Why does a waterfall cool a pond in the summer, but not freeze in the winter?

Question

I have a small waterfall and a pond in my backyard. In the summer, it helps cool the temperature of the pond, but in the winter, even when the pond is mostly frozen, the waterfall is not. If the energy from the moving water is keeping it from freezing (I assume...), why does it cool in the summer? Is it because the air around it is actually cooler than the water in the summer? If so, why is the water in summer warmer than the surrounding air? :) Thanks!

Thank you! So does it not freeze in winter because of the energy of the moving water? And if that's the case, then why does it have a cooling effect on a pond in summer, but keep it from freezing in winter? Does motion change the freezing point, or the temperature? :)

I should add when I say "Pond", that it's only about a foot deep, and 5 wide, tops. :D

Answer 1

The waterfall cools the pond in the summer because it "mixes" the water, so the water from below the surface mixes with the sun-warmed surface. Water does not cool or warm as fast as land anyway, due to its high specific heat capacity. In the winter, the waterfall will freeze if its cold enough. The flow of the water makes it harder for the water molecules to accumulate around an ice nucleus.

Answer 2

The waterfall is not cooling your pond it is actually helping the sun to heat it by rippling the water and giving more area exposed to warm air.
It is the cool water that is closer to the earths temperture that cools your pond because earth heats slower than air exposed to the sun and cools slower than air.
It is the creek bed above and before the waterfall that determines the temperture of the water. Being lower than the surounding earth the creek bed or river bed has more earth [rock mud vegatation] around it as water is surounded by three sides earth 1 side air so water will be cooler on hot air days and warmer on cold air days.

Answer 3

As the water falls, it evaporates. Evaporation removes heat from the remaining water, thus cooling it. It takes energy form water to change from a liquid to vapor. The water is usually warmer because it absorbs heat from the sun. The dark pool bottom will absorb heat.