Pond Boss Forums POND CONSTRUCTION Soil questions Leaky Levee, here we go again

Some of you may remember my posts from last year about this time when I was re-working a levee that wasn't holding water. We thought we had it covered, we did all we knew to do at the time, and when it filled up again in March-April and I turned the well and pump off, it immediatley began to leak back down about an inch a day. It's dropped the same amount as last time, about 6-8 feet. Gets to the same elevation and seems to level off.

This summer I hired a backhoe to come in and just dig into the levee. My eye is not as trained, but the operator said the sand content was very high for a levee. He also pointed out a strata of what appeared to be grass and grass roots mised in pretty heavily. I'll have to admit, the soil was pretty junky looking compared to other levees I've built. Also, we left some small mounds of excavated dirt along the edges of the trench we back filled. A day later, a week later, month, and so on...I could always pick up the dirt and squeeze it like sand and it was powdery. I could kick it like sand. There just wasn't much clay in there.

Some of you watched the project last year as I posted pictures here. This year I'm going to work on it some more. Trial and error and method of elimination.

First and foremost question. We all know plastic is waterproof. I have visited countless web sites that sell polyethylene.

My questions are:
1. Will ordinary 6 mil visqueen work? And how long can it be expected to last when buried under a couple of feet of soil? I've read that it can take (theoretically) 500 years for it (plastic garbage bags, visqueen, etc.) to beak down in a land fill.
2. Do I need any specail kind of plastic? Are the thicker kinds made of the same material as visqueen?
3. I know that 6 mil is as water proof as 45 mil. If this is going to be installed on a clean surface and covered with 2-4 feet of clay soil so I need thicker plastic? Or will the 6 mil be enough?
4. Is there anything I need to particularly avoid?
5. Is there anything I need to particulary ask for concerning the compostition of the plastic?

I plan to cover the entire face of the levee, water side, with plastic. Probably 30 feet wide x 400 feet long. I will over lap as many feet as recommended. I'm planning to coer the whole water side of the levee, and then run at least 100 feet down each bank on both ends of the levee. I then want to cover that the plastic with clay soil.

I also want to take a bulldozer and blade off a working platform at the lowered water level. I'll open the drain and drop it as much as needed to do this right and safely. I then want to take a track hoe and dig a new core ditch about 15 feet deep, which would extend deeper than the eeeexisting core ditch, which is in the center of the levee. I'd like to drape a piece of plastic into this core trench and then pack it with clay dirt. In essence, I'd be double sealing everything with plastic and then a plating of clay soil.

I can go on and on into the details, but all of you good soil men and good pond builders have the experience to know what I'm talking about and the basics of the scenerio that I will encounter. IE, installing a liner, diging a new core ditch, and plating over everything.

Anything that you can suggest would be very much appreciated. Any ideas on what to avoid, what to watch for, and what to do.

It will be at least 30 days before I start, and with the weather I might wait till late winter. I'm starting to get my plans in line now. Would love to hear anything that any of you could offer.

Thanks again,

"Bill"

Bill, I haven't used plastic to do what you're planning, but I have thought about it. A couple of things that crossed my mind with the thinner plastics are:

What about critters that burrough, and live underground. How easily can they dig their way thru it?

What about tree roots? I've seen grass and weeds push up a couple inched of ashpalt.....

Is the 6 mil thick enough to sustain any "whoops"?

When I thought about overlapping it, I also thought about using a caulking gun and laying at least one bead of sealer on the overlap, silicone, roofing mastic, something cheap and sticky.

Hi Essup. This is on the water side of the levee, so no critters shold be burrowing where I can't see them. This is not a dam on a running stream, so I don't have much critter problem, ie beavers, muskrats, etc.

I would not do this on top of the ground. This will be placed and installed on smooth bround that we dress for this specifically, and then we'll top it with at least 2 feet of clay soil.

Another consideration is I like to burn off the pastures every year. If you get even a small grass fire on the levee it will get the plastic down to the water line. MORE IMPORTANTLY...if you are new to this be VERY careful about fires on a levee, esp if you have a black plastic pipe serving as drainage. The fire can get to that and do a slow burn all the way through a levee and destroy the pipe and damage the levee too.

Thanks for the note.

Bill

No problem Bill. I didn't think about Muskrats and Beavers, I was thinking more along the lines of crayfish, moles and maybe a groundhog. Even with the pond not being on a stream/river, muskrats & kits will travel a ways to find new places to live when the young 'uns get kicked out of the nest in the Spring.