Pond Boss Forums POND CONSTRUCTION Building a dam I think I have a leak around the overflow pipe

Wasn’t sure exactly where to post this. Hopefully this is the correct place. This is the first time in years my pond is full. I’ve noticed it really seems to drop quickly when completely full. It’s down about 4” now, which would have been fantastic a few months ago, because it was almost 2 feet down. I was back at the base of the dam looking for any evidence of a leak. There was a trickle of water in the old ravine we dammed up to build the pond. It didn’t appear to be coming out at the base of the dam. When walking around back there, which is very brushy with briars and poison ivy, I stepped near where the drain pipe comes out at the base of the dam. My foot sank in to deep mud, with water coming to the surface. It almost has to be from water seeping along the pipe.
The guys that built the dam put in the pipe. I was there 10 years ago when they put it in. They put collars on it to block seepage. I’m not sure they’re in the right places, and I’m fairly certain they didn’t get the clay packed in tight enough around the pipe and collars.
I’ve dug it out around the head of the pipe and packed in kitty litter, and soil floc. I thought it was fixed, or at least slowed down. Now I’m not so sure. Maybe from being so low for so long, the leaking area has opened back up.
I’m thinking of getting a hold of some heavy plastic and trying to fit it around the pipe at the inflow. Cinch it very tightly around the pipe. Then spread the plastic out maybe 8 feet down into the water and along the water line. Then dumping clay on top of the plastic.
Any thoughts on this being a viable solution? Any better ideas?
Just an FYI, I was told by a member here (Rex Rainman) many years ago, that this was probably my situation. His recommendation was to completely remove the drain pipe, and put in a siphoning system. I elected not to go that direction. The soil above the pipe at the top of the dam, definitely settled where the pipe goes through. That indicated to Rex that the pipe wasn’t packed in properly, and why he suspected a leak.