My guess is that once they get IN the water, you'll never see them get OUT of it ... ever again. What a way to clog a filter!These are sand wasps. They are a solitary wasp that lives in a burrow underground. I have never had any of these be aggressive. There are lots of other wasps that look similar. I doubt you have sand wasps since they don't survive wet ground conditions. I have also never seen these in the water.