Updating Puget Sound tidal channel design guidelines

Many tidal estuaries in Puget Sound have been impacted by development and are a focus for restoration efforts as they are known to provide important habitat for juvenile and adult salmonids. Current design guidelines developed as part of the Puget Sound Nearshore Ecosystem Restoration Project (PSNERP) use regression analyses founded primarily on data collected in San Francisco Bay. Rainfall, geological history, and tidal range all impact channel geomorphology and are noticeably different between Puget Sound and San Francisco. Design guidelines based on data that does not represent the local conditions may lead to under or overdesigning of restoration projects and decrease the effectiveness of restoration projects in reaching physical and ecological goals. During the first phase of an Estuary and Salmon Restoration Program (ESRP) learning project is data were collected in seven functional embayments in 2017 to provide data for updating design guidelines for Puget Sound estuaries. In August through September 2017 at each of the seven sites, Acoustic Doppler Current Profiler (ADCP) transects were collected to evaluate the tidal input into the estuary over a complete flood tide. Real-time or post-processed high precision Geographic Positioning System (GPS) data were collected to delineate primary tidal channel and marsh geometry. In addition, GPS linked photos were collected to characterize site conditions and document sediment type. At one site a drone survey was completed and used to create a 3D model of the marsh and beach area. This project is being completed with assistance and input from the Washington State Department of Fish and Wildlife and the Skagit River System Cooperative. This presentation will document results from the 2017 site visits and hopes to solicit feedback on results and work planned for data collection and desktop analysis in 2018 and 2019