Wave field modification by bathymetric anomalies and resulting shoreline changes: a review with recent results

Abstract

This paper provides a review of available studies on wave transformation by bathymetric changes and the resulting shoreline impacts. Three case studies of beach nourishment projects with significant nearshore borrow areas are examined: Grand Isle, Louisiana constructed in 1984, Anna Maria Key, Florida in 1993, and Martin County, Florida in 1996. A review is presented of field and laboratory scale studies that have examined the impact of offshore pits on the local wave field and sediment dynamics. Solutions for wave transformation by changes in bathymetry are outlined primarily in chronological order following the development from analytical solutions for long waves in one horizontal dimension (1-D) through numerical models for arbitrary bathymetry that include many wave-related nearshore processes. Modeling of shoreline responses due to wave field modification owing to changes in offshore bathymetry is examined with models that include both wave field and shoreline changes and by coupling models that evaluate these processes independently. The wave transformation processes included in nearshore models are important factors in the capability to predict a salient leeward of a pit; the shoreline responses observed in the limited laboratory experiments and at Grand Isle, LA.