Bahr el-Ghazal (wadi in Chad)
The Bahr el-Ghazal is a wadi, or dry riverbed, in central Chad. When water flows through it, it flows from southwest to northeast, away from Lake Chad and into the Bodélé Depression.
The "sill" of the Bahr el-Ghazal is the lowest point on the drainage divide between the Lake Chad and Bodélé basins. In the past, when Lake Chad filled to this point and overflowed, it was drained by the Bahr el-Ghazal.