Grant: Alliance Grants

Aquatic ecosystems provide many valuable ecosystem services but are susceptible to multiple environmental drivers (e.g., changes in nutrients and production related to large-scale water diversions; landscape changes associated with forestry, urbanization, agriculture, and industry; and changes related to climate). This Alliance grant will result in the development and application of paleolimnological approaches, using both chemical and biological proxies, to provide information to water managers and fisheries biologists on the extent to which dams have changed nutrient budgets in large lakes and the resultant impact on algal production and secondary producers including the Cladocera, a preferred source of food for planktivorous fish. Paleolimnological approaches use the physical, chemical, and biological information preserved in lake sediment profiles to reconstruct past changes in limnological conditions. In this study our focus is understanding changes in nutrients and production because of changes in dam operations in 2007 and prior to and following the establishment of the Duncan Dam in 1967. Reference lakes of similar physical size will be used to assess for changes in lake production not related to recent change in dam operations will provide valuable information on changes in production of aquatic ecosystems due to other regional factors including recent changes in climate-related factors. The framework developed in this study will be used by BC Hydro to assess, understand, and develop strategies for the management of water flow to help mitigate undesirable changes in nutrients on primary and secondary producers. Further, Fisheries and Oceans Canada will use this data to help understanding and manage vulnerable fish population. While the focus of this study is on Duncan Reservoir and Kootenay Lake, this framework may serve as a model for other regions in western North America to assess changes in aquatic ecosystems, both in the reservoir and the downstream water bodies.