How do man-made lakes get filled with water?

Question

How are some man-made lakes so deep? And where does the water come from and how can that much water be transported? It seems impossible to me that we can fill lakes that are 250+ feet deep.

In: Engineering

Answer 1

Rainwater. Lakes are just low-lying areas that water builds up in. All the humans need to do is prevent an already low area from draining, usually with a dam of some sort, and the water cycle will do the rest of the filling.