ABSTRACT OF THE DISSERTATION An Investigation of Sediment Delivery and Accumulation on a Developed Estuarine Shore: Manasquan, New Jersey by MICHAEL CRAGHAN Dissertation Director: Dr. Norbert P. Psuty This is an investigation of sediment transport and accumulation in a developed area on an estuarine shore. People alter estuarine shores and potentially change geomorphic activity. Understanding similar salt marsh processes, knowing how people change estuaries, and an endogenous determination for human action lead to a framework for evaluating some effects of development on estuarine geo morphology. A study site in the Manasquan River Estuary was selected to test sediment movement from a salt marsh into a low-lying road. The site was once marsh and was filled for a street and housing, it floods on spring tides. Tides at the study area are determined to be highly correlated with Sandy Hook. The correlation held during storm surges. The initial flooding path from a tidal creek into the street involves passage through an engineered drainage system. This catchbasin network had no effect on the availability of sediment in the street; suspended sediment levels at the catchbasin very closely track concentrations in the creek. As flood height increased, water passed freely among the creek, high salt marsh, and street environments. As flood waters from surges or spring tides reach higher, the suspended sediment concentrations in marshes and developed areas converge at minimum values. Sediment traps in the street accumulated some sand sized material and little fine sized matter. In contrast, traps placed in the adjacent marsh accumulated little coarse material, and some fine sized particles. Despite the availability of suspended sediment in quantities comparable to the salt marsh, very little fine material is deposited on samplers in the street, especially compared to identical samplers meters away in the adjacent marsh which collect 3-5 times as much material. The marsh and street are statistically different accumulation regimes?three tests each give greater than 99 % confidence. In the marsh, more material accumulated in summer than winter, and storms deposited more than spring tide floods. Because development features at this site do not restrict sediment availability, the drastic differences in accumulation are due to some effect on sediment deposition. Absence of marsh plants and wave energy from passing automobiles may reduce sedimentation in the street.