Pond Boss Forums POND CONSTRUCTION Soil questions Fix it or forget it?

My new pond has been built about 9 weeks now and is still waiting on the first rain. When it was built I knew nothing about pond construction but I found a reputable dozer operator that had been building around here for 25 years. He seemed knowledgeable and said when we started that he was looking for a clay layer to seal the pond. He found a orange layer he said was the best clay around and took the time to spread and pack it over most of the acre bottom. Now that it has been setting so long it sure seems dry. Is this extreme dryness something to worry about? I am also concerned about one small area about 3' square at the very bottom that is sandy and remaining damp. Some of the shallow places still have topsoil without clay covering it. There is also a big bentonite mine only 35 miles away in Comanche, Tx. Would you (A) forget such a small spot? (B) Order a load of bentonite and till and pack it in the worst places and shallow topsoil? (C) order enough bentonite to cover the whole pond? or (D)Some other suggestion which I have not mentioned?

PondsForFun,

My take: Cover the small spot(all around it as well)with 2 feet of well packed clay...your operator should have done so initially. Bentonite has mixed results, but if you want an insurance policy and since it is nearby, you might be able to get it cheap. The shallow places should be okay, just be sure you have good thick clay everywhere there will be pressure from water to escape.

How are ponds in your local area as far as tendencies to leaking?

Most hold water very well. One of my neighbors built a stock tank and was very glad to have hit a "spring" (seep) at 12'. I have not had the heart to tell him that it might not be so good. In any case his stock tank filled up and still has 6' of water with it being almost 5 months without rain. one other neighbor which is higher elevation hit rock from 1/2 to 3' in diameter. The pond was built deep and holds water fine below the dam level but seeps through the rock dam. It still has several feet of water in spite of the fact I can see rock down as deep as vision allows. The closest pond to me the dam looks like it has exactly the same material as mine. It is 45% full despite drought.

Where would I get the clay to pack around wet spot? Hire a backhoe to dig down to the clay layer?

Ideally you would have the dozer guy come back and do that job. He can dig the clay from the shallow end and push it to the spot that needs covering. He can also pack it really well with the dozer. Probably a couple of hours of work, no more than an afternoon. Next time he is moving his dozer have him swing by and fix it...before the pond starts filling. Better safe than sorry.

With other ponds in your area being successful, once you fix that sandy area, you should be good to go...assuming he has done a good job applying clay everywhere it is needed.

Meadowlark- The clay layer starts at 9' and goes to 13.5' where we stopped digging. Do dozer operators swing by where you are from? We must do some major begging or butt kicking here to get them out. Here is the website with the sodium bentonite.

http://www.texassodiumbentonite.com/

I could get them out here tomorrow and do the repairs myself. Who knows when I could get the dozer operator. The weather pattern is changing here at last. We had a 30% chance of rain today and I actually felt a drop hit me. Don't you think the fix it yourself method more practical? We have three days at the end of the week with a 20-30% chance for rain.

I'd put a mess of bentonite in the possibly get it into the cracks. Then I'd call the dozer guy and tell him you had a hole in the bottom of your pond and don't want to wait. I'm sure he understands that it may never hold water and that he is the guy that dug it.

Bentonite is OK but is iffy. I would cover that hole and everything close to it with a couple of feet of well packed clay.

PondsForFun,

Actually, yes they will and we are about as remote as it gets ( but still within a few miles from a major highway)....but we don't have the distances as West Texas. I was referring to when he moves his dozer on the truck from one job site to another, if its anywhere in close proximity, they will "swing" by ...maybe its a local thing.

The dozer is preferable to a back-hoe or even tractor with a box blade because it can be so effective at packing clay by running the tracks back and forth over the subject area.....but heck the main thing is to get it covered and packed as best you can. Good luck and yes, it is raining here tonight, thank God.

One other thought which has escaped this thread...if you have topsoil sitting on top of clay, you probably don't have an issue. Here's where you would have an issue. Water seeks the path of least resistance. As long has you have clay contacting clay around the entire pond, (whether the clay is two feet or nine feet down,with sandy soil on top), you will have a seal. If the 'hole' in a shallow area leaks, water must pass through it via a connecting area of porous soil or other fracture, then pass beyond or around the dam to escape.
While bentonite or clay does no harm, it may be money unnecessarily spent.
My leaning would be to buy a few bags of bentonite, dig out the questionable area, work the bentonite into the sandy spot with a rake, mix with existing soils, and forget about it.

I plan on getting the sodium bentonite, mixing it according to their instructions and maybe even renting a Vibratory Plate Compactor to make sure I get a good seal. I want to thank everyone for the wonderful help!

Could someone fluent in Pond speak please translate this for me: "I'd put a mess of bentonite in the possibly get it into the tracks."

LOOK what is in our forecast:
Today Precip. %
Jan 20 20 %
Jan 21 20 %
Jan 22 20 %
Jan 23 30 %
Jan 24 60 %
Jan 25 60 %

Ok Ponds, I blew that. It should have been cracks. The bentonite that I have used comes in the consistency of flour. It's biggest redeeming feature, to me, is its ability to sift down into the small areas, get wet, and then expand. Normal clay doesn't do that.

Where are you getting those rain forecasts? I envy you. Ours say a chance of scattered showers Thursday. Yesterdays much ballyhooed rains left less than a trace.

Dave- thank you for your clarification. you are the only one that mentioned the question about super dry conditions of the clay. Some of it is crumbly to the touch. I will try the bentonite. The web site says they sell grades from a fine sand size particle to marble size pellets. What you would use marble size for I have no idea. The web site also says:

Years ago the NRCS or Soil Conservation Agents recommended using 1 to 3 pounds of sodium bentonite per square foot. Texas Sodium Bentonite, Inc. has been sealing ponds for over 14 years and after many years of field-testing a high quality sodium bentonite with various soils; we determined that this recommendation was not adequate to successfully seal most soils. These tests proved that the more porous soils did require more sodium bentonite clay to successfully treat.

Maybe this recommendation resulted in some of the dissatisfaction with SB as a pond sealant.

Ponds,

I would encourage you to talk directly with George, the owner of Texas SB. He talks straight and of course he is selling his product. Tell him your situation and he will tell you how much SB is needed. He told me 8 pounds per sq. ft. for a leak in one isolated area of one of my ponds. I decided that clay was a better choice for me and my situation, but each situation is different.

Meadowlark- I called them today and I will probably go over there tomorrow.

Ponds, a word of caution. Wear a face mask when you work with the stuff. There is no way to keep from breathing it and you don't want it in your lungs.

"The dozer is preferable to a back-hoe or even tractor with a box blade because it can be so effective at packing clay by running the tracks back and forth over the subject area....."

Meadowlark,

Dozers are actually low ground pressure machines, designed to be able to get around in soft ground conditions where a wheeled vehicle can't. For instance I have a Cat D5 which weighs about 25,500 as it is configured, but since it has about 3800 in^2 of track area in contact with the ground, it only exerts a ground pressure of about 6.7 psi. That is an average pressure of course. On the other hand I have an international cub tractor which weighs about 1950 with the wheel weights on. However it only has about 58 in^2 of contact with the ground over all 4 wheels. This equates to 33 psi which means that my little tractor exerts almost 5 times as much pressure as my considerably larger dozer. Appearances can be decieving. I'd run a sheepsfoot over the worst areas. A sheepsfoot can pack at around 250-300 psi. Don't use a sheepsfoot over a bentonite liner however. Just my $.02 from an engineer's perspective.

Good info Hillbilly! Thanks for posting!

In most all cases where building/construction is going on its wise to listen carefully to the .02 (2 cents) of the engineer's perspective. If you don't you will probably end up with a bunch of dollars worth of hindsight and you will be and .

It is very hard to watch 12 tons run back and forth without being impressed. A question for TN Hillbilly: Which one would you pick if you had to lay down and let one run across you? I would pick the cub every time!

Just an update as I have had to let work get in the way of fun for a couple of days. I hate it when that happens. I had delivered 3 tons of Sodium Bentonite and was very surprised to see it was the size of very small mouse turds. ( I tried to think of something else that size but could not.) A quick panicky phone call to George confirmed it was the right material for the job. The size was really 620 for those that don't want to order by the previous description. I guess we have all been conditioned from years of borrowing this material from the oilfield where it is used as drillers mud, to expect a very fine powder. George says this works just as well and is much easier to work with.
I guess I should explain why I got so much material for such a small job. Before I ordered it I went with a sharp-shooter and picked around and found about 100 square feet of this damp suspicious material and I had a few more spots on the bottom where it looked like the dozer might have broken through the clay layer. I wanted to cover this even though it was dry. I will spend Saturday tilling and packing with a Vibratory Planar Packer. The truck driver I hired to go and pick up the bentonite, said he used them to pack asphalt. I will let everyone know how this works and try to post some pictures when I have time, of this and my pond project.

Take some photos and keep notes. This could make a good follow up story to Otto's in Pond Boss.

That's not quite the point is it? We were discussing compacting dirt. You can't change the laws of phisics. Hillbilly offers sound advice.

The tracks of a dozer will always hit the high points. If the tracks of a dozer were always perfectly flat on the ground the pressure would be exactly as he said it was. This happens only in a perfectly flat world. When a 20 ton dozer runs over an area of clay or mud everything will be flat on the other side because if you have a mound sticking up at some point it will have half of the weight of the dozer sitting on it.

Ric's point is when you are talking about people it doesn't matter if you get hit by the back side of a shovel or the point of a knife ,they both will kill you but the knife will penetrate further.

Hillbilly's engineer point to me was clear -- while there are different facts to consider , like his on psi and Ponds on flat vs. mounded -- the point was not psi, but was use the right tool for the job , a sheepsfoot as Hillbilly stated.

Ponds keep us posted on the progress with your pond.

Thanks for the support fellas.

Pondsforfun

No doubt the vast majority of ponds in my part of the country (watershed impoundments)are constructed using nothing but a dozer to tromp the dirt in and in a lot of situations that is all that's needed and works out fine. But in a case where you have marginal soil or problem areas in the rock underneath you need more compaction in the liner, and a tracked vehicle just can't provide it. No doubt that if I run over a high spot with the dozer it gets a lot more pressure than if the tracks are on level ground. Problem is that the soil on either side of the high spot received virtually no pressure, therefore no compaction. Once the high spot is down I can apply no more pressure than the distributed load of the dozer. Hope you get your pond fixed up. Take care.

For simple jobs, Otto compacts with a fully loaded scraper, never the dozer. For bigger jobs, he'll rent a sheepsfoot roller for compaction, never a dozer. I love the way he explains things for a simple mind such as mine. He says compaction is the process to force tiny particles of dirt closer together. Bulldozer tracks are designed to stay on top, not sink.

PB admits:
:D