MODELING WAVE-DRIVEN CHANNEL ACCRETION IN THE LITTORAL ZONE

Abstract

Cross-shore channels dredged in the littoral zone may be helpful to naval amphibious landing operations. Research and experiments conducted in the U.S. Army Corps of Engineers’ (USACE) large-scale sediment transport facility (LSTF) show that these channels fill in due to longshore sediment transport and cross-shore sediment transport. This thesis describes the process of modeling a 2019 experiment conducted in the LSTF with the Surface-water Modeling System (SMS). Waves were modeled with the Steady-State Spectral Wave (STWAVE) model, and sediment transport was modeled using the Adaptive Hydraulics (ADH) model. The main tuning parameter for STWAVE was the bottom friction value, quantified by Manning’s roughness coefficient, n. The n values that caused STWAVE wave height outputs to match experimental values were 0.425 in the channel and 0.325 in the rest of the basin. Wave stresses from the STWAVE model were input to the ADH model, along with bathymetry extracted from LIDAR scans of the LSTF, to examine the change in the bathymetry of the LSTF due to sediment transport. The bathymetry output of the model after an initial 20-minute run of waves matched the experiment closely. Several courses of action for future development of the model will contribute to USACE’s dredge development and research of channel accretion.