Well,the general wisdom is, of course, to keep them away from the pools. But mesquite is a very popular ornamental tree most everywhere, so they are certainly quite commonly around pools. And for those with tiny tract homes, if not in your own yard, then you may have one next door that you can do nothing about. While searching I found a fellow desert dweller who complained of a large mesquite just past the wall next to his pool. But his focus was on the stuff going to the bottom and hot to get it out before clogging, which I've already dealt with to my satisfaction. As he noted, the only saving grace is that these do tend to sink quickly, as long as they are not dead and dry. Good for him since most of the dry dead leaves are on the ground opposite the fence, and wind won't carry too many to his pool. Not good for me with flat ground between.

On that note, I have done things to help minimize the problem before it gets in the pool. For instance, I noticed that any little ridge or obstruction causes the blasted dry leaves to congregate on the up-wind side. So I dug out a sort of shallow drain trench beside the deck so that the concrete lip went from 1/2" or so up to about 1.25". Becomes a bit more of a trip hazard, but it's only about 5" wide (hoe width), and no small kids or elderly, so tolerable. Of course that means that if there is any wind, I have to clean it out regularly or it just builds a ramp over the edge. Once a month we go through and blow out all the accumulated leaves (I can't believe there are any actually on the @$%# tree any more!) into a pile and remove. I also vacuum (yeah, I vacuum my back yard) to gather the little collections next to every semi-vertical edge where they collect. Hoses, expansion joints, planter edges, etc. So I take my shop vac and gather the piles periodically, oh joy...