Determination of fishery losses in the Flathead system resulting from the construction of Hungry Horse Dam

This study is part of the Northwest Power Planning Council's residential fish and wildlife plan, which is responsible for mitigating damages to fish and wildlife resources caused by hydroelectric development in the Columbia River basin. The major goal of this study was to provide estimates of fishery losses to the Flathead system as a result of the completion of Hungry Horse Dam and to propose mitigation alternatives for enhancing the fishery. Construction of Hungry Horse Dam had the greatest adverse impacts on cutthroat and full trout from Flathead Lake and mitigative measures should be taken to offset these losses, if biologically and economically feasible. Also, other losses to fish and wildlife have been documented in the Flathead basin due to hydroelectric facilities and their operation. Some of these research projects will not be completed until 1989, when mitigation will be recommended using a basin-wide approach. Since HHR is at the headwaters of the Columbia system, mitigative measures may also affect downstream projects. Therefore, we presented an array of possible mitigation alternatives for consideration by decision-makers, with suggestions on the ones we feel are the most cost effective. Possible mitigation measures are included.