River catchment areas

The catchment area in hydrography is the surface area of the Earth, from which all surface and ground waters drain into a particular body of water or watercourse, including all its tributaries.[1] The borders between the two basins are called a watershed. Schematic representation of the river basin. Blue lines denote a river with its tributaries, and a clawed brown line — a watershed. The basins are divided into run-off and non-definitive areas. The zero-definition area is a basin situated within the continent and not connected to the ocean. The lake with such a pool is called no-socket.