Our pond was built in the late '70s. It is 4 or 5 acres, spring fed, and approx. 15 to 20 feet deep. About 5 years ago there was a leak and just about all of the water drained out. Come to find out the pipe that runs through the bottom of the dam to the drain valve rusted through. There is a "T" in the horizontal pipe with a pipe running vertically to the desired water level that acted as an overflow. The leak was on the horizontal pipe between the "T" and the valve. We sealed off the valve side of the "T" leaving a 90 degree elbow running up to the overflow. Apparently this worked b/c the pond level rose a considerable amount, but is still about 4 feet lower than rhe pre-leak level. We just recently sealed off the "T" by dumping quickcrete down the vertical overflow pipe. Apparently this worked b/c the overflow pipe is now full of water, but it did not solve the problem b/c the pond remains at the same level. Water is still coming from the pipe in the backside of the dam. Seems like our only option is to try plugging from the pipe on the backside of the dam. Any suggestions?
Welcome to the forum clemsnwill!! I'm sure you will get lots of suggestions besides mine. Pictures will help a great deal to give more ACCURATE help. You can find out how to post pics by clicking on the "Common Questions and Answers" threads.
The safest and surest way to repair this is to breach the dam and replace the pipe with PVC and anti-seep collars. This is not an area you will want to "kinda" fix. If the dam were to fail during a large rain event, you will be liable for the resulting flood and damages. You could possibly make a temporary fix by draining the pond and digging into the wet side of the dam and sliding a new pipe through the existing one then compacting around the new SMALLER pipe.
Water flowing under the levee is surely causing a lot of erosion and after 5 years, I would imagine only the weight of the dam is what has kept it from failing so far.
I'd seal or plug up the pipe and install a syphon. A lot safer and cheaper than breaching the dam, and you don't have to drain the pond.
How big is the pipe? Could you put a deflated football or basketball in it, then pump it up?
What kind of pipe at the exit? Corrugated or smooth wall? ID and/or OD? How much water is exiting....approx? (how many 5 gal buckets per min)
ps; what are your plans for an overflow?
pss; Welcome to the Pond Boss Forum, Clemsnwill
How much water is comming out of the pipe?
How big is the pipe?
the pipe is corrugated. about 10 or 12 inches in diameter. i'm considering using an expanding foam sealer of some sort. maybe get a can that has an auto release/flow option. the tricky part will be getting the can far enough into the pipe. the dam is about 35' across at the base so i think the plug should be at least halfway (the middle of the dam). i think this will be possible if i run a piece of pvc to the halfway point then push the can of foam sealer through the pipe to the midway point. what are yall's opinions on using expanding foam sealer. i like the basketball idea...........
"across" at the base of the dam being from wet side to dry side. therefore the pipe is approx. 35'.
i'd say the flow is about 5 gallons per hour (or less) regularly, but after a rain the flow increases proportionate to the amount of rainfall.... ie: the heavier the rainfall, the more water flowing from the pipe.
the pond has a designed "emergency" overflow around the side of the dam. once i get it plugged i plan to add a pvc drain in the area of the overflow to make it the normal spillway and prevent erosion.......
Lets think about this. 5 gal of water per hour is not enough to make the level of the lake to fall, at least to where we would see it.
Have you had enough rain to fill the lake? Could it be leaking any other place.
i'd rather try all of the cheap options first.
no 5 gallons of water per hour is not much at all, but when it does rain, the flow is a lot greater than that. after it rains, the water level rises for a few days (while outflow increases), and then returns to the previous level.
honestly i cant decide how/where it is leaking. all i know is when it rains it flows pretty heavily out of the drain pipe at the base of the dam.
clemsnwill, the hydraulic pressure will increase as the level rises. I also doubt you fully sealed the stand pipe. Maybe the valve is leaking too.
clemsnwill, did you look down in the stand pipe before you filled it with concrete to see if water was coming through the valve or flowing down the pipe through a rust hole? If you filled with concrete with water flowing, the current probably washed a small tunnel through while it cured. I have poured sawdust by the 50 gallon drum down around leaky valves before to stop small leaks. If you are still able to pour concrete down the stand pipe, you can by a pipe plug from aquacenter.com that has a rubber bladder that is expanded like a boat plug to stop the flow wile you fill the whole pipe with concrete.
-HH
