Hydrology of Southern Cumberland Island, Georgia. Kings Bay Environmental Monitoring Program, Cumberland Island National Seashore.

摘要

A hydrogeologic investigation of southern Cumberland Island was conducted to determine the effect of channel dredging on the ground-water quality in an aquifer consisting of Pliocene to Miocene sediments. An aquifer test performed in the sand and limestone aquifer indicates that transmissivity of the aquifer ranges from 235 to 504 square feet per day (sq ft/d), hydraulic conductivity ranges from 34 to 72 ft/d. Storage coefficient ranges from 1.4 x 10-5 to 5.6 x 10-5 and diffusivity ranges were included. Test data indicate lateral heterogeneities exist in the aquifer. Analysis of hydraulic data indicates that intrusion of seawater into the sand and limestone aquifer is insignificant in the area of the channel. The amount of freshwater discharged from the aquifer during low tide was an order of magnitude greater than the volume of seawater that intruded the aquifer during high tide. High chloride concentrations in water from aquifer at two sites (13,000 to 17,000 mg/l) indicate that these wells lie within the mixing zone of diffusion.