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

Ponds,

Your thread seeking options(as in d above) other than the SB has taken a turn to discussion of the relative merits or demerits of a bulldozer for compacting clay.

As you requested, I tried to offer an alternative option to SB in the form of the clay, which you indicated was resident in good quality at your site. If the option is still relevant, here’s my logic for suggesting it:

The leak game is to some extent a game of probabilities vs costs. The suggestion for two feet of clay packed with a dozer provided by your original operator was intended to be my best-shot at the most favorable probabilities vs costs trade. Good quality clay at the site is the best, cheapest form of leak protection you can get, IMHO. The suggestion to make the request of your original operator to fix the problem was aimed at minimizing the costs to you. I assumed the original construction was with a dozer, but if a sheepsfoot roller was also used in the original construction and available for the repair, certainly that is a better compaction tool than a dozer alone as pointed out above.

The approach for the clay packing in a repair like yours with a dozer alone that I have seen successfully applied is to mound up two feet of clay over the subject area... a little bit of clay at a time. The mounding not only offers good leak protection, but also makes the best use of the dozer’s packing abilities, concentrating the weight on a smaller area on top of the mound. Build up the mound gradually while running the dozer back and forth over the mounded area and you will get adequate compaction assuming you have sufficient moisture in the clay.

Certainly, other equipment options are available for this approach including a back-hoe or farmall tractor with box blade. My thought was that the use of your site good quality clay was/is your best option and the best way to get it in place was with your original operator and his equipment.

It will be very interesting to get your perspective down the road a bit on the SB. I sincerely hope you get great results and report on those results to other Forum readers.


Relative to the discussion on the demerits of a dozer for clay compaction, I certainly agree that a sheepsfoot roller is superior, but is a bulldozer unacceptable as perhaps implied in above posts?

Hundreds, no thousands of ponds have been built in my area with nothing more than a bulldozer, including 4 on my place, none of which leak. One pond that I renovated with only a dozer did leak because of previously undetected animal damage and my own misjudgment of not applying enough clay thickness in one corner area of the dam. The dozer alone fixed both of those problems as well.

A bulldozer, even a small one like mine, is not optimal for compaction, but it can certainly offer a reliable means of building a leak free pond in my area.

Meadowlark- I have had 3 days in a row where nothing works out exactly as you plan. The good news is that the outcome seems good. I got the load of three tons of bentonite and had two helpers coming the next morning. They did not show. I ended up spreading and tilling about 2 tons by myself with a 70% chance of rain that night and 100% the next day. I ran short on time and used my golf cart to pack it. I was pleased with the way it looked and fell into bed that night with every muscle in my body sore. I woke up to thunder about 2:30Am and just turned over and went back to sleep. I woke up the next day to wonderful, beautiful rain. You don't remember how great rain smells or how clean the air is after a rain until you go several months with dew points in the teens. I only got 6/10 of a inch. The creek did not get close to running but I have two large puddles in the bottom which have lasted 48 hours without even going down one inch. One of them sits across some of the bentonite i spread. I know it does not have any pressure with 18" of water on it but it makes me feel good anyway. I covered all the wet sand with about 15# to the sq foot of bentonite mixed and packed it. We have another good chance of rain on Thursday and Friday. I don't think I will get another chance to work on the bottom. I just can't wait to see the creek come on a good run and watch my pond fill not just with water but with the hopes and dreams of my own Pond to Boss as I see fit. Thank you everyone for the advice and help. You all together make this a great forum.

My .02 cents for what its worth.

I believe a dozer is an extremely valuable piece of equipment on a construction site; (ie.) grading, shaping, debris and tree removal, etc., however there are compaction limitations. This is especially true when structures get higher and/or taller.
I received this technical guide notice about two months ago and although it is for Wyoming it can probably be applied nation-wide.



December 2, 2005

TECHNICAL GUIDE NOTICE WY - 84

Purpose: This notice transmits the revised construction specification for Pond, 378 in Section IV FOTG. The only change in the specification is to paragraph COMPACTION METHODS. Track laying equipment (Bulldozer) will no longer be an acceptable method of compacting earthfill for an embankment pond.

Effective Date. This notice is effective when received.

Filing Instructions: The revised construction specification is electronically filed in the Wyoming eFOTG:





ADOLFO PEREZ, JR
State Conservationist

Man can I ever empathize with that, Ponds!

You did your best and that's all we can ever expect of ourselves. Great report.

Ponds :

Sounds like you are off to a good start. BTW none of us are entitled to more than 3 days a year where everything goes as planned and I will settle for 2. One thing DD sort of noted and I can confirm about bentonite is that it will often mix with water and move toward the low pressure spot (leak area) and expand to seal the leak. That is a major reason (along with lubrication) that it is used in oil well drilling muds. I think you have a good chance that it will work. We look forward to tagging along with you on your pond journey via your posts.

How much bentonite do you need? And, how much does it cost?

My just completed pond excavation has a portion of the bottom which is suspiciously sandy. The clayey sand has less clay than I expected, and I believe my dozer operator went a little deeper than he should have, leaving me with only about one foot of the clayey sand (or sandy clay, I didn't have it analyzed) above what I know is coarse gravelly sand. We had a shower over the weekend, and the clay lined portions are holding water "on top" in shallow puddles, while this sandier material is saturated, but not holding the water "on top". I fear that it may be too porous to hold water.

Therefore, I started thinking about bentonite. This is on the flat bottom of the tank. The sides have been lined with clay, seemingly adequately. Now, I don't know for sure...it might hold, or some of the clay from the sides may wash down into the flat bottom, and seal it off.

But, if I were to consider bentonite, for a clayey sand bottom, of say 50x50 feet, how thick and at what cost am I looking at?

Oh, and the obvious answer is to get the contractor back out, but I had to wait for him for 9 months last time, and I'm not willing to entertain that again. Also, I'll probably wait to know for sure before I do anything at all, and at the rate of rain we've been having, it may be 2007.

Go to the website and read all that is available for sealing ponds.

http://www.texassodiumbentonite.com/

The recomended amount of bentonite for a porus sand is 8# to the sq foot. That means 10 tons. It is only $80 ton at the mine in Alpine, Texas but the trucking will cost you as much as the bentonite. Then you need to mix it with a few inches of the topsoil and pack the heck out of it. You must decide for yourself if it is worth the money and effort. My sand layer was staying wet in the worst drought conditions possible so I was sure it could transport water.

http://srac.tamu.edu/tmppdfs/9718650-105fs.pdf

This is from another SRAC document:

Coarse soils containing large amounts of
sand and/or gravel are unsuitable. If the soil can be formed into a tight ball that maintains its shape or is moldable, it is suitable for pond construction. A rule ofthumb is that soil must contain at least 20 percent clay.

If it will mold or pack into a ball you might get by just packing with a padfoot or sheepsfoot roller.

With an area no larger than that I'd rent a skid loader for a weekend and dig my self some clay up above the pond basin somewhere. That would be a lot cheaper than bentonite and form a better seal.

TN Hillbilly,

By skid loader, are you talking about a front end loader? I have experience using a rubber-tired backhoe with a front end loader bucket (something like 1 cy size). I think you're right, I could probably get by with that. I have a clay layer just below the surface that I could mine such a small amount, from nearby. I'd have to make sure the slopes were dry, I suppose, they were pretty slippery after the rain last weekend.

You've given me a good idea which I hadn't thought about. Thanks!

There's a great story in Jan/Feb Pond Boss about bentonite. Otto goes into detail.

poland_jack,

I actually had in mind a skid loader such as a bobcat. Preferrably one fitted with rubber tracks over the tires. With the tracks they will dig pretty well. You usually come out a bit cheaper since you can tow these generally with a 1/2 ton pickup. So for a 50x50 area with a 1ft blanket your talking 2500 ft^3 or about 95 yds^3. Or a 50 hp tractor with a good front end loader could do that job. Or you might do some testing on the material that is there now. If it has enough clay you may just be able to compact what is there now with a sheepsfoot and form a seal.