream Ice Simulation Study.Prepared for Alaska Power Authority.Anchorage,AK. Hauston,W.R.and D.Mackinnon.1957.Use of an artificial spaWning channel by salmon.Trans.American Fish.Soc.86:220-230. King-,D;'1984;PersonalCommunication-;"Wash;Dept.,Fisheries,----,j Lister,D.B.,D.E.Marshall and D.G.Hickey.1980a.Chum Salmon survival and production at seven improved groundwater-fed spawning areas.Can.M.S.Rep.Fish Aquat.Sci.1595:X +58 pp. tister,D.B.&A~sQciate~,~td.1980Q.,Strea~EnhaIlcement Guide. Province of British Columbia,Ministry of Environment,Vancouver, BC,Canada. Meekin,T.K.1967.McNary Supplemental Spawning Channel.Sum.Rep. (1957 through 1966).Wash.Dept.Fish,Army Eng.Cont.N.D.A. 35-026-Civeng-58-23 and No.D.A.45-164 Civeng-65-4. Meekin,T.K.,R.L.Allen and A.C.Moser 1971.An Evaluation of the Rocky Reach Chinook Salmon Spawning Channel,1961-1968.In Wash. Dept.Fish Tech Rep.6. 92 1') I ,I ,I I 1 I I r I It I I I,J Moulton,L.L.and L.A.Rundquist.1984.Woodward-Clyde Consultants. Memorandum to L.Gilbertson.April 26,1984.Anchorage,Alaska. Parks,D.1984.Personal Communication.ADF&G Clear,Alaska. R&M Consultants,Inc.1982.Task 3 -Hydrology,Slough Hydrology Preliminary Report.Prepared for Acres American,Inc.New York. R&M Consultants,Inc.1983.Susitna Hydroelectric Project:Susitna River Ice Study (Task 4).Prepared for Harza/Ebasco Joint Venture.Anchorage,AK.183 pp +maps. R&M Consultants,Inc.1984.Memorandum Report:Local Runoff into Sloughs.Prepared for Harza-Ebasco Joint Venture.Anchorage, AK. Roberson,K.1984.Personal Communication ADF&G.Glennallen,Alaska. Sautner,J.S.,L.J.Vining,L.A.Rundquist.1984.An evaluation of passage conditions for adult salmon in sloughs and side channels of the middle Susitna River.In:Aquatic habitat and instream flow investigations,May-Octobe~1983.No.3.,Chapter 6.C.C. Estes and D.S.Vincent-Lang (eds.).Prepared for Alaska Power Authority.Anchorage,Alaska. Schmidt,D.C.,S.S.Hale,and D.L.Crawford (eds.).1984.Resident and Juvenile Anadromous Fish Investigations (May-October 1983). Alaska Department of Fish and Game.Su Hydro Aquatic Studies Report Series No.2.Alaska Department of Fish and Game. Anchorage,Alaska. Seagren,D.1984.ADF&G Su Hydro.Memorandum to S.Crumley. October 26,1984.Anchorage,Alaska. Stewart,T.1984.Personal Communication.Harza-Ebasco.Anchorage, Alaska. U.S.Fish &Wildlife Service.1981.Endangered and Threatened Wildlife and Plants.Federal Register 50 CFR 17.11 and 17.12.January 1, 1982. Vincent-Lang,D.S.,A.E.Bingham,C.Estes,D.Hilliard,C.R.Steward, E.W.Trihey,and S.C.Crumley.1984.An evaluation of chum and sockeye salmon spawning habitat in sloughs and side channels of the middle Susitna River.In:Aquatic habitat and instream flow investigations,May-October 1983.No.3.,Chapter 7.C.C. Estes and D.S.Vincent-Lang (eds.).Prepared for Alaska Power Authority.Anchorage,Alaska. 93 ~'-~L.--.- Table 1.Summary of estimated costs for habitat modification measures in selected sloughs and side channels. Slough 8A Slough 9 Slough 9A Slough 11 USC 11 Slough 21 Si de Channel 21 Total Capital Capital Capital Capital Capital .Capital Capital Capital! Costs O&M Costs O&M Costs O&M Costs O&M Costs O&M Costs O&M Costs O&M Costs O&M Slough Mouth Excavation 26,000 26,000 52,000 Wing Deflector 24,000 24,000 240,000 288,000 Passage Reach Excavations 10,000 7,000 17,000 ,! Protective Berm 61,000 59,000 42,000 24,000 161,000 347,000 Log Barriers 30,000 24,000 54,000 Bank Stabilization 25,000 25,000 Rock Wei r 37,000 61,000 98,000 Total Slough Excavations 76,000 26,000 26,000 34,000 45,000 207,000 i II Total 121,000 4,000 159,000 4,000 118,000 4,000 184,000 4,000 187,000 4,000 34,000 5,000 285,000 5,000 1,088,000 rO,OOO :i Table 2.Susitna River average ~nn~al salmon escapement by sub-basin and species. 1 i ;2 2 Pink3 4SockeyeI:Chum Coho Chinook %of !%olf %of %of % Sub-basin I !Number Totial Number Total Number Total Number TotalNumberTotal I ! i Lower Susitna5 i Even 427,400 32 (RM 0 to 80)11,900 i5 17,000 is 39,900 46 Odd 44,800 33! 6 I Yentna i Even 447,300 34 (RM 28)119,200 48 19,500 :5 20,000 23 Odd 48,400 35 Talkeetn,.- Even 338,400 30Chulitna (RM 80 to 98.6)116,000 46 295,600 ~3 24,700 28 Odd 40,600 29 62,000 Talkeetna-8DevilCanyon Even 54,800 4 (RM 98.6 to 152)2,800 1 24;100 7 2,200 3 Odd 4,400 3 9,500 Total Susitna 249,900 190 356,200 100 86,800 Even 1,267,900 100 Odd 138,200 100 1 2 3 4 5 6 7 8 9 ! I 1981-83 aver~ge of ADF&G secohdtrun sockeye escapements 1981-83 average,of ADF&G escabe~ent estimates . Even year 1982 only;odd yearl 1981 and 1983 average;from ADF&G escapement estimates 1982-83 average of ADF&G escapement estimates Lower Susitn~s~b-basin equal~total Susitna basin escapement minus Yentna and Sunshine escapements Yentna sub-basin escapement f~o~ADF&G estimates!at Yentna Stat~on (TRM 04) Talkeetna-Chulitna sub-basin ~s~apement equals Sunshine Station (RM 80)escapement minus Talkeet~a-Devil Canyon sub-bC}sin escapement !.i Talkeetna-Devil Canyon sub-b~si~escapement equals Talkeetna Station (RM 103)escapement minus milling fish,that return d0wnistfeam.Milling raFes:sockeye 30%,chum 40%,pink 25%,chinook 25%,coho 40%. (Barrett 1984):! Total Susitna basin escapeme~t ~quals Yentna Station (TRM 04)escapement plus Sunshine Station (RM 80) escapement plus:5%for soc~ey~,48%for pink,5%for chum,85%for coho (Barrett 1984) I I I I I] I ) 11 Table 3.Chum salmon peak index counts by habitat type above RM 98.6, 1981-1983. 3-Year Habitat Type 1981 1982 1983 Average Mainstem1 16 550 219 262 II Streams 241 1,737 1,500 1,159 2 2,596 2,244 1,467 2,102 II Sloughs Total 2,853 4,531 3,186 3,523 IJ Source:ADF&G 1981a,1982a,Barrett et al.1984 1 Includes main channel and side channel habitats 2 Includes upland slough and side slough habitats III I I I I J U 11 j Table 4.Chum salmon peak index counts in sloughs above RM 98.6,1 1981-83. j River 3-Year Slough Mile 1981 1982 1983 Average I 1 99.6 6 0 0 2 I2100.2 27 0 49 25 3B 101.4 0 0 3 1 3A 101.9 0 0 0 0 I4105.2 0 0 0 0 5 107.6 0 2 1 1 6 108.2 0 0 0 0 6A 112.3 11 2 6 6 17113.2 0 0 0 0 8 113.7 302 0 0 101 8D 121 ..8 0 23 1 8 )8C 121.9 0 48 4 17 8B 122.2 1 80 104 62 Moose 123.5 167 23 68 86 IA'124.6 140 0 77 72 A 124.7 34 0 2 12 8A 125.1 620 336 37 331 B 126.3 58 7 J9128.3 260 300 169 243 9A 133.8 182 105 135 J10133.8 0 2 1 1 11 135.3 411 459 238 369 12 135.4 0 0 0 0 1 13 135.9 4 0 4 3 14 135.9 0 0 0 0 15 137.2 1 1 2 1 ..1~L ..~3 0 0 1 I17138.9 38 21 90 50 19 139.7 3 0 3 2 )20 140.0 14 30 63 36 21 141.1 274 736 319 443 22 144.5 114 21A 144.3 8 0 0 3 1 Total 2~596 2,244··1~467 2;102 1 1 Source:ADF&G 1981a,1982a,Barrett et al.1984 11Three-year average of totals j 1 I] I 1II Table 5.Second-run sockeye salmon peak survey counts in sloughs above RM 98.6,1981-1983. Source:ADF&G 1981a,1982a,Barrett et al.1984 River Slough Mile 1981 1982 1983 8 113.7 38 0 0 Moose 123.5 0 2 0 8A 125.1 0 5 0 B 126.3 0 18 0 9 128.3 0 18 0 11 135.3 0 170 0 20 140.0 0 75 0 21 14L1 0 -9 0 Pink salmon total slough escapement above RM 98.6, 1981-1983. Table 6. Total Source:Barrett et al.1984 38 297 o I I j I I I J ] . J I 1 1 -.J I J 1 J I I I II Table 7.Selected rivers with hydroelectric projects and associated mitigations for anadromous fish species. Terror Lake,AI< Average Discharge:Pre-project 279 cfs,post-project 181 cfs.I] I I Species:Pink,chum and coho salmon,Dolly Varden. Projects:Alaska Power Authority project. diversion dam for hydroelectric II [ III Mitigation: Tyee Creek,AI< Species: Projects: Mitigation: Blue Lake,AI< Species: Projects: Mitigation: Ketchikan Creek,AI< Instream flow requirements and monitoring program. Intertidal spawning pink and chum salmon. Alaska Power Authority diversion dam for hydroelectric projects may eliminate flow to Tyee Creek. Spawning gravels were added to the tailrace area as replacement spawning habitat. Pink,chum and coho salmon,Dolly Varden. City of Sitka,diversion dam Instream flow requirements. Species: Projects: I Mitigation: Solomon Creek,AI< I I Species:IJ IJ Projects: Mitigation: Natural and hatchery runs of chinook,pink,coho and chum salmon. Ketchikan Public Utility,dam and powerhouse Instream flow requirements Chum,pink,and coho salmon. Alaska Light and Power,dam and powerhouse. Instream flow requirements and flow fluctuation restrictions to prevent deposition of fines during high flow period. Table 7 (Continued) Skagit River,WA Average Discharge:15,190 cfs (below Baker River).Below City of Seattle project average discharge 4282 cfs to Baker River. Species:Summer chinook,fall chinook,sockeye,pink,coho and chum salmon,steelhead;spring,summer and fall chinook (main river and tributary spawning)'.Pinks and chums (main river spawning and tributary spawning).Steelhead (mainstem and tributary 'spawning)• Projects:Three City of Seattle projects (1 large,1 medium,1 small storage reservoirs,all with power plants). Average Discharge:2,520 cfs Mitigation: Baker River,WA Species: Projects: Mitigation: Sultan River,WA Species: Projects: Minimum flows for prevention of juvenile stranding.Ramping rate restrictions.Augmentation from a hatchery at Marblemount.These features were not in operation when the City of Seattle began operations and resulted from a voluntary agreement between the City of Seattle and state agencies. River had spring chinook,sockeye,coho and steelhead.Now ,..--has.-onl.y..socke;y:e-and.coho. Puget Sound Power &Light Company (2 dams &2 powerhouses) Fish ,are trapped below lower dam and hauled above the upper dam.Traps are used in the lakes for collection and downstream passage. Coho and steelhead present. City of Everett -water supply.Snohomish County P.U.D.(l dam and 1 powerhouse). J 1 .J j 'J j Mitigation:None for flow control program. j I 1 ,1 I Table 7 (Continued) Tolt River,WA Average Discharge:575 cfs Species:Pink,coho,fall chinook and chum salmon,fall chinook and steelhead trout Projects: Mitigation: Cedar River,WA Diversion dam.City of Seattle -water supply. Has minimum flow control regulation Average Discharge:684 cfs Species: I I, i Projects:!J \ I Mitigation: I I Green River,WA II Average Discharge: \.I Species: Projects: Mitigation: White River,WA Sockeye,steelhead,chinook City of Seattle -water supply and small powerhouse Flow control regulation implemented,plus a new hatchery. 1,270 cfs Summer and fall chinook and steelhead (Many years ago had pink and chum runs.) City of Tacoma -water supply (diversion of flow) Has minimum flow release regulation for fisheries. Average Discharge:1,372 cfs Species:Spring chinook and steelhead (small coho run) Projects:Corps of Engineers -flood control.Puget Sound Power &Light Company -diversion of flow with lake storage. Mitigation:Has minimum flow release.Screen diversion.Issue resolution continuing Table 7 (Continued) Nisqually River,WA Average Discharge:1,695 cfs Species:Spring and fall chinook,pink,coho and chum salmon Projects: Mitigation: City of Tacoma (2 powerhouses and 1 storage dam).City of Centralia -diversion of flow. Instream flow requirements for salmon.City built a hatchery (about 1916)which was not used and is now gone. Elwha River,WA Average Discharge:1,450 cfs Species:Summer chinook,pink,coho and summer and winter steelhead Projects:RayoriierPulp and Washington Pulp arid Paper (2 daIlls,2 power plants and 1 storage reservoir behind upper powerhouse). Mitigation:No mitigation initially (1914)at lower dam.Leakage has kept fish runs below the lower dam alive.Now has rearing pond and Indian hatchery to help support salmon runs.National Parks Service plans to reopen area above upper dam for anadromous Wynoochee River,WA Average Discharge: Species: Mitigation: Cowlitz River,WA 750 cfs (above the dam) Coho,chum and steelhead .....~~QJ~:P-!L.QJ ....~1:l,g.:j,:t1.~~:r:§..c:laJl!(lJ,.QQc:l ....c.Q1:l,!;:r:Ql.~l:l.c:l!1~!;~:r:.....l:l:«,1I>P ly>-..~...A .. .power .-R.~an~and _~E:<:I._~~~ry.....~~~...nO~E..lan.J:l~ed.__.._._~._.__._~.__.~_.._ Flow release based on river cross sectional work. Average Discharge:9,330 cfs Species:Spring chinook,fall,chinook and.coho salmon and steelhead trout Projects:9ity of Tacoma (1 large storage basin and 2 power plants) Mitigation:Flow regulation required in license.Now has two hatcheries. i I I I IIi Table 7 (Continued) Lewis River,WA Average Discharge:4,897 cfs Species:Spring chinook,fall chinook and coho salmon and steelhead Projects:Three major dams and powerhouses. Mitigation:Has flow regulation below lower dam.Initially a hatchery for spring chinook was constructed and operated.Flow control used to maintain fall chinook runs. Big White Salmon River,WA Average Discharge:1,075 cfs Species:Fall chinook.Very limited area for spawning below dam. Projects:Pacific Power and Light -Condit Dam i III Mitigation:Fish are taken and eggs shipped to a hatchery for artificial propagation.Early fish ladder failed,rebuilt and failed again.Site of first attempt to brail fish above a dam. II Upper Columbia River,WA II Average Discharge:(Grand Coulee Dam)64,800 cfs Mitigation:Three hatcheries built to perpetuate runs which went above dam. Snake River,ID Average Discharge:20,650 cfs Species:Spring and late summer chinook and steelhead.(Had at one time a run of coho.) II I J Projects: Mitigation: Idaho Power Company -Hells Canyon Dam (lowest of three dams) \Flow regulation and hatchery at Brownlee..Fish are trapped at Hells Canyon for artificial propagation.There are minimum flow requirements and ramping rate limitations. Table 7 (Continued) North Santiam River,OR Average Discharge:3,367 cfs. Species:Spring chinook.There is "main stream spaWning. I j I Project:Has 1 large storage reservoir and power plant and 1 reregulation pool and power plant (Corps of Engineers).I. Mitigation:Adults trapped for egg collection and hatchery rearing. Clackamas River,OR Average Discharge:3,636 cfs. Species:Spring chinook Projects:Portland General Electric Company -3 plants Mitigation:Have fishways and partial screening. Deschutes River,OR Average Discharge:830 cfs Species:"Spring-and-'f-al--l .ch;inook·and·-spr-in~-and--summeJ:·.··steelhead· Projects:Pelton Dam -Portland General Electric Company Mitigation:Hatchery.Has a fishway which has problems associated with seasonal flow changes. l 1 ..I 'I Table 8.Area spawned between passage reaches within Slough 8A for 1982,1983 and 1984.The ratio of the composite to the total area spawned for all years and percent distribution of spawning fish in 1984 are also shown. 2 Composite1Percent Passage Area Spawned (ft2 )Distribution Area Composite/ Reaches 1982 1983 1984 1984 1982-1984 Total I Mouth -I 1,800 11 ,000 17,100 5 26,200 0.88 I-II 20,900 9,700 90,600 1 93,800 0.77 II II-III 3,800 2,600 36,200 60 36,800 0.86 III-IV 5,700 12,000 96,500 i 102,200 0.89 IV-V 0 0 10,700 20 10,700 1.0 V-VI 0 0 9,600 ~9,600 1.0 I I VI-VII 3,900 0 11 ,200 5 13,700 0.91 I j VII-VIII 7,700 0 500 1 8,100 0.99 VIII-IX 0 0 200 200 1.0 IX-head 0 0 4,900 4,900 1.0 II I III 11 1 2 As designated in Sautner et al.1984 Seagren 1984,memo 1 As designated in Sautner et al.1984 Table 9.Area spawned between passage reaches within Slough 9 for 1982,1983 and 1984.The ratio of the composite to the total area spawned for all years and percent distribution of spawning fish in 1984 are also shown. 2 Composite1Percent Passage Area Spawned (ft 2 )Distribution Area Composite/ Reaches 1982 1983 1984 1984 1982-1984 Total Mouth -II 17,200 4,700 0 21,800 .99 II-III 21,500 25,300 24,300 60 41,500 0.58 III-IV 7,000 4,000 4,900 J,10,700 0.67 IV-V 7,700 3,200 3,800 8 8,100 0.55 V-head 33,000 6,800 31,500 32 50,500 .71 2 Seagren 1984,memo 1 I ! J 1 I ~ \ ~ .1 J ! j I ! I ! 1 ] Table 10.Area spawned between passage reaches within Slough 9A for 1982,1983 and 1984.The ratio of the composite to the total area spawned for all years and percent distribution of spawning fish in 1984 are also shown. 2 Composite1Percent Passage Area Spawned (ft2 )Distribution Area Composite/ Reaches 1982 1983 1984 1984 1982-1984 Total Mouth -I 4,500 3,900 0 50 4,800 0.57 I-II 1,300 8,200 2,200 1 15,700 0.67 I II-III 4,500 4,800 1,600 6,100 0.56 !III-IV 10,700 4,600 5,500 11 ,400 0.55 IV-V 20,600 13,200 11 ,800 28,400 0.62 V-VI 9,000 10,000 11 ,500 10 18,300 0.60 VI-VII 13,000 2,800 1,700 10 15,200 0.87 VII-VIII 7,400 6,400 6,100 J,13,100 0.66 VIII-IX 0 2,500 3,800 10 6,300 1.00 IX-X 8,600 5,800 12,600 12,500 0.46 X-head 9,400 0 5,800 20 10,200 9.67 1 2 As designated in Sautner et ala 1984 Seagren,1984,memo 2 ·Seagren~1984·,·memo ..--...~.. Table 11.Area spawned between passage reaches within Slough 11 for 1982,1983 and 1984.The ratio of the composite to the total area spawned for all years and percent distribution of spawning fish in 1984 are also shown. 2 Composite1Percent Passage Area Spawned (ft2 )Distribution Area Composite/ Reaches 1982 1983 1984 1984 1982-1984 Total Mouth -I 23,500 43,600 33,300 10 76,900 0.77 I-II 12,400 18,300 22,200 15 30,400 0.57 II-III 24,000 7,700 37,600 40 54,100 0.78 III-IV 5,900 8,000 5,200 5 77 ,000 0.69 IV.;..V···5,800 8,000 10;400 25 12,000 0.50 V-head 24,000 4,700 14,100 5 33,400 0.78 1 As designated in Sautner et al.1984 J .! ! J J J .-i J J .1 ] [ I I ·1 I 1 I II II Table 12.Area spawned between passage reaches within Upper Side Channel 11 for 1982,1983 and 1984.The ratio of the composite to the total area spawned for all years and percent distribution of spawning fish in 1984 are also shown. 2 Composite1Percent Passage Area Spawned (ft 2 )Distribution Area Composite/ Reaches 1982 1983 1984 1984 1982-1984 Total Mouth -I 12,100 40,600 24,500 60 48,200 0.62 I-II 12,300 21,800 8,200 1 25,700-0.61 II-III 12,300 11,300 23,400 40 35,700 0.76 III-IV 0 5,500 6,100 6,100 0.53 II'.J Iif .1 1 2 As designated in Sautner et al.1984 Seagren 1984,memo --------------------..............,..............,..............,==========~. Table 13.Area spawned between passage reaches within Slough 21 Complex for 1982,1983 and 1984.The ratio of the composite to the total area -spawned for all years and percent distribution of spawning fish in 1984 are also shown. As designated in Sautner et al.1984 Seagren 1984,memo I I 1 I I ! I I -I I I ! I f ! I 1 I I I 0.57 1.0 0.70 o o 1.0 0.71 0.65 0.67 1.0 1.0 0.99 ..(h75 0.55 Composite/ Total 36,900 1,700 21,300 o o 8,700 4,800 75,000 12,600 4,000 300 13,300 ..95,600 49,800 Composit~ Area 1982-1984 25 40 2Percent Distribution 1984 26,600 o 7,300 1983 1984 32,000 1,700 15,600 o 0 o 0 5,900 '·'2,800 4,100 2,700 20 27,400 67,800 15 . 11,300 6,300 Io0o300. o 1,400 9',600''''-81,400'__-.-.. 27,500 42,600 Area Spawned (ft 2 ) . 1982 6,100 o 7,700 o o o o 20,000 1,000 4,000 o 12,000 ""'-3-5,-700' 20,700 2 1 1Passage Reaches I -IIC &IIR Slough 21 IlL IIR Side Channel 21 Mouth - I I-II 11...;1 II III-IV IV-V V-VI VI-VII VII-VIII VIII-IX....."rx:...X-"-.. X-SL21/PRI Table 14.Mean monthly discharges at Gold Creek for natural conditions and Case P-1. Natural Case P-1 Month (cfs)(cfs) January 1,440 10,900 February 1,210 9,200 March 1,090 7,900 April 1,340 7,300 I I May 13 ,400 8,800 I I June 28,150 10,500 July 23,990 8,900 Ii August 21,950 9,800 September 13,770 10,900 October 5,580 10,200 November 2,430 10,600 December 1,750 12,100 Table 15.Relationship between mitigation alternatives and the impacts for which they are applicable. l I Mitigation alter- natives/impact issue channel width modification - channeTbarrier construction Flow augmentation Inadequate passage p p p Loss of physical habitat p Loss of upwelling s Winter overtopping of slough berm I I Upwelling augmentation .-S-rough~xcavat:ton- creating spawning habitat in pools Increase berm height .~.__..~--_._.~--_.-=-CO--- P =primary effect S =secondary effect s ..-p . s p p ._p-.. S p I 1 BW is backwater condition which neglects the-effect of local flow BR is breaching condition which represents controlling discharge through the slough SW/GW is surface water and groundwater condition with a median natural flow or minimum project flow controlling groundwater levels and surface water related to precipitation events. Appendix B contains an explanation of the derivation of the percent exceedance-values Table 17.Condition which provides successful passage most frequently and approximate percent of time that passage is successful during the period 20 August -20 September at Slough 9. [ Project 12,000 cfs Project 9,000 cfs Cond.Occurrence Cond.Occurrence Passage Reach Natural Cond.Occurrence (%)(%)(%) Project 8,000 cfs Cond.Occurrence (%) All Project Flows With Mitigation Cond.Occurrence (%) II III IV V SW/GW SW/GW SW/GW SW/GW BR 100 100 18 17 29 SwiGw SW/GW SW/GW SW/GW 100 100 16 16 o SW/GW SW/GW SW/GW SW/GW 47 100 15 14 o SW/GW SW/GW SW/GW SW/GW 44 100 14 14 o SW/GW SW/GW SW/GW SW/GW SW/GW 100 100 100 100 100 .f BR is breaching condition which represents controlling discharge through the slough SW/GW is surface water and groundwater condition with a median natural flow or minimum project flow controlling groundwater levels and surface water related to precipitation events • ...Appendix .Bcontai.ns.an explanation..of.the ..derivation.oLthe.percent.exceedancevaJues. 1 I Table 18.Condition which provides successful passage most frequently and approximate percent of time that passage is successful during the period 20 August - r ! 20 September at Slough 9A. ,I All Project Flows Passage Natural Project 12,000 cfs Project 9,000 cfs Project 8,000 cfs With Mitigation Reach Condo Occurrence Cond.Occurrence Cond.Occurrence Cond.Occurrence Condo Occurrence (90)(90)(90)(90 )(90) SW/GW 100 SW/GW 100 SW/GW 100 SW/GW 100 SW/GW 100 II SW/GW 100 SW/GW 100 SW/GW 100 SW/GW 41 SW/GW 100 III SW/GW 100 SW/GW 100 SW/GW 32 SW/GW 14 SW/GW 100 IV SW/GW 100 SW/GW 100 SW/GW 100 SW/GW 100 SW/GW 100 II V SW/GW 100 SW/GW 100 SW/GW 100 SW/GW 20 SW/GW 100 VI SW/GW 100 BR 100 SW/GW 24 SW/GW 14 SW/GW 100 VII SW/GW 100 BR 100 SW/GW 10 SW/GW 7 SW/GW 100 VIII SW/GW 100 BR 100 SW/GW 6 SW/GW 3 SW/GW 100 IX SW/GW 100 SW/GW 100 SW/GW 3 SW/GW 2 SW/GW 0 X 0 0 0 0 SW/GW 0 BW is backwater condition which neglects the effect of local flow BR is breaching condition which represents controlling discharge through the slough SW/GW is surface water and groundwater condition with a median natural flow or minimum project flow controlling groundwater levels and surface water related to precipitation events. Appendix B contains an explanation of the derivation of the percent exceedance'values Table 19.Condition which provides successful passage most frequently and approximate percent of time that passage is successful during the period 20 August - 20 September at Slough 11. I Project.12,000 ..cfs Project 9,000.cfs Condo Occurrence Condo Occurrence Passage Reach Natural Condo Occurrence (t)(t)(t) Project 8,000 cfs Condo Occurrence (t) All Project Flows With Mitigation Cond.Occurrence (t) II III IV V SW/GW SW/GW SW/GW BR BR 70 43 12 1 SW/GW 60 20 5 o o o o o o o o o o o o SW/GW SW/GW SW/GW SW/GW . SW/GW 100 100 100 100 100 J BW is backwater condition which neglects the effect of local flow BR is breaching condition which represents controlling discharge through the slough SW/GW is surface water and groundwater condition with a median natural flow or minimum project flow controlling groundwater levels and surface water related to precipitation events. Appendix B contains an explanation of the derivation of the percent exceedance values .j I j 'I I Table 20.Condition which provides successful passage most frequently and approximate percent of time that passage is successful during the period 20 August - 20 September at Upper Side Channel 11. All Project Flows Passage Natural Project 12,000 cfs Project 9,000 cfs Project 8,000 cfs With Mitigation Re"ach Condo Occurrence Cond.Occurrence Cond.Occurrence Cond.Occurrence Cond.Occurrence (%)(%)(%)(%)(%) SW/GW 100 0 0 0 SW/GW 100 II BR 45 0 0 0 SW/GW 100 I j III BR 45 0 0 0 SW/GW 100 BW is backwater condition which neglects the effect of local flow i I \j BR is breaching condition which represents controlling discharge through the slough SW/GW is surface water and groundwater condition with a median natural flow or minimum project flow controlling groundwater levels and surface water related to precipitation events. Appendix B contains an explanation of the derivation of the percent exceedance values Table 21.Condition which provides successful passage most frequently and approximate percent of time that passage is successful during the period 20 August - 20 September at Slough 21. All Project Flows Passage Natural Project 12,000 cfs Project 9,000 cfs Project 8,000 cfs With Mitigation Reach Condo Occurrence Condo Occurrence Condo Occurrence Condo Occurrence Condo Occurrence (%)(%)(%)(%)(%) SW/GW 100 SW/GW 100 SW/GW 6 SW/GW 4 SW/GW 100 IlL SW/GW 10 0 0 0 SW/GW 0 IIR SW/GW 4 SW/GW 2 SW/GW SW/GW SW/GW 100 BR is breaching condition which represents controlling discharge through the slough SW/GW is surface water and groundwater condition with a median natural flow or minimum project flow controlling groundwater levels and surface water related to precipitation events. Appendix B contains an explanation of the derivation of the percent exceedance values .J 'j .J '\ 'I I l )Table 22.Condition which provides successful passage most frequently and approximateI !I percent of time that passage is successful during the period 20 August - 20 September at Side Channel 21. I 1I ~ All Project Flows Passage Natural Project 12,000 cfs Project 9,000 cfs Project 8,000 cfs With Mitigation Reach Condo Occurrence ·Cond.Occurrence Condo Occurrence Condo Occurrence Condo Occurrence (90)(90)(90)(90)(90) SW/GW 100 BR 100 SW/GW 28 SW/GW 24 SW/GW 100 II SW/GW 100 BR 100 SW/GW 28 SW/GW 24 SW/GW 100 III SW/GW 100 BR 100 SW/GW 31 SW/GW 26 SW/GW 100 IV SW/GW 100 BR 100 SW/GW 31 SW/GW 26 SW/GW 100 V BR 71 BR 100 SW/GW SW/GW 0.5 SW/GW 100 VI BR 71 BR 100 SW/GW 0.5 0 SW/GW 100 VII BR 71 BR 100 SW/GW 0.5 0 SW/GW 100 VIII BR 71 BR 100 SW/GW 0.5 0 SW/GW 100 IX BR 71 BR 100 SW/GW 0.5 0 SW/GW 100 X SW/GW 100 SW/GW 100 SW/GW 9 SW/GW 5 SW/GW 100 BW is backwater condition which neglects the effect of local flow BR is breaching condition which represents controlling discharge through the slough SW/GW is surface water and groundwater condition with a median natural flow or minimum project flow controlling groundwater levels and surface water related to precipitation events. Appendix B contains an explanation of the derivation of the percent exceedance values Table 23.Candidate sites for development of replacement spawning habitat. *Historical RM Site Location Spawning Use 110.1 L Mouth of Oxbow I chum 115.0 R Mainstem 2,right channel chum 117.9 L Channel outside of Bushrod 118.9 L Downstream of Oxbow II mouth chum 127.1 L or C Complex Downstream of mouth SL 9 129.8 R Right side of side channel at head of SL 9 chum 131.3 L Upstream of 4th of July Creek chum 132.9 R Downstream of mouth of SL 9A chum 137.5 L Downstream of mouth of SL 16 139.0 L Between mouth of SL 17 arid 18 chum,sockeye 143.2 L Upstream of intertie chum C Center of channel R Right side of channel looking upstream 1 ] I ,} ) 1 '1 ,\ J I 1 I ,1 i 1 I ,1 I .[I II i I II j I II I J IDENTIFICATION OF IMPACTS AND GOALS OF PLAN OPTION ANALYSIS 1 NEGOTIATION OF ACCEPTABLE PLAN IMPLEMENTATION OF PLAN ... MONITORING OF PLAN PLAN MODIFICATIONS COMPLETION OF MITIGATION TERMINATION OF MONITORING .FIGURE 1,MITIGATION PLAN DEVELOPMENT AND IMPLEMENTATION ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT WDocIwaIdoClJfde CansuRanIa 6 HARZA-EBASCO SUS'TNA JOINT VENTURE FIGURE 2 OPTION ANALYSIS ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT PARTIAL AVOIDANCE +---1 PARTIAL RECTIFICATION PARTIAL COMPENSATION AVOIDANCE NO AVOIDANCE MINIMIZATION NO MINIMIZATION RECTIFICATION NO RECTIFICATION REDUCTION NO REDUCTION COMPENSATION UNMITIGATED/LOSS RES IDUAL IMPACT TOTAL AVOIDANCE I---~SOME MINIMIZATION I----~TOTAL RECTIFICATION I----~SOME REDUCTION t-----:lTOTAL COMPENSATION .1 ) I ) ) I l'] .1 ~ I ) I ) I ) I 1 I .-1f00 c::I:b.HARZA..EBASCO . III -c..'CJ.~SUSITNA JOINT VENTURE + ALASKA POWER AuTHORITY SUSITNA HYDROELECTRIC PROJECT COMPO.ITE AREA SPAWNED la THE TOTAL SURFACE AREA uaED FOR-SPAWNING (AREA W""'N DARKENED PERIMETER) ~~AREA S"AWNED IN 1883. l\.\\ARU 8PAWMED 8N 1884", -=AREA SPAWNaDI..1882.-- + TOTAL AlUlA ••A••IID'"TNII aUM OF THI!AREA SItAWNE.D POR BACH 01'TNIII TNIIII..YEARS.-- 'IGURII3 SCHEMATIC DIAGRAII ILLUSTRATING DIFFERENCE BETWEEN COMPOSITE AREA AND TOTAL AREA SPAWNED. II j1 [] 11 11 II 1] (] 11 II 1 j I] I ]I I I I \1 [J [J 11 ~HARZA-EBASCO..od'MIs 41..r;;;::;:;JCiIde~SUSITNA JOINT VENTURE MAIN STEM CHANNEL'-... i FlpURE ..SHORE SHORE ICE BUILDUP WITHOUT OVERTOPPING SLOUGH BERM AT LOWER ELEVATION THAN MAINSTEM STAGE SLOUGH ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT . Woodward-Clyde -IIXJ£OOtz&cam®&®OO Consultants fI 8UIITNA JOINT VENTURE ~ -----'------.~~'--------'--'-----~----------~~_.------- 5~l THI E8HOLD EI EV.,-~__,.,---..,..m _~~..g r J----.,\,-'\!".,,,.",..___\~..,_,<II , 585 --.---,I I>~w id 580+------+------+-----+-----+------+----...... ai •5~.. NOVEUBER DECIEU.Eft JANUARY FEBRUARY MARCH APRIL 1871 1872 WEATHER 8»ERIOD 1 NOV 71 -50 APR 72 (COLD WINTIER) 595-r------.........-----..,..-----.,..-----......-----..,..-------. THylHOLD IL V. 590 ! f 5U+------+-----+------I-----+------+-----t-.,,->.--_-"-.--~-f----...__"---...---"'-~580 -----,-... W ~575-1------+-------+-------+-----+-------+-------1 •NOVIEMBER DECEMBER JANUARY FEBRUARY MARCH APRIL 1882 1985 WEATHER PERIOD 1 NOV 12 -50'APR 85 (AVERAGE WINTER) LEGEND -NATURAL FLOW AND WEATHER ----WATANA 1988 FLOW AND NATURAL WEATHER REF:HARZA-EBASCO 8U81TNA JOINT VENJURIE.1884.INSTRtEAM A lAS KA POW ERA UTHO RIT Y ICE 81MULATION 8TUDY.DRAFT REPORT PREPARED FOR ALASKA POWER . AUTHORITY FOR SUSITNA HYDROELECTRIC PROJECT.SEPTEMBER.SUSITNA HYDROELECTRIC PROJECT! fiGURE I)PREDICTED WINTER MAIN~TEM 8TAGE8 fOR NATURAL AND 'WoodwardaClyde : PROJECT fLOWS NEAR THE HEAD Of SLOUGH 8A ConsuJtants ~OO~OO~ClIrn[ID&~ 8UIITN4 JOINT VI!NTU,( APRI. :","\ ." MARCH ---,--.,--,.I J.,,.. I I iJANU~RY I 'IEIRUARV :.:w Ld ~ 615 B ,•I', ,I i ,. . 610 ,..,i ••p...THRIE.'HOLD IEL~V.i •/"--_......--'.-.'----..~lot"..IJ .J-;' 605 ;.I'!',;,,,ii,•~.__~.I .,I .,--_.':.....--,--_.....----...,,600 ...,. I i 595 I !I I NOVEMBER PE~IMBIR 1171 i 1872 IWIEATHER i . l'ERIOD 1 N,OV 71 -10 APR 72 (COLD WINTIER) 62°1tn~----1-ti----l----~--,-------r-------"'-------i I •i iI'I I I IIIIII I;610 ! •LEV. :>I ;I~605 I ;! W __J.-'-----'--'-i-....----.,,~--------......__J--------~ cd I --....•600 , .i j:~ECEMBE"JANU~RY fEBRUARY MARCH APRIL 1882 \1~83 IW'ATHER PERIOD 1 NqV 82.-30 APR 83 (AVERAGE WINTER) LEGEND ".I !I -NATURAL FLqW!AND WEATHER i i ......WATANA U~8'!~LOW AND NATUR~L ~EATHER I !' OO~rrJ~CI~[ID&~ RUIITN4 JOINT YENtURI WoodwanI-CIyde Consultants ~. ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT REf;HARZA-EBASCO IUSITNA JOINT ~E~TURE.1884.INSTREAM,'"I I .I ICE SIMULATION Srr;UDY.DRAFT REPO\FITlpREPAREDFOR ALA~KA POWER AUTHORITY FOR SUSITNA HYDROELEGTRIC PROJECT.SEPTEMBER.i',;,-.--'...-.._..!'-'....! fiGURE 8 PREDICTED W~.NTER MAIN~TEM ~Tr'GES FOR,NATURAL ~ND PROJECT FLOWS NEAR THE HE~D pF SLOUGH 8 i :I i ----,-"-.---------------_.-----------------------~ ----~---_.__..--~-----------'~~---~--- 665 660 ~THR 8HOlD El v.~.---"---'----,,..-.-~--'-..;-'----""'"',.655 /l'>, W _.I ,...,I W 650 --....,"--'---,------,-Ju$. ~64· NOVEMBER DECEMBER JANUARY FEIRUARY MARCH APRIL 1871 1872 WEATHER 'ERIOD 1 NOV 71 -ao APR 7 •.(COlD WINTER) 665 660 f THR IHOlO III ev. 655-:;; ~650 ------J ~--,-------w fd 645~NOVEMBER DECEMBER JANUARY FEBRUARY MARCH APRil 1812 1883 WEATHER PERIOD 1 NOV .2 -10 APR 13 (AVERAGE WINTER) LEGEND -NATURAL fLOW AND WEATHER •••-WATANA 1888 fLOW AND NATILJRAL WEATHER REf:HARZA-EBASCO 8USITNA JOINT VENTURE.1884.INSTREAM ALASKA POWER AUTHORITi1'ICE SIMULATION STUDY.DRAFT REPORT PREPARED fOR ALASKA POWER , AUTHORITY fOR SUSITNA HYDROELECTRIC PROJECT.SEPTEMBER.SUSITNA HYDROELECTRIC PROJECT i I ! FIGURE 7 PREDICTED WINTER MAINSTEM STAGES fOR NATURAL AND \Yoodward-Clyde ! PROJECT fLOWS NEAR THE HEAD Of SLOUGH 9A Consultants ~OO£OO~~rn:fID&~ I 8UIITN4 JOINT VIENlU"!, ! ; 695 nil I •B I TIHR'SHOLD IEL ;Y.l n 690 n n :..'B ..........,....:.....-1-....---j I ,_-,!". 685 ',,..........._...~,···7-.,.,.'-....,..----.~\,----......--•__._1---'j ""....."\• j -------'-680 i' g >w id:675 wi 1NOVEMIEA 1871 ~EqEMBEA ! JANUA~Y I FEBRUARY 1872 MARCH APRIL !f ~I WEATHER PERIOD 1 Nav 71 -30 APA 72 (COLD WINTER) 1 !' 1 ' I I 695.l'~AIIIHOLD IL~I f- 690 II I I I I I ~ I 6U :1 ,I 'r-i,:,'••- •.,----------i--------'~------,---~-~.,.._----~,,---..-.........--,-~_----.,I I'--•'I .'----.--- 680 'iT I U,,",UII:UB'!!!-.I OEC...IIER·'I JANUA~Y 1882 I fEBRUARY 1883 MARCH APRIL 1 i WEATHER PERIOD!\. LEGEND I I -NATURAL fLO,W AND WEATHER ----WATANA 188'[FLOW AND NATURAL WEATHERi"",; , 1 NOV 12 -30 APR a3CAYERAGE WINTER) .1 I I !I,! I:ALASKA POWER AUTHORITY I SUSITNA HYDROELECTRIC PROJECT I I 1 '.I IREf:HARZA-EBASpO SUSITNA JOINT ~E~TURE.1114.1N8TR~AM ICE SIMULATION STIlJD ....DRAFT REPO~T ~REPARED fOR ALAS:KA POWER AUTHORITY FOR SUSITNA HYDROELEqTRIC PROJECT.8EPTE,MBER. i FIGURE 8 PREDICTED WINTER MAINSTEM STAGES fOR NATURAL AND 1 'PROJECT FL10WSNEAR.TH~HEAD OF SLOUGH 11 I !I 'NoodwanI-ayde Consultants " OO&~tzL!\C3~[ID&~ .UIITN"JOIHT Vt:NTUP'I« I '--'- ------'---.~L.-_-------'_._-~---------------._--~---..,----~---- 765 760g TH~ESHOLD EL ~V. •755 >---,---_...--------------......-----------"'-..-....,.......--..~_t/------,-,._.,...._-.,-W -----~iii 750 at ~745 'NOVIEUBER DECEMBER JANUARY fEIRUARY MARCH APRIL 1871 1811 WEATHER '-ERIOD 1 NOV 71 -10 APR 72 (COLD WINTER) 765 760 E THRleHOLD IL v. 755-:>____•.r-.-,_-..---------.....-.-.----~-~-.---.-----..r-I -·-~...•,--------,---,.--~_.."-....-,_.-_._.....~750 W cd 7..5. it NOVEUaER DECEMBER JANUARY fEBRUARY MARCH APRIL 1882 1883 WEATHER PERIOD 1 NOV 12 -30 APR I.(AVERAGE WINTER) LEGEND -NATURAL FLOW AND WEATHER ----WATANA 1888 FLOW AND NATURAL WEATHER REF:HARZA-EBASCO SUSITNA JOINT VENTURE.1884.INSTIREAM ALASKA POWER AUTHORITYICESIMULATIONSTUDY.DRAFT REPORT PREPARED FOR ALASKA POWER AUTHORITY FOR SUSITNA HYDROELECTRIC PROJECT.SEPTEMBER.SUSITNA HYDROELECTRIC PROJECT I FIGURE 8 PREDICTED WINTER MAINSTEM STAGES FOR NATURAL AND W'oocIward-CIyde I(}{J&rrJtz&.c:a§lID&~PROJECT FLOWS NEAR THE HEAD OF SLOUGH 21 Consultants fit I IUIITN4 JOINT VENTURE I eo,oool ~I !-I F=FFFFR I FeR I o I10,ooor---t--t-ri!Hr---f--r-+--.J-~-:--t--~I-J+---~~--I--l-...J CDI' ....co...2 40,0001 I I'~1,1:11 1i:l I I I I I I I III I I I I ~.o ...ar·T'---r-rTI~Ht=~tfi~Er~'!§~~~f~~~----1--1-1~ oC o IO'OOOh __T~~~~~~rF~~t-l-t-+-+~1~W~-j __l_l~ 10,000 I I I:I :I I I .:1 I I.I.d I I I I I I.I I 0' !I j 0--,1.01'1.1 1.1 "i1.41•• ! I •a 4 I e 7 ••10 i ftlCURRI,ENCE INTERVAL.IN VIAI" 10 10 40 10 ,!I .i FIGURE 10 RIECURIUSNCEINTIERVAL bFf THIE PEAKDIIQHARGE AT GOLD CREEK DURING AUGUST ~O-'8EPTIEMBIER 12f FROM 1800 T~_118.- i ;i : il ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT IWoodw8nl-ClJrde~6 I HARZA-EBASCO .SU~ITNA JOINT VENTURE 50,000 I I I I I ~I I I I I 1 -en LL 30,0000-w Ga:« :I: 0 20,000 CJ)-C 10,000 ...;·:·:·:·~.:.:.·.w·:·:·~;.::a::~:~::::::~:~~:::;:;:;=:::::;:;::i:=;:::::;:: ;::~::::::~::::::~:::::~::::::: ~.~n~=~-rTmn~-35'''W'o JAN FEB MAR -APR MAY JUN .JUL AUG .SEP OCT NOV DEC fiGURE 11 SIMULATED MINIMUM.MAXIMUM AND MEAN MONTHLY DISCHARGES.fOR MAXIMUM POWER CASE P-1 ·'COMPAREDWITH M8NIMUMtUAXIMUMAND" MEAN MONTHLY DISCHARGES fOR NA:rURA~"'eONDrrIOr:S... 1':I:I'!:Mtm:':;1 AREA WITHIN THE BOUNDS Of THE SIMULATED MINIMUM AND MAXIMUM {"":"""',:"":",,,:,MONTHLY DISCHARGES fOR CASE P-1. m:mn AREA WITHIN THE BOyNDS Of THE MINIMUM AND MAXIMUM MONTHLYt:t::ttI:l:lI DISCHARGES fOR·NA URAL CONDIJIONS fOR 33 YEARS Of RECORD. ~;NATURAL MEAN MONTH'-Y DISCHARGE. I***SIMULATED MEAN MONTHLY DISCHARGE fOR CASE P-1. ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT . Woodward·Clyde L:AConsultants.. DECNOV OO~[fJ~~CJ~fID~®©@ sUSBTNA JOINT VENTURE OCT ::rNoi'EW'A"'M ..="",~~".~",= ,11.DISCHARGE FOR SISITNA RIVER AT :~GOLD CREEK ;2.NO MAXIMUM FLOW LIMITS WERE ::i:i ESTABLISHED FOR CASE C ::i 3.PERCENT PROBABILITY OF 11 EXCEEDENCE CURVES DURING WITH PROJECT CONDITIONS.PROBABILIT CURVES ARE BASED ON WEEKLY AVERAGE FLOWS FROM 33 YEARS OF SYNTHESIZED PROJECT OPERATION. Woodward-Clyde ~.AConsultants• ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT 10,000 w CJa:« :I:o 20,000en-c -en LLo 30,000- ;;;;t:::'~:.':.:.:.:.:.:.:.::.::.:"':':':':':':':':~;-.:::::::':..:.•';;m:":::':::':':.:::::.::.::.:••:::.::::.:•.:..•...••....•..•1.....I''I ~! !...m ;;::;I:r-m.~.•...•... o·:!..1 I FIGURE 12 .JAN',FEB MA~[APR .MAY I JUN JUl AUG SEP MINIMUM AND MAXIMUM ytEEKLy ..DISCItIA~GEI-FOR CASE.~fLOWS COMPARED WITt{!·MIN~MUIlll.MAXIMUM i,\Np MEAN MONTHL~.. DISCHARGES FOR NA1'I1URAL CONDITIO~S~! :i I.I 1::1.)::i:l;i:)i:i1i:i1:::):1 AREA WITHIN THE BO~NDS OF CASE f 8~STREAM'FLOW REQ~IREMENT8. !i f 1 !::IrmmAREAWITHINTHEBOONDSOFTHEMINIMUMAND.MAXIMUM ~MONTHLYW±W DISCHARGES FOR:NATURAL CONDITIONS FOR 33 YEARS OFIRECORD..l i :-!-.. :I f II.I •..NATURAL MEAN MONTHLY DISCHARGES.' i '------' 50,000 NOTE 1.DISCHARGE FOR SUSITNA RIVER AT GOLD CREEK 40,000 Woodward·Clyde 1".JilConsultants'WI' ALASKA POWER AUTHORITyl SUSITNA HYDROELECTRIC PROJECT I •I [}{]~[R1~~r=[g(ID~®©© SUSITNA JOINT VENTUR!E -en LL 30,0000-W CJa: ~ J: 0 20,000en-Q 10,000 I:::::;:::::I:I:::I:I:I AREA WITHIN THE BOUNDS Of CASE EV INST.REAM FLOW REQUIREMENTS. fEEffEI AREA WITHIN THE BOUNDS OF THE MINIMUM AND MAXIMUM MONTHLYI:±:I±I:±:I DISCHARGES FOR NATURAL CO~DITIONS FOR 33 YEARS OF RECORD. a II ...NATURAL MEAN MONTHLY DISCHARGES.' FIGURE ,.0 ~MAY I JUN I JUL i AUG I SEP I OCT IJ ~~~]I~ MINIMUM AND MAXIMUM WE~KL Y DOSCHARGEI FOR CASIE EV FLOWI COMPARED WITH MINIMU~I MAXIMUM A~MEAN MONTHLY .DI$CHARGES FOR NATURAL CONDnrIONS. 50,000 I . NOTE 1.DISCHARGE FOR SUSITNA RIVER AT GOLD CREEK ALASKA POWER 'AUTHORITY SUSITNA HYDROELECTRIC PROJ ECT NOV OOD:\[ffi~D:\c=[gfIDD:\®©@ SU81TNA JOINT VENTURE OCT Woodward·Clyde AD".Consultants ~ AUG .SEP ttttttI'INDICATES MIN FOR I!!!!II !I !~ ,LOW FLOW YEAR ' -(J) LL 30,0000-W CJa:« J: 0 20,000 (J)-C 10,000 0--MAR I'APR 'MAY II.JUN •JUl u:IGURE 14 .i :. MINIMUM AND M~IMUMWEEKLY DISCHAR~ES.fOR CASE EVi1 FLOWS COMPARED WrrHMINIMUM.MAXNUM A~D,MEAN MONTHLY D,ISCHARGEI FOR NATURAL CONDITIONS.i.i I I:;;::::::::::;!:!:;:::!I AREA WITHIN nl!;BOUNDS OF CASE E~I IrSTREAM FLOW'REQU~REMENTS. ,,I .!•.Imm.AREA WITHIN THE BOUNDS OF THE MINIMlLIM.AND MAXIMUM MONTHL..YItW1lIDISCHARGESFQRNATURALCONDITION~FOR 33 YEARS OF'RECO~D. ---NATURAL-MEAN MONTHLY DISCHARGES. '--~--'--' 50,000 NOTE I I I I I I I I I I 1.DISCHARGE FOR SUSITNA RIVER AT GOLD CREEK 40,000 I I I 1 1 1 1 I 1 1 I 1 I -enu.30,0000-W CJa:«:r: 0 20,000en-c I.I OO~~~~=~~~®©@ SUSITNA JOINT VENTURE I OCTSEP Woodward·Clyde .1'...Consultants OW' I ALASKA POWER AUTHORIT"I SUSITNA HYDROELECTRIC PROJECT I AUG 10,000 AREA WITHIN THE BOUNDS Of CASE EVI INSTREAM FLOW REQUIREMENTS. AREA WITHIN THE BOUNDS Of THE SIMULATED MINIMUM AND MAXIMUM MONTHLY DISCHARGES fOR CASE EV1. SIMULATED MEAN MONTHLY DISCHARGE FOR CASE EV 1. 01 I I I ~ FIGURE 15 JAN FEB MAR APR MAY'JUN v JUL SIMULATED MINIMUM,MAXIMUM AND MEAN MONTHLY DISCHARGES . COMPARED WITH MINIMUM AND MAXIMUM WEEKLY DISCHARGES. FOR CASE EV 1 INSTREAM fLOW REQUIREMENTS.-m 1 I ] 1 I 1 'J J ] 1 I I I 1 1 I l I '[ OO~fP3~c:{~[ID&~ .8U8ITNAJOIfICT YENlU"'! ~...---WING DEFLECTOR WALLS ......-+--LARGE COBBLE FILL .. ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT 2'TYP .. STREA FLOW .. .. .. . --=:;J'M~~~~I~DF Je..-.--ORIGINAL WIDTH -.... -,.-_..~.-.._."~_.-_._.••....,_._._._._..- FIGURE 16 WING DEFLECTOR T PASSAGE REACH NOT TO SCALE FLOW-....... PASSAGE REACH SIDE VIEW PASSAGE REACH 0 0 ()0 0 FLOW POOL I 0 0 I POOL~ ~0 £)6(\0 - EXPOSED ROCKS PLAN VIEW FIGURE 17 TYPICAL PASSAGE REACH OF SLOUGH ALONG MIDDLE SECTION Of THE SUSITNA RIVER ALASKA POWER AUTHORITyi SUSITNA HYDROELECTRIC PROJECT I ~Clyde II.IXJ&OO~c::a~OO&~ Consultants ,,'aualTNA JOINT VENTUI/E I HEIGHT Of MAXIMUM SLOUGH DISCHARGE ,.ORIGINAL CHANNEL I I tB 7 ROCK 'GABIONS •••.EMBEDDED IN CHANNEL BANKS FIGURE 18 ROCK GABDON CHANNELt...1 ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT NOT TO SCALE VIoodward-CIyde Consultants " lXJ&OOtz&e::t~®&~ au II TN A JOINT VENTURE ;rJ'i?~'---~----'_.-.-~-....---'---'---.----------,' I 1 II,} FLOW- ~---REBAR REINFORCING ANCHOR GAS ION BARRIER FLOW-CONCRETE HIGHWAY CURS I ,,I I I I I \."---REBAR ANCHOR HIGHWAY CURB BARRIER FLOW........... NATURAL DEPTH OF FLOW TYPICAL SLOPE POOL AND WEIR STRUCTURE CREATION OF POOLS BETWEEN BARRIERS FIGURE 19 GASION BARRIER HIGHWAY CURS BARRIER ROCK SIU.BARRIER POOL AND WEIR STRUCTURE NOT TO SCALE ALASKA POWER AUTHORITY SUS1TNA HYDROELECTRIC PROJECT !XJ&~~t=~®&~ SUSITN4 JOINT vunul'lll!: BERM AT 604 FT. 3' T/ CONCRETE COLLECTOR SYSTEM 2'x 4'x 18' 2' __'SZ. I I ==tt 1 CFS r ~TO PR V 20' "" ~RILL OF STEEL B,AR ... ~/4 x 2'"AND #4 ~EBAR II ! MAINSTEM'ELEVATION AT 600 FT. ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT i FIGURE 20 COLLECTOR SYSTEM AT SLOUGH 9,!! ; :NOT TO SCALE Woodward-Clyde Consultants " oo£ootz&Clm(ID&~ GUIITNA JOINT ytNTuRe "";~,....:'L.:...--, --._-_.....-----------I I ...' .1"._'.'-'0 ..vi·TA\ /----~'"'.."/--t ./,/"-~'/Y'--~.~..' --"f.'''\'./~O~~LET /i:~~;...'~;j('/-,-,~,,-=:=,"./?./,..' (.../lc~_"-i£-J'I.....--.".. . /"'--O.OOlr.;;;.----....:.:.(~ .~~0 N'O'Il(stun.,."tf, ,.....0.STAlt....&rU SUfiOIf 6CC 600 .... z ~1 w5[lr..9 ---... '"'>........... ....~90 :>rr.... ~~ OUTLET STRUCTURE OF COARSE GRAVELS AND COBBLES1'DEPTH SLOUGH 9 PASSAGE REACH LOCATIONS c::J SIU"SAND G3 GRAVEL'RU88LE ~COBBLE'BOULDER ....-..PASSAGE REACH CORRUGATED'METAL PIPE MAINSTEM COLLECTOR SVSTl .i'i'---Y 10-00 1:'o-110 20.00 2~>OO »00 S~40.0<1 4:,><01)50-00 5~60-00 STREAMB[I) 1:.R ~o I r----.--,--- -10 00 ~.oo 0.00 t-_ll_._.; ~oo III iJ.. !-"--!H H FIGURE 21 THALWEG PROfiLE Of SLOUGH 9 ALA'SKA POWER AUTHORITY.i SUSITNA HYDROELECTRIC PROJECT I SOURCE SAUTNE~ET AL.1984 WoodwanI-CIyde ComuJtants " . I OOb\f?J~e::t~[ID&~ IIUIITN"JOIHT YENTU1JIIIE liU lieo--••--z 0 j:li7~ .;>IIJ..J IIJ IIJ ~.li70... lili~ ~. SLOUGH 11 o SI ...TI SAHDoGIlAVl...I Au l ~COIlllLl 1 8DU DlIl 15U5lfHA IlIV(1l lilAC"GIIADI(HT"Q.~",..., ~ 20' I COLLECTOR SYSTEM liliO I I I ::I Ii:I ,I'd I I I I -10'00 ·~'OO 0.00 ~'OO 10'00,'I~'OO 20~2~00 1I0tOO '3:"00 40100 4:"00 ~·OO 5TRfAM£lED 5TATION I FIGURE 2~THALweo PROIfILE OF SLOU~H 111 ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT SOURCE SAUTNER ET:'AIL"1984 \Yoodward.CIyde Consultants (I. .........JL OO~OOtz&Ct~tID&~ SUStTH".I0INT VENlUfIl! c:::J SILY I S"ND ~COULl/•.,aaU ..........""SlAGl .lACH SLOUGH 21 COMPlEX PASSAGE REACH LOCATIONS !lOU'"I.CO....ll. o .,..atIL'""•••••• A·U •••••••t"'IIO_ / I.,..::;.-...•.OUT~LET'"A"'::::o r-.'-,......:_... ..-._/-.::--...~..•.~':'~"":::~~,.~..-:r~NK ..~,,'..... ""."·Ct_....':-"Y.-k~:'"~ MAINSTEM COLLECTOR SYSTEM "a . i ~: J OUTLET STRUCTURE OF COARSE GRAVELS AND COBBLES l'DEPTH r~ 1~~ ~~~~"..::'IOCQ,"~. 14:1-1 ..:.-..~..,.......-,;;~1.~~:::B __~__~...."-'1tn::.P:• 730 140 15~ .. z 2....,. w ..Jw w "".. r..IGHT CtI,.,..ttk'l. __nA- • I I lrr.("_..Nt...~• •lLL ..... 12~iii •i •i •i i '1:1100 '10000 -:1'00 0'00 :1'00 10'00 1:1'00 20'00 1:1'00 )0'00 STREAMBED STATION I ..... FIGURE 23 THALWEG PROFILE OF SLOUGH 21 . I ALASKA POWER AUTHORITYj SUSITNA HYDROELECTRIC PROJECT I SOURCE SAUTNER ET AL.1984 YIoodwatd-CIyde I .I Consultants "1XJ&[fiJtz&~rn:[ID&~ IUIITNA JOINT YENTU~( i o 0 0 000 o 0 o 0 0 PERF PIPE 5'O.C. FLOW CONTROL OO&OO~~~@&~ IUIITNA JOINT VENTURE Woodward-Clyde Consultants " CLEAN OUT A~ I L.-WATER SUPPLY LINEA~I ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT IIU". i I UNDER BED,COARSE (3-PLUS)GRAVEL I ...RIVER I..21'0-: !. SECTION A-A,f SIDE SLOPE.•.'_'-0-GR~rrL~STABILlZAT!ON~.I "Off,IC.i ff"L PE@RFJ~~~.WATER~----:--.,~..,\,,-.......SUPPLY LINEK~ FIGURE 24 SUSITNAi ~'VER FISHERY IMflTIGATION INDU~ED UPWELLING USING TRIBUTARY WATER SUPPLY f f I i 'I I -''--~-'~ f_.__ I IMPERMEABLE SECTION WEIR STRUCTURE WITH NOTCH FOR ISH PASSAGE ::::y«\l~~ATER FLOW 'V J&:• ~GOOQ'ORIG-INAlSAtBi'~'1-G "l~3E~ GROUNDWATER.NEW SPAWNING HABITAT UPWELLING FIGURE 26 WEIR TO INCREASE SPAWNING HABITAT ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT NOT TO SCALE \\foodward.CIyde ~Q' IOO&~tl&c::{~~~ aUSITNA JOINT YENTU ..I! I I I I t ] 'I 1 I I J I I I 'j I 'I I I J J ,RIPRAP AS SIDE P-ROTECTION C:O~®~e=t~~~ SUSITN4 JOIHf V!H'fUJIlII! - ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT T ...... -..JI ~-4.~.1''''=~_ ... . IMPERMEABLE MATERIAL (PLASTIC LINER) FLOW .~......... FIGURE 28 TIMBER POST WEIR ~()rTO SCALE ROCKGABIONS "3 #8 REBAR·ANCHORS .....#8 REBAR ANCHOR TYP .-,--;--1--1---)---1 L_L~L_L_L_ I I I I I I --,-,--,--,~ ORIGINAL CHANNEL I .1 EXCAVATED BANK TO PROVIDE I .. FIRM STRUCTURE EMBEDMENT ~1'+1~ SPAWNING GRAVEL REINFORCING BAR PLVWOOD SHEETS ~- ~ ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT NOT TO SCALE FIGURE 27 ROCK GABION WEIR I 'Noodward-Clyde IOO&rmtz.&c{~~~ Consultants CI BUIITN"JOINT YENTUA~ , CROSS-SECTION J l 1 1 I j I J :~l ! I ! 1 1 1j 3' v REINFORCING BAR TO STABILIZE PI.,YWOOD LARGER ROCKS SIDEVIEW AfIIlj~:"---ORIGINAL CHANNEL FLOW ~ EXCAVATION TO EMBED. STRUCTURE IN CHANNEL FIGURE 28 ROCK WEIR .NOT TO$CAL.E ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT G{}~lFJ~=tm(ID&~ 8U8nN~JOtHT YtHru"t! I 1 I 1 ""'-...._---~- ..--SUSITNA RIVER MAINSTEM lJ PLAN VIEW I.;::LENGTH OF BERM LARGE ROCK FACING CROSS SECTIONAL VIEW FIGURE 29 BERM DESIGN TO PREVENT OVERTOPPING ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT NOT TO SCALE (XJ&rro~~~@&OOQ) SUSITN"JO'Hr Y!NTUA! I..1 .J J ,I 'J ,I 'j I J !) /'1 '.] 20%- "~-.,. 6$2000 PR V 6$1000 CAPITAL COSTS $121,000' O&M COSTS $4.000 $20 00 500 J 250 I FEET SLOUGH 8A o 1 FUGURE 31 LOCATIONS OF MITIGATION MEASURES AND PERCENT DISTRIBUTION OF SPAWNING CHUM SALMON DURING 1984 IN SLOUGH 8A. t t I I I I I I I I I I I I I I I , GD&~~~rn[ID&OOQ) BUilTH".I0lH1 V[HTU"[ ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT MAINSTEM 5% FOREST GRAVEL SHRUBS SL.OUGH EXCAVATION CHANNEL OUTLINE ·i ..00 CFS AT GOLD CREEKouri..JNe OF WETTED &lRFACE AREA AT IWNST~DISCHARGEOF 12,5 RAJL,ROAD BEAVERDAM PIPE INLET AND OU11.ET WEIR BERY WING DeFLECTORS ~ D--......... m LEGEHD: ( 0 LOG BARRIERS Qo C\a ..I • 1000 CAPITAL COSTS $159, O&M COSTS $4,000 500250 I .. FEET SLOUGH 9 o PR I LOCATIONS OF MITIGATION MEASURES AND PERCENT DISTRIBUTION WNING CHUM SALMON DURING 1984 IN SLOUGH 9. I I I I I I I, I I I I I I I I I I I ..........----- -- ..-..----",,- MAINSTEM ......__-------c ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT i\loodward.Oydo O{J&(?J~c::a ffi~~'Consultants ~IUalTHA JOIHT YfHTU~f GRAVEL FOREST SHRUBS SLOUGH EXCAVATlOH CHANNEL OUTUNE OUTUNE OF WETTED SURFACE AREA AT MAJNSTEJoI DISCHARGE OF 12,600 CFS AT GOLD CREEK RA1J,.R 0 AD SEAVER DAJoI WElR PIPE INLET AN.O OUTLET aERY WING DEFLECTORS ~ ~~ LEGEND: ( 0 LOG BARRIERS Bo C\a f $3,500 PR IV r9 • 000 I 6.ENTIRE SLC)UCIH CAPITAL COSTS $118,000 O&M COSTS $4,000 500 I 250 I FEET SLOUGH 9A • o I FIGURE :8 LOCATIONS OF MITIGATION MEJ~SIJRE~S AND PERCENT DISTRIBUTION OF SALMON DURING 1984 IN SLOUGH 9A. I I I I I I· I I I I I I,, I I I I I ----~-------------------'---- !Xl&~~c:a~~~ •u a I TH ...J 0 I H T ...f H TU "f ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT FOREST GRAVEl. SHRUBS RA11.ROAD BEAVER DAY &LOUGH EXCAVATlOH LOG BARRlaiS WEJR PIPE INLET AND OUTLET BERY WING DEFLECTORS ~ cf ( 0 Qo ~ U ----MAINSTEM 10%------"'IE:-- L----~f:"--10%-7'f'---__ tSUM E SLOt BEAVERDAM SLOUGH EXCAVATION LOG BARRIERS WEJR PJPE INLET AND OUTLET FIGURE 3J DISTRIBU LEGeHD:IN SlQUG ~FOREST r~:·-:J GRA VEL. mE SHRUBS -CHANNEL OUTUNE OUTUNE OF WETTED SURFACE AREA AT MAJNSl ~RAJLROAD ~ c5 c a Qo MAINSTEM I I I I I I I I I I, I I I I I I I I ~~ ." I $161,000 D<J&(jJ~c:2rn[ID&~ IUIITH4 JOIHT Yf:HTU"e: ALA'SKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT UPPER SIDE CHANNEL 1,1 CAPITAL COSTS $187,000 O&M COSTS $4,000 $24,000 ---~~-----"----- ..., ... 5% ENTIRE SLOUGH $26,000 .'/- $30,000 I Jliiiiiiii;;;iiiii'r-:Z J? ICAPITALCOSTS$184,000 O&M COSTS $4,000 500 f 8ERM WING DEFLECTORS 250, FEET •3"LOCATJONSOF MITJGA TION MEAS/1RESAND.PERCENT BUTION OF SPAWNING CHUM SALMON DURING 1984 UGH 11 AND UPPER SIDE CHANNEL 11. ENTIRE SLOUGH '..\$26,000of I ! SIDE CHANNEL 21 CAPITAL COSTS O&M COSTS $~ FOREST GRAVEl. SHRUBS CHANNEL OUTUHE OUTUHE OF WETTED SURFACE AREA AT MAJNSTEY DISCKARc RAJLJlOAD BEAVERDAM WEIR SLOUGH EXCAVATJOH LOG BARRLERS PIPE INLET AND OUTLET BER" WING DEFLECTORS LEGEND: Q o C\ (J ( 0 500 I 250 FEET etmESLOUGH $45,000 o I FIGURE 3.LOCATIONS OF MITIGATION MEASURES AND PERCENT DISTRIBUTION OF SPAWNING CHUM SALMON DURING 1984 IN SLOUGH 21 AND LOWER SIDE CHANNEL 21. ...-...---------'-0-.....-...-.....--...............,.....---.._-- ,-..----....'-"..-.,..._""".....-...._-"" I I I I I I I I I I I I I I I I I I P- I '- ---------MAINSTEM ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT WoodwardoQyde !XJ&OO2Z&~~[ID&~Consultants Q 8USITHA JOINT V[NTU"t CAPIT ALCOSTS $34,000 O&M COSTS $5,000 , PRIIA SLOUGH 21 EN'T'R:SlOUGH $34,000 40%------ .CHARGE OF 12.500 CFS AT GOLD CRee< lrs $285,000 S $5,000 I ! I I, [1 !]. 11 11 11 II II I I II II IJ I j I III APPENDIX A Passage Reach Flow Evaluation~ 1 j .J j I .] J ., .j ~j j .j I ..1 1 I I I'I II 11 I I ) APPENDIX A Passage Reach Flow Evaluation A previous analysis estimated the required local flow for successful fish passage through the passage reaches of the sloughs along the middle section of the Susitna River (Sautner et ale 1984c).In order to evaluate the available local flow in Sloughs 8A,9,9A,11 and 21 in comparison to the required local flows,an analysis of the local flow sources for each slough was conducted.Local flow is composed of groundwater upwelling and surface inflow.A primary component of grou~dwater upwelling is related to the mainstem discharge (APA 1984). The relationships developed for the apparent groundwater upwelling component of slough flow at the R&M gage site within the slough versus mainstem discharge measured at Gold Creek are listed below (APA 1984 and pers.corom.B.Bates?). Slough Regression Equation r 2 8A S =-.10 +.00017G .53 9 S =-.62 +.00039G .82 11 S =1.43 +.000087G .63 21 S =-7.55 +.00105G .542 S =slough flow (cfs) G =mainstem discharge at Gold Creek (cfs) The limitations and applications of these equations are discussed in the following paragraphs. Use of the regression equation developed for Slough 8A appears to be a relatively accurate method of determining slough flows for given mainstem flows.The equation was developed for the period from 3 July to 30 October 1984 excluding the 23 August to 28 August period of high runoff.Passage is critical in August and September;the data used to calculate the regression equation represents these mouths.However, the equation does not separate slough flow into tributary inflow and groundwater inflow;the tributary inflow component is assumed to be small at low mainstem discharges. For Slough 9,the regression equation was developed for the period from 8 September to 30 October 1984 corresponding to the period of non-overtopped flows.The slough flow estimated using the equation includes tributary inflow and groundwater inflow.In order to be able to predict:the groundwater slough flow,an alternate equation was developed.Slough flow versus mainstem discharge data for 1982,1983, and 1984 were plotted (Figure AI).Using a slope for the regression line approximating the slope developed for Slough 8A which was assumed to be the slough most similar to Slough 9,a line was drawn through the values corresponding to the lowest slough flows.A minimum groundwater component for the slough was chosen to be 1 cfs,which is about 75 percent of the minimum recorded flow.Using these lines as shown in Figure AI,the groundwater flow at the gage was obtained for various mainstem discharges. The regression flow appeared to be a fairly accurate means of predicting slough flows corresponding to mainstem discharges.It was based on data collected from 25 May to 27 October 1983 and from 1 June to 30 October 1984. At Slough 21,the correlation vallJe p;fO .542_fgr tl1el?l()ugl1.flo~ -"---"versusmainstem-f1:ow··re1:ationship is'cons±stentw±th ·t=he--peer sleugh discharge predictions at low mainstem discharges.Data from 10 August to 22 October 1982 was used to develop the equation.A minimum base flow was estimated to be 75 percent of the minimum slough discharge recorded;at low mainstem discharges,.Le.<8,300'cfs,the base flow component of the i~calfiow is ass~IIl~d to be const'~nt at Litfs. With these limitations in mind,the regression equations were used to estimate the apparent groundwater upwelling component of local flow at the R&M gage site in a slough given a mainstem discharge.In order to J ] I 1 J J 1 .j ] 1 ] I J 1 j l I I 1 II !] Ii I ! II II I IIJ obtain the upwelling component of local flow at other points within the slough,the amounts of upwelling throughout the slough were estimated in terms of percent of the gage flow using aerial photographs,observations by R&M personnel (R&M Consultants,Inc. 1982),and measured upwelling values (APA 1984 and Moulton &Rundquist 1984).The percentage values (Tables A1-A4)were applied to the calculated flow at the gage resulting in estimates of the upwelling component of local flow at points corresponding to passage reaches in the slough (Figures A2-A5).For Slough 9A,measured upwelling values were correlated witp mainstem discharge to yield the upwelling component of local flow at the passage reaches.For Upper Side Ch<;innel 11,the base flows corresponding to selected mainstem discharges were estimated at each passage reach (Sautner et al.1984c and ADF&G 1984).Side Channel 21 was assumed to be a hydraulic extension of Slough 21. A comparison between required local flow and estimated available upwelling component of local flow was made at each passage reach (Tables A5 to A50).An evaluation was conducted of how much of the time the local flow requirements could be satisfied by groundwater -flow alone.The required local flow was input to the relationship between slough flow and mainstem discharge to obtain the required mainstem discharge.The flow duration curve developed for the period 20 August to 20 September (Sautner et al.1984c)for the mainstem discharge was used to evaluate the percent occurrence of these flows under natural conditions. For project conditions,the minimum instream flow requirement for each project flow case was compared to the mainstem discharge estimated to be necessary to produce upwelling flows sufficient for passage.If the minimum instream flow requirement was greater than the estimated mainstem discharge,a value of 100 percent was assigned to the percent occurrence of successful passage with groundwater alone. Alternatively,a value of 0 percent occurrence was assigned if the minimum instream flow requirement was less than the estimated mainstem discharge.Use of minimum instream flow requirements in the analysis addresses potential impacts during low to average flow years compared with median natural flows.Proj ect effects during high flow years would be less. A combination of surface water and groundwater sources was analyzed. The groundwater component of the local flow was determined from the regression equation based on selected mainstem discharges.For natural slough flows,the mainstem discharge of 50 percent occurrence equalling 15,000 cfs was chosen as the basis for groundwater flows. Project flows were assumed constant at the minimum required flows of 8,000 cfs or 9,000 cfs for Case EVI and 12,000 cfs for Cases C and EV. Also,for Case EV,the effect of a spike of mainstem discharge of 18,000 cfs during spawning was evaluated.If the higher mainstem discharge increased the frequency of passage over that available for the minimum requirements of 12,000 cfs,this was indicated in Tables AS to ASO.Proj ect effects during high flow years wou,ld be less.The percent of time that tributary inflow was sufficient to supplement'groundwater in order to provide the required flow for passage was based on an estimate of the contributing basin area,an assumedrunoff-percentage~o-f--40-percent,-and pred.pitaEio-n duration _. curves for'Talkeetna for the period of 1972 to 1981 (Tables A5 to ASO).The percent occurrence of successful passage for passage reaches affected by backwater and breaching was previously analyzed (Sautner et al.1984c). --The--f-ina:l--va±uese±ectred---f,o'I'-··each-~passage'I'eaGh~-was--the--la:r-gest.-'.._-~--~--. percent successful passage occurrence value of those calculated (Tables A5 to ASO).Passage reaches impacted by a decrease in mainstem flow are identified by significant decreases in percents occurrence between natural arid project flows.Any additive effects of accumulation of percent occurrences were assumed negligible. I ] I 1 j j j I 'j 1 J I IU j I I Table AI.Percent groundwater relative to gage flow at passage reaches in Slough 8A. Table A2.Percent groundwater relative to gage flow at passage reaches in Slough 9. Passage Reach I II III IV V Percent of Groundwater Relative to Gage Flow 124 117 100 95 77 \ l I I .I j I j :--1 1 J I 1 I 1 I J 1 III I I] I J I Table A3.Percent groundwater relative to gage flow at passage reaches in Slough 11. If III. il I Passage Reach I II III IV V Percent of Groundwater Relative to Gage Flow 145 127 102 97 65 Table A4.Percent groundwater relative to gage flow at passage reaches in Slough 21 and Side Channel 21. Passage Reach Slough 21 I IlL IlR Side Channel 21 I II III IV V VI VII VIII IX X Percent of Groundwater Relative to Gage Flow 122 35 39 221 219 214 214 212 210 205 ~201 :[(m- 153 ] I I I I I 'I I j I ] I .( I I ! ] .j Table AS.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 8A for Passage Reach I. Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 I )II Groundwater &Surface water Required flow (cfs)2 2 2 2 Groundwater baseflow (cfs) corresponding to'specified mainstem flow 2.6 2.0 1.4 1.3 II Surface water necessary forIlpassage(cfs)0.0 0.0 0.6 0.7 ( Amount of ppt needed for basin area of 1.36 mile 2 (in)0.0 0.0 .of .01 I %Exceeded based on total daily ppt and groundwater 100 100 34 32 Il Breaching %exceeded for controlling discharge of 27,000 cfs 7 0 0 0 Backwater %exceeded for mainstem discharge of <10 ~600 cfs 79 100 0 0 Maximum %exceeded 100 100 b 34 32 a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et ale 1984c) I b For Case EV,the mainstem discharge period of 18000 cfs will assist passage J through PR I by backwater effects I) ,J c Required flow estimated assuming that required flow at upstream PR is sufficient for passage at downstream PR a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et ale 1984c) l I I j I ,I ..I j I ] I ( I I ! 4 1.3 o o 20 .05 4 1.4 o 20 o· 2.6 .04 1.9 o o 22 2.1 .04 Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 Amount of ppt needed for basin area of 1.36 mile 2 (in)".03 Surface water necessary for passage (cfs)1.5 %Exceeded based on total daily ppt and groundwater 25 Required flow (cfs)4c Groundwater baseflow (cfs) corresponding to specified mainstem flow 2.5 Backwater %exceeded for mainstem discharge of 15,600 cfs 48 b For Case EV,the mainstem disclJ.arge period ofl§P90c:.fs will assist pas~age through PR II by backwater effects Breaching %exceeded for controlling discharge of 27,000 cfs 7 Groundwater &Surface water Table A6.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 8A for Passage Reach II. ...Maximum~%-exceeded~--..._-- f ! Table A7.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 8A for Passage Reach III. Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 Groundwater &Surface water Required flow (cfs)4 4 4 4 Groundwater baseflow (cfs) corresponding to specified mainstem flow 2.5 1.9 1.4 1.3 Surface water necessary for passage (cfs)1.5 2.1 2.6 2.7 Amount of ppt needed for basin area of 1.36 mile 2 (in).03 .04 .04 .05 %Exceeded based on total daily ppt and groundwater 25 22 20 20 Breaching %exceeded for controlling discharge.of 27,000 cfs 7 o o o Backwater %exceeded for mainstem discharge of d cfs d d d d Maximum %exceeded 25 22 20 20 a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et ala 1984c) b For Case EV,the mainstem discharge period of 18000 cfs will not assist passage through PR III I \J d Breaching occurs prior to backwater effects Table AS.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough SA for Passage Reach IV. 1 j ! Mainstem flow at Gold Creek (cfs) Natural8 12000 9000 SOOO Groundwater &Surface water Required flow (cfs)5 c 5 5 5 I Groundwater baseflow (cfs) corresponding to specified mainstem flow 1.5 Surface water necessary for passage (cfs)3.5 Amount of ppt needed for basin area of 1.09 mile 2 (in).07 %Exceeded based on total daily ppt and groundwater 14 1.1 3.9 .OS 12 .S 4.2 .09 10 .S 4.2 .09 10 J ] .l d d d d .14..12 b 10 10 Breaching %exceeded for controlling discharge of 33,000 cfs 2 Backwater %exceeded for mainstem discharge of d cfs o o o I I j a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.19S4c) b For Case EV,the mainstem discharge period of lS,OOO cfs will not assist passage through Fk IV c Required flow estimated assuming that required flow at upstream PR is sufficient for passage at downstream PR d Breaching occurs prior to backwater effects Table A9.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 8A for Passage Reach V. Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 Groundwater &Surface water Required flow (cfs)5 5 5 5 Groundwater baseflow (cfs) corresponding to specified mainstem flow 1.3 1.0 .7 .7 II Surface water necessary for passage (cfs)3.7 4.0 4.3 4.3 Amount of ppt needed for basin area of 1.09 mile2 (in).08 .08 .09 .09 %Exceeded based on total daily ppt and groundwater 13 11 9 9 IJ Breaching %exceeded for controlling discharge of 33,000 cfs 2 o o o II I J Backwater %exceeded for mainstem discharge of d cfs d d d d Maximum %exceeded 13 11 9 9 a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et ale 1984c) b For Case EV,the mainstem discharge period o~18,000 cfs will not assist passage through PR V 11 d Breaching occurs prior to backwater effects Table AIO.Required flow,passage reach flow's and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 8A for Passage Reach VI. .1 ! Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 Groundwater &Surface water Required flow (cfs)4 4 4 4 Groundwater baseflow (cfs) corresponding to specified mainstem flow Surface water necessary for passage (cfs) 1.1 2.9 .8 3.2 .6 3.4 .6 3.4 j ...1 Amount of ppt needed for basin area of 0.96 mile 2 (in).07 .08 .08 .•08 %Exceeded based on total daily ppt and groundwater 14 13 12 12 Breaching %exceeded for controlling discharge of 33,000 cfs 2 o o o Backwater %exceeded for mainstem discharge of d cfs d d .............········b '....'. 13 d d 12 12 a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) b For Case EV,the mainstem discharge period of 18000 cfswill not assist passage through PR VI c Required flow estimated assuming thatreql.li.red flow·at upstream sufficient for passage at downstream PR d Breaching occurs prior to backwater effects Table All.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 8A for Passage Reach VII. Mainstem flow at Gold Creek (cfs).a: 12000 9000 8000Natural Groundwater &Surface water Required flow (cfs)4 c 4 4 4 Groundwater baseflow (cfs) corresponding to specified mainstem flow .9 .7 .5 .5 Ii Surface water necessary for passage (cfs)3.1 3.3 3.5 3.5 II Amount of ppt needed for basin area of .96 mile2 (in).08 .08 .08 .08 I i %Exceeded based on total i l daily ppt and groundwater 13 13 11 11 Breaching %exceeded for I~j controlling discharge of 33,000 cfs 2 0 0 0 Backwater %exceeded for mainstem discharge of d cfs d d d d Maximum %exceeded 13 13 11 11 a Natural flows identifi~d by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) j b For Case EV,the mainstem discharge period of 18000 cfs will not assist passage through PR VII c Required flow estimated assuming that required flow at upstream PR is sufficient for passage at downstream PR d Breaching occurs prior to backwater effects Table A12.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 8A for Passage Reach VIII. .] J I Mainstem flow at Gold Creek (cfs) NaturalB 12000 9000 8000 Groundwater &Surface water Required flow (cfs)4 4 4 4 Groundwater baseflow (cfs) corresponding to specified mainstem flow .6 Surface water necessary for passage (cfs)3.4 .5 3.5 .4 3.6 .3 3.7 Amount of ppt needed for basin area of .55 mile 2 (in).14 .15 .15 .16 %Exceeded based on total daily ppt and groundwater 6 6 5 4 a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et ale 1984c) Breaching %exceeded for controlling discharge of 33,000 cfs Backwater %exceeded for mainstem discharge of d cfs ...Maximum %exceeded ... 2 d 6 o d o d 5 o d 4 ( I l 1 b For Case EV,the mainstem discharge period of 18000 cfs will not assist passage through PR VIII ____._.•..••••·__···••••__u.__.·._·_ d Breaching occurs prior to backwater effects Table A13.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 8A for Passage Reach IX. Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 Groundwater &Surface water I ) !I Required flow (cfs) Groundwater baseflow (cfs) corresponding to specified mainstem flow Surface water necessary for passage (cfs) 4 .4 3.6 4 .3 3.7 4 .2 3.8 4 .2 3.8 II Amount of ppt needed for basin area of 0 mile 2 (in)e e e e %Exceeded based on total daily ppt and groundwater Breaching %exceeded for controlling discharge of 33,000 cfs Backwater %exceeded for mainstem discharge of d cfs Maximum %exceeded o 2 d 2 o o o o d o o o d o a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1~84c) I,]b i~~o~:~ep~V:i:xthe mainstem discharge period of 18000 cfs will not assist passage d Breaching occurs prior to backwater effects e Not possible,basin area is insufficient to provide surface runoff a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) b For Case EV,the mainstem discharge period of 18000 cfs will assist passage throughPR I by backwater effects Table A14.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to,20 September at Slough 9 for Passage Reach I. I .J l J ! t .-l r I I [ I I 1 .1 1 J I l 2 1.5 o .5 .004 44 2 o 1.6 .003 47 .4 2 o o 100 o 2.1 Mainstem flow at Gold Creek (cfs) 70 0 0 0 16b iO-Ob ·47 Naturala 12000 9000 8000 exceeded Surface water necessary for passage (cfs)0 Amount of ppt needed for basin area of 2.99 mile2 (in)0 %Exceeded based on total daily ppt and groundwater 100 Required flow (cfs)2 Groundwater baseflow (cfs) corresponding to specified mainstem flow 2.6 Maximum Backwater %exceeded for mainstem discharge of <12,200 cfs Breaching %exceeded for controlling discharge of 19,000 cfs 29 Groundwater &Surface water Table A15.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September i I at Slough 9 for Passage Reach II. ,..1 Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 I . I I Groundwater &Surface water Required flow (cfs)1 1 1 1 Groundwater baseflow (cfs) corresponding to specified mainstem flow 2.5 2.0 1.5 1.4 /\ !\Surface water necessary for passage (cfs)o o o o Amount of ppt needed for basin area of 1.73 mile 2 (in)0 o o o %Exceeded based on total daily ppt and groundwater 100 100 100 100 Breaching %exceeded for controlling discharge of 19,000 cfs 29 o o o Backwater %exceeded for mainstem discharge of d cfs d d d d Maximum %exceeded 100 100 100 11 I ! a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et ale 1984c) b For Case EV,the mainstem discharge period of 18000 cfs will not assist passage through PR II d Breaching occurs prior to backwater effects Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 Table A16.Required flow,passage reach flows and percent exceedance of successful passage due to g~oundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 9 for Passage Reach III. Groundwater &Surface water Required flow (cfs)6 Groundwater baseflow (cfs) corresponding to specified mainstem flow 2.1 Surface water necessary for passage (cfs)3.9 Amount of ppt needed for basin area of 1.73 mile 2 (in).05 %Exceeded based on total daily ppt and groundwater 18 6 1.7 4.3 .06 16 6 1.3 4.7 ~06 15 6 1.2 4.8 .06 14 ! I \ -J I Breaching %exceeded for controlling discharge of 19,000 cfs'29 o o d Breaching occurs prior to backwater effeCts a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) b For Case EV,the mainstem di~charge period of 18000 cfs will not assist passage through PR III I '\ I l j I d d d d 16b Backwater %exceeded for mainstem discharge of d cfs Maximum %exceeded I ) I Table A17.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 9 for Passage Reach IV. Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 Groundwater &Surface water Required flow (cfs)6 6 6 Groundwater baseflow (cfs) corresponding to specified mainstem flow 2.0 1.6 1.2 1.1 I 1 I iI I Ii Surface water necessary for passage (cfs)4.0 Amount of ppt needed for basin area of 1.73 mile 2 (in).05 4.4 .06 4.8 .06 4.9 .07 1\ %Exceeded based on total daily ppt ,and groundwater 17 16 14 14 i I) LI Breaching %exceeded for controlling discharge of 19,000 cfs 29 o o o Backwater %exceeded for mainstem discharge of d cfs Maximum %exceeded d 29 d 14 d 14 u a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) b For Case EV,the mainstem discharge period of 18000 cfs will not assist passage through PR IV c Required flow estimated assuming that required flow at downstream PR is sufficient for passage at upstream PR d Breaching occurs prior to backwater effects Table A18.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 9 for Passage Reach V. I J Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 Groundwater &Surface water Required flow (cfs)6 6 6 I Groundwater baseflow (cfs) corresponding to specified mainstem flow Surface water necessary for passage (cfs) 1.6 1.3 1.0 0.9 4.4 .j 4.7 5 5~1 Amount of ppt needed for basin area of 0 mile 2 (in)e e e e %Exceeded based on total daily ppt and groundwater o o o o Breaching %exceeded for controlling discharge of 19,000 cfs 29 o o o 'j 1 Backwater %exceeded for mainstem discharge of d cfs d d Q d a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) b For Case EV,the mainstem discharge period of 18000 cfswill not assist passage through PR V ) I c Required flow estimated assuming that required flow at downstream PR is sufficient for passage at upstream PR d Breaching occurs prior to backwater effects e Not possible;basin area is insufficient to provide surface runoff r Table A19.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 9A for Passage Reach I. Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 i I 1.1 Groundwater &Surface water Required flow (cfs)1 1 1 1 , I Groundwater baseflow (cfs) I 1 corresponding to specified , i mainstem flow 4 3.5 3.1 3.0 Surface water necessary for passage (cfs)0 0 0 0 Amount of ppt needed for basin area of 2.27 mile 2 (in)0 0 0 0 %Exceeded based on total daily ppt and groundwater 100 100 100 100 Breaching %exceeded for controlling discharge of f cfs f f f f Backwater %exceeded for mainstem discharge of f cfs f f f f Maximum %exceeded 100 100 100 100 a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) b For Case EV,the mainstem discharge period of 18000 cfs will not assist passage through PR I according to existing data f No data available Table A20.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 9A for Passage Reach II. 1 I 1 I l I 1 I ) I If 3 f 3.0 2.5 0 .5 0 .005 100 41 3 f 3 o 100 o 3.4 Mainstem flow at Gold Creek (cfs) f 3 Natural8 12000 9000 8000 Surface water necessary for passage (cfs)0 Amount of ppt needed for basin area of 2.27 mile 2 (in)0 Required flow (cfs) %Exceeded based on total daily ppt and groundwater 100 Groundwater baseflow (cfs) corresponding to specified mainstem flow 3.9 Groundwater &Surface water Breaching %exceeded for controlling discharge of f cfs f No data available a Natural flows ident1fied by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) b For Case EV,the mainstem discharge period of 18000 cfs will not assist passage through PR!!according fo·existing data ( I l I 'l I l I f 41 f 100 f ...··-b 100 f 100 Backwater %exceeded for mainstem discharge of f cfs Ii il Table A21.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 9A for Passage Reach III. Mainstem flow at Gold Creek (cfs) Natural8 12000 9000 8000 i j Groundwater &Surface water Required flow (cfs)3 3 3 3 I Groundwater baseflow (cfs) corresponding to specified mainstem flow 3.7 3.2-2.8 2.0 )Surface water necessary for passage (cfs)0 0 .2 1.0 Amount of ppt needed for basin area of .35 mile 2 (in)0 0 .01 .07 I I %Exceeded based on totalIIdailypptandgroundwater 100 100 32 14 Breaching %exceeded for controlling discharge of f cfs f f f f II Backwater %exceeded for I 1 mainstem discharge of f cfs f f f f Maximum %exceeded 100 100 b 32 14 a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et ale 1984c) u b -For Case EV,the mainstem discharge period of 18000 cfs will not assist passage through PR III according to existing data f No data available Table A22.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 9A for Passage Reach IV. ,I I 1 f No data available a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) b For Case EV,themaillstemdischargep~:r:~c:>dof180g.0.~ff3~~:g~~llot<ll3s:i:l:ltl.al:l!:l<l~e through PR IV according to existing data j I j j .] I ) I ~l I J l I I f 1 1.9 o o 100 f o o 1 100 2.5 f 1 100 o o 2.9 Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 Surface water necessary for passage (cfs)0 %Exceeded based on total daily ppt and groundwater 100 Required flow (cfs)1 . Groundwater baseflow (cfs) corresponding to specified mainstem flow 3.4 Amount of ppt needed for basin area of .35 mile 2 (in)0 Breaching %exceeded for controlling discharge of f cfs f Groundwater &Surface wate~ Backwater %exceeded for mainstem discharge of f cfs f f f f ~~~---Maximum~-%~~exceeded--~-~~---~-~~--~---.~~_100__~_._~~=__~~OO~=~=_~.~==~i:QO~~=~~__.==i(W_...~__._~_.. Table A23.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 9A for Passage Reach V. Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 i I 1\ [J I I II [J Groundwater &Surface water Required flow (cfs)2c 2 2 2 Groundwater baseflow (cfs) corresponding to specified mainstem flow 2.9 2.4 2.0 106 Surface water necessary for passage (ds)0 0 0 .4 Amount of ppt needed for basin area of .21 mile 2 (in)0 0 0 .04 %Exceeded based on total daily ppt and groundwater 100 100 100 20 Breaching %exceeded for controlling discharge of f cfs f f f f Backwater %exceeded for mainstem discharge of f cfs f f f f Maximum %exceeded 100 100 b 100 20 a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et ale 1984c) " 1 b For Case EV,the mainstem discharge period of 18000 cfs will not assist passage __J through PR V according to existing data c Required flow estimated assuming that required flow at upstream PR is sufficient for passage at downstream PR f No data available Table·A24.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 9A for Passage Reach VI. Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) b For Case EV,the mainstem discharge through PR VI according 1:0 exIsting of 18000 cfs will not assist passage ._-__-.•......_--....•..............._......__-__._.__. c Required flow estimated assuming that required flow at upstream PR is sufficient for passage at downstream PR f No data available n Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 Table A25.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 9A for Passage Reach VII. I II n Groundwater &Surface water Required flow (cfs)2 2 2 I] Groundwater baseflow (cfs) corresponding to specified mainstem flow 2.4 1.9 1.5 1.3 [J Surface water necessary for passage (cfs)0 .1 .5 .7 [~J Amount of ppt needed for basin area of .13 mile 2 (in)0 .02 .09 .13 I I II %Exceeded based on total daily ppt and groundwater 100 40 10 7 II Breaching %exceeded for controlling discharge of f cfs f f f f Backwater %exceeded for mainstem discharge of f cfs f I 1 I j Maximum %exceeded 100 f 10 f 7 1 I a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et ale 1984c) b For Case EV,the mainstem discharge period of 18000 cfs will not assist passage through PR VII according to existing data u c Required flow estimated assuming that required flow at upstream PR is sufficient for passage at downstream PR f No data available Table A26.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 9A for Passage Reach VIII. Mainstemflow at Gold Creek (cfs) Naturala 12000 9000 8000 Groundwater &Surface water Requi~ed flow (cfs)2c 2 2 2 Groundwater baseflow (cfs) corresponding to specified mainstem flow 2.3 1.8 1.4 1.2 Surface water necessary for passage (cfs)0 .2 .6 .8 Amount of ppt needed for basin area of .10 mile 2 (in)0 .05 14 .19 %Exceeded based on total <!?:i.1.Y ppj:?!1c1 g'r0undwater 100 31 6 3 Breaching %exceeded for controlling discharge of f cfs f f f f Backwater %exceeded for mainstem discharge of f cfs f f f f .~'-Maximum--%--exceeded '--~----+00~-b ~--6----·-----3·~-----·---3-l~-·-~._--_.__._._---------- a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) b For Case EV,the mainstem discharge period of 18000 cfs will not assist passage through PR VIII according to existing data I .J I I I I I I I c Required flow estimated assuming that required flow at upstream PR is sufficient for passage at 'downstream PR f No data available Table A27.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 9A for Passage Reach IX. Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 II Groundwater &Surface water Required flow (cfs)2 2 2 2 11 I j Groundwater baseflow (cfs) corresponding to specified mainstem flow 2.1 Surface water necessary for passage (cfs)a 1.6 ~4 1.3 .7 1.1 .9 II [ j Amount of ppt needed for basin area of .08 mile 2 (in)a %Exceeded based on total daily ppt and groundwater 100 .12 24 .20 3 .25 2 II Breaching %exceeded for controlling discharge of f cfs f f f f B~ckwater %exceeded for mJinstem discharge of f cfs Maximum %exceeded f 100 f 3 f 2 a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) II b For Case EV,the mainstem discharge period of 18000 cfs will not assist passage through PR IX according to existing data I I f No data available 1 I ,) ] Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 Table A28.Required flow,passage reach flows and percent exceedance of suc~essful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 9A for Passage Reach X. Amount of ppt needed for basin area of .02 mile 2 (in)e e e e a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et ale 1984c) b For Case.EV,the mainstem discharge period of.JSPPO cf,swill no1.:aEls:L~tEa.$$a.ge through PR X according to existing data %Exceeded based on total ~~~il:L~Pl:..cmd~~Eoundwater Breaching %exceeded for controlling discharge of f cfs Backwater %exceeded for mainstem discharge of f cfs --Maximum%--exceeded----- o f f -"-0-- o f f o f f o f. f 1 j I I j ] e Not possible,basin area is insufficient to provide surface runoff f No data available -I n II Table A29.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 11 for Passage Reach I. Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 n n Groundwater &Surface water Required flow (cfs)4 4 4 4 n n Groundwater baseflow (cfs) corresponding to specified mainstem flow 4.0 Surface water necessary for passage (cfs)0 3.6 .4 3.2 .8 3.0 1.0 Amount of ppt needed for basin area of 0 mile 2 (in)e e e e IJ %Exceeded based on total daily ppt and groundwater 70 50 o o II Breaching %exceeded for controlling discharge of 42,000 cfs 1 o o o Backwater %exceeded for mainstem discharge of 16,200 cfs Maximum %exceeded 44 50 o o o o I lJ a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) b For Case EV,the mainstem discharge period of 18000 cfs will assist passage through PR Iby backwater effects u e Not possible,basin area is insufficient to provide surface runoff Table A30.Required flow,passage reach flows and percent exceedanc'eof successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 11 for Passage Reach II. 1 ] I Mainstem flow at Gold Creek (cfs) Natura1a 12000 9000 8000 Groundwater &Surface water Required flow (cfs)4 4 4 4 Groundwater basef10w (cfs) corresponding to specified mainstem flow 3.5 Surface water necessary for passage (cis).5 3.2 .8 2.8 1.2 2.7 1.3 ~l ,.J Amount of ppt needed for basin area of 0 mi1e 2 (in)e %Exceeded based on total daily ppt and groundwater 30 e 18 e o e o 1 1 Breaching %exceeded for controlling discharge,of 42,000 cfs 1 o o o a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et a1.1984c) b For Caf;eEV,the maiIlstem discharge period of 18000 c~fl..'t.'!~J:L..n;ota~s~~t.J~Cl§l~Clge through PR II Backwater %exceeded for mainstem discharge of 33,100 cfs ..Maximum%.exceeded~..._. 2 ...30 o =~~.~8~..o o .0.. j 1 J ,] e Not possible,basin area is insufficient to provide surface runoff Table A31.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 11 for Passage Reach III. Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 Groundwater &Surface water Required flow (cfs)4 4 4 4 IIII II II I j Groundwater baseflow (cfs) corresponding to specified mainstem flow 2.8 Surface water necessary for passage (cfs)1.2 Amount of ppt needed for basin area of 0 mile 2 (in)e %Exceeded based on total daily ppt and groundwater 10 Breaching %exceeded for controlling discharge of 42,000 cfs 1 2.5 1.5 e 5 o 2.2 1.8 e o o 2.1 1.9 e o o Backwater %exceeded for mainstem discharge of 39,600 cfs Maximum %exceeded 1 10 o o o o I j a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) b For Case EV,the mainstem discharge period of 18000 cfs will not assist passage through PR III e Not possible,basin area is insufficient to provide surface runoff Table A32.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 11 for Passage Reach IV. ] j888 Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 Required flow (cfs)8 Groundwater &Surface water Groundwater baseflow (cfs) corresponding to specified mainstem flow 2.6 Surface water necessary for passage (cfs)5.4 2.4 5.6 2.1 5.9 2.0 6.0 ~] 'J Amount of ppt needed for basin area of 0 mile2 (in)e e e e %Exceeded based on total daily ppt and groundwater o o o o Breaching %exceeded for controlling discharge of 42,000 cfs 1 o o o Backwater %exceeded for mainstem discharge of d cfs d d d d o a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) b For Case EV,the mainstem discharge period of 18000 cfs will not assist pass~ge through PR IV d Breaching occUrs prior toblfckwatereffects e Not possible,basin area is insufficient to provide surface runoff Table A33.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 11 for Passage Reach V. Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 I II \ I I Groundwater &Surface water Required flow (cfs)4 4 4 4 I ! Groundwater baseflow (cfs) corresponding to specified mainstem flow 1.7 1.6 1.4 1.4 I I I !Surface water necessary for passage (cfs)2.3 2.4 2.6 2.6 Amount of ppt needed for basin area of 0 mile 2 (in)e e e e %Exceeded based on total daily ppt and groundwater 0 o o o Breaching %exceeded for controlling discharge of 42,000 cfs 1 o o o Backwater %exceeded for mainstem discharge of d cfs Maximum %exceeded d 1 d o d o a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) b For Case EV,the mainstem discharge period of 18000 cfs will not assist passage through PR V d Breaching occurs prior to backwater effects e Not possible,basin area is insufficient to provide surface runoff Table A34.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Upper Side Channel 11 for Passage Reach I. j 1 I j I I -, ] -le 6 5 1 e 6 1 5 6 e 1 5 Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 Amount of ppt needed for basin area of 0 mile 2 (in)e Surface water necessary for passage (cfs)0 Groundwater baseflow (cfs) corresponding to specified mainstem flow 6 Required flow (cfs)6 Groundwater &Surface water %Exceeded based on total daily ppt and groundwater 50 o o o Breaching %exceeded for controlling discharge of 16,000 cfs Backwater %exceeded for mainstem discharge of 12,400 cfs 45 68 o o o o o o j I exceeded 68 o a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) b For Case EV,the mainstem discharge period of 18000 cfs will assist passage through PR I py breaching effects d Breaching occurs prior to backWater effects ] .j j j 1 Table A35.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Upper Side Channel 11 for Passage Reach II. Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 11 Groundwater &Surface water Required flow (cfs)12 12 12 12 I~]Groundwater baseflow (cfs) corresponding to specified mainstem flow 6 5 5 5 Surface water necessary for passage (cfs)6 7 7 7 I j Amount of ppt needed for basin area of 0 mile 2 (in)e e e e II I \I I %Exceeded based on total daily ppt and groundwater 0 o o o II Breaching %exceeded for controlling discharge of 16,000 cfs 45 o o o Backwater %exceeded for mainstem discharge of d cfs Maximum %exceeded d 45 d o d o a Natural flows identified by 5D percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) u b For Case EV,the mainstem discharge period of 18000 cfs will assist passage through PR II by breaching effects d Breaching occurs prior to backwater effects e Not possible;basin area is insufficient to provide surface runoff Table A36.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Upper Side Channel 11 for Passage Reach III. .1 I j j 1MainstemflowatGoldCreek(cfs) Naturala 12000 9000 8000 Groundwater &Surface water Required flow (cfs)12 12 12 Groundwater baseflow (cfs) corresponding to specified mainstem flow 3 Surface water necessary for passage (cfs)9 2 10 2 10 2 10 I I Amount of ppt needed for basin area of 0 mile 2 (in)e e e e -j %Exceeded based on total daily ppt and groundwater o o o o Breaching %exceeded for controlling discharge of 16,000 cfs 45 o o o Backwater %exceeded for mainstem discharge of d cfs d d d d "MaxImum %exceeaed a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) b For CaseEV,the mainstem discharge period of 18000 cfs will assist passage through PR III by breaching effects c Required flOW-estimated assum.ing thatrequired'-'fluwat-downstream-PR"is--- sufficient for passage at upstream PR J d Breaching occurs prior to backwater effects e Not possible;basin area is insufficient to provide surface runoff Table A37.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 21 for Passage Reach I. Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 Groundwater &Surface water Required flow (cfs)5 5 5 5 Groundwater baseflow (cfs) corresponding to specified mainstem flow 10 6.2 2.3 1.1 .Surface water necessary for passage (cfs)0 0 2.7 4.9 II Amount of ppt needed for basin area of .52 mile 2 (in)0 0 .12 .22 %Exceeded based on total daily ppt and groundwater 100 100 6 4 I ; Breaching %exceeded for \ I controlling discharge of 25,000 cfs 10 0 0 0 Backwater %exceeded for mainstem discharge of d cfs d d d d Maximum %exceeded 100 100b 6 4 a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et aL 1984c) iJ b For Case EV,.the mainstem discharge period of 18000 cfs will not assist passage through PR I d Breaching occurs prior to backwater effects . Table A38.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 21 for Passage Reach IlL. ( I I ..l I555 Mainstem flow at Gold Creek (cfs) 5 Naturala 12000 9000 8000 Required flow (cfs). Groundwater &Surface water Groundwater baseflow (cfs) corresponding to specified mainstem flow Surface water necessary for passage (cfs) 2.9 2.1 1.8 3.2 0.7 4.3 0.3 4.7 l I Amount of ppt needed for basin area of 0 mile 2 (in)e e e e %Exceeded based on total daily ppt and groundwater 0 o o o Breaching %exceeded for controlling discharge of 25,000 cfs 10 o o o Backwater %exceeded for mainstem discharge of d cfs d d d d Maximum %exceeded o a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c).1 b For Case EV,the mainstemdischarge period of 18000 cfs will not assist passage through·PR IlL d Breaching occurs p:dor to backwater effects e Not possible;basin area is insufficient to provide surface runoff Table A39.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Slough 21 for Passage Reach IIR. Mainstem flow at Gold Creek (cfs) Naturala 12000 90008000 Groundwater &Surface water Required flow (cfs)5 5 5 5 Groundwater baseflow (cfs) corresponding to specified mainstem flow 3.2 2.0 0.7 0.4 I !Surface water necessary for passage (cfs)1.8 3.0 4.3 4.6 Amount of ppt needed for basin area of .26 mile 2 (in).16 .27 .39 .41 %Exceeded based on total daily ppt and groundwater 4 2 1 1 I ! Breaching %exceeded for controlling discharge of f cfs f f f f Backwater %exceeded for mainstem discharge of f cfs f f f f Maximum %exceeded 4 2b 1 1 a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) b For Case EV,the mainstem discharge period of 18000 cfs will not assist passage through PR IIR f No data available Table A40.Required flow,passage reach flows and percent exceedance of successful· passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Side Channel 21 for Passage Reach I. 1 I 8 oo 8 4.2 2.0 3.8 6.0 .02 .03 .28 24 100 o 100 o 8 11.3 Mainstem flow at Gold Creek (cfs) 71 100 Naturala 12000 90GO 8000 Amount of ppt needed for basin area of 5.03 mile 2 (in)0 Required flow (cfs) Surface water necessary for passage (cfs)0 Groundwater baseflow (cfs) corresponding to specified mainstem flow 18.1 %Exceeded based on total daily ppt and groundwater Breaching %exceeded for controlling discharge of 12,000 cfs Groundwater &Surface water b For Case EV,themainstem discharge period of 18000 cfs will assist passage through PR I by breaching effects a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) [ I [ ! ·1 I 1 o 24 o 28 100 -·b100._-_. 71 ...100 _ Backwater %exceeded for mainstem discharge of 12,000 cfs c Required flow estimated assuming that required sufficient for passage at downstream PR Maximum __%.....exc.eeded__.__.._ Table A41.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Side Channel 21 for Passage Reach II. Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 80001 I i I I I' i I II Groundwater &Surface water Required flow (cfs)8 8 8 8 Groundwater baseflow (cfs) corresponding to specified mainstem flow 18.0 11.2 4.2 2.0 I !Surface water necessary for passage (cfs)0 o 3.8 6.0 II Amount of ppt needed for basin area of 5.03 mile 2 (in)0 o .02 .03 %Exceeded based on total daily ppt and groundwater 100 100 28 24 II Breaching %exceeded for controlling discharge of 12,000 cfs 71 100 o o I.I I I Backwater %exceeded for mainstem discharge of d cfs Maximum %exceeded d 100 d 28 d 24 a Natural flows identified by 50 percent exceedance mainstem discharge of 15,.000 cfs (Sautner et al.1984c) b For Case EV,the mainstem discharge period of 18000 cfs will assist passage through PR II by breaching effects I~I d Breaching occurs prior to backwater effects Table A42.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Side Channel 21 for Passage Reach III. j Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 Groundwater &Surface water Required flow (cfs)7 7 7 Groundwater baseflow (cfs) corresponding to specified mainstem flow 17.5 Surface water necessary for passage (cfs)0 10.9 o 4.1 2.9 1.9 5.1 J 1 Amount of ppt needed for basin area of 5.03 mile2 (in)0 %Exceeded based on total daily ppt and groundwater 100 Breaching %exceeded for controlling discharge of 12,000 cfs 71 o 100 100 .01 31 o .02 26 o I ] I Backwater %exceeded for mainstem discharge of d cfs -~~..-._-_._.,._....,.._,,_...__.._-.- Maximum %exceeded d 100- d ---TaO b d 31 d a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et aL 1984c) b For Case EV,the mainstem discharge period of 18000 cfs will assist passage through PR III by breaching effects c Requi.red flow estimated assuming that required fl6wat lipl:ftream PR sufficient for passage at downstream PR is d Breaching occurs prior to backwater effects Table A43.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Side Channel 21 for Passage Reach IV. Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 Groundwater &Surface water Required flow (cfs)7 7 7 7 !j ! Groundwater baseflow (cfs) corresponding to specified mainstem flow 17.5 Surface water necessary for passage (cfs)0 10.9 o 4.1 2.9 1.9 5.1 II Amount of ppt needed for basin area of 5.03 mile 2 (in)0 o .01 .02 %Exceeded based on total daily ppt an~groundwater 100 100 31 26 II\ ! Breaching %exceeded for controlling discharge of 12,000 cfs 71 100 o o Backwater %exceeded for mainstem discharge of d cfs Maximum %exceeded d 100 d 31 d 26 a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et ale 1984c) b For Case EV,the mainstem discharge period of 18000 cfs will assist passage through PR IV by breaching effects d Breaching occurs prior to backwater effects J I I ! 1 I I I 1 I j ! J ! I l ,J r 1 Mainstemflow at Gold Creek (cfs) Naturala 12000 9000 8000 a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) d Breaching occurs prior to backwater effects b For Case EV,the mainstem discharge period o:i:J8QQQ ~:l:f3w:i,:Ll a13l:l±st Pi:l.Sl:lC3.gl; through PR V by breaching effects Table A44.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Side Channel 21 for Passage Reach V. Groundwater &Surface water Required flow (cfs)18 18 18 18 Groundwater baseflow (cfs) corresponding to specified mainstem flow 17.4 10.8 4.0 1.9 Surface water necessary for passage (cfs)0.6 7.2 14.0 16.1 Amount of ppt needed for basin area of .52 mile 2 (in).03 .32 .63 .73 %Exceeded based on total .'!~~!YPP!_.<3.!l~f?;l:"0undwa ter 24 2 1 .5 Breaching %exceeded for controlling discharge of 12,000 cfs 71 100 0 0 Backwater %exceeded for mainstem discharge of d cfs d d d d -----·Max-imum·%exceeded·-·······-7·1·····b ·--1---.5--··100- Table A45.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Side Channel 21 for Passage Reach VI. Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 .I Groundwater &Surface water Required flow (cfs)20 20 20 Groundwater baseflow (cfs) corresponding to specified mainstem flow 17.2 10.7 4.0 1.9 Surface water necessary for passage (cfs)2.8 9.3 16.0 18.1 'I j Amount of ppt needed for basin area of .52 mile 2 (in).13 .42 .72 ~81 %Exceeded based on total daily ppt and groundwater 7 1 .5 o I J Breaching %exceeded for controlling discharge of 12,000 cfs 71 100 o o I .! Backwater %exceeded for mainstem discharge of d cfs Maximum %exceeded d 71 d .5 d o a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) (\ b For Case EV,the mainstem discharge period of 18000 cfs will assist passage through PR VI by breaching effects c Required flow estimated assuming that required flow at upstream PR is sufficient for passage at downstream PR d Breaching occurs prior to backwater effects I Table A46.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Side Channel 21 for Pas~age Reach VII. l I,202020 Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 Required flow (cfs) Groundwater &Surface water 'j 10.4 3.9 1.8 9.6 16.1 Ja.z . .43 .73 .82 1 .5 0 %Exceeded based on total daily ppt and groundwater 6 Amount of ppt needed for basin area of .52 mile 2 (in).14 Groundwater baseflow (cfs) corresponding to specified mainstem flow 16.8 Surface water necessary for passage (cfs)3.2 Breaching %exceeded for controlling discharge of 12,000 cfs 71 100 o o b For Case EV,the mainstem discharge period of 18000 cfs will assist passage through PR VII by breaching effects a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) Backwater %exceeded for mainstem discharge of d cfs MaxImum %exceeded d d d d c Required fl(j~restifi1ated assuming that required flowat~upstreamPR ~is . sufficient for passage at downstream PR d Breaching occurs prior to backwater effects ..1 I I Table A47.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Side Channel 21 for Passage Reach VIII. Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 Groundwater &Surface water Required.flow (cfs)ZOc 20 20 20 Groundwater baseflow (cfs) corresponding to specified mainstem flow 16.5 10.2 3.8 1.8 Surface water necessary for passage (ds)3.5 9.8 16.2 18.2 Amount of ppt needed for basin area of .52 mile 2 (in).16 .44 .73 .82 %Exceeded based on total daily ppt and groundwater 4 1 .5 0 Breaching %exceeded for IJ controlling discharge of 16,000 cfs 71 100 0 0 Backwater %exceeded for mainstem discharge of d cfs d d d d Maximum %exceeded 71 100b .5 0 a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et ale 1984c) ) b For Case EV,the mainstem discharge period of 18000 cfs will assist passage through PR VIII by breaching effects c Required flow estimated assuming that required flow at upstream PR is sufficient for passage at downstream PR d Breaching occurs prior to backwater effects Table A48.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 September at Side Channel 21 for Passage Reach IX. Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 d Breaching'occurs prior tobackwatereIIects b For Case EV,the mainstem discharge period of 18000 cfs will assist passage through PRIX by breaching effects a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) '\ '/';1 I ,,I, J J ,'I I J \ ,1 J "'::!t~ d 1.8 a a 18.2 a 20 .82 d 16.2 20 a 3.8 .5 .5 .73 1 100 10.2 d "~'b100 20 .44 9.8 d 71 %Exceeded based on total daily ppt and groundwater 4 Amount of ppt needed for basin area of .52 mile 2 (in).16 Surface water necess~ry for passage (cfs)3.6 Required flow (cfs)20 Groundwater baseflow (cfs) corresponding to specified mainstem flow 16.4 Breaching %exceeded for controlling discharge of 12,000 cfs 71 Backwater %exceeded for mainstem discharge of d cfs Maximum %exceeded .~_.,._-----_.._._..-_._...._----_.~-_.__.-..--_.~------_..-_.--_._._~._---- Groundwater &Surface water I,::/ 'j ], Table A49.Required flow,passage reach flows and percent exceedance of successful passage due to groundwater and surface water discharges,breaching flows and backwater effects for the period of 20 August to 20 SeptemberI]at Side Channel 21 for Passage Reach X. I j Mainstem flow at Gold Creek (cfs) Naturala 12000 9000 8000 Groundwater &Surface water Required flow (cfs)5 c 5 5 5 Groundwater baseflow (cfs) corresponding to specified mainstem flow 12.5 7.8 2.9 1.4 Surface water necessary for passage (cfs)0 o 2.1 3.6 Amount of ppt needed for basin area of .52 mile 2 (in)0 o .09 .16 %Exceeded based on total daily ppt and groundwater 100 100 9 5 Breaching %exceeded for controlling discharge of 24,000 cfs 12 o o o Backwater %exceeded for mainstem discharge of d cfs d Maximum %exceeded 100 d 9 d 5 a Natural flows identified by 50 percent exceedance mainstem discharge of 15,000 cfs (Sautner et al.1984c) b For Case EV,the mainstem discharge period of 18000 cfs will not assist passage through PR X [IJ!c Required flow estimated assuming that required flow at upstream PR is sufficient for passage at downstream PR LJ d Breaching occurs prior to backwater effects ,J 1 J , 1 _1 .I ~I 1 ] ..1 1 ..1 .1 J j .J I \ J --- ILOUGH. NOTE:S=SLOUGH DISCHARGE G=-MAINSTEM DISCHARGE AT GOLD CREEK 10- oIf:.0 EJ:)0 o .. 11::.11::..£\. •a a 2:\·•a ·.•·~11::.11::.•..•.& 11::.11::. 11::. 00 11::.'1 0 G.AI 0 0 o 11::.,~Q 000l!l 0@ 0 c§>~00~<ix:>0 ~0\A 8=0.11+.000130 •BS.11::. 8- m... 2 w 0 8-a::c:z:u III Q :I:0::l 0 4--I II) I o I I I J I 1 I I I I I I:I 4 II 8 S 10 11 12 13 n 15 MAlN8TEM DISCHARGE AT GOLD CREEK (1l1.000 CFS) Ii:!.DATA FOR 11182 •DATA FOR 1883oDATAFOR1884 ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECTFIGUREA1.IDENTIFICATIOINI OF RELATIONSHIP BETWEEN SLOUGH DISCHARGE AND MAINSTEM DISCHARGE FOR SLOUGH 9.Woodward-Clyde Consultants " Ci1&rrJtl&I::{~[ID&~ IUIITH4 JOINT YENTUJIIIE SOURCE RaM CONSULTANTS,1982,1983,1984 'J j I I I I rl 1 .J 1 l ,I I 1. .J .) ) I .1 I I I I I I I I I I I I I I I I I I I FIGURE A2.PERCENT GROUNDWATER FLOW RELATIVE TO GAGE FLOW FOR SLOUGH SA SLOUGH 8A o 250 500.,I..L.'......1 FEET PR III ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT Woocfward.ctvde Conauitanta 6 HARZA-EBASCO '.$USITNA JOINT VENTURE ---------MAINSTEM 1&82) STAGE RECORDER (RaM GAGE) UPWELLING SITE (AERIAL PHOTOGRAPHS) SHRUBS GRAVEL CHANNEL OUTLINE OUTLINE OF WETTED SURFACE AREA AT MAINSTEM DISCHARGE OF 12,5DO CFS AT GOLD CREEK RAILROAD o 6 PR VII I I SEEPAGE METER U TRIBUTARY INFLOW -[:::::::>UPWELLING OBSERVATION SITE (RaM c) II FOREST D··' ....-.6 it! •I (I ...~•...".:; -.--_._-'------ LEGEND PR VI I I I I I I I FIGURE A3.PERCENT GROUNDWATER FLOW RELATIVE SLOUGH 9 I I I I I I I I I I I PR I o 250 I FEET 500 100% HARZA-EBASCO SUSITNA JOINT VENTURE MAINSTEM ""'-,"--'--------.;,........... ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT CHANNEL OUTLINE OUTLINE OF WETTED SURFACE AREA AT MAIN STEW DISCHARGE OF 1 ~.500 CFS AT GOLD CREEK I I I RAILROAD SHRUBS [~)·<d GRAVEL LEGENDo STAGE RECORDER (RaU GAGE) 6 SEEPAGE METER U TRIBUTARY INFLOW -{:>UPWELLING OBSERVATION SITE (RaW 1982) c)UPWELLING SITE (AERIAL PHOTOGRAPHS) III FOREST PR III TO GAGE FLOW FOR SLOUGH 9 / /' I I I FIGURE A4.PERCENT GROUNDWATER FLOW REL 2 FE SLOU o I GRAVEL SHRUI!IS CHANNEL OUTLINE OUTLINE OF WETTED SURFACE"AR~A AT MAINSTEM DISCHARGE OF 12,800 CFS AT GOLD CREEK RAILROADI I LEGENDo STAGE RECORDER (RU'GAGE) 6.SEEPAGE METER U TRIBUTARY INFLOW -[:::::::>UPWELLING OBSERVATION SIT!(RaM 1882)c>UPWELLING SITE (AERIAL PHOTOGRAPHS) II FOR~ST MAINSTEM I I I I I I I I I I I I I I I I )UGH 11 ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT ~~6 HARZA-EBASCO I SUSITNAJOINT ••.VENTURE ... 1 1H I ~J_iiiiiiiii)-z :r I 500 I TO GAGE FLOW FOR SL 250 I FEET ELATIVE ~ C? It) ~ ~oo N ~ ~ 0 N ~~.',\,....l 1'_ I ", \ \,~\It)-I 0->I N a:"0.... ",,, \ \, I ~, 0,,~ N,,,'~f:b :\t~f.'r,-'..' •I~'I'·IE';, :(Jf.~,I •(rf I , '~~!r I , t c~:,\ ,."(I I I~II.', t;1 \1\, H~\Ii,.(l" ,f..<\Jif,',e ...~•r I>~'~I ,~ I Na:(,:l.~I ~ 0./,:':1 ,,N'trt~J,, J, / I \ J \ J I, \ tuwu.. o It) N o ,.. C'I ..J UJ ,... Z C\Jz«-IJ:W0ZUJ C Z-«en c :r: z () « ,..W C'I 0-J:en ~~a: C)-~-0. :J 0 ..Jen 0:: 0 LL ==0 ..J LL W C)« C) 0 I- W 0 0 It) It)« w 0:: :J C)-LL ==o ..J LL 0:: UJ I-« ==cz ;:) o 0:: C) I- Z UJo 0:: UJ D. --------_..--------------------------------------------~-----_._----_._----------------- - --- - -- ---- SITE (Rail 18S2) (AERIAL PHOTOGRAPHS) HARZA-EBASCO SUSITNA JOINT VENTURE SHRUSS qRAYEL ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT c) •FOREST lliJ···.··f~~·~"·/ ••'',.....oJ. CHANNEL OUTLINE - - - -OUTLINE OF WETTED SURFACE AREA AT MAIN ITEM DISCHARGE OF 12,500 CFS AT GOLD CREEK -+--+-+1-+1 RAILROAD SLOUGH 21 MAINSTEM ,"""----------- 153% Ir-- Federal Register /Vol.44.No:242 /Friday,December 14.1979 /Rules and Regulations==•'f":"'·.fwtf:::tCWt i r~R 110~·-1-40 E.J:'a n J 82 ....i2SSG .~~~~~~~~~~~~~~~~~ 1",1·,·," 1 ,01"...1'.•~t.1 (I.'11 benefit from energy produced by hydroelectric powerplants will be measured instead by the resource cost of the most likely alternative to be implemented kJ the absence of the hydroelectric powerplant. (b)The benefits from nonstructural measures are also computed using the cost of the most likely alternative. However.the net benefits of certain nonstructural measures that alter the electric power load cannot be measure.d effectively by the alternative cost procedures for the following reasons:(lJ Structural measures and many nonstructural measures (except those that alter the load) result in similar plan outputs,whereas load-altering measures (e.g.,revised rate structures)may change levels of output;and (2)load-altering measures rI1ay hllw~feW'efdirect resource costs than measures based on higher levels of output.Recognizing this lack of comparability.the benefits from such load-altering non structural measures shall not be based on the cost of the most likely alternative.Attempts to measure the benefits of load-altering nonstructural measures on the basis of direct willingness to pay are encouraged. although the display of such benefits is not required. §713.605 Planning HttIng. (a)Without-project condition.The without-project condition is the most likely condition expected to exist in the future in the absence of a project.including any known changes in law or public policy.The following specific assumptions shall be included: (1)Existing resources.Existing generating resources are part of the without-project condition.Adjustments shall b-e made to account for anticipated plant retirements and changes in plant output due to age or environmental restrictions assoCiated with existing policy and regulations. (2)Existing institutional arrangements.Existing and reasonably expected future power system and water management contracts.treaties.and non power river operating criteria are part of the without-project condition unless revision of these arrangements is one of the alternative plans being studied.In that case,the new arrangement (revised contract.criteria.etc.)would be one of the alternatives considered in the with-project condition. (3)Alternative actions anticipated or underway.The without-project condition includes those generating resources that can reasonably be expected to be available in the forecast period. (4)Nonstructural measures and conservation.The without-project condition shall include the effects of implementing all reasonably expected nonstructural and conservation measures.including those required or encouraged by Federal.State.and local policies. (b)With-project condition.(1)The with-project condition is the most likely condition expected .to exist in the future with the plan under consideration.Examples of alternative plans include:Alternative combinations of projects in a basin study;alternative sites in a reach study;alternative plant sizes at a specific site;alternative reservoir sizes at a reservoir site;use of reregulation and/or pumpback to increase firm capacity;and reallocation of storage to increase firm energy output. PU "III P:O pJU P4U _su P1'1l)·. ~""'Illhl • I It :"0 '.~'J-l"--'."'!~i.l'"If \•.;;l"~II}ft /,.":C1·11"I .....' 1-:,t,i ."':"'1"~.,••,~r J :"L t :! !:.!~oa?:"Jb{.totbt ••.Ih.al t b1 ~.for'All ..lcGrtUl.cLves,1f pert1n.nt. !.l ro··dllstJf\Alton.,to ":'1~"20 :~..nt1!y th.e 10th ..nd ~Oth ye&r., fur-rc:t(v.ly.at fJroJ ..ct lUot... •_:'J~h::..\';.t~I.>1tL'" ..' r :'t""..~",nt 1 ... ",:",t,., Subp,;:rt H-NED Benefit Evaluation Procedure.:Power (Hyc'ropowsr) v;13~1 Introduction. (e)T nis chapter descrihes procedures for the evaluation of n!l~iC'nal economic development (NED)benefits of l-.ydr rower features of water resources projects and plans. Thes~featureB ;"c1ude single-purpose hydropower.the :'lc!u ..i"n of hyc.i "power as a function in new multipurpose p:-c:'~'.s.addition of power-generating facilities to existing water rerlOurce projects.end expansion of existing hydr'~power plants. (b I ror th e purpose of ensuring efficiency in the use of plenning resourC(,8.simplifications of the procedures set :0r')',n ~his subpart are permitted in the cases of single purpose small lIca i e hydropower projects (25 MW or less) propo~cd at existing dams and other facilities (e.g.•irrigation \oil n El ':or a1 undeveloped sites.if no significant adverse ':11VIT,,':1;:nenta!:mpacts would result from the installation and operation of power ge~erating facilities.if these 9jmp;:~lcatjons lead to ad'!quate approximations of NED benefits and costs.For example.an analysis of marketability me?h,;substituted for determination of need for future genera'lOn.In addition.an alternative that is primarily nonst!1Jctural is not required for the small scale hydropower proje-::ls described above. §713.603 CO~(,'·;::.lJell bmelll. (lI)';'!IC conceptual baBis for evaluating the benefit from e~~~gy produced by hydroelectric powerplants is soclety's wl,lI:igness to pay for these outputs.Where energy from electr.~()werplants is priced at its marginal cost.this price shal!he used to calculate willingness to pay.In the absence of such direct measures of marginal willingness to pay.the ,.' 8 Jan 82 Federal Register /Vol.44,No.242 /Friday,December 14,1979 /Rules and Regulations 72939 {J.o o (2)Nonstructural alternatives to hydropower may be used alone or in combination with structural measures.If the proposed nonstructural measures are already in the process of implementation,they shall be considered part of the without-project condition.Nonstructural measures to be considered include but are not limited to reducing the level and/or time pattern of demand by time-of-day pricing; utility-sponsored loans for insula tion;appliance efficiency standards;education programs;inter-regional power transfers;and increased transmission efficiency. §713.607 Evalulltlon procedure:General. Given one or more alternative plans for hydropower projects,the following steps are necessary to estimate NED bertefits that would accrue to these projects.(See Figure 713.607-1.)The level of effort expended on each step . depends upon the nature of the proposed development,the state of the art for accurately refining the estimate,and the likely effect of further refinement on project formulation and justification. §713.609.Evaluation procedure:Identify system for analysIs. Because of the trend toward interconnection and coordination among utilities and power systems,it is most appropriate to evaluate NED benefits for hydropower on a system basis,rather than on the needs of an individual utility or local area.The size of the system would depend on the situation but could consist of a power pool,a National Electric Reliability Council (NERC)regional area,the marketing area of a Federal power marketing administration, or other geographic region. I ItJrnt Hy lllyscem for dnalysis I I I I I I Determine net:d f",r I future g~ndrat Lon I Detenuint!most 1 ik~Lv I non-Ft:deral ..Ilt~rnat 1Vt! I I;omputt!b~n4!:i it~I In some cases,physical or institutional constraints may Ii'mi the analysis to a smaller area,but care must he taken to ensure that benefits are not misstated hy sllch anulysis. §713.611 Evaluation procedure:Determine need for future generation. (a)Estimate future demand for dectric;!}(JWI.'I'.Forecasts of fdectric:power loads shull he made in t~!rmll uf annual Hnc monthly energy (including peak)demands.Weekly load shapes shall also be forecast to represent a minimum of three periods in the year (e.g.~typical summer,winter,und spring/fall days)to assist in determining the type of loud that a hydropower project could carry.Load forecasts shoul. reflect the effects of all load management and conserva tion measures that,on the basis of present and future public and private programs.can reasonably be expected to be implemented during the forecast period.Load forecasts should be made and analyzed by sectoral use (residential, industrial.governmental,institutional,etc.)if an adequate forecasting model exists and is in use in the potential projec· market area.Load estimates shall be made.at increments of no more than 10 years.from the present to a lime when the proposed plant will·be operating in a state representative of the majority of its project life.In the case of staged hydropower development,or where generation system resource mixes may change markedly.load forecasts may b. required for 20 years or more beyond the initial operation date.Estimates shall account for system exports and reserVI requirements. lb}Define base system generating resources.Project futur generating resources and imports at various points in time without the proposed plan or any alternative plan.Resource estimates shall be made for the time periods stated in §713.611(a).Information shall be provided both on the average annual energy production and on peaking capabilit: Data are readily available on projected system resources fOi about 10 years.Projected resource additions beyond that time shall be based on system studies.Retirement of older plants shall be accounted for.as well as the reduction of output of some plants due to age or environmental constraints.. (c)Evaluate need for additional generation.Compare the loads identified under §713.611(a}with the resources identified under §713.611(h}to determine:(l)When . generating resource deficits will occur,(2)the magnitude of these deficits,and (3)what portion of these deficits could b( met by the hydropower project.If nonstructural·measures are components of an alternative plan and these measures reduce system loads,the amount of such reduction shall be considered to contribute to meeting system deficits.Some hydropower siles can be developed to provide either a base load,mid-range.or peaking service.The system demand for each class of hydropower generation shall be evaluated. Simple tabulation of annual peak and energy loads and resources is generally adequate for preliminary st4dies.but A-47 \. e Jan 82 . .Foooral Register f Vol.«,No.242 I Friday.De~ember 14.1979 I Rules and Regulations • lIyalem load-resource models that account for load charllcteristics and generating planl operating capabilities IIhall be uaed.if available,to evaluate accurately the 4.l8ability of specific projects. §713.813 EvaluaUon procedure:Determine the most IIkGlfy non- Fod<mlIllttornatlve.. .(a)General.The one allernative most likely to be implemented in the absence of the proposed Federal project shall be selected.Consideration of the likely alternatives shall begin with the least costly.If an alternative with a lesser cost is passed over for a more expensive one, justification for nol selecting the lower cost plan shall be presented. (b)&reen alternatives.The alternatives 10 a specific hydropower project must be viable in terms of engineering. environmental quality,and other national policy considerations.Engineering viability limits thermal alternatives 10 commercially available electric powerplants. Environmental viability implies that plant costs include all equipment required to m£;et environmental quality criteria. National policy considerations include factors such as legal limitations on the use of oil.'natural gas.and.other "scarce" fuels for electric power generation.Each alternative need not in itself deliver service similar in kind to the hydropower project,but the tolal power system with Ihe alternative must deliver service similar in kind to the system with the hydropower project.If nonstructural measures or conservation are components of an alternative plan and' these measures reduce the need for additional capacity or for additional power,the amount of such reduction shall be considered provision of service similar in kind;this is done so that evaluation procedures will not be biased against the selection of an alternative that utilizes nonstructural measures. (c)Identify the most likely alternative.(1)The system with hydropower must be compared with other alternatives capable of meeting system loads within established criteria of system reliability.The comparison shall be made on the basis of cost and other factors to determine the most likely alternative.i.e ..the structural or nonstructural alterna'live that will be implemented if the project under consideration is not implemented. .(2)If political or institutional obstacles to implementation are noted,an alternative plan may still be considered the mosl likely if the barriers are substantially within the power of the affected users to correct.If an alternative is eliminated because of inslitutional or political obstacles,a sensitivity analysis shall be performed to determine whether the Federal projecl is economically justified when the rejected alternative is used as the basis 'of the benefit calculation.If this analysis indicates that the project would not remain justified.an explanation sh811 be given for recommending a Federal project over the more economical rejected alternative.A detailed description of the political or institutional obstacles shall be included.with a discussion of the basis for the conclusion that the obstacles cannot be overcome. (3)If the most likely alternative is a thermal plant,that planl's capacity costs (including amortized investment costs. transmission costs,Interim replacement costs,and fixed operating and maintenance (8&M)costs)shall be used as tlle measure of the value of the hydropower project's generating capacity,and the thermal plant's energy costs (primarily variable OerM costs and fuel costs)shall be used as the measure of the value of the hydropower project's energy production. A-48 §713.815 Evaluation proceduro:Compute b4moftta.. .{a)Compute hydropower plant annual benefits. Annualized benefits based on the costs of the most likely alternative shall be computed for each hy<Iropower development and installation component.. (I)Alternative costs.(i)The calculation of alternative costs to be used as a measure of NED benefits shall be on the following basis:(A)AIl interest and amortization costs charged 10 the alternative shall be calculated on the basis of the Federal discount rate;(B)no costs for taxes or Insurance shall be charged to the alternative:and (e)all other assumptions and procedures used in calculaling the cosl.B of the alternatives,including external diseconomies,shall parallel those used in calculating the costs of the proposed project... .(ii)In many cases,benefits may vary over the life of a project.This may be due to such factors as staged development of the hydropower project,changes In operation of the hydropower project resultiilg from changes in the resource mix in the total generating system.and real escalation in fuel costs (if the most likely alternative I.a thermal plant).Project benefits shall be computed by time intervals and discounted to derive annualized power benefits.. (iii)When applicable,the evaluation shall reflect differences in the cost of transmission,distrlbution,and other facilities compared to the most likely alternative. (iv)Occasionally,the initial output of a hydropower project is large compared to annual growth In system load. and two or more years may be required'to fully absorb its output into the load.In these cases credit (benefitJ shall be adjusted to reflect the generating capacity and energy actually uned in the load in the early years Qf project life. (2)Energy value adjustment.The effect on system production expenses shall be taken into account when computing the value of hydroelectric power.Adding the structural or nonstructural plan to a system instead of adding an alternative power source may result in greater or lesser system production expenses than If a particular thermal capacity were added;the effect on production expenses can be determined by performing a system analysis.If there Is a difference in system production expenses.an adjustment to the energy value shall be made in the economic analysis of the plan.If the alternative plan would lower,system production costs,the adjustment would be negalive.If the .alternative plan would increase system production expenses, the adjustment would be positive.System production expenses shall be considered In determining the most likely alternative. (3J Capacity value adjustment.The physical operating . characteristics of hydropower projects differ significantly from alternative thermal plants.Appropriate credit may be given to hydropower projects to reflect their greater reliability and operating flexibility.When the value of these characteristics cannot otherwise be quantified,an adjustment can be made to the alternative plant capacity costs.Typically,the adjustment per kilowatt of capacity ranges from 5 to 10 percent of the cost per kilowatt of . thermal capacity,depending on the operating characteristics of the hydropower project and alternatives that include thermal capacity.The adjustment may be applied by increasing the capacity cost of the most likely alternative by the appropriate percentage determined by the Federal Energy Regulatory Commission (PERC). (4)Intermittent capacity adjustment.The dependable capacity of a hydropower project is based on the lo.ad- carrying capability of the project under the most adverse combination of system loads,hydrologic conditions,and plant capabilities.This very conservative approach is .....-'"~':_";' •,~·l.·':..,., '.... • ER 1105-2-40 8 J~ti'82 .Fodmd ~I Vol.44,No,242 I Friday,December 14,197"I RuJ~s and Reg1WmOIUl 4Q er ,q.FI1"'''.'*r.q 'fa=; r. ..'..\. h.....'..v."Su","J,·d. 1:.It1~"rvl:.f.Uhl "~,t ,'" ......af rl~t"r rl''':''Titl ..·~t:'r ttl,1 - ~l An~u ..ll~r C"et - ($10011) ~.....r,It/"""..1 PrJ.m.arU)'blonllcructur.l1 (:is)rlda :~-It''~(l,td .'1 Anill ....i ....I'rt ..·,·1..-,,,·1.UI ...·...W(M.I'··' by pealdng capacity and system load factor.and presenta the CO.llts of each alternative plan.Tablea 713.61&-,2 and :I summarb:.es ilie output of the stroctural component of each alternative,the benefits of the structural components,and the resource coats of all structural and nonstructural . .~mponents of each alternative plan.The number of benefit categories included will vary from project to project.Not all projects will bave intermittent capacity.for example.and in some casas it will be appropriate to account separately for firm and secondary energy,System energy Ct!st impacts are sometimes included in the unit energy values and In those cases would not have to be accounted for separately. (b)Table 713.619-3 Is suggested if the nature or magnitude of hY9ropower benefits changes substantially over time. Examples are:staged construction of the hydropower .project:change in the role of hydropower in the system over time;and situations in which several years are required 10 absorb a large project into the aystem. f 713.619 Report lind ~~ (a)Tables 713.619-1 through 713.619-3 are suggested for presentation for all reports that include hydropower meallUrea.Table 713.619-1 summarizes the output of all plans unrellllted to the dependable capacity of a bydroPower project's alternative if thermal capacity is included.and given no credit (or the lI'alue of capacity that i.availabJe a aubatantial amount or the time.When power system operation studies show that there is an tntennJttent capacity value to the system.a capaclty adjustment shall be made. (5)Price relationships.Relative price relationships and the general level of prices prevailing during the planning study will be assumed 10 hold generally for the future.unless "pecified studies and considerations indicate otherwise. Examples of the latter include escalation of relative fuel cost (e.g.•due 10 increasing scarcity).or increased capital costs expected to result from changed environmental or safety criteria.Fuel costs used in the analysis Bbould reflect economic prices (ma:lmt clearing)rather than regulated prices., (b)Compute benefits ofnonstructural measures.The average annual benefits of nonstructural alternatives shall be computed uain.B the cost of the most likely alternative t.dentlfied above.except as specified in §nS.OO3(b). ,i 713,617 Evdua.Uon ~0tib1 flOUr'COa. nata on exillting and planned resources,loads. marketability criteria.nnd e1ternative costs are available £rom various agencies and groups.including the Department of Energy,NERC regional councils,FERC regional offices. Federal power marketing administrations.State energy agencies,utility companies,and regional planning groups.If specific operating characteristics of individual plants are not available.generalized data can be obtained from other mources.including the Electric Power Research Institute. Load-resources models based on simulated system operation may be used if available,Some of these models are available from various sources,including PERc,Federal power marketing administrations.and a number of consulting services. ~,... ..:;. '" .-u I (Xl r, 't... tj ill . ;.J .,. ! .c (Xl L t<1'\I t I J ( ::'Q. CD.. !!. i lIlI ~..-<: ~ ~ Z ~ ~ ~-~ 0: II) ~ 0 CDn CD 3r:r CD..,.... !""....ce~-~ I:;- lID II)::s Q. ~ CD OQ I:;-... 0-::slID PN ---) '---) ,-_-----:) '---) P3P2 Alternative PI Installed capacity,MW Dependable capacity,MW Intermittent capacity,~v Average'annual energy,gWh Average annual capacity factor (percent) TABLE 713.619-2 --SUMMARY OF ANNUALIZED NED BENEFITS FOR STRUCIURAL MEASURES AND NED COSTS FOR STRUCTURAL AND NON STRUCTURAL MEASURES~/ (Thousands of ~onth,year dollars) Applicable Discount Rate:_ Unit capacity value ($/kW-yr)()()()( Dependable capacity benefits Intermittent capacity benefits Unit energy value (mills/kWh)(---)()() Energy benefits Unit system energy cost adjustment (mills/kWh)()()()( System energy cost adjustment Real fuel cost escalation rate (percent)() ( ) ()( Period of real fuel cost adjustment (years)()()()( Real fuel cost adjustment TOTAL HYDRO BENEFITS Other purpose benefits (list) Annualized Cost Structural Measures Nonstructural Measures Net Annual Benefits Plant Data Benefits :J> I V1o ~/Note that benefits from load-altering nonstructural measures are excluded. This table may be used for displaying the benefits of nonstructural measures that do not alter the load (See Section 7l3.603(b». C>"..•..>.J..;::?)CE)"'f"'"~...;:;~.t."_~J '''v. @);.~!\.~":··.j.(~-.!~l :..-~ G·····':,'\.'c::.J ....----,---.(·..·T ..· " ~f~:~I ." TABLE 713.619-3 --TIME DISTRIBUTION OF NED ELECTRIC POWER BENEFITS FOR STRUCTURAL MEASURES OF ALTERNATIVE a/ Applicable Discount Rate: a/Note that benefits from load altering nonstructural measures are excluded. -This 'tab,le may be used for displaying the benefits of nonstructural measures that do not alter the load (See Section 713.603(b». bl Time periods selected depend on nature of project and power sysceQ.EJ Ave~age annual equivalent~ Unit capacity value ($/kW-yr)()()()( Dependable capacity benefits Intermittent capacity benefits Unit energy value,(mills/kWh)(--~_~)(-_.._-_._---)() Energy benefit Unit system energy cost adjustment (mills/kWh)()()() System energy cost adjustment Real fuel cost escalation rate (percent)()c.)() ·Period of real fuel cost adjustment (years)...-.() ( Real fuel cost adjustment ~~UALIZED BENEFITS .:> . I U1 PI Plant Data Installed capacity,MY Dependable capacity,HW Intermittent capacity,HW Average annual energy,gWh Average annual capacity factor (percent) Benefits Time Period 'E..! Pi P3 "!1tll C. tll...III PN ME c/Iii lit ED...-<~ ~ z ~ N0&:- N-"%j )II S: III ~ 0 )II ~ CD 3 C'" )II ~.... '!>'.... )II ~-)II :::a=.. CD CD III ::l 0- :::a CD OQ=.. III oc-o'c-::l OJCD:::l ce "-', t:j f to) ',' DEPART~t:~T OF FISH :\NO Gr\:tIt: OFRCE OF THE COMMISSIONER JA Y S.HAMMOND.GOVERNOR P.O.BOX 3-2000 JUNEAU.ALASKA 99802 PHONE:465-4100 RECEIVED AUG 91982 ALASKA POWER AUTHORITY •':••'"''t"..··~f .FilED August 6,1982 Alaska Power Author ty 334 W.5th Avenue '-_----------w Anchorage,Alaska 99501 Attention:Mr.Eric P.Yould,Executive Director Gentlemen: Re:Grant Lake Hydroproject Letter of July 14,1982 and Instream Flow Evaluation Letter Report. Thank you for your recent letter and the opportunity to comment.We understand,on the basis of the information you have provided us,that there is no practicable means of maintaining a fishery in Grant Creek if the proposed hydropower project is constructed. As you may already know,the Oepartment1s policy regarding mitigation of project impacts embodies a hierarchic approach and is described as follows in order of implementation:. 1.Avoiding the impact altogether by not taking a certain action or parts of an action. 2.Minimize impacts by limiting the degree or magnitude of the action or its implementation. 3.Rectify the impact by repairing,rehabilitating"or restoring the affected environment. 4.Reduce or eliminate the impact over time by preservation and maintenance operations during the life of the action. 5.Compensate for the impact by replacing substitute resources or environments.' It appears that,at least during the real life of the project,the only suitable means of mitigation of fisheries losses is (5),compensating for the impact by replacing or providing substitute resources or environments. We understand that you are currently developing mitigation options along these lines and will be pleased to meet with you to discuss them. FISH HOLDING TANK 1'/IV ~-..../,/ , ,RECESSED BUCKET •••·."..t ~PRIMARY D1VERTER ~~~~'''It ~:SEAL GUARDS ~Jf::~TRASH RACK •A > > > >):;::::: TO TREATMENT VALVE o INTAKE OPENING G).INTAKE WELL o INTAKE BAY 0 WEST RESERVOIBoEASTRESERVOIR ~ MLR OUTFALL ,. Prudhoe Bay Waterflood Project -Seawater Treatment Plant Marine Life Return System (Schematic) ,. i ,I,' I --------=---------- I PL~N VIEW$. ~..~t~FLOW,. ...................•......••......... LICENSING AND PERMITTING TOTIIL BUDGET ~UPPL. BUDGET YY8&CAPITAL allDeET DOLLARS sustTNA IIVOROELECTRIC PKOJEt:1' BASE BUDGET -~---------------------------------------- J I---~. C.:. No.v 100 PERSONAL SERvtCES.B.O,HJ o ~oo iRA VEL •lh2.20a 70.000 232,200 300 CONTRAr.TUAt. n""1.~OO.000 (3"'1)Ir'~,J(/" l.200.00lJ--' (I) (2 ) ( J ) (.) (n {.I (1) (I" (1\) (21 ) (2.2.) ( 2 J ) f 24) {211 (l&) ( 3 I I DJ) (34 l (42 l (8 \1 (91 I (<J2) (9J ) (97) (981 PrOject HanaBement •••• Pro3ect Support ServlCCY. Englneerlns Pro~r.m • Evironmental Pro~r.m••• ~r.oteChnlcol Prosram ••• tier-natn@ Support'PermltttnR. ElecLric Power Sy.tem.Stt'dy. EnVironmental rro~r.m ... Ceotechnical 1.nve.ti~.tton.·, Dellgn Hemo No.t -Ceneral •• Deaign Memo No.2 -Hydrology_ OCli,n Memo No.3 -Ceolo8~' OellRn Hemo No.4 -RiVer Olver.lon ••••••• O~.i~n Hemo No.~-Dam Embankment ••••••• DealRn Hemo No.6 -Geotechnical Conatructton Hatertala •• Dea18n Hemo No.ll -rower Generating Fac111tlca •~ Deaign Hemo No.13 -Cold Cr ...k 7ranvm1aalon ~tne ~~•~•• Dealgn Henno No.1"-Fftc:,lltte. ~esl~n Crl:erta • LORtstlcs •••• Neec (or Pouer StUdy •. Tranamt.alon FaCllltie. 51LlnM and Llcen8ln8~• H~draultc ,Hydrologic Studtes. Cole Creek Tran8ml ••ton Line •• Field Support Staff ••~••• Hana~ement of SubcontrucLV for Eng1ne~rln~ProJecta Support Facllttle •••••• LoglatlcM .•••~••••• rroject H.n4~~m~nt•.~••• rroject Stlppnit SerVlcea and Relocation •••~•••••• 420.000 2.400.000 I~,OOO .,710,000 aJ,OOO 700,000 o 1,~OO.Of}O :.200,000 17':"000 820,000 100,000 100,000 o ~OO,OOO o .0.000 b 1,000 n a o o HO,OOO 2,\00,000""(4) I LOUO \,230,000 ..... B3,OOO HO,OOO 61.000 a o o fl o o a o 27~.(l0f) 820,000 fJ fJ o n o o p..,~f'o'\Pl/'''''''''7 5 -.,.,1 ,:;r.r~r..,J (J h (.(.'f'j ".''j f_ ,'f ,_' Subtotal H-£::LI43.000 801,000 ADA.DP I~O,OOO 150.000 AOF&C 5~-Hydro TerreatrLa:••• Habltat ~IVl.:.on Admlntatratlon Dtvlal0n. 'Z.,"t.')l)r Clt.·~ \,000,000 300,000 100.000 JO,OOC ...... ~OO,OOO 100,000 o o ~,?,O,'il,)0 I.50(),ouo 400.000 jlj-O,ll co :00.000 '0,000 Subtotal AOF'60r.600,000 2.030,000 ADNR . •o Board of ConsultAnt.o o o C:RI/CIRI Vl11A~e.Land Use Agreement.144.000 I,JOO,OOO 200,000 1.500,OOIJ '-and Field ServlceA.227.7'iO 227.no ~Ana~emen:Services International.\0,000 o ~O,OOO ~Ol:Con.crv.tton S~rvlce •.6.000 o b.OOCl 20,000 o 20,OOU ':SCS • • •3~O,OOO o 3!10 t OOO Other Con:rftctual.9n ,000 o 9n.000 TOTAL -CONTRACTUAL !6.90'i.190 IB.~06,190 loOO S::PPL:ES •!O.OOO o Iq.f1f1U !lua EOU:PMENT.10,000 o 10.1)00 TOTAL -PROJECT 17.927,91J 1.671.000 ..•..•••............................. ~USITNA HYDROELECTRIC PROJECT FY86 CAPITAL BUDGET DOLLARS ENCINEERINC ANO OESICN .3 2.3,I ~" TOTAL 8UOCr.T o o SUPPL. 8UOCET 12,050 123,1$4 8ASE 8UOCET B~.D F::?I (r IV Cat. No. 100 PEaSQNAL Sr.IlVICr.S. 200 TIlAVEL • 100 CONTRACTUAL. 3,24',100 608.700 3,852.800 6,654.460 510,000 7.164,460 \14,600 0 D4,600 1.007,600 ~O,OOO I,OH,600------------------------ ------------20.365,560 4,482,600 24,848,160 1\0,000 0 l~O,OOO \00,000 0 SOO.OOO 100,000 0 100,000 0 0 0 0 0 0------------------------------------600,000 0 600,000 89,100 40,200 6,491,500 I,H8,600 866.000 0 132,000 0 194.000 331,~OO 409,000 0 216,000 129,000 0 0 68~.600 207,000 0 91.000 18~.000 H&rza-Eb ••co (1)Project Han_sement •••• (2)Project Support Service •• ()Enltneerins Progr ••••• (4)[viron.ental Prolr&•••. (S)Ceotechnical Proar ••••• (6)Ltc.natna Support'Permttttng. (1)Electric Power Syatem&Study. (14)Environ ••ntal Prolra•••• (15)eeocechnical tov.attaatlona • (21)o••l&n H••o No.1 -Ceneral •• (22)O••lan Hemo No.2 -Hydrology. (23)Deotan HeQo No.3 -CeololYo (24)O••lan H.mo No.4 -Rlver Diverolon ••••••• (25)0 ••18n Hemo No.5 - D•• Embank ••nt ••••••• (26)D••18n H••o No.6 -Ceotechnical Conatructlon Hateriala •• (31)O••lsn H••o No.ll -Power Ceneratina Facl1ttlea •• (ll)O••lln Hemo No.1l -Cold Creek Tran ••i.eion Line ~~~••~ (34)Deeiln He.o No.14 -Facilltiee o.eiln Criteria ~ (39)Loai«tic ••••• (40)Need for Power Study •• (41)Tran ••l.«lon Facilttie. SitinB and Licen.ing •• (42)Hydraullc "Hydrololic Studiee~ (85)Cold Creek Tron ••i.elon Line.~ (91)Field Support Staff •••••• (92)HanaBement of Subcontracte for Enalneering Project.Support Fa.cll1tiea ••••• (93)LOll.tlc ••••••••••• (97)Project H.na8ement~••••• (98)Project Support SerViceD and Relocation •••••~•~•• ADA,Of ADFIoC Su-Hydro Terre.trlal~•• Habltat 01vl.1on Ad_lni.tratlon Divl.ion~ o 283,000 o o o o o o o 129,IlOO 8,080,100 866,000 212,000 U~.~OO 409.000 216,000 129,000 207,000 476,000 o o o o 281,000 o ADNR ..o o 80,000 o 80,000 o Department of Law~10,000 o 30,000 land Field Service ••o o Hanal.ment Service«Internatlonal.o o o Soil Con.erv.tion Service ••o o o o o o USCS • • •o o o Other Contractual.o o o TOTAL •CONTIlACTUAL 21,169,560 4.482,600 400 SUPPLIES •o o o ~OO EOUIPHENT.o o o TOTAL •PIlOJECT 26,197,164 ) 1\ II -1-\ II 1\ 11 11 III IIJ APPENDIX B Detailed Mitigation Costs ,.\ II II l I \I II I, I \ 11 APPENDIX B Detailed Mitigation Costs This appendix presents the preliminary costs for the various mitigation measures presented in Chapter 3.A major cost is that for mobilizing equipment,materials and men to the sites.These costs are based on using the Alaska Railroad to transport much of the equipment and materials.Details regarding timing an'd cost associated with loading and unloading the railroad cars have not been evaluated. Side Channel 21 and Slough 21 do not have access to the railroad or other land transportation during the summer construction season. Three alternatives exist to mobilize equipment to this site. \\ I ' I \ 1)Helicopter:Advantages scheduling.Disadvantages equipment size. include timing, include high cost speed and and limited II II 2) 3) Barge:Advantages include lower costs,and ability to schedule and operate efficiently.Disadvantage of shallow draft in river that may limit equipment size. Mobilizing during winter:Advantage includes low cost of getting large equipment and supplies into work site by transport over river ice.Disadvantages are posed by long lead time to mobilize materials and tying'up equipment for one year before demobilization could be completed. 1\ Costs in this section for Slough and Side Channel 21 are based on the assumption that river conditions are such that parges may be operated to the site. AVERAGE ANNUAL OPERATING AND MAINTENANCE COS.TS TOTAL INITIAL COSTS OF MITIGATION MEASURES FOR SLOUGH 8A Slough 8A J cl J ./ j I ..J ,J j .1 .J I J I j J I j $26,000 $10,000 $61,000 $121,000 $4,000 . $24,000 6,000 8,000 7,000 5,000 5,000 9,000 5,000 5,000 2,000 3,000 2,000 3,000 37,000 11 ,000 S-;OOO~--_·-c-., 8,000 of 2 Slough Berms Labor Equipment/Materials ~Mobi-lizationIDemobi:-lizCati~on'·~-·.~,~~" Engineering/Management Total 1 Slough Mouth Excavation Labor Equipment Mobilization/Demobilization Engineering/Management Total 1 Wing Deflector..300 ft Labor Equipment/Materials Mobilization/Demobilization Engineering/Management Total Excavation of 6 Passage Reaches 1,400 ft Labor Equipment/Materials Mobilization/Demobiliza.tion Engineering/Management Total Buildup r-: II II Slough 9 r--\ 1 Rock Weir Labor 9,000 Equipment/Materials 14,000 Mobilization/Demobilization 8,000 II Engineering/Management 6,000 Total $37,000 [--I 1 Buildup of Slough Berm Labor·36,000 Equipment/Materials 10,000 [] Mobilization/Demobilization 5.,000 Engineering/Management 8,000 Total $59,000 11 20 Log Barriers 1,000 ft Labor 20,000 Equipment/Materials 2,000 II Mobilization/Demobilization 2,000 I Engineering/Management 6,000 Total $30,000 Excavation of 2 Passage Reaches 300 ft Labor 2,000 1~1 Equipment/Materials 1,000 Mobilization/Demobilization 2,000 Engineering/Management 2,000 Total $7,000 AVERAGE ANNUAL OPERATING AND MAINTENANCE COSTS TOTAL INITIAL COSTS OF MITIGATION MEASURES FOR SLQUGH 9 1 Slough Mouth Excavation Labor Equipment Mobilization/Demobilization Engineering/Management Total 6,000 8,000 7,000 5,000 $26,000 $159,000 $4,000 Slough 9A 1 Buildup of Slough Berm Labor Equipment/Materials Mobilization/Demobilization Engineering/Management Total Excavation of Entire Slough Labor Equipment/Materials Mobilization/Demobilization Gravel Processing Engineering/Management Total· 23,000 7,000 5,000 7,000 6,000 7,000 5,000 55,000 3,000 $42,000 $76,000 TOTAL INITIAL COSTS OF MITIGATION MEASURES FOR SLOUGH 9A AVERAGE ANNUAL OPERATING AND MAINTENANCE COSTS $118,000 $4,000 Slough 11 Ii I',J 11 2 Weirs Labor Equipment/Materials Mobilization/Demobilization Engineering/Management Total Bank Stabilization 1,200 ft Labor Equipment/Materials Mobilization/Demobilization 'Engineering/Management Total Slough Excavation Labor Equipment/Materials Mobilization/Demobilization Gravel Processing Engineering/Management Total 10 Log Barriers 500 ft Labor Equipment/Materials Mobilization/Demobilization Engineering/Management Total 1 Wing Deflector 300 ft Labor Equipment/Materials Mobilization/Demobilization Engineering/Management Total . 1 Buildup of Protective Berm Labor Equipment Mobilization/Demobilization Engineering/Management Total 18,000 28,000 8,000 7,000 8,000 7,000 5,000 5,000 6,000 7,000 5,000 5,000 3,000 15,000 2,000 2,090 5,000 5,000 9,000 5,000 5,000 10,000 5,000 5,000 4,000 $61,000 $25,000 $26,000 $24,000 $24,000 $24,000 TOTAL INITIAL COSTS OF MITIGATION FOR SLOUGH 11 AVERAGE ANNUAL OPERATING AND MAINTENANCE COSTS $184,000 $4,000 AVERAGE ANNUAL OPERATING AND MAINTENANCE COSTS TOTAL INITIAL COSTS OF MITIGATION FOR SIDE CHANNEL 11 Upper Side Channel 11 Excavation of Channel Labor Equipment/Materials Mobilization/Demobilization Gravel Processing Engineering/Management Total Buildup of Protective Berm Labor Equipment/Materials Mobilization/Demobilization Engineering/Management Total 6,000 7,000 5,000 5,000 3,000 100,000 44,000 5,000 12,000 $26,000 $161,000 $187;000 $4,000 I .1 I ! I I J l I I I ··1 ! "j 1 ] J ~I AVERAGE ANNUAL OPERATING AND MAINTENANCE COSTS TOTAL INITIAL COSTS OF MITIGATION MEASURES FOR SIDE CHANNEL 21 [I I. I I [1 i i III., r I[, II 11 II Side Channel 21 Excavation of Channel Labor Equipment/Materials Mobilization/Demobilization Gravel Processing Engineering/Management Total 6 Wing Deflectors Bank.Stabilization Labor Equipment/~aterials Mobilization/Demobilization Oversize Material Removal Engineering/Management Total 250 ft 8,000 9,000 11 ,000 8,000 9,000 70,000 65,000 20,000 35,000 50,000 $45,000 $240,000 $285,000 $5,000 I AVERAGE ANNUAL .OPERATING AND MAINTENANCE COSTS TOTAL INITIAL COSTS OF MITIGATION MEASURES FOR SLOUGH 21 Slough 21 Excavation to Lower Slough Profile Labor Equipment/Materials Mobilization/Demobilization Oversize Substrate Removal Engineering/Management Total 5,000 6,000 5,000 10,000 8,000 $34,00Q $34,000 $5,000 ) J ) j <1 I 'j [-I I Curry Slough AVERAGE ANNUAL OPERATING AND MAINTENANCE COSTS AVERAGE ANNUAL OPERAT+NG AND MAINTENANCE COSTS TOTAL INITIAL COSTS OF MITIGATION MEASUREp $81,000 $35,000 $531,000 $450,000 $50,000 15,000 35,000 8,000 10,000 13,000 .135,000 80,000 100,000 30,000 35,000 70,000 Curry Slough Development Propagation System :):,.abor Equipment/Materials Pipe Gravel Processing Mobilization/Demobilization Engineering/Management Total Curry Station Development Propagation System Labor Equipment Materials Gravel Processing MobilizationDemobilization Engineering/Management Total ['.I [] :\. 1 I ) I I .1 J J .) ) ~] ,') -__._-_._.._-,---_.__......•.•..•...__..•_._.__•...•._--__.._-_..______._.....•_.._..___--__-___._-_._.._-___-.-_._---_..-._._-"._._---~,._.__._._--_._..,_•..._..•..•....___._-_.._--_._..__._,._..•.._-_.~.__._-_._..___.....•__.•.._.._---__--_.._..---..-_._------_.._-----_.__._._._-_..~._._.._-__--~-_._. 1 ] j J J