The Sewanee Watershed
Sewanee is located on top of the Cumberland Plateau and therefore obtains all its freshwater from rainwater-fed reservoirs (Lake Jackson and Lake O'Donnell).
Sewanee straddles the Lower Crow Creek subwatershed and the Upper Elk subwatershed. The Lower Crow is part of the Guntersville Lake Watershed. The Upper Elk is part of the Elk River Watershed. Guntersville Lake and the Elk River drain into the Tennessee River, which drains into the Mississippi River. The Mississippi River eventually makes its way to the Gulf of Mexico.
Source for the above text is the Guntersville Lake Water Quality Management Plan (2008).