Interpretative Analysis of Surfical Sediments as an Aid in Transport Studies of Dredged Materials, Cape Canaveral, Florida

Abstract

Source: https://erdc-library.erdc.dren.mil/jspui/Analyses of surface and core sediment samples; dredging records; bathymetric surveys; wind, wave, and current data; and pertinent literature were undertaken to determine the amount and direction of sediment transport from a dredge disposal site. The site is located 4.5 miles east of Cocoa Beach, Florida, in 40-55 ft of water, on the inner continental shelf. Dredge disposal material is composed of clay, silt, and fine sand removed from the entrance channel t o Port Canaveral Harbor located approximately 7 miles to the north. Volumetric calculations were made using 1983 bathymetric data. Comparison between the bathymetric data and the known amount of sediment placed on the site during disposal operations (1974-1983) indicates a loss of material from the site. However, consolidation of disposal material, unknown predisposal bathymetry, and "short-dumping" could account for much of the loss. Sediment analysis and subsequent plotting of sedimentologic parameters (mean grain size, standard deviation, and skewness) revealed no trends in sediment distribution at the disposal site. Insufficient sample intensity and the general similarity in the size and composition of the dredge disposal material and the indigenous shelf sediments may explain the lack of identifiable trends in sediment distribution. Sediment transport studies conducted in the Cape Canaveral region by previous investigators indicate that net movement is alongshore, or approximately north- south. The variability of local winds and currents in the vicinity of Cape Canaveral makes such generalizations only moderately reliable relative to this specific disposal site. Sand waves on the shelf surface, detected on side- scan sonar profiles, indicate recent current activity at the disposal site capable of transporting sediment. Results of this study suggest that detailed site-specific data are necessary in order to make conclusive statements about sediment transport off the disposal site