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FEASIBILITY OF REINTRODUCING SOCKEYE AND OTHER SPECIES OF PACIFIC SALMON IN THE ALOUETTE RESERVOIR, BC Prepared for: Alouette River Management Society P.O. Box 21117 Ridge Post Office 24949 Alouette Road Maple Ridge, BC V2X 1P7 March 2004 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 21117 Ridge Post Office 24949 Alouette Road Maple Ridge, BC V2X 1P7 March 2004 Feasibility for Salmon Reintroduction – Alouette Reservoir March 2004 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 Feasibility for Salmon Reintroduction – Alouette Reservoir March 2004 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 re- introducing 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 shore- spawning 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 Feasibility for Salmon Reintroduction – Alouette Reservoir March 2004 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 m3/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

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