Spillway leak due to poorly compacted clay around pipe and perhaps no antiseep collars installed. Clay must be HAND TAMPED around pipe and as collars.
Fixing is simple in my experience: Either drain pond 2-3' or wait for Summer drop and excavate as much material as possible from pipe on pond side. Compact layer of clay followed by layer of SeekLeak polymer or Sodium Bentonite, and keep adding these compacted layers until original excavated material has been replaced. Resolved hundreds of spillway leaks this way - process take a couple hours.
Thx TJ. That was similar to plan I was thinking of earlier. Only I was thinking of concrete around the pipe. Water just has not been low enough to try it. There are 2 seep collars in place. I think maybe they are too far back from the front of the dam. I thought they compacted the soil pretty well around the pipe and collars, but the ground settled about 6” after a few years, so my take is they did not pack the soil properly.
Is SeekLeak, the same as the SoilFloc I got from you before? It would be easier than mixing concrete down there.
Thx again.
