Does falling over a waterfall raise or lower the temperature of the water?

This post was in response to Waterfalls FAQ

I’m wondering if creating n artificial waterfall in a pond using a solar-powered pump would have an effect on the temperature of the pond water. On the one hand, I can imagine that the exposure of the individual water droplets to the sunlight might heat them up more than if would if they remained under the surface. On the other hand, it’s theoretically possible that some of the water would evaporate while falling, thus extracting energy from the unevaporated water.

Does either theory hold weight and if they do, which effect would be stronger?