Pond Boss Forums POND CONSTRUCTION Soil questions Renovated pond dropping a little

We finished completely renovating a 47 year old 0.3 acre pond last August. It was completely dried out and re-dozed, with almost 5 feet of sludge removed. Got a good rain, filled about 1/3 and stocked fingerlings in late September. Recently, we had flooding rains, and the pond came up almost 3 feet in two days to stand about 3/4 full. By mid day last Friday, the water had ceased to run in. Since then the level has dropped about an inch. I don't see any leaks on the back of the dam. Could it be losing water due to saturation of the clay in the dam, which runs about 2/3 of the perimeter? The dam is nearly pure orange-red and a little blue clay, very little rock, and was not deeply disturbed during the renovation, but it did dry out very well before refilling. Thanks for any insight.

Yep, new ponds wick a lot of water into the surrounding soil.

It has only dropped 2 inches in six days. We have had no rain and quite a bit of wind, so it is mostly evaporation, I think.

The clay in the dam may have cracked when it dried. Clay needs some moisture to swell, compact, and seal well. If it had dried, there could have been cracks that formed as the clay shrunk. Filling quickly, the clay won't remoisten and swell as fast as the water coming in.

It was up 9 inches when the rain stopped Monday morning, and had spread a lot into shallow, undisturbed areas on the upper end. By this morning (Wed), it has dropped an inch. Don't see any leaks below the dam. I guess still saturating?

Should be good to go after it wicks it all up. I went through the same thing with mine. At .3 acres you are looking at about 8000 gallons per inch. I would bet the ground wants at least that much.

I pumped three inches of water into the pond Thursday. By this morning (Sat), had lost 1-1/4 inches. Still no obvious leaks. This pond used to hold water well before the renovation and removal of four to five feet of mud and sludge. The area of the pond was dried out for a couple of months total before, during, and after the renovation. The original dam was not deeply disturbed, and is very wide and only about six feet high. The rest of the pond is excavated into a bowl of nearly pure orange colored clay with only a few rocks, and they are very small. The upper end backs up into the edge of a hayfield. Could someone please explain absorption and how long to expect it to occur? Will the underwater soil structure gradually change? BTW, We left weeds and such on the upper end edges to hold the soil against runoff.

You are pumping water into virgin dirt every time it rises.

Patience!!!!!!!.... It takes a little while to saturate............... I agree, a lot of your loss is likely due to evaporation; hence the smoke on the water during these cold mornings.

How big is the pipe you are pumping through? I am using 2 inch poly.

Update: Pond went down six inches in nine mostly warm and windy days, but now is back up eight inches and still slowly rising after nearly two inches of rain. About ten inches to go until gets to grassy spillway. It holds better after a rain than after a pumping session.

Makes sense to me if the rain saturated the soil surrounding the pond. Soil can only hold so much water. Once it's saturated it will not pull water from the pond and may very well be shedding excess water to the pond right now.

Pond came up nine inches during last rain. It is now down four inches in five days. Seems like it will never fill. I may have to abandon the project if it won't hold water. The bottom and sides are clay good enough to make pottery. Can't see how it is losing so much. When I dug the post holes for the little dock,the clay was so dense and sticky I had a very difficult time with the post hole diggers.

It hasn't been a month yet. It will be fine. Don't look at it for awhile. A watched pond never fills.

Five inches of rain and still coming down. The pond is over the emergency (only) spillway now by about three or so inches, but that spillway is wide and flat, so no erosion that I could see. Backed way up into the field, lots of shallows under six inches deep. About 1/4 acre at what I would call normal full pool, but over 1/3 acre now.

Edit: Here are some pictures

Edit: As of 9:00 PM, we have received 8.8 inches of rain with this storm since yesterday, and still raining.

This storm has stretched a lot of water holes.

As you can see, the minnow pond and main pond joined at high water. Before renovation, a neighbor said he never saw that pond close to spillway in 40 years, but we have increased the watershed by maybe 50%.
No worries about the minnow pond, as there were no minnows in it yet plus I do not have LMB yet, and it's easily pumped out in a couple of hours and can be refilled with screened creek water in about three hours.
Here's a photo from today. I didn't find any fish in the field below the spillway.

A couple of weeks before starting to renovate the pond, my dirt mover brought his backhoe and cut a 16 inch wide trench through the deepest part of the dam, which allowed the pond to drain about 2/3 of its volume (we pumped the rest using the same trench). After renovation was almost completed, he filled the trench, but was not able to compact it fully as it is about six feet deep, and about four feet into the maximum water level. It settled some (like a grave does) and I packed and hammered pure clay into it to bring it back above the level of the rest of the dam. It has not settled any more, even after our 10.4 inch rain early last week. Since the pond got close to full (about a month ago), it has developed a fairly significant seep through the former trench. The water is not visibly flowing, but the clay is very soft and wet on top and saturated on the back of the dam where the trench was, and a small amount of water has pooled. The part that is seeping on the inside of the dam could not be more than about 30 square feet. The original core trench he cut through was very dense clay like pottery clay, very hard to dig. I think the seep is going through that area, then spreading out under the toe of the dam, which is why I am not seeing any water running. There is an area about 40 feet long centered on that former trench that is wet behind the dam at the very bottom. I am losing about 7/8 inch per day, but still don't see any water actually running (only seeping) out behind the dam. I have just ordered, and will be trying some soil-floc (55 pounds) sometime next week. The pond builder says give it a year or so to settle. I don't think that will happen, and it would be difficult to repair without a 2/3 or more draining of the pond, and making a big clay muddy mess on the dam that is already grassed.

Sorry to hear that John. I guess you have your answer to why your pond water level is dropping. IMHO your pond builder is dreaming if he thinks the leak will seal itself. In my experience, when water finds a path to flow, the leak gets bigger over time not smaller. Good luck with the Soil-floc. I would get it applied ASAP before the leak gets bigger. Hope it solves the problem.

I plan to make a floating PVC rectangle about 2.5 x 10 feet to help to contain the Soil-floc to the area I need to treat. The consultant at Aqua-Ben suggested throwing some of my native clay or Bentonite in granular form on top of the two parts of the polymer to help it sink more quickly into the localized area.

My opinion on seepage (for what little it is worth) is that if water is actually flowing to a degree it can cause erosion, then yes the leak will only get worse. But if it is a very slow seep, then particles in the water could potentially "clog up" the flow and seal it (over time). Particularly if there is a lot of suspended clay in the water to provide for sealant.

That is kind of the philosophy on radiator stop leak. A very minor seep it will often stop. But something flowing has little chance. I would imagine the soilflock operates on the same principal.

The other thing that will happen over time is that a dam will "settle". Local NRCS guy when he designed our dam put in a figure for this in the dam height calculations. In other words the dam was designed a little higher just to account for it to settle. But he also told me that with the way we were compacting the dam the amount it settled would likely be less than he calculated or maybe even nil. Point is, as a dam naturally settles, it also compacts somewhat.

Just an opinion. No scientific proof or references.

There is a robotic vibrating sheep's foot out there. Controlled by remote. It is about 4' wide. Used for compacting soil. if you are able to re-dig the trench, you should be able to add clay in layers while compacting as each layer is added. I am no expert but I have seen one work to pact soil. I would think it would have to be tied into the original core in the dam. Might be a lot easier to contact TJ for his product.

Tracy

I have the Soil-floc on hand (55 pounds), but it has been too windy to try applying it. The consultant at Aqua Ben (Sandra) said not to try applying it in any wind at all. I bought some concentrated blue pond dye at the Farmer's Co-Op today and poured it around a few feet out from the edge in the areas where I suspect there could be even a small leak. After four hours, no coloration has been seen on any of the clay at the toe of the dam. I will check again in the morning. I have been losing about 3/4 inch of water a day since the flood.
To help with the application of Soil-floc to make it more precise, I made a floating enclosure that is 10 feet long and 2-1/2 feet wide from 3 inch thin wall PVC. About 10 ounces of soil-floc is needed for each move of the enclosure, five ounces of each part. The sequence will be throw one third of the part A, one third of the part B, then a handful of granular Bentonite to help with sinking, then repeat with the next third of the enclosure. I think all the leaks are in the dam, since they did not start until the water reached past the base of it.
After using the enclosure for Soil-floc, it can later (in spring) be used to prevent floating fish food from drifting.

Enjoyed meeting and consulting with John for a spell the other day and providing all the direction possible. I suggested he contact Aquaben directly as he was inquiring on pricing of half units which I have never dealt with. Hope the project goes well for you John, and keep in touch regarding your results. I'm a phone call away if I can help in any manner.

No dye seen outside the pond this morning. Amazingly, the seep through the former ditch through the dam has stopped. I wonder where the water is going? Could the clay filter out the dye?