Sediment Model Assessment of Geomorphic Channel, Napa River

This paper describes a sediment modeling assessment of a geomorphic channel design proposed for restoration and flood damage mitigation of a six mile tidally influenced reach of the Napa River. The model study employs the unsteady quasi-two-dimensional hydrodynamic and sediment transport model, MIKE 11, and the Rouse equation to calculate sediment transport, erosion and deposition at specific areas across the channel cross-section (i.e. the main channel, the marshplain and floodplain terraces) and a dry bypass channel, and to assess the morphologic stability of the channel. This modeling approach allows for the simulation of salient sediment transport processes including lateral and vertical sorting and distribution of sediments, resuspension due to riverine and tidal flows and local flushing of fine cohesive sediments during flooding.