I am looking for recommendations for someone experienced in repairing leaking ponds. This will likely be a "dam" issue and not the bottom (although I am not sure it isn't both). I definitely see water rushing after a heavy rain and a lot of erosion near the "dam". This is in College Station. (crossed on Outdoor board)

there used to be a little Dutch kid around here that was able to fix leaks such as what you describe but I think he has since grown up & moved away.....

Go over to the Texas Fishing Forum and post this in the Private Waters section. There are some very knowledgeable folks that post there.

There's a local company you can call to come out and take a look. Lochow Ranch
https://lochowranch.com