Seal it with Water$ave!
Leaking pond or dam? Stop that leak with Water$ave Plug or Water$ave Seep dam sealers.
Ken used Water$ave Plug on the dam above with amazing results. This is what he had to say about the product:
You will be pleased to know the finer grain dam plug you sent me worked a treat. I am really impressed. I have never seen the dam so full & stay full. The bloody thing has leaked like it had a plughole in it for 11 years & now I can plan my gardens because I know I have plenty of water.