I built a pond in clay that had a massive amount of groundwater coming in. We could only get down 8' because it was coming in so fast, and this was at the end of summer too. We never compacted the clay, or even ran it over too much with the dozer as it was all applesauce from all of the water. This is a re-dug pond with only a little 2' dam. The pond ended up 5' deep with zero rain. By early fall it was using its 8" overflow pipe. The pond builder wanted to use 8" pipe for this small .4 acre pond because of the water. We had a drought last summer where my other pond dropped a foot. Ponds uphill of mine dropped 3', or more. The .4 acre pond? Never dropped an inch.
