The turtle garden pond and stream drains into an underground cistern made from a large sportsmans cooler with two return pumps to the spitting frog and old hand pump. Without a picture would never guess what I used for biological filter media in the cistern.
Gravel, small fossils, and small shells cover the grated drain/pvc pipe in the middle of the pool at the end of the stream to the underground cooler. One end is only covered by dirt and has a door so I can easily remove the dirt off the door to access the pumps if I need to. Wiring for everything from a breaker box is underground as well. The pond has Butterfly Koi that take care of any mosquitoes.