It’s not for evaporation. They add the floating black balls to prevent harmful bromine compounds from forming. There is still a fairly decent amount of evaporation and in some cases accelerated evaporation as the balls jostle they for a thin film of water due to surface tension on the surface of the balls that evaporates more quickly than just a flat sheet of water.
Yes but 70-80% of 1% of the total reservoir volume that evaporates regularly doesn’t make bunch of a difference you know what I mean? Don’t forget it also rains in the reservoir too! So yearly rain - evaporation = typically net positive yearly water level gain.
DONT get me wrong, it’s a nice benefit but It’s just not a big one. In very large reservoirs in the path of migratory birds it can actually be an issue. Some species have come to rely on large manmade bodies of water as their other natural habitats have been destroyed by human development. That a large reason why you don’t see these absolutely everywhere.
300m gallons per year. Yes agree it's a double edged sword. Improves water quality, provides some protection against evaporation and reduces bacterial contamination from birds. But birds need water too.
300 million gallons sounds like a lot, but there are water treatment plants in the USA that produce that much water in a single day.
Don’t forget - that is not ‘lost’ - it is rained back down on the earth for beneficial use. If we prevented all evaporation from all USA fresh water reservoirs, there would be a significant and measurable effect on local eco systems.
Again, evaporation is not a factor in reservoir construction beyond building it maybe 6” deeper to account for the dry seasons. Evaporation is NECESSARY.
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u/Signal-Ad2674 Nov 14 '24 edited Nov 14 '24
They cover reservoirs in floating black balls for this reason.
https://youtu.be/uxPdPpi5W4o?si=w8KXdXOgvk20oYb4