Report on a Biologic and Sedimentologic Study Related to the Tybee Island Beach Nourishment Project and the Offshore Area for Dredge Disposal.

摘要

Sediment transport along the foreshore of Tybee Island is related to suspended sand concentrations and longshore currents. In August 1975, swells out of the east-southeast with 8 second periods and maximum heights of 50 centimeters transported sediment in a northerly direction along the foreshore. Approximately 500-700 pounds of sand were in continuous transport at .5 meters per second. The construction of an 800 foot terminal groin at the northern end of Tybee Island may trap much of the sand being transported toward the north. Surveys before groin construction indicated a shore parallel flow of water toward the north and south. The nourishment of the foreshore of Tybee Island with a new sediment cover has not had an obvious damaging effect on the biologic community. Four surveys of the benthic infauna of the foreshore illustrate a greater variance resulting from seasonal change than from burial. Increased turbidity in the water at the depositing end of the pipeline may have an 'attractive effect' on haustorid amphipods in that the highest density of amphipods occurred in the vicinity of the outfall even after a major seasonal decline at other stations.