How do dams conserve water?

Question

How do dams conserve water?

Answer 1

They're not generally meant to conserve water.  The points concern water storage, control of flow and sometimes power generation.  Recreational facilities can also be involved in some cases with the resultant lakes.

Answer 2

By preventing freshwater from flowing into the ocean.

Answer 3

by retaining the downfalls of rain.

Answer 4

I CONCUR WITH THE FIRST THREE ANSWERS THEY ARE CORRECT TO A DEGREE.