Hi all,
I have a problem maybe someone else has encountered. I have an approx 2 acre pond that I think is about 25 years old. In the back is a galvanized steel overflow pipe which goes through the dam and empties behind the pond. Over the years this pipe has begun to leak and I am loosing who knows how much water to this leak. I spoke with someone this week who suggested pumping the pipe full of concrete from the back side to cure my problem.

Has anyone else had this type of problem, and how did you fix it without digging up the pipe and replaceing it?

thanks

Scott, are you tring to save the tube or do you want to stop the water from flowing thru it?
If you want the water to continue to go thru it then I have a cure. In Michigan there is a company that makes plastic liners that go inside of the old galvinized tubes. For example, if you have a 15" tube then you would slide this liner in and put a little concrete around the ends and you would end up with a 12" plastic tube.I can't remember the name of the company but if you call your local Road Comission or someone that deals in drainage alot they could give you the name of a company in your area.

I hope this helps, I have put these in before and they work great.

Right now my leak is somewhere below the waterline, and I am pretty sure it is in the wall of the horizontal pipe that goes through the dam. How tight does this liner fit? If it will stop my leak and allow me to keep the overflow it would be perfect.

Most of the time they fit very tight. You would have to pull or push them in with a backhoe or something of the sort.

We've had to deal with similar situations several times. I'm assuming it is a horizontal drain pipe through the dam with an elbow and a vertical riser standpipe inside the pond designed to determine the full pond water level. I'm also assuming you don't want to completely drain the pond. You may be able to look down the riser standpipe with a flashlight and and see the leak. If it is along the vertical section of pipe, you may be able to temporarily seal the leak with heavy plastic film or liner material. If the hole is larger than a quarter, you will probably need to support the plastic with hardware cloth or screen of some type.

With the leak stopped you may be able to pump the pipe full of concrete from the back side. If you have a flange or can attach a flange to the back side of the pipe you can install a valve. The valve can be opened so the concrete can be pumped into the pipe and then the valve can be closed to contain the concrete while it sets up.

We often siphon the water level down at least 4 feet or below the leak. If done when the water is cool, the fish can still survive. We cut off the old pipe and fill with the elbow area of the drain with concrete mix (you might have to pour some concrete in, let it set up and add some more until water will not flow through the pipe) from the top. We then install a new pipe through the dam. The new pipe is installed in as shallow a trench as possible. We want the new drain to have an elbow and very short riser standpipe. Concrete is poured around the elbow to help seal and stabilize the new drain. The riser allows the full capacity of the horizontal drain pipe to be utilized with even a couple of inches of rise in the water level above the top of the pipe. A horizontal pipe alone would allow much less water to be discharged since only the bottom of the pipe would be wet. It is very important to compact good clay soil carefully around the pipe as it is buried. The shallow trench is less likely to leak since there is less water pressure and the rest of the dam is undisturbed. If the water level needs to be lowered sometime in the future, it must be siphoned (or pumped), but the repair is less risky.

The slip liner described earlier will work well if you can get access to both ends of the horizontal pipe (assuming you don't have a vertical riser standpipe or are willing to drain the lake to cut the standpipe off). You must seal both ends of the slip liner's connection with the old drain pipe.

I hope this isn't too hard to understand. It's hard to describe without being able to use my hands to demonstrate.