Effects of Tides on Suspended Sediment Concentration in the Elwha River After Dam Removal

Abstract

River plumes are a form of sediment transport from the river to the sea. In the Elwha River, Washington, suspended sediment forms a river plume that is released into the Strait of Juan de Fuca. Here, we evaluate the suspended-sediment concentration in water-column profiles and sensor calibration to determine the location of the plume in the Strait. The results suggest that in general, suspended-sediment concentrations were higher on the west side of the delta than to the east side, and a bottom plume was observed in the east. Based on changes in salinity and tides, we suggest that tides control the movement of suspended sediment in the vicinity of the Elwha River mouth, and that low salinity and suspended-sediment concentration are correlated.