Lake Roosevelt Fisheries Evaluation Program : Limnological and Fisheries Monitoring Annual Report 1999.

Abstract

The Grand Coulee Dam was constructed in 1939 without a fish ladder, which eliminated steelhead (Onchorhynchus mykiss), chinook salmon (O. twshwastica), coho salmon (O. kisutch) and sockeye salmon (O. nerka) from returning to approximately 1,835 km (1,140 miles) of natal streams and tributaries found in the upper Columbia River Drainage in the United States and Canada. The Pacific Northwest Electric Power Planning and Conservation Act of 1980 gave the Bonneville Power Administration (BPA), the authority and responsibility to use its legal and financial resources, 'to protect, mitigate, and enhance fish and wildlife to the extent affected by the development and operation of any hydroelectric project of the Columbia River and its tributaries. This is to be done in a manner consistent with the program adopted by the Northwest Power Planning Council (NWPPC), and the purposes of the Act' (NWPPC, 1987). With the phrase 'protect, mitigate and enhance', Congress signaled its intent that the NWPPC's fish and wildlife program should do more than avoid future hydroelectric damage to the basin's fish and wildlife. The program must also counter past damage, work toward rebuilding those fish and wildlife populations that have been harmed by the hydropower system, protect the Columbia Basin's fishmore » and wildlife resources, and mitigate for harm caused by decades of hydroelectric development and operations. By law, this program is limited to measures that deal with impacts created by the development, operation and management of hydroelectric facilities on the Columbia River and its tributaries. However, off-site enhancement projects are used to address the effects of the hydropower system on fish and wildlife (NWPPC 1987). Resident game fish populations have been established in Franklin D. Roosevelt Lake, the reservoir behind Grand Coulee Dam, since the extirpation of anadromous fish species. The resident game fish populations are now responsible for attracting a large percentage of the recreational visits to the region. An increase in popularity has placed Lake Roosevelt fifth amongst the most visited State and Federal parks in Washington. Increased use of the reservoir prompted amplified efforts to enhance the Native American subsistence fishery and the resident sport fishery in 1984 with hatchery supplementation of rainbow trout (O. mykiss) and kokanee salmon (O. nerka). This was followed by the formation of the Spokane Tribal Lake Roosevelt Monitoring Project (LRMP) in 1988 and later by formation of the Lake Roosevelt Data Collection Project in 1991. The Lake Roosevelt Data Collection Project began in July 1991 as part of the BPA, Bureau of Reclamation, and U.S. Army Corps of Engineers System Operation Review process. This process sought to develop an operational scenario for the federal Columbia River hydropower system to maximize the in-reservoir fisheries with minimal impacts to all other stakeholders in the management of the Columbia River. The Lake Roosevelt Monitoring/Data Collection Program (LRMP) is the result of a merger between the Lake Roosevelt Monitoring Program (BPA No. 8806300) and the Lake Roosevelt Data Collection Project (BPA No. 9404300). These projects were merged in 1996 forming the Lake Roosevelt Monitoring Program (LRMP), which continues the work historically completed under the separate projects. The LRMP has two main goals. The first is to develop a biological model for Lake Roosevelt that will predict in-reservoir biological responses to a range of water management operational scenarios, and to develop fisheries and reservoir management strategies accordingly. The model will allow identification of lake operations that minimize impacts on lake biota while addressing the needs of other interests (e.g. flood control, hydropower generation, irrigation, and downstream resident and anadromous fisheries). Major components of the model will include: (1) quantification of entrainment and other impacts to phytoplankton, zooplankton and fish caused by reservoir drawdowns and low water retention times; (2) quantification of seasonal distributions, standing crop, and habitat use of fish food organisms; (3) examination of variations in fish growth and abundance in relation to reservoir operations, prey abundance and predator/prey relationships; and (4) quantification of habitat alterations due to hydrooperations. The second goal of the LRMP is to evaluate the impacts of hatchery kokanee salmon and rainbow trout on the ecosystem and to determine stocking strategies that maximize angler harvest and return of adult kokanee salmon to egg collection facilities. Major tasks of the hatchery evaluation portion of the project include conducting a year round reservoir wide creel survey, sampling the fishery during spring, summer and fall via electro-fishing and gillnet surveys, and collecting information on diet, growth, and age composition of various fish species in Lake Roosevelt.« less