FEASIBILITY OF REINTRODUCING SOCKEYE AND OTHER SPECIES OF PACIFIC SALMON IN THE ALOUETTE RESERVOIR, BC

Transcription

1 FEASIBILITY OF REINTRODUCING SOCKEYE AND OTHER SPECIES OF PACIFIC SALMON IN THE ALOUETTE RESERVOIR, BC Prepared for: Alouette River Management Society P.O. Box Ridge Post Office Alouette Road Maple Ridge, BC V2X 1P7 March 2004

2 FEASIBILITY OF REINTRODUCING SOCKEYE AND OTHER SPECIES OF PACIFIC SALMON IN THE ALOUETTE RESERVOIR, BC Prepared by: M.N. Gaboury and R.C. Bocking LGL Limited environmental research associates 9768 Second Street Sidney, BC V8L 3Y8 Prepared for: Alouette River Management Society P.O. Box Ridge Post Office Alouette Road Maple Ridge, BC V2X 1P7 March 2004

3 ACKNOWLEDGMENTS Many people participated in one way or another in the completion of this study. First, we would like to thank Geoff Clayton and Jenny Ljunggren of Alouette River Management Society for their guidance and assistance in providing historic and current information on the watershed and its fish populations, and for providing thoughtful project and contract management. We thank the BC Hydro Bridge Coastal Fish and Wildlife Restoration Program for recognizing the importance of this issue and financially supporting the study. We especially like to thank Chief Peter James and Michael Leon of the Katzie First Nation for passing on the wisdom of elders regarding historical use and presence of salmon in the Alouette watershed. We would also like to thank all the local users and volunteers with an interest in Alouette salmon for their insights at public meetings and workshops. We would like to thank Mike Ilaender who provided assistance during the stream habitat assessments. Thanks also to Paul Vassilev and his staff at BC Hydro for providing data on flow releases and reservoir elevations for Alouette Reservoir. Peter Ward and Hassen Yassien of Ward & Associates Ltd. examined, through hydrological modeling, an operational scenario for Alouette Reservoir that would facilitate downstream smolt migration. Marvin Rosenau (MWLAP), Greg Wilson (MWLAP), Sheldon Reddekkopp (MWLAP), Megan McCusker (MWLAP), and Matt Foy (FOC) provided helpful advice and discussions regarding re-introduction of sockeye. Bruce Murray of LGL Limited assisted with stream habitat assessments. Robin Tamasi, also of LGL Limited, prepared map figures in the report. LGL Limited Page i

4 EXECUTIVE SUMMARY The Alouette hydroelectric project was completed in 1928 and, with construction of a dam at its natural outlet, impounded the waters of Alouette Lake. The dam also blocked access to all anadromous fish. The Katzie First Nation fished for sockeye, coho, chum and pink salmon and steelhead during spawning migrations in the South and North Alouette rivers. The Katzie also utilized the abundant sockeye that spawned in Gold Creek. It is believed the sockeye migrated into the Alouette River and lake in May of each year and spawned in October. The kokanee population in Alouette Reservoir is believed to be a recent descendent of the original sockeye population. The current population of kokanee spawns in the fall (October/November) in fluvial outwash gravel fans on the east side of the reservoir. A total of 28 species of fish have been recorded from the Alouette River system, with 12 species presently found in the Alouette Reservoir. While there remains considerable uncertainty regarding the potential for success, this feasibility assessment found that there appears to be no serious impediments to the reintroduction of sockeye salmon and other salmon species such as coho to Alouette Reservoir. However, a number of baseline research studies will be required to confirm the assumptions of the feasibility assessment. The proposed studies focus on sockeye and pertain to determining the amount of productive capacity in the reservoir available to sockeye, testing propagation approaches for reintroducing sockeye, evaluating spawning habitat suitability, examining smolt migration behaviour, and assessing alternative operational regimes for the reservoir. It is estimated that the reservoir and tributaries have the capacity to support a spawning population of between 65,000 and 68,000 sockeye, around 380 coho salmon and about 50 steelhead. With re-introduction of sockeye, a reduction in kokanee abundance is anticipated as sockeye and kokanee will compete for food during rearing. The availability and viability of spawning habitat for sockeye needs further investigation, but given the presence of shorespawning kokanee and high quality habitat in Gold Creek, there is a reasonable probability that sufficient habitat exists. Moderate to high quality spawning and rearing habitat exists for coho in Gold, Viking and North Twin creeks. Steelhead could utilize high quality spawning and rearing habitat in Gold Creek, but production would be limited by low nutrient levels. The re-introduction of sockeye will not affect reservoir water quality significantly. If the sockeye population eventually attained a level of 68,000 adults, total phosphorous load from the salmon would increase to a peak of about 550 kg/yr. This would equal about 17% of the average 2000 and 2001 phosphorous input of 3178 kg/yr under the fertilization program. The reservoir has remained in an oligotrophic to ultra-oligotrophic state at this level of artificial phosphorous input and would not be impacted significantly by the comparatively small phosphorous load from salmon carcasses. Re-introduction of sockeye salmon to the Alouette Reservoir will require propagation of the stock, while coho salmon, steelhead and anadromous cutthroat would likely colonize the watershed naturally over time. Propagation of sockeye will not be easy, but a multiple approach of re-anadromization of the existing kokanee stock and introduction of a suitable donor stock may provide the best chance for success. The Pitt River may provide the best alternate source of donor stock. Also, Pitt River sockeye migrate through lower Fraser River fisheries in early July, LGL Limited Page ii

5 prior to the large summer run of Fraser sockeye. Establishing a sockeye run with early run timing (mid-july or earlier) is important from a fisheries management perspective to minimize mixed-stock harvest pressure on the new stock. Sockeye salmon can be significant vectors for disease, particularly infectious hematopoietic necrosis. Culturing sockeye has specific mandatory requirements for fish handling and discharge of effluent water. Transplant Committee approval will be required for donor stock introductions and all necessary steps to prevent disease transfer will need to be followed. With a difference in water surface height at Alouette Dam of about 15.5 m, constructing a fish ladder to allow for upstream and downstream migrations of salmon should be feasible from an engineering perspective. Fluctuating reservoir levels during the upstream and downstream migration periods can be accommodated by including a multiple orifice vertical slot fishway exit with a pool and weir or rock riffle fishway for the lower fish transport section. Fishway discharge is expected to be about 2.83 cms, equivalent to the discharge to be released to the South Alouette River as specified in the Alouette Generating Station Water Use Plan (WUP). Minimal fluctuations are expected at the fishway entrance in the South Alouette River below the dam. An alternative strategy for moving anadromous fish upstream and downstream could be implemented if a fishway is not constructed. Returning adults could be transported above the dam using a trap and truck operation. An existing bladder fish fence downstream of the dam, operated with the assistance of the Fraser Regional Correctional Centre, could be used to trap the adults and move the anadromous fish above the dam. Downstream migrating smolts could depart the reservoir through the lift gate on the spillway. One operational scenario was analyzed that would raise the reservoir level about 1 m during the winter months (after January 1) by keeping the adit closed one additional week. The flow under the lift gate would be approximately 2.83 cms, the release to the South Alouette River specified in the Alouette WUP. The simulation showed that in 7 out of 8 years it would be possible to release flows of 2.6 m 3 /s or more past the crest gate opening into the river, assuming that additional water had been stored the previous winter. Further hydrological and flow routing analyses are needed to determine the feasibility and flood risks of maintaining a higher Alouette Reservoir elevation to accommodate smolt migration at the lift gate during the April to mid-june period. A significant reduction in diversion flows to Stave Reservoir during the smolt migration period (i.e., April to mid-june) would reduce the likelihood of smolts exiting the reservoir through the diversion and promote smolts exiting at the dam. The maximum diversion discharge under an anadromous re-introduction scenario should be less than 20.5 cms between April and mid-june, with no discharge through the adit tunnel. Further hydrological and flow routing analyses will be required to determine if there is operational flexibility for reducing the diversion releases during the April to mid-june period. The estimated total costs over a ten-year period of providing for fish passage at the Alouette Dam range from $1.23 M (million) for trap and truck to between $3.5 and $4.3 M for a fishway. We estimate an additional $2.5 M will be required over the same ten-year period for supporting biological studies and sockeye propagation. Should spawning channels be required for sockeye, an additional $0.125 M will be required. These costs are very approximate at this time. LGL Limited Page iii

6 TABLE OF CONTENTS ACKNOWLEDGMENTS... i EXECUTIVE SUMMARY... ii LIST OF FIGURES... vi LIST OF TABLES... vii LIST OF PHOTOS... vii LIST OF APPENDICES...viii 1 INTRODUCTION OBJECTIVES PHYSICAL SETTING ALOUETTE HYDRO GENERATION PROJECT ALOUETTE RIVER ALOUETTE RESERVOIR AND TRIBUTARIES PRESENT FISH RESOURCES SOUTH ALOUETTE RIVER AND TRIBUTARIES Fish Stocks Coho Salmon Chum Salmon Pink Salmon Chinook Salmon Steelhead Rainbow Trout Cutthroat Trout Migratory Timing Stock Exploitation ALOUETTE RESERVOIR AND TRIBUTARIES Tributary Stream Habitat Surveys Enhancement History FEASIBILITY OF REINTRODUCING SOCKEYE SALMON HISTORICAL ABUNDANCE AND DECLINE ESTIMATES OF POTENTIAL SOCKEYE PRODUCTION BIOLOGICAL AND PHYSICAL REQUIREMENTS FOR REINTRODUCTION Sockeye Propagation Option 1: Reversion to Anadromy Option 2: Donor Stock Habitat Requirements Rearing Spawning Habitat - Streams Spawning Habitat - Lakeshore BIOLOGICAL AND PHYSICAL IMPACTS FROM REINTRODUCTION Disease Water Quality Resident Species Potential Harvests and Management OPERATIONAL REQUIREMENTS FOR REINTRODUCTION LGL Limited Page iv

7 4.5.1 Upstream Migration Downstream Migration Egg Incubation Enhanced Spawning SUMMARY OF FEASIBILITY AND RECOMMENDATIONS Anadromous Stock Available Attainable Production Goals Impacts to Resident Species and Water Quality Host or Vector for Disease Fish Management Constraints Dam/Diversion Water Releases Smolt Migration Behaviour Reservoir Elevations Structural Requirements SUMMARY OF ESTIMATED COSTS FOR REINTRODUCTION REINTRODUCTION OF OTHER SPECIES BIOLOGICAL AND PHYSICAL REQUIREMENTS Coho Steelhead Anadromous Cutthroat Chinook OPERATIONAL REQUIREMENTS Upstream Migration Downstream Migration REFERENCES APPENDICES LGL Limited Page v

8 LIST OF FIGURES Figure 1. Index map of Alouette River watershed... 3 Figure 2. Alouette-Stave-Ruskin hydroelectric generation system (courtesy of BC Hydro, 4 Figure 3. Map of Alouette River watershed... 5 Figure 4. Pre-impoundment flows at outlet of Alouette Lake, Reproduced from Anonymous (1995) Figure 5. Coho salmon escapements in the South Alouette River from 1925 through 1997 (FISS, Wilson et al. 2003) Figure 6. Chum salmon escapements in the South Alouette River from 1925 through 1999 (FISS, Wilson et al. 2003, Walter and Cope 2000) Figure 7. Pink salmon escapements in the South Alouette River (FISS, Wilson et al. 2003) Figure 8. Probable fish periodicity for anadromous sockeye, coho, chinook and steelhead in the Alouette River Figure 9. Combined recoveries (%) of coded-wire tagged Kanaka Creek coho for return years (Fisheries and Oceans MRP database) Figure 10. Combined recoveries (%) of coded-wire tagged Chehalis River coho for return years (Fisheries and Oceans MRP database) Figure 11. Long profiles for Gold, Viking and Twin North creeks. Gradients shown in percent.19 Figure 12. Long profiles for Moyer Creek and upper Alouette River. Gradients shown in percent Figure 13. Fraser River sockeye stock timing curves through Area 20 fisheries Figure 14. Average Alouette Reservoir elevations, inflows, diversion flows and dam outflows over the 1984 to 2002 period. Hydrometric data over period of analysis, 1984 to 2002, provided by BC Hydro Figure 15. Alouette Reservoir elevations over the 1984 to 2002 period. Hydrometric data over period of analysis, 1984 to 2002, provided by BC Hydro Figure 16. Percentage of days during three critical time periods for sockeye when Alouette Reservoir elevations were greater than the specified elevation (x-axis). Time periods: 1 April to 15 June smolt migration; 1 April to 31 July spawner migration; 1 September to 30 November spawning. Hydrometric data over period of analysis, 1984 to 2002, provided by BC Hydro Figure 17. Average daily discharge (cms) from Alouette Reservoir to the South Alouette River for three time periods. Hydrometric data over period of analysis, 1984 to 2002, provided by BC Hydro Figure 18. Alouette Reservoir discharges to South Alouette River over the 1984 to 2002 period. Hydrometric data over period of analysis, 1984 to 2002, provided by BC Hydro Figure 19. Percentage of days during the periods: April 1 to June 15 and May 1 to June 15 when Alouette Reservoir elevations were greater than the specified elevation (x-axis). Hydrometric data over period of analysis, 1984 to 2002, provided by BC Hydro Figure 20. Alouette Reservoir discharges to Stave Reservoir over the 1984 to 2002 period. Hydrometric data over period of analysis, 1984 to 2002, provided by BC Hydro Figure 21. Alouette Reservoir discharge into Stave Reservoir, based on daily averages for 1984 to 2002 period. Hydrometric data over period of analysis, 1984 to 2002, provided by BC Hydro LGL Limited Page vi

9 Figure 22. Percentage of days between April 1 and June 15 when discharges from Alouette Reservoir to Stave Reservoir were greater than the specified discharge (x-axis). Hydrometric data over period of analysis, 1984 to 2002, provided by BC Hydro Figure 23. Percentage of years during the sockeye egg incubation period, 1 September to 31 March when reservoir elevations decreased below the elevation at spawning by greater than the specified elevation change (x-axis). Hydrometric data over period of analysis, 1984 to 2002, provided by BC Hydro Figure 24. Feasibility matrix for anadromous species reintroduction to Alouette Reservoir Figure 25. Percentage of days during three spawning migration periods when Alouette Reservoir elevations were greater than the specified elevation (x-axis). Time periods: Jan. 1 to May 15 steelhead spawner migration; 15 September to 30 November chinook spawner migration; 1 October to 31 December coho spawner migration. Hydrometric data over period of analysis, 1984 to 2002, provided by BC Hydro LIST OF TABLES Table 1. Fish species of the Alouette River system. Modified after Cope (2002)... 9 Table 2. Summary of salmonid habitat condition in Gold, Moyer, Viking, Twin North creeks and upper Alouette River Table 3. Estimation of optimum sockeye salmon production in Alouette Reservoir and other B.C. lakes and reservoirs of similar size Table 4. Suitability of stream habitat in tributaries to Alouette Reservoir for anadromous salmon re-introduction Table 5. Minimum and maximum Alouette Reservoir elevations and discharges to Stave Reservoir at various life stages for sockeye, coho, chinook and steelhead, with recommended (hypothetical) diversion and water level conditions under an anadromous salmonid re-introduction scenario. Based on daily water levels and discharges between 1984 and Data provided by BC Hydro Table 6. Percentage of years between 1984 and 2002 when reservoir was at or above a minimum elevation during the specified time period Table 7. Additional research required to determine feasibility Table 8. Potential coho smolt production and spawner requirements in Gold, Twin North and Viking creeks, and Alouette Reservoir Table 9. Potential steelhead smolt production and spawner requirements in Gold Creek LIST OF PHOTOS Photo 1. Riffle habitat downstream of bridge crossing in Reach 1 of Gold Creek at approximately m Photo 2. Rapid habitat in Reach 1 of Gold Creek at m (June 24, 2003), highly suitable for steelhead parr rearing Photo 3. Lower gradient riffle-pool habitat in Reach 2 of Gold Creek at m, suitable for sockeye, coho and steelhead spawning and/or rearing Photo 4. Riffle-pool habitat in Reach 2 of Gold Creek at m Photo 5. Cascade habitat in upper Alouette River at m Photo 6. Cascade habitat in Moyer Creek at m LGL Limited Page vii

10 Photo 7. Riffle habitat in Viking Creek at m upstream of mouth (June 2003) Photo 8. Lower gradient gravel section in Twin North Creek at m (September 2003) Photo 9. Riffle-pool habitat in Twin North Creek at approximately m upstream of mouth (June 2003) Photo 10. Typical tributary outwash gravel fan on the east side of the south basin of Alouette Reservoir LIST OF APPENDICES Appendix A. Table of persons attending the workshop on October 15, Appendix B. Alouette Dam facility statistics. Modified after Anonymous (1996), Bengeyfield (2001) and Wilson et al. (2003) Appendix C. Historical salmon escapement to the South Alouette River. Modified after FISS, Wilson et al. (2003), and Walter and Cope (2000) Appendix D. Record of historical fish stocking to South Alouette River from Alouette River Correctional Unit hatchery (ALLCO) Appendix E. Stocking History for Alouette River (Fisheries Data Warehouse, FOC) Appendix F. Substrate characteristics of bed paving material in Gold Creek, June 24, Appendix G. Life history of Oncorhynchus nerka (see references in main document) Appendix H. Overview of some common types of fish passes. Where measurements are given, they are only minimum requirements. The various fish passes are classified by functional and ecological aspects, but no account is taken of local geographical factors that may limit the use of some structures. Modified after FAO (2002) Appendix I. Alouette reservoir operations and fish passage improvements, year 1 report. Prepared by Ward & Associates Ltd. (2003) LGL Limited Page viii

11 1 INTRODUCTION The Alouette hydroelectric project was completed in The dam impounded the waters of the Alouette River watershed, creating Alouette Reservoir. As a result, access to what was formerly known as Alouette Lake was blocked for all anadromous fish. The question of restoring fish passage to Alouette Reservoir and its tributaries has been the subject of intense debate among resource users and BC Hydro in recent years. Although most if not all species of Pacific salmon were present, sockeye salmon was the main anadromous species known to have inhabited the lake. Very little is known regarding the historical status of that population of sockeye. What is known, however, is that they were quite important to the Katzie First Nation (KFN) (Michael Leon, KFN pers. comm.). It is believed the sockeye migrated into the Alouette River and lake in May of each year and spawned in October (Wilson et al. 2003). Katzie people fished for sockeye, coho, chum and pink salmon and steelhead in the South and North Alouette rivers (Driver and Spurgeon 1998). The Katzie First Nation also utilized the abundant sockeye that spawned in Gold Creek (Wilson et al. 2003). The question of restoring anadromous fish access to Alouette Reservoir is a complex one. Bocking and Gaboury (2002) established a framework for the evaluation of restoring fish passage for anadromous species upstream of hydroelectric dams. The framework addresses key biological, physical, operational, and structural issues related to restoring fish passage. This report addresses the first three components of the fish passage feasibility assessment framework; namely biological, physical and operational issues. In this report, we present an analysis of existing data, information gaps, and required research to rationally determine the feasibility of reintroduction and recommend the steps necessary should decision-makers decide to pursue the issue further. A similar assessment to examine the feasibility of reintroducing sockeye and other salmonid species to the Coquitlam Reservoir has been completed by Bocking and Gaboury (2003). Consultations with professionals and interested parties were held throughout the development of this report. Telephone interviews, meetings, and a workshop were convened between May 2003 and February Discussions relating to the history of fish populations in the Alouette watershed were held with the Katzie First Nation, represented by Chief Peter James, Michael Leon, Wayne Florence, and Vernon Chapman, on 23 June Appendix A contains a list of all persons and organizations that attended the Alouette Workshop on Fish Passage Feasibility on 15 October OBJECTIVES The main objectives of this feasibility assessment are: 1. Conduct analyses of existing biological, physical and operational data; 2. Ascertain the biological, physical and operational feasibility of reintroducing salmon to Alouette Reservoir; 3. Identify key issues to be addressed before further decisions can be made regarding the reintroduction of anadromous species to Alouette Reservoir; LGL Limited Page 1

12 4. Identify the approximate costs associated with reintroduction; 5. Identify timelines for reintroduction; and 6. Recommend next steps to the BC Hydro Bridge-Coastal Fish and Wildlife Restoration Program. The specific objectives that support the above overarching objectives are: 1. Determination of target species for reintroduction; 2. Evaluation of options for donor stocks; 3. Evaluation of artificial propagation requirements; 4. Evaluation of existing and potential habitats; 5. Evaluation of production potential; 6. Evaluation of species interactions and disease concerns; 7. Evaluation of potential impacts on water quality, downstream flows, etc; 8. Evaluation of operational requirements to support spawning, incubation and rearing; 9. Evaluation of operational requirements to support migrations; 10. Identification of conceptual structural requirements to support fish passage; 11. Identification of steps to reintroduction and timelines; 12. Determination of approximate program costs; and 13. Recommendations for further studies. 2 PHYSICAL SETTING 2.1 ALOUETTE HYDRO GENERATION PROJECT The Alouette watershed is located in the south mainland of British Columbia (Figure 1). The river originates in the Coastal Mountains and flows through the District of Maple Ridge, Pitt Meadows and into the Pitt River. Alouette Reservoir is located in a steep-sided glacial trench above the Alouette Dam and is part of the Alouette-Stave-Ruskin hydroelectric generating system. The 21 m high Alouette Dam, located at the south end of the south basin of Alouette Reservoir, was first built in and then reconstructed as an earthfill structure in 1983 (Appendix B; Wilson et al. 2003). Power is generated by diverting flow from the reservoir via a 1067 m tunnel to a single 8 MW Alouette Generating Station on Stave Reservoir (Anonymous 1996). Alouette diversion flows also contribute to further hydroelectric generation which occurs downstream in Stave Reservoir through the Stave Falls power plant (90 MW) and in Hayward Lake through the Ruskin power plant (105.5 MW). Figure 2 is a schematic of the current infrastructure and operation of the Alouette-Stave-Ruskin hydroelectric generating system. The diversion to Stave Reservoir is located on the east shore of the north basin of Alouette Reservoir. The diversion intake is located at a sill elevation of m, which is about 19.7 m below the normal maximum reservoir elevation of m. LGL Limited Page 2

13 Figure 1. Index map of Alouette River watershed. 2.2 ALOUETTE RIVER The Alouette River exists as two distinct entities: the upper Alouette River, which flows into the north end of Alouette Reservoir and the South Alouette River which begins at the outlet of the Alouette Dam (Figure 3). South Alouette River flows west into the Pitt River, a tributary to the Fraser River. The Alouette River watershed has a drainage area of km 2, of which about 106 km 2 lies downstream of Alouette Dam. The upper Alouette River is a typical west coast stream with a drainage area of 17.9 km 2. It is the third largest tributary to the Reservoir, smaller in drainage area than either Gold or Moyer creeks. Approximately 20 km of mainstem length was lost when the dam was constructed (Bengeyfield 2001). LGL Limited Page 3

14 Figure 2. Alouette-Stave-Ruskin hydroelectric generation system (courtesy of BC Hydro, LGL Limited Page 4

15 Figure 3. Map of Alouette River watershed. LGL Limited Page 5

16 Prior to construction of the Alouette Dam, the South Alouette River had an average annual discharge of about 23 cms and flows ranged from 66 cms during the winter to 4 cms during the late summer (Figure 4; Anonymous 1995). A minimum flow release from the dam was not initiated until Under the 1971 water release agreement, a base flow of 0.06 cms had to be released from the low level outlet (LLO) at the dam to maintain a minimum flow of 0.7 cms at the 232 nd Street bridge. Over the years, minimum releases at the Dam have increased to the current 2.83 cms under the Alouette Water Use Plan (Anonymous 1996). The South Alouette River and associated tributaries downstream of the dam are important production areas for resident and anadromous fishes. The North Alouette River is the main fish producing tributary of the South Alouette River. Lengths of channel available to anadromous species are 24.1 km in South Alouette, 12.1 km in North Alouette, and 4.9 km in Blaney Creek, a tributary of the North Alouette (Griffith and Russell 1980; Figure 3). Griffith and Russell (1980) investigated enhancement opportunities in the South and North Alouette rivers and recommended headwater stocking in Blaney Creek and North Alouette River, hatchery facilities at the Alouette River Correctional Centre (ARCC), and rearing ponds at the base of the Alouette Dam and beside the BC Hydro access road about 2.5 km downstream of the dam. They also recommended habitat improvements to enhance steelhead production be placed in selected tributaries and Reach 2 in both the South and North Alouette rivers. A considerable amount of habitat improvement has been completed within the South Alouette River. A number of side channels and other instream habitat improvements have been constructed. In 1994, the Grey Gables Channel near 232 nd Street was constructed by Fisheries and Oceans Canada (FOC) for coho spawning, rearing and overwintering (Matt Foy, FOC pers. comm.). The Latimer Channel near 239 th Street was built in 1997 by FOC for coho spawning and rearing. Under the Watershed Restoration Program and Habitat Conservation Trust Fund, 48 LWD structures were placed in the river between the dam and ARCC in 1997 and 1998 (Zaldokas and Clayton 1999). The restoration objective for the placement of LWD structures was to provide rearing and holding habitat for juvenile and adult salmon and steelhead. In 2000, the BC Hydro Bridge-Coastal Fish and Wildlife Restoration Program funded the placement of spawning gravel on the outside bank of two meander pools, 0.5 and 2.0 km downstream of the Alouette Dam (ARMS 2002). Flushing flows, prescribed under the Alouette Water Use Plan Agreement, will gradually distribute the gravel downstream. LGL Limited Page 6

17 Figure 4. Pre-impoundment flows at outlet of Alouette Lake, Reproduced from Anonymous (1995). 2.3 ALOUETTE RESERVOIR AND TRIBUTARIES The watershed of Alouette Reservoir is 200 km 2 and has steep, mountainous terrain. The reservoir itself has a surface area of 1666 ha at full pool ( m elevation above sea level) and has a normal operating range between and m (Appendix B). The mean depth of the reservoir at full pool is 78.4 m with a maximum depth of 152 m, which places the lake depths below sea level (Wilson et al. 2003). The major tributaries to the Reservoir include: Tributary Drainage Area (km 2 ) Channel Length with <10% Gradient (m) Gold Creek Moyer Creek Upper Alouette River Twin North Creek Viking Creek The reservoir shoreline is generally steep, with narrow littoral areas often composed of sand, gravel and boulders. Only 10% of the lake area is less than 9 m in depth (Vernon 1954), and the reservoir surface area drops 10% from full to minimum pool (Wilson et al. 2000). The widest littoral shelves are alluvial fans found at the mouths of the largest tributaries, and at the south end extending up from the dam. Vernon (1954) conducted the first known limnology study on Alouette Reservoir and concluded the reservoir was LGL Limited Page 7

18 extremely oligotrophic, based on a lack of shoal area, depth of the reservoir, and large water level fluctuations. Alouette Reservoir has been fertilized with low-level inorganic nutrients (phosphorous and nitrogen) since 1999 (Wilson et al. 2000, 2003). The overall goal of the experiment was to determine the effectiveness of nutrient additions at restoring productivity of the reservoir where, as a consequence of impoundment, the elimination of marine derived nutrients from anadromous fish, large water level fluctuations and altered hydraulic regime have reduced reservoir productivity to unnaturally low levels. The experiment has successfully increased the reservoir s productive capacity, increasing the standing stock of phytoplankton, zooplankton and fish. For the fish populations, kokanee, a planktivore, has shown the greatest increase in size and number with age 3+ weights increasing 5-fold and total population numbers increasing 10-fold. Prospective artificial kokanee spawning channels were investigated on Gold and Moyer creeks by Wightman and Neuman (1981). A small (0.7 km) channel capable of producing 18,000 to 67,500 adult returns was identified in Gold Creek (Wilson et al. 2003). Spawning channel development in Moyer Creek was rejected because of its steep gradient. 3 PRESENT FISH RESOURCES A total of 28 species of fish have been recorded from the Alouette River system, with 22 of these species being found in recent surveys in the South Alouette River (Cope 2002), and 12 in recent surveys on the Alouette Reservoir (Wilson et al. 2003) (Table 1). 3.1 SOUTH ALOUETTE RIVER AND TRIBUTARIES The Alouette River downstream of the Alouette Dam supports populations of chum, coho, chinook, and pink salmon, steelhead, resident rainbow trout, cutthroat trout, and bull trout (Table 1, Cope 2002, 2003). Although Elson (1985) indicated that chinook, pink and sockeye were extinct from the Alouette system, all three species have been caught recently in the South Alouette River by Cope (2002). Salmon escapement records show that chum, pink and coho account for the majority of salmon utilizing the South Alouette River for spawning (Appendix C). Note that escapement estimates for Alouette River salmon stocks were poorly documented historically, and should be interpreted with caution. However, more intensive surveys providing more accurate escapement counts were conducted on chum in 1998 and 1999 (Walter and Scott 1999, 2000). During the years prior to and immediately after dam construction (i.e., 1925 to 1930), escapements to the South Alouette River numbered about 11,000-45,000 fish per year (Appendix C). The majority of fish were pink salmon, estimated at 35,000 in odd years, with chum, sockeye and coho each numbering 1,000-5,000 and a few steelhead being reported (Wilson et al. 2003). Pre-spawning sockeye were last seen below the dam in 1930 (Wilson et al. 2003). Sockeye smolts have been captured recently in the South Alouette River but were found, through genetic analysis, to have originated from Weaver LGL Limited Page 8

19 Creek stock. This implies that sockeye fry migrated downstream in the Fraser River from Weaver Creek, and then upstream into the lower Alouette River for some stream rearing, before heading to sea (M. Rosenau, MWLAP pers. comm.). Table 1. Fish species of the Alouette River system. Modified after Cope (2002). Watershed South Alouette Alouette Reservoir Scientific Name Elson (1985) Cope (2002;2003) Wilson et al. (2003) Chinook Salmon Oncorhynchus tshawytscha X* X Chum Salmon Oncorhynchus keta X X Coho Salmon Oncorhynchus kisutch X X Pink Salmon Oncorhynchus gorbuscha X X Sockeye Salmon Oncorhynchus nerka X* X Kokanee Oncorhynchus nerka X X X Steelhead Oncorhynchus mykiss X X Rainbow Trout Oncorhynchus mykiss X X X Bridge-lip Sucker Catostomus columbianus X Bull Trout Salvelinus confluentus X X X Cutthroat Trout Oncorhynchus clarki clarki X X X Lake Trout Salvelinus namaycush X X Mountain Whitefish Prosopium williamsoni X X Stickleback Gasterosteus sp. X X X Sculpin Cottus sp. X X X Lamprey Lampetra sp. X X Northern Pikeminnow Ptycheilus oregonensis X X X Peamouth Chub Mylocheilus caurinus X X X Largescale Sucker Catostomus macrocheilus X X X Longnose Sucker Catostomus castostomus X Longnose Dace Rhinichthys cataractae X X Redside Shiner Richardsonius balteatus X X X Black Crappie Pomoxis nigromaculatus X Brown Bullhead Ictalurus nebulosus X 1 Brown Catfish Ameiurus nebulosus X X Brassy Minnow Hybognathus hankinsoni X X Eulachon Thaleichthys pacificus X Common Carp Cyprinus carpio X X - presence known X* - isolated after dam construction, extinct X - extinct X 1 - found in Blaney Creek (Griffith and Russell 1980) LGL Limited Page 9

20 3.1.1 Fish Stocks Coho Salmon Coho escapement to the South Alouette River has ranged from an historic low of 25 fish to a high of 1530 adults in 1988 (Figure 5). South Alouette coho have shown wide oscillations in escapement numbers, but in the last 30 years have averaged about 530 per year (Appendix C). Alouette River Correctional Unit hatchery (ALLCO) workers counted coho at the bladder fence in 2002, recording 490 between November 23 and 27 (J. Ljunggren, ARMS pers. comm.). ALLCO has augmented coho since 1979, stocking an average of 60,064 annually (Appendix D). Presently, coho spawn and rear primarily in tributaries to the South Alouette River including Millionaire, Coho, and McKenny creeks. In addition, coho utilize off-channel habitats at Jenny Brook (opposite ARCC), Latimer Channel (239 th St.), and Grey Gables Channel (232 nd St.). Mainstem spawning is restricted primarily to areas between 228 th Street and the tailrace of the dam (G. Clayton, ARMS pers. comm.) Coho Figure 5. Coho salmon escapements in the South Alouette River from 1925 through 1997 (FISS, Wilson et al. 2003) Chum Salmon Chum escapement to the South Alouette River has ranged from a low of 200 fish reported in several years to an historic high of 123,000 in 1998 (Figure 7; Appendix C). Escapements averaged 1,700 from 1931 to Alouette chum abundance has increased recently, attributable in large part to the augmentation from ALLCO (G. Clayton, ARMS pers. comm.). An average annual stocking of 742,772 chum fry has occurred between 1979 and 2002 (Appendix D). Between 1981 and 1999, the average annual chum escapement has increased to about 27,059 spawners, prompting the hatchery to withdraw from chum production as of 2002 (G. Clayton, ARMS pers. comm.). LGL Limited Page 10

21 The majority of chum spawning occurs between 212 th Street and the ARCC (G. Clayton, ARMS pers. comm.; Walter and Scott 2000). Latimer Channel near 239 th Street and Coho Creek near 224 th Street are the two most important tributaries for chum spawning. Chum Figure 6. Chum salmon escapements in the South Alouette River from 1925 through 1999 (FISS, Wilson et al. 2003, Walter and Cope 2000) Pink Salmon Pink salmon were believed by Elson (1985) to have been extirpated from the South Alouette River. Since 1983, the Alouette River Correctional Unit hatchery has stocked an average of 301,887 pink salmon in each odd year into the South Alouette River (Appendix D). Escapement counts between 1985 and 1997 have averaged about 1,700 (Figure 7; Appendix C). The majority of pink spawning occurs from 216 th Street up to the Mud Creek confluence (G. Clayton, ARMS pers. comm.). LGL Limited Page 11

22 40000 Pink Figure 7. Pink salmon escapements in the South Alouette River (FISS, Wilson et al. 2003) Chinook Salmon Wild chinook were last seen in the Alouette River in the early 1930 s (Bob Franklin, retired Post Master in Maple Ridge pers. comm.) just after the completion of dam construction. An intensive stocking program was initiated by ALLCO in 1996 to reintroduce chinook stocks to the South Alouette River. Between 1996 and 2000, an average of about 113,175 chinook fry were stocked annually (Appendix D). A limited number of chinook salmon were observed in escapement counts in 1998 and 1999 (Walter and Scott 2000). Twelve carcasses were recovered in 1998 and 272 in ALLCO workers have counted chinook at the bladder fence since 2000 with about 30 being observed in 2002 (J. Ljunggren, ARMS pers. comm.). The majority of chinook spawning occurs between 216 th Street and the Alouette Dam (G. Clayton, ARMS pers. comm.). Latimer Channel is also used by some chinook for spawning Steelhead Both wild and hatchery winter steelhead reside in the South Alouette River. Steelhead spawning occurs primarily in the steeper reaches between 232 nd Street and the Alouette Dam (G. Clayton, ARMS pers. comm.). Between 1961 and 1995, a few snorkel surveys (n=7 yrs) had maximum daily counts ranging between 9 and 42 steelhead adults (van Dishoeck 2001). A concerted effort was made in 2001 to assess adult steelhead abundance with 179 being counted on 23 March. This visual count equates to approximately 12 steelhead per kilometre (van Dishoeck 2001). Steelhead have also been counted in North Alouette River snorkel surveys that were conducted on a single day in each of three years, 1976, 1977 and The daily maximum counts were 41, 4 and 10, respectively (van Dishoeck 2001). LGL Limited Page 12

23 Based on a smolt to adult survival of 6 to 8%, Griffith and Russell (1980) estimated an existing (1980) annual smolt output of 3311 to 3974 smolts would return between 200 and 318 steelhead adults to the South Alouette River. For the North Alouette River, they estimated that the existing estimated production of 467 to 561 smolts would return approximately 28 to 45 adults. They predicted that with some natural enhancement of the South and North Alouette rivers, adult steelhead returns could be between 427 and 681. In the Greater Georgia Basin Steelhead Recovery Action Plan, Lill (2002) estimated the capacity for the Alouette at 4600 steelhead smolts with 600 returning adults, assuming a marine survival of 13%. Steelhead smolts have been stocked in the river by the Fraser Valley Trout Hatchery since 1998 (Appendix E) and by the Alouette River Correctional Unit hatchery since 1981 (Appendix D). The Fraser Valley Trout Hatchery has stocked, on average, 10,205 steelhead smolts annually whereas ALLCO has stocked 27,444 annually, most of these being fry Rainbow Trout Rainbow trout were also observed during snorkel surveys of the South Alouette River conducted in 2001 (van Dishoeck 2001). Maximum daily count ranged between 9 and 26 fish Cutthroat Trout Cutthroat trout were also observed during 2001 snorkel surveys (van Dischoeck 2001). Maximum daily counts ranged between 2 and 54 fish, some of which were likely anadromous. Anadromous cutthroat trout have been stocked in the South Alouette River by the Fraser Valley Hatchery since 1998 (Appendix E) and by the Alouette Correctional Institute hatchery since 1984 (Appendix D). Average annual releases have been 6,622 anadromous cutthroat smolts by The Fraser Valley Hatchery and about 38,810, mostly fry, by ALLCO. Griffith and Russell (1980) estimated a population size of 500 to 600 anadromous adults for the South and North Alouette rivers, with 94% of these from the South Alouette. They indicated that the primary habitat for cutthroat were the tributaries of these rivers, including Blaney, Millionaire, McKenny, and Coho creeks. In South Alouette River, cutthroat spawn mainly between ARCC and Mud Creek (G. Clayton, ARMS pers. comm.) Migratory Timing Figure 8 shows the approximate run timing for the major salmon stocks (including the extinct early-run sockeye) for Alouette River. Chum and pink salmon spawning also occurs in the late summer and fall with the eggs hatching in early spring. Juvenile chum and pink salmon migrate directly to sea after hatching. LGL Limited Page 13

24 Species Lifestage Passage Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Sockeye adults upstream spawning incubation smolts downstream Coho adults upstream spawning incubation smolts downstream Chinook adults upstream spawning incubation smolts downstream Steelhead adults upstream spawning incubation smolts downstream Figure 8. Probable fish periodicity for anadromous sockeye, coho, chinook and steelhead in the Alouette River Stock Exploitation The now extinct sockeye stock was harvested in First Nation terminal fisheries within the river itself. Fishing sites and villages are known to have existed at the mouths of Alouette River and the South Alouette and North Alouette branches, as well as a village site downstream of Neaves Road and a fishing site upstream of 224 th Street (Driver and Spurgeon 1998). Oral history indicates that weirs and traps constructed of cedar limbs were used to harvest sockeye and pinks (odd years) as they migrated upstream in the South Alouette River (Driver and Spurgeon 1998). Steelhead were also harvested by the Katzie during the late winter to spring seasons. Coho, chum, and pink salmon from the South Alouette River are currently harvested in saltwater commercial fisheries and from tidewater to ALLCO park in recreational fisheries. Although there has been no coded-wire tagging of Alouette fish, the nearby Chehalis and Kanaka rivers provide some indication of fisheries that may be harvesting Alouette coho salmon. Chehalis River flows into the Fraser River approximately 60 km east of the Alouette River. Kanaka Creek also flows into the Fraser River at Maple Ridge, approximately 7 km southwest of the Alouette River. Combined recoveries of coded-wire tagged Kanaka coho for return years 1996 and 1997 are shown in Figure 9. In those years, Kanaka coho were harvested mainly in US sport fisheries and Canadian troll fisheries. Since 1998, with the severe restrictions on coho imposed in 1997 to protect Thompson River coho, the pattern of harvests has substantially changed. Combined recoveries of tagged Chehalis coho from return years show that the majority of coho were harvested in freshwater sport fisheries within the Fraser River and Chehalis River itself (Figure 10). This likely reflects the LGL Limited Page 14

25 recent pattern of harvests for Alouette River coho as well. Harvest rates for Alouette River coho are believed to be quite low in recent years. 30.0% 25.0% 20.0% 15.0% 10.0% 5.0% 0.0% Fraser Gillnet Fraser River Sport Georgia Strait Troll Georgia Strait Sport Juan de Fuca Net Juan de Fuca Sport Washington Sport Washington Net Washington Troll West Vancouver Island Troll West Vancouver Island Sport Central Coast Sport Northcoast Net Northcoast Troll Alaska Troll Figure 9. Combined recoveries (%) of coded-wire tagged Kanaka Creek coho for return years (Fisheries and Oceans MRP database) % 90.0% 80.0% 70.0% 60.0% 50.0% 40.0% 30.0% 20.0% 10.0% 0.0% Fraser Gillnet Fraser River Sport Georgia Strait Troll Georgia Strait Sport Juan de Fuca Net Juan de Fuca Sport Washington Sport Washington Net Washington Troll West Vancouver Island Troll West Vancouver Island Sport Central Coast Sport Northcoast Net Northcoast Troll Alaska Troll Figure 10. Combined recoveries (%) of coded-wire tagged Chehalis River coho for return years (Fisheries and Oceans MRP database). LGL Limited Page 15

26 Alouette River chum salmon are harvested in mixed stock Canadian and US net fisheries, which are managed under the Chum Clockwork Decision Process (DFO 2002b). Fraser River chum stocks are managed as an aggregate, not stock-specific. Harvests of Fraser chum occur primarily in mixed-stock fisheries in Johnstone Strait and in terminal areas as abundances permit. Abundances of Fraser steelhead and Thompson River coho are major determinants of terminal chum fishing opportunities. Alouette River pink salmon were re-introduced in 1984 and would be harvested in fisheries intercepting Fraser River pinks during odd years. 3.2 ALOUETTE RESERVOIR AND TRIBUTARIES Prior to the completion of the Alouette Dam in 1928, anadromous fish species were able to migrate into Alouette Lake. The lake is believed to have supported an early run (May) of sockeye salmon (Wilson et al. 2003). This run was extirpated by 1930 (Wilson et al. 2003), although a population of lake-resident kokanee persists. One of the most fundamental questions to be addressed during the process of assessing the feasibility of reestablishing a sockeye run is whether a kokanee population existed in the lake prior to the elimination of the sockeye run. A second important question to be addressed is whether there is sufficient spawning and rearing habitat above the dam to support reintroduced salmon populations. To address the latter question, LGL conducted reconnaissance habitat assessments in the major tributaries to the reservoir Tributary Stream Habitat Surveys The upper Alouette, Gold, Moyer, Twin North, and Viking contribute approximately 70% of the total inflow to the reservoir during the summer low flow period (Wilson et al. 2000). Gold Creek is the largest tributary to the reservoir and represents approximately 40% of the inflow to the reservoir. The upper Alouette River (above the reservoir) and Moyer Creek are the next largest tributaries to the reservoir. Viking and Twin North creeks are smaller tributaries that drain sections of the only developed area around the reservoir, the campgrounds and day use areas. Both are also predominantly groundwater fed. In some years, as in late September 1998, discharges in these creeks decline to minimal values. As a result, the tributaries are perched several meters above the reservoir surface with flows going subsurface in their respective gravel fans. This is important to cutthroat, rainbow and bull trout which require access from the reservoir to spawn in the tributaries during fall (Wilson et al. 2000). Stream habitat assessments of Gold Creek, Moyer Creek and upper Alouette River were conducted during 5-9 June 2003 to determine the suitability of these streams to support spawning and rearing salmon. Viking and Twin North creeks were assessed on 22 September The habitat surveys involved a crew of two people and were conducted following procedures outlined in Watershed Restoration Technical Circular No. 8 (Johnston and Slaney 1996). Within each habitat type (pool, riffle, glide, cascade, other), physical attributes were measured and recorded according to methodologies and LGL Limited Page 16

27 procedures either described or referenced in Johnston and Slaney (1996). Fish habitat surveys involved complete sampling of all habitat units throughout the length of the reach, including photo documentation. Pebble counts (Wolman 1954) were made in three locations of Gold Creek to assess substrate diameter distribution (Appendix F). Gold Creek was surveyed from the mouth of the creek (approximately 1000 m downstream of the road crossing) to a barrier falls (15-17 m height) 2819 m upstream of the road. The lower 223 m of Moyer Creek and 419 m of upper Alouette River were surveyed beginning at their mouths. Viking and Twin North creeks were surveyed for 454 and 989 m, respectively, beginning at their mouths. Both creeks were found to have some limited discharge during visual inspections in June, August and during the assessment in September (~0.03 cms). No fish barriers were found in the surveyed sections with gradients less than 6% in both streams. Table 2 summarizes the stream habitats in these major tributaries. There is a total of 3819 m of lower gradient habitat in Gold Creek which offers good rearing and / or spawning potential for anadromous salmon and steelhead (Figure 11; Photo 1 to Photo 4). Upper Alouette River and Moyer Creek have very limited suitable habitat for anadromous spawning or rearing with average stream gradients of 6.3 and 7.5%, respectively in the lower reaches and higher gradients progressing further upstream (Figure 12; Photo 5 and Photo 6). Viking Creek is flow-limited and currently quite disturbed in the lower reaches with evidence of high coarse sediments and an overwidened channel (Photo 7). It is expected that Viking Creek would provide some low to moderate quality spawning and rearing habitat for anadromous salmonids, particularly coho. Twin North Creek would provide consistent spawning and rearing habitat for primarily coho (Photo 8 and Photo 9). High quality anadromous spawning habitat was found between chainage and m of Twin North with additional pockets of gravel distributed sporadically to the creek mouth. Moderate quality rearing habitat for coho was also evident throughout the surveyed portion of the creek Enhancement History Between 1938 and 1990, rainbow trout, steelhead, lake trout, and cutthroat trout were stocked into the reservoir (Wilson et al. 2003). In 1991, the Bell-Cor Fisheries Project was initiated jointly by BC Hydro, BC Corrections (Alouette River Corrections Centre), and BC Ministry of Environment, Lands and Parks (Fraser Valley Trout Hatchery) to improve the reservoir sport fishery (Wilson et al. 2003). Using netpens located in the reservoir across from Gold Creek, rainbow and cutthroat trout have been raised and released annually to the reservoir and its tributaries. LGL Limited Page 17