Experimental Observations of Overwash Deposits on Berm Beach with Shoreface Nourishments

Coastal overwash occurs frequently on the crest of dunes or berms under hurricanes and storm surges. It is well recognized that the volume of overwash deposits depends on tidal level, setup induced by storms, wave setup, short wave runup, standing wave height and berm/dune shapes (i.e., crest level and foreshore slope). However, previous analysis was based on datasets collected on natural beaches, and there are hardly any studies focusing on overwash process with shoreface nourishments. Laboratory experiments regarding overwash deposits on berm beach with shoreface nourishment were conducted in a wave flume. Results showed a morphological coupling between overwash deposits and shoreface nourishment. The volume of overwash deposits decreased with the seaward slope and increased with the ratio of crest depth to the shoreface nourishment height.