A 3-D MODEL USING REPRESENTATIVE WAVES METHOD FOR SHORELINE MORPHODYNAMICS AROUND COASTAL STRUCTURES

Abstract

The Fort Pierce Shore Protection Project nourishes a 2.1-km Atlantic Ocean shoreline south of Fort Pierce Inlet in St. Lucie County, Florida. The beach fill erodes nonuniformly with a hotspot along the northernmost 0.7 km requiring nourishment after about two years of normal wave regime. This study validated and applied to beach stabilization a shoreline morphology model to evaluate designs and combinations of coastal structures to increase the nourishment interval. Simulations of long-term normal tides, waves, and storm conditions show (a) shoreline movement pattern similar to the general historical pattern observed in the project area, including accurately indicating the largest erosion rate and shoreline retreat along the first 0.7 km south of the jetty; (b) the coastal structures retain beach fill longer, resulting in lower erosion rates from 0.8 to 6.4 km south of the jetty; and (c) the coastal structures alternative extends the normal beach nourishment interval from the current two years to four years. Application of representative waves allows accurate and efficient modeling of long-term 3-D beach and shoreline deformation.