Nonuniform Sediment Transport Modeling at Grays Harbor

A depth-averaged two-dimensional nonuniform sediment transport model is applied to the beaches adjacent to Grays Harbor, WA, USA to test the model skill in predicting nearshore morphology change. The model considers bed material hiding, exposure, sorting, stratification, bed-slope effects, avalanching, non-erodible bed surfaces, and transport due to asymmetrical waves, Stokes drift, roller and undertow. The sediment transport, bed change and sorting equations are solved simultaneously and implicitly at the same time step as the hydrodynamics. The model is able to capture the onshore migration of the offshore bar and filling of the trough but has difficulty in the foreshore region where swash zone processes are neglected. The calculated nearshore water depths agree with measurements with an average Brier Skill Scores of 0.3 and bed changes with an average correlation coefficient R of 0.53.