# Dam Leak!



## Mushijobah (May 4, 2004)

Hey guys,

A friend of mine has a 1/2 acre pond that has developed a leak at its overflow pipe. Instead of overflowing into the pipe, it was eroded a hole about 1 foot below the pipe. Are there any do-it-yourself guides on proper dam patching? The low water level has caused the pond to become quite weedy, and cat tails are begining to grow.

Thanks!


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## SummersOff (Feb 11, 2007)

I am probably not the best person to take advice from as I have some serious pond issues of my own that when I get a minute I will post, but I might have an idea. If I am following you correctly the leak is not in the pipe, but in the ground surrounding the pipe. I know a guy who had a similar problem, he got some bentonite clay I believe it's called from a well digging company and put it around his pipe. I guess the stuff expands and doesn't allow the water to penetrate it. I know this is an effective treatment if you know exactly where the leak is. I would just google "bentonite" and I'm sure you will find something. Good luck!


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## Salmonid (Apr 14, 2004)

Yes, if its not too big a hole,. the bentonite would/should work but once he gets the hole plugged, he should make sure to cover the area with some #2 or#4 stone to keep it from eroding again. Also, make sure Muskrats did not start the whole problem. If so, its target practice or trapping time.

Salmonid


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## Mushijobah (May 4, 2004)

Thanks a ton guys, I will forward your knowledge!


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## [email protected] (Dec 22, 2006)

It sounds like your friend has two problems. First, there probably wasn't an anti-seep collar installed and second, the backfill around the pipe likely wasn't properly compacted. The best fix would be to install an anti-seep collar and carefully compact regular old Ohio clay around it. A "jumping jack" style compactor can be rented and is probably best suited but a hand tamper may suffice.


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## Mushijobah (May 4, 2004)

PondFinatic. Do you have any typed up or website info on the seep collar? This pond is pretty darn old, and seems to have just developed a leak in the last few years.


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## Bob4246 (Dec 30, 2004)

Check out this link

http://www.wi.nrcs.usda.gov/technical/eng_cad_200-299.asp

Antiseep collars can be constructed of metal, plactic, or simply by excavating and pouring a slug of concrete around the outside of the pipe. 

The bentonite should work to fix the erosion. I would use the pellets. They are available in large bags (like quickcrete). I would mix the bentonite in with the backfill soil. For best results, use clay soils for backfill. Compact the backfill as described in the proir post. Granular backfill (soil with lots of sand and gravel) won't work as well since water tends to seep through. Once you make the repair, wet the bentonite/soil mixture. The bentonite will swell, and hopefully the problem is solved. I would also seed the repair area, as vegetation will prevent future erosion.


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