Looking at your drawing again, I think the dozer could remove most of the top of the new part of the dam while leaving a foot or so on the inside, creating a slope towards the back slope. Then with the dozer go in and cut a vee shape roughly in the middle of the dam down into the old dam (to create the core seal). Then rebuild the dam while compacting it.

It is hard to know without knowing the width there is to work with, but a six way blade on a dozer can do quite a bit to make a vee shaped trench as long as you do not need it over a couple feet deep. If the dam is wide enough I think it would be all doable with a dozer plus whatever you can come up for compaction.

That is pretty much what I did with my old refurbished pond. Scuffed the top of the old dam off, then cut a vee in the middle of it with the dozer with the blade angled and tilted to tie the old dam together with the new material. then layered and compacted the rest of the new portion of the dam with a loaded 12 yard rubber tired dolly style scraper. It does not leak at that new dam/old dam junction and I probably have about 3' of water like you above the top of where the old dam was.

Last edited by snrub; 04/21/18 07:07 PM.
John

I subscribe to Pond Boss Magazine