Hello everyone

I am in the process of trying to fix a leaky farm pond located in Nebraska.

First some history:
The dam and pond held water great for years pre-1998 or so but had filled in with silt so my grandpa hired a contractor to dig out the slug, raise the dam a couple feet, put all the silt on the back side of the dam. He also had a number of smaller dams created above to catch most of the sediment before it made it to the large dam.

The dam itself is about .75-1 acre and probably 20 feet deep when full to the overflow.

Ever since the pond was dug out it has not held water. Recently (2019-2020), the pond did fill all the way up to the overflow and then quickly began to drain again. I tried throwing bentonite out into the water and also used a trash pump and siphon device to spray a bentonite slurry out into the water with no success.

It has gotten to the point now where in was only 1.5 feet deep in the deepest part. I decided to just bite the bullet and drain the rest of the water out so it can start to dry and this would also allow me to inspect the rest of the bottom for any abnormal marks or depressions that may show me where the weak spots are. The edges don’t seem to have a ton of muck but the deepest part seems to have about 1.5 feet of soft sludge/muck.

I dug some test holes and found that 6-8 inches down you hit a very hard layer that is fairly hard to dig into. I took some of that soil and did the bucket test and the results were very good. It has maybe dropped 1/8” in like 4-5 days. I assume this can be attributed to evaporation. The soils packs extremely well in the bucket and smells like clay. The soil map shows that it is all silty clay loam with 21-27% clay. I don’t have a lot of details about the original construction of the pond/dam as it was constructed before I was born and my grandpa has since passed. My dad did say that prior to digging it out it held water very well.

My question for the group is what should I do next? I have been in talks with TJ and also beginning some talks with some local contractors to get some quotes to clean it out and try and re-compact to seal it but don’t know if I will be able to able to afford all that. I haven’t gotten any quotes yet but if they do come back high what would be the next steps for me to try an fix this issue.

Thanks