Pond Boss Forums GENERAL QUESTIONS Help Draining pond for repair

I'm new to this forum, but have found many great insights while reading it.

I bought property with a pond that was created around 2000 by damming up a small ravine. The resulting pond is approx. 90' wide by 180 long. In Illinois in August without any rain, the pond has dropped a good foot. I am planning to have an excavator come in to shape the pond and add thickness to the dam. The depth runs from around 6 ft at one end to 12-14 at the other by the dam. There is a standpipe at that end.

A simple question to start. If I am going to clean the pond and check the sides, bottom and dam for potential leaking areas, I need to pump it out and dry it completely? Correct? If so, I have 5 years of fish to deal with. How does one handle all of these dead fish? Shock the pond first and scoop them out? (Neighbor has a pond 500 feet away where I could dump them).

The pond has very little inflow during the summer and a 8" field tile that feeds it very well in the spring. If I don't fix the suspected leakage, the pond starts to look terrible by summers end.

The outside of the dam feels spongy in places and we've had a muskrat burrow at the center which may be part of the problem. I am planning to widen the dam 3-4 feet, move the stand pipe and hopefully elimate any leakage through the dam.

Would appreciate any thoughts and observations you might have.

Thanks,

Tony

Assuming that the neighbor wants the fish, I would pump it down and then seine. I might do that anyway and put some of them in the freezer.

What kind of fish do you have?

Editing here. You just might be able to pump it down below the leak, repair the leak and save the fish. If you're doing some contouring that will kill the fish anyway, remove what you can and let the rest die. Dirt work like a dozer might pretty well cover them.

Making the decision to drain your pond is a tough one but is probably the right one. If you do, reline the whole pond, not just the dam. Don't take any chances. If your water inflow is low like mine, you may choose to have small retainer pond built above your pond where you can pump the water to and move the fish until the renovation is complete.

I battled the decision for years. Tried to fix the leak with bentonite, drain it down to find the leak and so forth. It was all a waste of time. I finally drained the entire pond and had just about the whole thing relined (except for the upper shallow side). I only wish I would have done it sooner.

I think you should assess how much water you are losing on a daily basis. In August you could be losing a half inch each day just from evaporation and normal seepage. So you're saying that you lost 12 inches, right? If that's 24 days, then you may not be too bad off. If that's in 18 days I'd be a little concerned.

Welcome to the forum. It's great to have you here. Good first post.

Bruce

welcome to PB tony. you've gotten some great feedback. one thing i might add is that the best time to check for leaks is now when the pond is reasonably full and the water is exerting pressure on the sides, bottom, and inside dam face.

where on the dam is it spongy? if it is down low near the old creekbed, and the dam was not built w/ a keyway, simply adding thickness may not stop leakage beneath or through the bottom of the dam. if the sponginess is up in the middle of the dam face, adding thickness and compacting should work assuming you use good clay soils.

I agree with Bruce. We are in New York State and our 1 1/2 acre pond does not leak a drop. We had clay that looked like potters clay when we were excavationg.
During the hot dry days of July and August we go down a foot or more if we don't get some thunderstorm downpours. We were down about a foot until 2 weeks ago when we had some major thunder storms and now we are flowing water through the spill pipe.