Habitat Modification Due to Sediment Gravity Flows: Elwha Dam Removal Baseline Study

Andrea Ogston and Charles Nittrouer, School of Oceanography, University of Washington

R/ES-65

This project will conduct baseline studies prior to the removal of the Elwha River dam on Washington’s Olympic Peninsula. The dam removal provides a special opportunity to explore the sediment-transport mechanisms and seabed deposits resulting from concentrated flows of water and sediment from rivers.  Researchers with this project will undertake a combination of high-resolution seabed mapping, water-column profiling, time-series instrument deployment and seabed sampling as a baseline study, and will repeat these studies throughout the dam removal period.  By evaluating the pathways that sediment takes to reach the seabed, researchers will have a better understanding of the fate of nutrients and other chemicals bound to the sediment — an understanding that will help evaluate the impact of dam removal in the marine environment.