The Largest Dam Removal in U.S. History: Coastal Studies and the Elwha River Restoration Project

Join us for this fascinating talk by John Warrick of the U.S. Geological Survey. Two large dams were built on the Elwha River, Washington in the early 20th century and stopped the downstream flow of river sediment and upstream migrations of spawning salmon. Removal of both dams began on September 17, 2011 as part of the U.S. Department of Interior's Elwha River Restoration Project––full removal of these dams will take about two years. Dam removal will reconnect over 100 km of pristine salmon spawning habitat in the Olympic National Park and expose approximately 20 million cubic meters of sediment now trapped behind the dams.

This talk will provide an update of this unprecedented dam removal project and provide background of the cumulative effects of 100 years of damming of the Elwha River watershed. Focus will be given to the coastal portion of the Elwha River watershed, where the river and delta have been starved of sediment, resulting in armoring of the river channel and erosion of the shoreline. Removal of the two dams on the Elwha River will result in the largest controlled release of sediment in history, and effects of this sediment release will also be presented.