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

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.