What effects do waste heat likely to have on the lakes and streams?

Answer 1

Waste heat? From what? Most lakes have enough water to deal with massive temperature changes. The water in the lower depths of most bodies of water is relatively consistent year round.

Take, for example, the Hoover Dam. Lake Powell behind it has frigid temperatures deep in it's depths. When water is run through the dam to provide power, the water which is released into the Colorado River is very cold. This cold water, which winds through the Grand Canyon, never sees enough sunlight to heat up. This change in temperature led to the total distruction of the existing eco-system, and none of the fish now found there were the fish that would have been found there in previous eras.

Answer 2

Overgrowth of algae. Killing off fish and plant life.

Answer 3

less water