Coastal Studies in Support of the Sargent Beach, Texas, Erosion Control Project

Abstract : One of the areas of highest coastal erosion rate along of the Texas coast is located in the deltaic headland coastal segment of the Brazos River in the vicinity of Sargent Beach. Sargent Beach is located south of Freeport, Texas, some 50 miles (80 km) southeast of Galveston. Because of this erosion, a section of the Gulf Intracoastal Waterway (GIWW) from Cedar Lake to East Matagorda Bay is in danger of intrusion from breaching of the narrow (less than 1000 ft wide) shorefront. If measures are not taken in the immediate future, this reach of the GIWW will no longer be a viable route for barge transportation of commercial goods. Owing to its deltaic origin, the beach is composed of cohensive fine grained clay and silt material, overlain by a narrow layer of coastal peat and topped by a thin veneer of fine-grained quartz beach sand with a high percentage of shell fragments. The northeastern half of the study area has an average erosion rate of 25 ft/ye and has a thin sandy flat sloping beach over the mud deposit. The southwestern section has up to a meter high clay bluffs outcropping into the surf zone and has an average 36 ft/yr erosion rate. It is speculated that this high erosion rate is a result of intermittent wave cutting of large chunks of the clay bluff material.