SBEACH : numerical model for simulating storm-induced beach change

19, ABSTRACT (Continue on reverse if necessary and identify by block number) A two-dimensional numerical model is presented for calculating dune and beach erosion produced by storm waves and water levels. The model is empirically based and was first developed from a large data set of net cross-shore sand transport rates and geomorphic change observed in large wave tanks, then verified using high-quality field data. The model is aimed to reproduce macroscale features of the beach profile, with focus on the formation and movement of longshore bars. The ultimate goal of the modeling effort is prediction of storm-induced beach erosion and post-storm recovery. Bars are simulated satisfactorily, but berm processes are less well reproduced, due in part to a lack of data for defining accre- tionary wave and profile processes. A new criterion is developed for predicting erosion and accretion, and the model uses this criterion to calculate net sand transport rates in four regions of the nearshore extending from deep water to the limit of wave runup. Wave height and setup across the profile are calculated to obtain the net cross-shore sand (Continued) 20.