I have a 1 acre pond on my property that has a stubborn leak. The pond has not been maintained over the years resulting in numerous trees on the dam. I have removed many of them right or wrong. Currently it's around half full and leaks 1/4 inch per day. Last year this time it was 1/2 inch. With all the rain we had last summer, I think it helped plug the leak. My theory is this problem started when the pond was renovated about 6 yrs ago before I owned it. I know it held water fine 15 yrs ago.
Today I decided I'd dig test holes around the pond to see what clay content it had. This area of Kansas has really rocky and gravely soil. I didn't find any of that and great clay. That was until I reached the North end and found sand about 8 inches deep with underlying clay and some rock. Holes I dug filled with water that percolated through the sand. Could this be my leak? The area is about 20-30 ft across.
I still question my dam though it's not wet anywhere behind it. My original plan was to treat with soilfoc which I have a pallet of... 10 units I think. Should be plenty to treat my dam and maybe that sand zone but how well does it stop sand??
Attached a few pictures. You can see the water leaking back through. Now I need to find out how far the sand vein extends. Building a pond siphon this week...
When the pond was renovated and deepened, I bet the original clay liner was breached. In areas where soils are suspect, it's a common practice to line the entire basin with clay, if available. Years later, when that pond is renovated, if the earthmover doesn't realize the pond was sealed with a clay liner, it is easily perforated, especially if the desire is to make it deeper.
Teach a man to grow fish... He can teach to catch fish...
I need to do more digging but my primary agenda at this point is getting the water out. My original plan was to observe the loss until it stops so I'd have an idea what level the leak began. Fortunately and unfortunately it isn't leaking fast enough before spring rain will hit and fill back up. Last year it was much lower by this time so I know that sand must extend out a ways. You can see in one of the pics a large dirt pile across the pond. One 4 times that size is back behind where I was standing. It was used to basically extend the dam on around I think. There is basically zero organic matter in the pond anymore. Maybe half on inch of dead leaves was over the sand.