A water return....

Has anyone ever thought about, installed, designed any kind of water return for an ag pool with a deck.
Over the weekend I lost about a 1/2 inch of water to kids getting in and out and jumping back in. Refilling is not a problem for me as I have a fresh water stream in my front yard just the pain of dragging the hoses and pump out to fill it every so often. Just thought if anyone had heard of doing anything like this I was thinking of adding thin sheet metal on an angle to try and return some of the water back into the pool my deck is about 4" higher than the top of the pool so I have room.

The first thing that came to mind was; what is your deck made of and what will be returning to the pool? Dirty water? Pressure treated chemicals? I know what you mean about losing water, but I don't know if it would be worth the aggravation and expense of installing sheet metal under the deck. Just my opinion.