You can see in this photo, that the water runs down off the platform when the pigeons splash. The shingles on the platform prevent any water damage. The water then drips on the grass and the cement.

Cleanup is easy. Craig just opens up the fronts, pulls the bath pans off the platform and dumps the water on the grass. He rinses them out with the hose, then leans the bath pans up against the steps to air dry for a few hours. Later he puts them away on a shelf in the loft storage area.