Inflow

Hydrological term for water entering a body of water

An inflow is a river that leads to a lake or some other body of water. The inflow gives the lake a supply of water. If lakes have no way of getting water added to them, they will eventually dry up through evaporation.

Some lakes are big enough that they can stay full through rain instead of inflows. An example of such a lake is the Great Salt Lake in Utah.