https://youtu.be/ACSwcEgPFoM

Above is my problem.

My question is how would you go about the process of repairing now that I have a deep cut in the dam?

I cut the pond dam to repair a leak under the core. I have cut down pretty far so it will not continue to fill. The pond is about 1-2ft deep now. I don't believe I have gone below the bowl yet in spots. Maybe at the very back in the valley, but not where the dam is going/has been.

Do I?

A) Scrape with high lift cross wise across the cut and recreate the core 3 ft lower than bowl? Possibly leave the ditch leading to the new core and back fill in lifts of 6 inches? Possibly build in front of it quite a bit???

B) Scrape length wise into the trench and back fill creating a deep solid pack since the trench is about 10ft deep, water wouldn't seep that far to leak under again. (dreaming)The trench is narrow and deep dug with a extenda hoe.

I would appreciate your take and any other suggestions as I will get this going this summer but once again.

One concern I have is that the water could seep around any patch. You will need to tie the patch to the existing dam (anti-seep collar).

Dang, that looks miserable. Mix clay and topsoil for repair.

That wont be too difficult, you will have to dig a much larger, wider ditch with your trackloader so that you can cover all of it with the trackpads to compact it in in lifts, blending it well with the clay in the sidewalls in a rough surface, no smooth cuts or surfaces, try to get the inside, water side, filled and compacted with your best cleanest clay you have available with no foreign materials or topsoil mixed in, the outside half isn't quite as critical, you can use up some of your mixed dirt there,, I have resealed quite a few of them that way with no problems.

Thanks EWest...that's what I thought too. That's why I came up with the across the trench solution. Just didn't know if that was the correct approach. I would have to cut into the existing dam about 10ft and repack a core tying to the existing core.

Dave - Why Topsoil? I've always read you want pure clay.

Gehajake - How would you go about getting the wide trench? Come cross wise and go down like a ramp to the bottom of the existing trench? DO that the length of the trench. Then rebuild the height for the dam in lifts. OR.....go in length wise to the trench and widen the trench?

My concern is that the pond will need to continue to drain so I dont create a wash out situation through the trench (or where it used to be once I am 1/2 way there) and the earth wont be workable. I dont see this as being a day or three kinda job.

Going in length ways with the trench will result in moving and disturbing a lot less dirt, my preference, however some times room is an issue of a property line behind the dam, or geographical limitations, say there is a deep holler or solid woods, you will need a good bit of space to store dirt while you excavate wide and deep enough to get good sealed dirt on bottom and both sides.
doing it sideways results in having to move considerably more dirt as sloping it back far enough to be able to drive a machine into and out of the excavation can be a pretty big hole in a good sized dam.

As far as the existing water in the pond, it may need to be lowered some but a couple buckets of clay inside the end of the cut, temporary dam, will usually hold it back well enough while you work, so that you wont lose all of your fish, if you have any in the pond. Hope that helps. Everybody have a blessed Easter!