Photo: Isles characterize the middle Susitna River above its confluences with the Chulitna and Talkeetna River. Corinne Smith/The Nature Conservancy 2012
The Susitna River, the 15th largest river by volume in the United States, supports the freshwater lifecycle needs of five species of Pacific salmon and has seen little impact from humans along its 313 miles. The State of Alaska is in the licensing process to build a 735-foot dam on the river, which would be the largest dam ever built in Alaska and possibly the tallest ever built in the western hemisphere. The decisions made about the design and operation of the dam, and whether or not to build it, will set precedence for how large-scale hydropower is implemented in large, glacially-fed, braided rivers with largely intact habitat and large runs of Pacific salmon in light of climate change, in Alaska and around the world.
The Conservancy has been engaged in the licensing process from the beginning to ensure that good science is being used to study the river, its processes, and the species that depend upon it. The Conservancy is working with many stakeholders, including agencies and NGOs and the Mat-Su Salmon Partnership, to assess potential impacts from the dam. The goal is to guide public policies and management decisions on hydropower that will ensure long-term conservation of salmon and salmon habitat. We are doing this by:
Completing an ecological risk assessment for wild salmon systems for large-scale hydropower based on the proposed design and operation of the Susitna-Watana Hydroelectric project
Summarizing contemporary approaches to sustainable hydropower development and supporting science, case studies and emerging technologies to avoid and minimize adverse ‘first order’ effects of hydropower development on flow, sediment, connectivity and water quality as they influence salmon populations; and providing a comparison with the proposed Susitna-Watana project.
Providing workshops and trainings to stakeholders on TNC tools and concepts that can be used to assess potential impacts from the dam (e.g. Indicators of Hydrologic Alteration)
Participating in the licensing process to review the state’s studies based on analysis with TNC environmental flow tools and the ecological risk assessment
