Got a leak in pond dam. Advice?

[Skychief]

Fished my acre pond this evening and heard water rushing in its drain pipe, though the water was a foot below the mouth of the pipe.

With a strong light after dark I could see a mini geyser of water where I think I recall two pipes were joined. I noticed that near the pipes mouth the ground was super soft to one side of it. I suspect a hole below the water in line with this soft spot. I also suspect the water found a path of least resistance under the pipe and is gushing up inside the pipe where I think the pipes join.

In any case, it's obvious I have a leak in the dam.

Has anyone any advice for plugging the leak, outside of a complete dam redo/lining?

Bentonite perhaps? How often is it successful?

Any thoughts and ideas appreciated!

Best regards, Skychief

[Sixgun]

I would do what that kid in Holland did...stick his thumb in it.

On a serious note, I have used bentonite on a water runway/waterfall leading to pond and it takes a lot of it and only lasts so long. I realize it really sucks but sometimes it all needs to be drained and fixed properly.----6

[Skychief]

Thanks Sixgun. Not what I hoped to hear, but, not surprised to hear it.

Best regards, Skychief

[Pete44ru]

Fished my acre pond this evening and heard water rushing in its drain pipe, though the water was a foot below the mouth of the pipe.

With a strong light after dark I could see a mini geyser of water where I think I recall two pipes were joined.

In any case, it's obvious I have a leak in the dam.

Has anyone any advice for plugging the leak, outside of a complete dam redo/lining?

DAM, that sucks !

The dam itself may be OK, but could your plumbing have sprung a leak ?

A leaker could create the void below & the soft spot above, that you describe. (how some roads collapse)

Can you get at the pipes/joint to effect a repair ?

.

[Skychief]

Howdy Pete. The soft spot is in front of and slightly to the side of the mouth of the drain pipe. There's no doubt that the pipe has been compromised. Looks like about 30' feet from it mouth.

I checked the water level this morning and its basically unchanged from late yesterday evening. And, the water coming up through the bottom of the pipe is not as heavy, though there's still a pretty good flow. Just isn't gushing now.

Kind of a head scratcher. I'm gonna keep my eye on the water level. Thankfully it's supposed to not rain for awhile so maybe I can find a hole then.

I said an acre, but, the pond may be closer to an acre and a half. Not sure how much leaking will need to take place before I see the level drop.

Thanks, Skychief

[Sixgun]

Maybe I should not have spoke as I've only had experience one time with bentonight. The stuff is relatively cheap so why not try it. ---6

[jeepnik]

What size pipe? What material? Does it have many 90's? If large enough, and not of complex design with regards to 90's and tee's you might be able to sleeve it with a smaller diameter pipe. Think of it as the pipe equivalent of sleeving a shot out or pitted barrel.

[wecsoger]

Heard a guy located a leak, laid out a layer of bags of quickcrete, then overlapped with another layer.

So saying, I'm not a hydrological engineer and would have trouble spelling it most of the time.

[Blaine]

Long shot, but you could have several yards of crushed rock dumped over the leak.

[Alan in Vermont]

Skychief, where are you located? Reason I ask is that if you are where the pond & ground freeze in the winter I may have some advice to offer. I'm currently dealing with a pond suffering with the same malady as yours.

[AJMD429]

The soil under pipes generally gives way, no matter how solidly you think you packed it. We've had several dams over the past 50 years on our property that failed this way.

If at all possible, re-do it with a gently-sloped grass surface spillway. They just have to be plenty wide to handle high flow rates, and sloped very gently and with a good packed surface with canary-grass or good strain of fescue.

[Buck Elliott]

Bentonite/clay..

[guntar]

From what you describe, you have a piping problem. Bentonite is good for sealing filtration-type leaks such as a sand seam becoming exposed. It has no structural strength to speak of, and is quickly worn away by "rushing water". You may need to apply bentonite as a sealer later, but from what you describe it won't do much good until you repair the leaks in your pipes.