A Sediment Budget Analysis and Management Strategy for Fort Pierce Inlet, Florida

Abstract

Quantification of the sediment transport processes in the Fort Pierce Inlet, Florida area and the influence of the inlet onto the adjacent beaches was performed by means of analytical methods. This analysis is formalized as a sediment budget and is based on available survey data, nourishment events, and dredging records of the navigational channel at Fort Pierce Inlet, which cover the period from 1972 to 2002. Available survey data encompass shoreline distances approximately 9.7 km north and 24.7 km south of Fort Pierce Inlet. Three intersurvey periods were examined in this study: 1972 to 1987, 1987 to 1997, and 1997 to 2002. Average annual sediment volume and shoreline changes derived from the profile data collected during these three periods were analyzed. Application of general sediment budget principles established that for the total period from 1972 to 2002, there was an average annual deficit of approximately 12,500 m3/y on the beach south (downdrift) of Fort Pierce Inlet. The general sediment budget suggests that 88,700 m3/y enter the north boundary of Riomar Beach some 18 km north of the inlet; 62,700 m3/y enter the north boundary of St. Lucie County some 10 km north of the inlet; and 43,600 m3/y leave the south boundary of St. Lucie County some 25 km south of the inlet. Application of numerical modeling to develop an understanding and predictability of the performance of beach nourishment south of the inlet was carried out as a supporting method to better understand the littoral processes in the area. Recommendations to improve the sediment management practices, including sand bypassing to restore balance to the south beaches, are presented.