GEOMORPHOLOGY OF THE REEDY RIVER IN THE VICINITY OF LAKE CONESTEE NATURE PARK, GREENVILLE COUNTY, SOUTH CAROLINA

Earliest historic records indicate that the Reedy River south of Greenville, SC was dammed in 1790 to produce Lake Conestee. The current stone-and-mortar dam was built in 1892 to provide power for Conestee Mill, an early textile operation. This study investigates the geomorphology of the Reedy River in this region to determine the relationship of channel morphology and lake shoreline with increased urbanization and industrialization since the early 1900s. Aerial photographs show that the surface area of Lake Conestee decreased tremendously between 1964 and 1970 as a result of significant sedimentation. Historic topographic maps and land records also show shifts in the river channel between the early 1900s and today, although there are insufficient data to correlate channel shifting to specific human activities or geologic processes. Bedrock in the region is dominated by biotite-quartz-feldspar gneiss with interlayered sillimanite-mica schist and amphibolite. Bedrock shoals along the Reedy River above and below Lake Conestee are regularly spaced (about 2.5km apart), have been the sites of historic dams, and display jointing, predominately N25W and EW. In order to better understand channel migration, ground-penetrating radar (GPR) data and 3-meter core samples were taken for a backswamp and a natural levee adjacent to the Reedy River 0.8 km upstream from Lake Conestee. The GPR transects reveal layers in the subsurface that correlate with the two 3m core samples investigated. For the backswamp, the core consisted of a thick layer of organic material above fine silt and clay with intermittent organic-rich zones. For the natural levee, the core consisted of fine to coarse sand with lesser clay. An additional GPR transect and manual probing along the middle of the river channel revealed a buried shoal, the possible site of an historic mill and dam referred to as Carruth’s dam. These studies confirm that the Reedy River is a dynamic geomorphic system affected by human inputs related to urbanization and industrialization. Understanding the geomorphology of the Reedy River and Lake Conestee provides vital information for the conservation and management plans for the dam, lake, and nature park.