Major River Basins of South Carolina

Land, Water, and Conservation Division

Earth Science Group

South Carolina’s water resources take part in a hydrologic cycle which extends beyond state boundaries. Rainfall from neighboring areas of Georgia, North Carolina, and even a portion of Virginia enters South Carolina through rivers and streams. This area can be divided in to four major hydrologic basins -- The Savannah, the Santee, the Pee Dee, and the Edisto/South Carolina Coastal Basins. Hydrologic basins (also called watersheds) are scientific concepts which describe lands with a common surface flow path - all of the water will eventually flow to the same place. Basins are also subdivided in to smaller basins. Each watershed is identified by a unique Hydrologic Unit Code, or "HUC". This helps in studying surface water from multiple scales. The SC DNR Hydrology Section is currently building detailed models of surface water for each basin.

The Pee Dee Basin is the largest and furthest North, extending all the way in to Virginia. Rainfall in this basin flows to the Pee Dee River and enters the Atlantic Ocean at Winyah Bay.

The Santee Basin also extends in to North Carolina. Major rivers such as the Saluda River, Broad River, Catawba River eventually merge into the Santee River before reaching the coast.

The Savannah Basin includes a small portion of North Carolina and all of the land in South Carolina and Georgia which drains to the Savannah River. The Pee Dee, Santee, and Savannah hydrologic basins all begin at the Eastern Continental Divide. Rain that falls to the West of the divide can eventually drain to the Gulf of Mexico, but rain that falls in these basins will enter the Atlantic Ocean.

The Edisto/South Carolina Coastal Basin is different from the other hydrologic basins of South Carolina. First, it is much smaller; it only extends to the Fall Line which distinguishes the Coastal Plain from the Piedmont. It is entirely within the state of South Carolina. While the Edisto River is the largest river in the basin, there are many smaller rivers that flow directly in to the Atlantic Ocean. For this reason, the basin can also be called the South Carolina Coastal hydrologic basin.

These Hydrologic basins are different from the legal, or regulatory, basins of the state. You can find out more about regulatory basins in the South Carolina Water Plan.

For more information, data, or publications, visit the website of the SC DNR Hydrology Section.