Pond Boss Forums INTRO Questions & Observations Help! Pond dam is disintegrating!

Today I was out mowing the grass on top of the levee, when I nearly drove into a sinkhole. It's about three to four feet wide, and several feet deep. This is a 2 acre pond on a property I just purchased. I'm devastated. Does anyone have any advice on how to proceed?

I just got a better look at the sink hole. It measures 3.5' across, and it drops down about 6 feet before turning and going out from the levee. It seems only a matter of time before the whole thing gives way.

Booger,
Do you have Muskrats in Al.? Sounds exactly like the problems I have from the darn digging critters. They love to dig and tunnel in dam's. I've tried to fill the holes with clay but it nevers seems to dry out so I added another layer to the top of the dam and the backside.
And I "relocated" all existing 'rats but they reappear from time to time. Constant battle but .22 Mag shells are cheap.
Is there a possibility that the dam was not packed properly when it was built?
Dan

Dan, I haven't seen any burrowing creatures such as muskrats since I've been here. However, I do know this: the dam has suffered from seepage for years. It was built for livestock (pigs or hogs, I don't know the difference). It has also been overgrown with small trees for a long time, which may have contributed to the problem. It's probably for the best that I re-do the pond now before spending the $$ on stocking, etc. However, it will be expensive. What I need someone to tell me is what the process is going to be like. And how much money it is going to take out of my rapidly shrinking bank account.

A local pond builder came over today to look at the dam. His idea is to drain the pond, dig out the problem area, and re-build that portion of the dam. Also plans on repacking the clay along the length of the dam. Additionally, we will be removing much of the silt/dirt that has accumulated in the pond over the years. Are there any flaws in his logic?

My fear is that the new part of the dam won't "mesh" with the existing part. I just see it as a logical place for the next leak to occur. We think it's going to be in the $5k range.

I dealt with simply doing a basic repair like this last year. My problem is that the dam is so old I now have problems in other areas. The spot I had repacked holds fine. We used a big front loader and clay from my yard to do the repair.

I don't know how big your entire dam is, but I know when I get mine redone in about 5-10 years I am going to have the entire dam redone so everything is new and locked in together.

My pond is maybe a tad over an acre, was made in the 60s or 70s by blocking a ravine, and since it has some excellant fish in it I plan to keep it for now.

When the bad spot was repacked I also had the guy stick a lot of clay on the back of the dam to make it a more gentle slope so I could manage clearing it better.

Your fear of the repair being the weak spot is a valid concern but if the repair is done properly it should blend into the existing dam over time. Using the proper material to make the patch and packing it well will be necessary. Refacing the whole dam with clay is a good beginning to seal the patch and having it blend in well.

A few years back we had a dam breach in a flash flood. The breach was large enoiugh to drive a semi truck through it and was 15 to 20 feet deep. Clay is at a premium in our area but the dam builder that did the repair managed to find enough to mix with the existing soil along with a good quantity of bentonite. The whole mixture was packed in with a power tamper in small layers. It was labor intensive but it paid off. The repair is not leaking at this point in time and the pond is looking good. We placed a drain gate and 3 foot down tube, to replace the original 12 inch tube, in the breach while we were making the repair.

The price sounds reasonable. Good luck on a successful repair.

Larry

BigOld- my pond is just year old and the muskrats hit me this sping. My brother in law was walking along and fell in a big sink hold and also saw what appeared a entry hole in the ground. Low and behold there were two of them and it took a bit of time but just waited in the truck with a refreshment and shot one with steel 2 shot and the other with 4 shot steel. Filled hole in and problems gone. Until next year that is as they will always show up according to other pond owners. Be diligent and keep up on them and good luck. happy hunting

jeff

Big O, I have the same problem only my pipe through the dam is the culprit it has gone bad after about 33 years of service. My contractor has told me between 5 and 7K, this includes digging out some silt in the shallow end as well as repairing the dam, it does not include the pipe for the new over flow so your price sounds reasonable. My dam is 410' long and probably 100' wide at the base. My sink hole is right above the pipe through the dam, from the top of the dam down to the pipe is 55'. So I have quite a challenge also.