It is just re-circulating the same water to keep it from becoming stagnant. Stagnant, or still water, is more prone to grow algae and whatnot. Helps out so you use less chlorine.

It circulates the water from the filter that removes the gunk from the water. A Lifeguard once told me that when filters are cleaned out they mostly contain curly hairs. If the water comes out with enough speed then they also can massage you, which makes some people stand in front of them and then they turn pink all over according to the Lifeguard. Sometimes I hold my hands in front of the strongest ones and let them push me away from the wall, and it feels good on your neck if its not cold. There is one pool that has a hot tub that reeeeally has strong water coming out of it. Its like sitting in soup because its soooo hot and the water comes out everywhere and all the air in the water makes it look like its boiling, especially with the suds on top. I can only stand being in it less than 15 minutes because it is so hot that I feel sick if I stay in it. I also got a terrible ear infection when I put my head under water in it. I was told you should _never_ put your head underwater in a hot tub because you will get an infection if you do. That seems strange, its so warm and there is so much foam on the water you’d think it would be okay. Also, these guys are also always bumping into me and the water pushes their fingers into my hands even if i’m just sitting there with my eyes shut trying to float on the water coming out. It doesn’t seem that crowded, usually I am the only one when I go in but then there is a stampede and I’m in people soup. So I stay until I’m nearly cooked and then get out. The other people look like cooked beets when they get out, I don’t know how they stand it.

Basically that’s where the water comes out of those holes that has been filtered and heated (if the pool is heated).