Pond Boss Forums POND CONSTRUCTION Building a dam forgot antiseep collar, need opinions

I just found this site a couple of days ago. If I found this site sooner, I'm sure I wouldn't need your expertice.

Well, I finished building my house so I thought I would build a pond. The pond is about an acre in size with a depth of seven to eight ft. Everything went well, except I wasn't aware that I needed an antiseep collar and now have a good leak around the pipe.

I tried a 1/2 ton of bentonite with no luck and am on my way home to drain the pond. Just as an FYI, I have two six inch pipes about 2 inches apart that drop about 6.5 ft straight down and T near the bottom of the pond then shoots about 20 ft through the bank

What do you guys think would be my best option?

1. Try to pull one pipe out and put an antiseep collar on the other?
2. Make my own concrete collar around both pipes?
3. Try to pull both pipes out and put a pipe at the top of the bank?
4. Or something else?

I am trying to avoid digging up the whole bank where the pipe is at because it has been down for a couple of years, is well packed, and is holding back the water very good except for around the pipe.

Any suggestions would be greatly appreciated!

I have a good "leak" around the pipe. Darn spell check.

I have read that antiseep collars are not really needed, but I used them on my big pond and will use two on the one that I put in this summer. I am not an expert, but I think the pipes need to come out and be replaced with good packing of the clay around the pipe. The seal between the lower side of the pipe and the soil is probably the hardest to do.

You can dig a hole with a backhoe then cut the pipe , slip in the collars and weld the pipe then and pack in clay and concrete. Coat the weld with an anti corrosive then replace and compact the hole/dam.

I've built my own anti-seep collars by digging above the pipe, to the sides and under the pipe. Then I poured in sackcrete mixed in wheelbarrow with a shovel and was good to go. This was however before I had any water working around the pipe. However I'd still give it a try instead of disturbing all the dirt. At least that's MHO.

I don't think it matters, but my pipes are plastic.

My pond is draining right now.
How far into the bank should the collar be? 2 ft? 3 ft?

Thanks again for the help

Mine is in the middle

My pond is now drained and the leak looks like it has stopped because there is barley any pressure there now.

I think I will try like Cecil did and dig with the trench bucket on the backhoe and use that as a form? If I do find a little water going past the pipe, would it affect the concrete when I dumped it in?

I am also thinking of lining the top, bottom, and sides with bentonite.
Bentonite gets really soft when wet though. Good idea or bad idea?

Thanks for the help!

Aaron,

Sorry to hear about your problem. I don't know much about the soil in you area. I just figured everybody's soil in your area was coal or rock. If you were 50-75 miles further south it would be easy.

There are downsides to doing it at the face of the dam, or doing it a few feet into the dam.

Is the pipe that goes through the dam smooth or corrugated? That may help making a determination.

Ken

It's smooth pipe, schedule 35.

Should I be doing it in the middle like Dave did?

The soil up here isn't the greatest (a lot of rock), but I don't have any other leaks beside this one.

Thanks for the help

If you use sackcrete it will help it set up as it will mix with any water and solidify.

I've dug down to find four star mole holes that go from one pond to another and then dug a trench by hand to produce a "form" for a concrete collar. Then I filled with sackcrete and eliminated the leak.



I wouldn't. You want a nice solid barrier for the water to come up to, stop, and then go down and completely stop.

As far as where to put it, anywhere in front of your leak is the best place. More than one would be even better.

Be careful with the bucket and the pipe! Some hand digging is in order if you're not too deep.

Pub 590, page 43
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The link is in the archives, page 3. With all the techno info for building ponds contained therein, suggest a sticky note atop one of the pertinent pond construction forum categories with the link.

My swing cylinder chain just broke on my backhoe, so I am now thinking of getting the rubber antiseep collar and digging by hand.

Are the rubber antiseep collars as good as concrete?

I was leaning towards the concrete one because of the two six inch pipes that are two inches apart. Can I cut the two six inch holes that close together in the rubber or should I get rid of one of the pipes?

If it wasn't for bad luck, I wouldn't have any luck at all.

Thanks for the help!

Aaron,

I've used the rubber antiseep collars with 4 inch PVC for my smaller ponds with good luck.

aaron:

Read what that publication that Brettski linked to about the size of the drain pipe. Will one pipe be enough for your pond, or will you cause larger problems in the future with only 1 pipe?

I hear ya on the luck. Mine runs like that at times. It doesn't matter what the anti-seep collar is made from as long as it seals to the pipe and goes out a ways from the pipe. I've seen metal ones welded to metal pipes too. If the anti-seep collar doesn't seal to the outside of the pipe, you'll be digging it up again.................

I read the link, but didn't understand it.
I found a link to a site that calculates runoff from this site.
I put in 20 acres of drainage and a 20% slope (double what I really think it is) with a coeificiant of 1 and its telling me a 5 inch pipe will work.

Does this sound right?
Average annual rainfall - 40"
Guessing 10 acres of run off into a 1 acre pond.

If this looks right, then removing the one pipe sounds like a good idea?

Thanks for the help!

The problem is not figuring out the average runoff, but the runoff potential for a "100 year flood". Lately, those have been happening more frequently than 100 years. Contact the local NRCS office and they can help - maybe they could help with just a phone call?

When Hurricane Ike rolled thru here in September 2008, we had over 12" of rain in one day. If that happened to you, that would be 10 ac/ft of water hitting your pond. That'd be 3,260,000 gallons........

(just kidding, aaron...hang in there)

I decided to leave the other pipe in and I will put two of the rubber anti seep collars (just for a little added security) in the middle of the bank about three to four feet apart. This way I only have to dig one hole.

I am also going to use a bentonite/topsoil mix to pack all around them.
I found a bentonite website that said to mix 1 part bentonite to 5 parts soil for big holes and/or cravases.
This seems a little on the low side, but they know better than me.

Any suggestions would be appreciated, if not I will let you know how I made out when I am done

The mixture of bentonite to soil depends on the type of soil. The more sand/rock/etc the more bentonite that is needed. Easiest way to determine the correct ratio is to do a bucket test.

Just wanted to give an update, I only kept one pipe and added two antiseep collars.
It seemed to work because the waterline came above the pipe without any heavy rains, but I have been waiting for months to get some substancial rain.
Will let everyone know once we get some good rain.

Thanks for the help

Thanks for the update. I'm glad that everything is working out for you, and that the pond is rising.

Hope it works out

May the force (of the antiseep collar) be with you

any comments to this?


http://www.mde.state.md.us/assets/document/damsafety/NRCS/2007_NRCS_Filter_Diaphragm.pdf

On what ? The link is talking about big lake impoundments not ponds.