BEACH-NOURISHMENT PERFORMANCE PREDICTIONS

A simple method is developed for representing wave retraction and shoaling in the vicinity of a beach-nourishment project. The method applies for the case of a one-line model of shoreline evolution in which the active profile is displaced seaward or landward without change of form. The model can include the presence of shore-perpendicular structures and background erosion. It is recommended that shoreline modeling of beach-nourishment projects be carried out by conducting an ad hoc transformation in which the preproject contours are represented as straight and parallel. The simple method is compared to the results of a one-line model, which includes a more detailed grid-based refraction and shoaling algorithm. For all cases tested, the simple method of representing refraction and shoaling results in shoreline evolution in good correspondence with the detailed method. The models are used to illustrate the effects of several features of beach-nourishment projects of engineering interest, including: shore-perpendicular structures placed at the ends of a project with background erosion; and nourishing with material more and less transportable than the native