A spillway's a structure used to provide for the controlled release of flows from a dam or levee into a downstream area, typically being the river that was dammed. Spillways release floods so that the water doesn't overtop and damage or even destroy the dam. Except during flood periods, water doesn't normally flow over a spillway. In contrast, an intake's a structure used to release water on a regular basis for water supply, hydroelectricity generation, etc. Floodgates and fuse plugs may be desi… (More on Spillway)