Carolina Bays and the Sewee Shell Ring Site, South Carolina: Evidence for Natural and Planned Water Gathering

Abstract

Abstract Natural water gathering in two newly discovered Carolina bays, designated as Oak Bay and Pine Bay was studied. These bays and the Sewee shell ring, a planned water gathering system built by man approximately 4,100 yr BP, provided a supply of freshwater. The Sewee shell ring is positioned in the lower southeast to southwest quadrant of Oak Bay. Freshwater entered Oak Bay via rainfall, an ephemeral stream and surface flow from Pine Bay. This freshwater moved downslope into a perennial stream that originated in Oak Bay. The perennial stream then flowed into a Slough adjacent to the Sewee shell ring. Evidence indicates that a Slough shell structure, the Sewee shell ring itself, and a Ridge line sequestered this freshwater in the Slough adjacent to the shell ring. Structures designated as Upper and Middle Weirs regulated downslope flow of water from the Slough. A watercourse located within the Upper and Middle Weirs of the Sewee shell ring conducted surface freshwater from the Slough to an Arena-tank at a lower topographic elevation. Water levels in this Arena-tank were controlled by a Lower Weir. This Lower Weir also showed evidence of a watercourse that ended in an estuarine creek. Accumulation of sandy sediments landward of the broad crested Upper and Lower Weirs is consistent with structures built for water retention and storage. The narrow crested Middle Weir, with no associated sediment deposition, was built to control the directional flow of water.