I have a very similar situation. Pond been here at least 40 years with the same type overflow pipe that goes through my dam. I think it is leaking somewhere. The pond is fed by a seasonal small creek. I have a spillway that in super heavy rains will take the water over the spillway. I could cover the back end of the pipe and when we get heavy inflow from the creek just let it go over the spillway?

I am in Georgetown Texas - any suggestions on someone who could come out and check it out?