Pond Boss Forums INTRO Questions & Observations Leaking pond - Sealing Process

New member here

We dug a 1.25 acre pond about 2 years ago, as we were pulling the red clay to use for 2 house foundations on the farm.

The pond wouldn’t fill up, as there was not enough run off acreage to come close to providing enough water.

The pond is about 300yds long by 100yds wide. At the dam side, it is about 16ft deep and on the opposite side it’s about 7 ft deep.

Last April, I pumped the pond full from a nearby swamp about 200 yards downhill from the pond. The water did not hold, and we were losing 6” per 24hrs - until it eventually drained out. A small section by the dam would hold water knee deep just fine but above that it was no good.

I found a leak on the back side of the dam - a slow trickle, and I had. Hard time believing it could be the sole contributor to my 6” per day water loss. I drilled 6” holes with an auger behind the dam - and they filled with water the general area around d that leak - but not the hole back side.

In January, the contractor who dug the pond came back out and scraped back the dam. Said he found a wet spot in the middle. Tranched down 6 feet at the foot of the dam and filled it in with fresh dirt. Packed it all back in with excavater and beefed up the base of the dam.

I filled the pond up last week again - 4 full days of pumping and I’m estimating
Caring 3million gallons. The pond is losing 6” per day again. There is no leak on the back side of the dam this time, and not presence of ground water on the low side behind the dam.

It did only lose 3” yesterday - but I’m not counting that as slowing down.

Any thoughts on how long it should take to seal a pond?

Soil is clay. There’s definately some rocks in it and part may have some sandy components - but we are in a heavy red clay area.

When the pond sat originally we had some major erosion on the banks - not sure this is a contributor. When I look at the ravines - it’s all really read clay and super compacted.

When they dug the pond, there was one small section that had water coming up from the ground- but not gushing by any means.

I’ve looked at the slick of/damit - but really don’t want to spend the $3k or so needed to cover this big pond on a hope and prayer.

Any thoughts, experience, wisdom?

If you had water coming UP from the ground when the pond was dug, and the contractor didn't dig that area out and pack it with clay to stop the water, that is the first place I'd start. If the contractor packed the back of the dam with dirt and not clay, that's place #2. He should have due in a keyway, packed that full of clay in 6"-8" lifts and compacted each lift with a sheepsfoot before adding more and compacting that.

Without proper compaction of the proper soil AND proper moisture content when packing you might have a problem. Call Tom Hudson for advice. He sells a polymer product that works good and he will take the time to talk to you on the phone so you understand what you are up against and how to properly use the product. I will send you a private message with his phone number. He's in Kansas, on Central Time.

PM sent

Thanks Scott - Hi Wekorneg and welcome to the Pond Boss forum family! Wish your intial post was showing off a big fish you raised - leaks are the worst! I help folks with pond construction, rehab, and leak abatement and as a volunteer moderator here my time is always free to the Pond Boss community. Feel free to reach out anytime so I can learn more about your situation and provide some options moving forward. If you're a candidate for a polymer treatment I work directly with the largest polymer manufacturer on the planet and provide wholesale rates to the PB family. I'm happy to help in any way I can!

tj@hudlandmgmt.com

Here are a few more photos I took today of it full.

Notice the erosion on the south bank. It is steeper and wider under the water level.

Go out and buy enough anti-erosion matting so that as soon as the next round of work is done at the pond, and the banks are smoothed out you can spread out grass/clover/rye/wheat seeds and cover them with the erosion matting. Get all natural fabric, not the stuff that has plastic netting holding the hay/straw together. That acts as a gill net once the water rises and lots of fish get caught in it.

Your upper bank appears to be all clay with no topsoil. That is going to make it tougher to get your ground cover established.

Another option may be to divert some of that water that is flowing down your hillside and then accelerating when it hits your pond cut. Do you have a tractor and an implement where you could make a diversion swale above your erosion area? If you could make a shallow cut in your undisturbed ground and remain in topsoil, then you could divert water and more easily establish groundcover in your swale.

Good luck on your pond improvements and repairs!

Good thought. You may not be able to see it but we did attempt this after the initial construction phase. There is a berm at the top that wraps around the south side of the pond. It diverts the water to the left or right and has 3 pipes that funnel water into the pond. That’s what those dark black lines are in the aerial photos - pipes that became uncovered after erosion.

The water does get diverted but somehow it’s still a problem.

This project has about done me in!

Yep, couldn't see it from the photos. But diverting the water from the exposed slope and still bringing it to the pond was a good plan. The erosion you are observing should be unlikely to cause any leaks. Instead, it is just costing you some of your valuable pond depth.

I re-read you original post. I think one of your main questions was how long should it take to seal a pond? The pond should be sealed immediately. However, a pond may still APPEAR to be leaking as some of the free water in the pond is lost to saturate the soil, and in the case of clay - the water is actually incorporated into the structure of the clay minerals.

I believe you are past that point. Everything should be well saturated at this time, AND you were observing water past the dam.

I expect you still have one or more leaks. Is the pond still going down 3" per day, or has your water loss slowed?

Fixing the dam leak is tough, because you have to nearly perfectly meld the repaired section to the original part of the dam. Keep checking your previously wet area below the dam. If that is still dry, then your contractor did get one leak. However, I don't like that you said he filled it in with "fresh dirt". It looks like your sub-soil is mostly clay, so hopefully dirt means "clay" as his material.

The other leak may be that one section where water was coming up from the ground during excavation. If water was flowing there (even though it wasn't gushing), that could be a major leak. Typically, the contractor would dig deeper in that area to find the expected sand or gravel layer or stringer. After digging that out, it needs to be compacted in 6" lifts of good clay at least a foot thick for 10' deep water, and maybe 2-feet thick if that is near where your water depth is 16' deep at full pool.

All of your solutions at this point are going to be expensive and that stinks. I would definitely recommend talking to TJ. Even though he sells a product, he can give you good advice for free and ask you some better questions to evaluate your problems and to determine your best solutions at this point.