The Elwha Dam Removal: an Opportunity to Achieve Large-Scale Aquatic Ecosystem Restoration

On September 17 of 2011, a 2.5 year deconstruction of two long-standing, high-head dams will begin on the Elwha River of the Olympic Peninsula, Washington State. Over the past decade, a variety of ecosystem related information (e.g., fish, riparian, in-stream habitat, and stream productivity) has been collected in the Elwha River basin to establish baseline conditions prior to one of the largest watershed and salmon restoration projects in North America. The design of these studies is based upon the geomorphic template of the watershed, as different channel types are expected to respond differently to the large amount of sediment that will be released as a result of dam removal. For example, we anticipate that floodplain channels will attenuate the impacts of sediment and provide biological refuges after dam removal. Over the last decade the group of scientists from several state, federal, and tribal organizations have collaborated to identify the most important questions and develop adequate study designs that can answer these questions such as how will salmon populations respond to the removal of large-scale, long-term barriers to migration? How will these same populations react to the large amount of sediment that will be released in combination with the large amount of pristine habitat that will be re-connected? Our ultimate goal is to quantify the ecological “signal” following dam removal in the Elwha River basin, in order to better tell the story of this unique watershed restoration and share critical findings with other dam removal projects.