Planning, implementation, and monitoring Pacific salmonid recovery following the removal of two hydroelectric dams on Washington\u27s Elwha River

The removal of Elwha and Glines Canyon dams on the Elwha River is the largest existing dam removal project in the United States. Project planning, implementation, and monitoring have occurred over 30 years and has required diverse technical expertise. Because of the size and nature of the project—two high-head dams releasing massive amounts of sediment into the river, estuary, and nearshore ecosystem—the project was unprecedented and required a great deal of technical expertise to plan, execute, and monitor. The relative success of this project required effective collaboration among individuals and organizations with varying missions. Individuals with diverse technical expertise (i.e., engineering, geomorphology, hydrology, botany, wildlife, fisheries, stream ecology, ecological monitoring) have successfully collaborated to develop several technical plans ensuring dam removal was completed, while at the same time protecting a city water supply, infrastructure, and listed and unlisted salmonids in the basin. This collaboration has continued following dam removal through the implementation of a monitoring and adaptive management plan. Our monitoring strategy often uses multiple scientific methods to evaluate metrics or performance indicators to create multiple lines of evidence, reduce uncertainty, and ensure data availability. Employing such diverse methods would not have been possible without multidisciplinary and multiagency collaboration. Collaboration and extensive monitoring has allowed project partners to identify potential barriers, assess the rate and extent of recolonization, estimate abundance, life history attributes, and productivity. This collaborative multidisciplinary approach has allowed us to monitor salmonid recovery, while also improving our understanding of ecosystem response and linkages. This has resulted in the Elwha River being one of the best studied dam removal projects in history