Pond Boss Forums GENERAL QUESTIONS Property Projects & Construction A story about a leaking pond and Soilfloc

So I'm the owner of a ~3 acre pond in central Texas. It's a leaky pond and I'm trying to do something about that. I decided to write up my story because I didn't find any really good detailed threads about trying to fix a leaky pond, at least not in my area.

We purchased the property in December of 2015. Didn't know much about pond management at that time. The pond is a beauty, around 3-4 acres when full and can reach almost 20 feet deep way out in the middle. The dam is high, but the back side of the dam is swampy. Didn't know it at the time, but that should have been a big red flag. I've looked at the pond using Google Earth and seen the pond got very small during a historic 100 year drought back in 2013. Less than half an acre. There are nice 3-4 lb bass in the lake, so I know it's held fish for at least 7+ years.

Now onto my story. The pond got really full in 2016 due to heavy rains, then we went back into a drought. The pond was steadily shrinking and I didn't know how to fix it. I investigated Sodium Bentonite, but never heard of anyone having success with it. Finally in December of 2017 I started investigating Soilfloc and heard some good things. I got hooked up with TJ from this site and he was very helpful explaining how to apply it and what I could expect. I was told 90% of people who apply it correctly see their leak slow by half.

So I started measuring my loss. I was running 0.15-0.25" per day of water loss. TJ recommended applying 4 oz of part A & part B to each 3'x3' area of the pond. He recommended treating to the bottom of the dam and then an additional 15 feet. My dam wall is about 200' long and I estimated how far the bottom of the dam is based on the lowest point of the pond. It's all kind of a big guess. We figured I'd need 2 units of Soilfloc at a minimum, but 3 would be safer. So I ordered 3 units. Grand total was in the neighborhood of $1000 after it was delivered. This is a pretty small investment, so we went for it.

I wound up sitting on the product for months. I continued to watch my pond drop and continued to measure it. Here are my pre-soilfloc measurements. I corrected for rain as best I could, and had to reset my depth gauge at one point.

Date Level Rain Level Change Days Loss per day
12/9/2017 17.5 NA
12/17/2017 15.75 0.25 2 8 0.25
12/28/2017 14 1.75 11 0.1590909091
1/20/2018 10 4 23 0.1739130435
Reset Pole
3/19/2018 16 NA
4/12/2018 12.5 3.5 24 0.1458333333
4/22/2018 8.75 3.75 10 0.375
4/28/2018 7 0.5 2.25 6 0.375

Finally I was able to get a weekend with low wind and a buddy out there to help me. We applied it by running a rope from T-posts across the shore. In hindsight it would go MUCH faster with 3 people. 2 on the boat and one on the shore moving ropes and T-posts. We ran out of time and only applied just over 2 units before the wind picked up. I figured we got to at least the bottom of the dam and was hopeful. I reset the depth gauge and got ready to wait.

Good news was that it rained very hard that next week. Over 2", which was much needed. But it made it damn near impossible to figure out my losses for that period. I did have a clue in that there was a mud ring on my depth gauge that was a good 2" above the current water level. And the back of the damn was still swampy... Maybe not a good sign.

Went back 2 weeks later and the pond is still leaking bad. If anything the vertical loss is accelerating because the pond surface area is decreasing.

As we're getting to bed my amazing wife says 2 things. First, take the boys out there in the morning and start catching fish to eat. Let's pull some fish out since they're getting crowded in our shrinking pond. Second, she's getting in the boat the next day and we're applying the rest of the Soilfloc. She's pretty cool like that...

Next morning we catch a few bass (my 8 year old lands a pond record 3.2 lb lunker he decides to name "dinner"), and the wind is down so we hop in the boat and apply the last of the material. We make another 7 passes across the lake, focusing on the deep parts. That's another 21 feet further from shore.

Here's my results post soilfloc (note I estimated 4" of rain due to the higher mud ring evidence):
Date Level Rain Level Change Days Loss per day
Applied Soilfloc - 2.2 Units
4/28/2018 14
5/11/2018 15.5 4 2.5 13 0.1923076923
5/27/2018 9.25 0.25 6.5 16 0.40625

So this is where we're at today. We're praying that this time we got the material where it needs to be. I will update this post in ~2 weeks when we make our next visit. There's no rain in the forecast, so hopefully we'll get an accurate measurement this time. Y'all say a prayer for us that it works this time. I'd love to be a Soilfloc success story.

Jeff

Hey Jeff, welcome to the forum!

Per our meetings, leaks can be tricky - could be dam face, could be sidewalls, could be main basin, could be all of them. I recommend spot treating in area of highest confidence to save time and money, but it can be an exploratory process...I like to try and address issues as cheaply as possible if at all possible, and go from there.

Ping me anytime, here to help in any way I can.

TJ

Welcome to the forum. Very interesting First Post. My leak is (was) about the same. 1/4” per day. I used the soil flock also, and I believe it’s helped. I just don’t have a wet spot anywhere to use as a guesstimate on where my leak may be originating.
I had two people on the ropes, one on each bank, that pulled me back and forth in a row boat. We had marked off 5’ grid. I also tossed bentonite to aid in the soil floc sinking.
I’m not sure I’m losing that much more than what is evaporating, so I’ve just quit worrying about it. Can’t get any rain either, I’m jealous of your rain! I hope you’ve got your leak stopped.
Looking forward to hearing about your results.

Welcome to the forum!! Great place to call home!

Isnt it true that evaporation can be close to 1/4" a day. With many variables, sun, wind, plants, animals (we have livestock), you may not be loosing as much as you think through a leak. 3 acres would be a hard one to go about finding a leak on, I can't imagine. Maybe dumb question but are you positive the swampy area is coming from the pond? Could it be a spring...with other springs in the pond? Maybe going up and down with water table? I'm by no means an expert, just some things ive learned from being here and observing.

The technical person at Aquaben Corp (soilfloc) told me that soilfloc's effectiveness is greatly reduced or negated by any coverings on the bottom of a pond like FA, old carpets, weeds, leaves, large rocks, or muck. For greatest effectiveness, she said the bottom should be as pristine as possible.

I have structure (brush piles) in the pond, FA, and a large area of old carpets covered with rocks and gravel for fish spawning/shelter areas.

I am going to try the cutoff wall approach, if conditions and funds permit. Dig a trench with a backhoe below the level of the bottom of the dam on the back side, at or above full pool level, breaking any root paths, and any paths under the dam, and pack it full of new clay, possibly also with a plastic sheet barrier against the upper side wall of the trench, extending to the bottom.

So I went out and measured again, one week later and lost about 3". It's been really hot, so evaporation is kicking up (more on that in a minute). Behind the dam still has moving water. So in my case the Soilfloc has had no effect whatsoever.

As to whether there happens to be a spring that has it's exit right where my dam is, I suppose anything is possible, but that seems unlikely.

As for evaporation, I've checked. I'm in Texas, quadrangle 709:
http://midgewater.twdb.texas.gov/evaporation/quadrangle/709/evaporation-tabular.txt

Last December I my evaporation rate was 1.73" for the entire month. Worst month of the year is July at about 7". That's less than 1/4" a day in July and should be about 1/10th inch in the fall/winter. If you look at my data you can see that my leak is about 1/4" per day and then evaporation is on top of that. And it tracks pretty close to the data in that table.

I'm not sure what my next step will be, but it won't be Soilfloc. I'm pretty disappointed that I applied at a higher rate than recommended and got at least 20' past the bottom of the dam and saw no improvement. I was able to apply it heavier and over more area because the pond shrank quite a bit before I got to apply it.

I've also not seen any evidence of the Soilfloc at the bottom of my pond. Some folks mentioned a hard crust they saw develop, but I don't see that.

I'm not saying that Soilfloc can't work. Maybe it can and I just didn't get it at the right spot. Or maybe it doesn't really work all that well. In my case it was certainly the latter.

Maybe you should dig a cutoff trench and fill it with new compacted clay. Some call it a cutoff wall or core wall.

Right now, my water loss is 3/4 inch to 1 inch per day.

It's still too wet behind the pond to attempt digging.

I can't even imagine what that would cost, nor would I have any idea how deep I would need to go. As I mentioned, there is still water flowing out the back of the dam, so it's a swampy mess with standing water. One quote I received about re coring the dam was $50-100k. My damn is 200 feet long and about 25-30 feet high.

Sodium Bentonite is pretty cheap in my area. That's what the state recommends. I know it also has no guarantees about results. But I can buy it from time to time, $8 for 50 lb bags and it's available locally.

So I could just start pouring it in there from time to time. It won't make anything worse, but also feels like a low change of success. I went with Soilfloc because I would have spent about $500 on nearly 2 tons of Bentonite which would have been more work to handle than just 300 lbs of Soilfloc which cost me $1000.

You don't need to re-core or build a cutoff at the full height of the dam. It can be done nearer the toe of the dam if there is sufficient clay to tie in and hold the hydrostatic pressure. That's what I am contemplating trying. It doesn't take much clay to hold the pressure of only two or three feet of water coming under the dam. Poured Bentonite almost never works. It has to be mixed with soil and compacted at the proper moisture level.