Increased demands on water resources coupled with an increased awareness of the need to preserve environmental flows have led to a need to understand how anthropogenic activities may have impacted water resources in South Carolina. The South Fork of the Edisto River has been facing increasing demands for both surface water and groundwater. This research investigated if and why hydrologic change, as indicated by a change in the rainfall/ stream discharge relationship, occurred in the South Fork Edisto Basin, in South Carolina, between the years 1980-2016. A double-mass curve analysis, which is corroborated by runoff coefficients, indicates that a fundamental change in the precipitation-runoff relationship in the South Fork Edisto Basin occurred in the early 2000s. Documented water diversions from the basin were examined as a possible driver of the changing relationship. A Soil Water Balance Model was developed to isolate water budget components and to examine how changes in climatic variables and land use and land cover acted as potential drivers of the change documented by the double mass curve. The results indicate that all three variables have had an impact on the basin. The results have implications to water availability, environmental flows, and water resources management within the basin