Pond Boss Forums POND CONSTRUCTION Renovating a Pond or Lake? How long does bentonite take to become water proof

Hello, all. First post here. Wish I found you all under better circumstances.

So I am in Southern California high desert. I recently moved to a property that had a 55' diameter, 2-6 foot deep seasonal pond in place. During rainy weeks, it fills up about 10% and holds water until it evaporates. Pretty decent clay soil with blue clay about ten feet deep. I decided to try and make it a year round pond and fill it and stock with fish and duck. During my research I initially planned a liner, but was getting quotes at $15k plus. I settled on and bought bentonite to do it. Quickly found out that professional pond builders wanted to charge the same to do the bentonite. Decided to do it myself (because I am occasionally an idiot).

Long story short, I mixed in 18,000 pounds of bentonite into a mixed blanket about 6" deep all the way around and spread the best I could with a small Home Depot backhoe. About 2x what online calculators suggested was needed for the size. I did not get to use a sheepsfoot or alternate compaction machine, mainly because I didn't feel comfortable riding the side walls, and I knew the bottom is already pretty solid. Probably the biggest mistake I made. Since doing that I have filled it with almost 90,000 gallons of water. This was 3 days ago. Since then I have lost the equivalent of probably 10,000 gallons. About an inch or two a day.

I have a separate runoff hole dug about 15 feet away to catch silt and whatnot during rain, and a culvert to direct overflow to the pond. Since filling the pond, this runoff hole has filled with about an inch of water. Obviously seeping from the pond. I have dug test holes between the two, and the ground is pretty saturated with water that pools in the test holes about 12" lower than the top of the pond level.

So my question(s). How long does sodium bentonite take to actually absorb and become waterproof? Is this amount of water loss normal in the first few days? Do I just continue to monitor and see what happens, or keep trying to top it off with water trucks for the first week? Would a bentonite slurry, granules, or SoilFloc help in this situation? Is there a fix for this or did I just throw away $6,000 on water that will probably keep getting lost?

Thanks all in advance.

You have to compact the lift (each lift) with 25-28% moisture for the Bentonite to form a seal. No compaction, no seal.
On the side-hills you can drive up and down, you don't have to parallel the shore line.
Now... Looks like you have a concrete wall there.. Is the water level at full pool suposed to be contained by the concrete? If so, that creates another issue.

Thanks for the reply. The crete wall has a spillway that dumps into a creek. The full pool is what is shown in the pic.

So, without draining the pond, is there a feasible way to get a seal?

I use a similar compound building ponds that works in a similar fashion to bentonite. I know of no "good" way to seal with water in it. There are products to help stop slight leakage but I'm not sure with little to any compaction that the other product would be adequate.

Bummer. I guess the next question is, if I pump the water out, am I able to compact it after it dries out, or has getting it fully submerged ruined the ability for compaction?

If I was hired to do that job, when it was dry enough to get in to work it, I would disk the bottom to loft and remix, then compact. you are only working with 1 layer so I don't think you will get a 95% seal. In fact, it might be a good idea to look up USDA Doc 590 and do a bit of reading on seals before you go any further.

Thank you for all the info. Yeah at this point I don't know how much more good money I want to put into it. I also built out a waterfall and return system so I'm 20k invested. Need to figure out when to cut my losses.

Any time. If you do some reading on that it will help with an understanding of why it's important to do it a certain way. I don't think you are at an end point, I'd say there is hope in this. Read 590 and make a plan going fwd.

It can work without compaction - depending on the facts . Not all dirt is the same. Here is the concept. The bentonite needs to fill the pore space.



Old post

https://forums.pondboss.com/ubbthre...rds=bentonite&Search=true#Post125536

I appreciate this! Hopefully the bentonite is just taking its time to swell (4 days so far). I used an over abundance of it in pretty good quality clay dirt, so I guess time will tell.

Hi and welcome to the forum. I help folks deal with leaking ponds nationwide and my time is free to the Pond Boss forum. Feel free to reach out - we could review your options together on a call. Happy to help however I can.

TJ

Tj@hudlandmgmt.com

Thanks again TJ. You were a huge help and I really appreciate you taking out the time to hop on a phone call with me. I appreciate your suggestions and honest feedback in regard to my options and expectations.