Santee (săntēˈ) [key], river, 143 mi (230 km) long, formed by the confluence of the Congaree and Wateree rivers, central S.C., and flowing SE to the Atlantic Ocean. The Santee-Wateree-Catawba system (c.440 mi/710 km long) is the chief waterway of South Carolina. A navigable canal (built 1792–1800) connects the Santee with the Cooper River. The Santee has been extensively developed for power and navigation. Santee Dam (48 ft/14.6 m high; c.8 mi/12.9 km long) impounds Lake Marion (172 sq mi/445 sq km), the largest lake in South Carolina. Pinopolis Dam impounds Lake Moultrie.