Pond Boss Forums POND CONSTRUCTION Selecting a site ESS13 For Leaking Pond

that may be it! The creek below the dam stays wet and by 200 yards has an excellent flow. I bet I have the same problem.

Therefore I have to line it to work? Is there plausible chance it will seal itself? I know it is impossible to say but if there is a 50-50 chance I may be willing to wait.

well it may be....one of the great enigmas in the world of leaky ponds.......whar's it leakin?

its like everything else, you have to operate w/ the philosophy of "multiple working hypotheses", and start to cull them out one by one. i would still survey your sides as suggested by bobad, inquire w/ you contractor as suggested by Brettski et.al., review your pics and post them here or provide a link (at a slightly reduced file size please for those dinosaurs like me still on dial-up). that would be really cool if the problem was isolated to say just the creek channel, but it could be endemic to your entire pond bottom.

in my case, waiting only made the problem worse as each year the hydraulic conductivity increased. the silt and muck accumulation did nothing to slow the seepage....so for me it was a complete overhaul when the pond was dry. if i had an additional 10k i could have completely covered the bottom in clay, but i chose to give it a shot only partially covered since the pond did hold year round water when we first moved up here (~11 yrs ago). by 1998, the pond could no longer hold out, and it got worse every year until last year when i finally pulled the trigger on one of the biggest projects of my life.

of course the longer you wait ( and i know its hard to do!!!) the more money you can save to fix it right if that is your goal. wish i could provide more specific help but as stated earlier in the thread, you'll have to develop the most logical theory, and weigh the scope/schedule/cost benefits of multiple solutions. if you had a local source of clay and were reasonably sure you had bedrock seepage, the best solution would be drain, clay, compact, re-fill. keep us posted.

Matt, you might want to get the ball rolling. If it is seeping into an underground streambed and the back of the dam is wet, it may be affecting the integrity of the dam. I'm not sure how you would check on that.

I have a creek that goes underground in dry weather. It emerges again but never makes it much further. The spring just won't support it this time of year.

I think I would dig a shallow trench the length of the dam, about 5-6 feet from the front face. I think 2-3 feet deep (a foot at a time!) would probably intercept any seepage that is coming to the surface farther down the creek bed. If you hit water, then simply re-doing the dam deeper would probably take care of the problem.

The ground below the dam is real wet. I am calling the builder to verify the measurements as Jim Troglio told me the dam may not be wide enough to hold that volume of water.

Mark,
When you say the core was constructed of clay, do you mean that a ditch or slot was cut down below the grade at the centerline of the dam. Are we talking the same "core" here? In a nutshell: did he use the dozer to cut a trench from one end of the proposed dam to the other end, perhaps 4 - 8 feet deep, may be 1 - 2 dozer blades wide? This is coring a dam (or cutting a keyway). Without beating this any further because we ARE talking about the same thing, is this what happened prior to building up the 20 ft tall dam?

Brettski,

Thanks for your reply. I did not see that. The pond was excavated from a small stream valley with a lot of fall from back to front as we are in hilly country.

The dam was going to be really high so I doubt(?) he dug down alot deeper at the base of the dam. This is what I think you mean by coring-a 4 to 8 foot trench basically parrallel to the dam at the base- not perpindicular to the dam along the streambed?

These replies have been great. I wish some of you guys lived closer to me!

OK, your next required reading may be this thread (if you haven't already been there). There is alot of good input and advice from knowledgeable folk, including Bob Lusk, Pond Boss extraordinaire.
"core help" thead

Brettski,

Now my head is swimming. I did not see that coring at my pond like in your pics. The questions:

1) drain, dig a core, hope to find more clay on the property and compact it

2) expand the dam

3) pay for the ESS13

4) lose another year waiting for the pond to fill like my excavator says?

BTW, your pond looked great- how did it turn out?

...one of my (many) blessings in the quest for pond-apolooza was to find this super group of knowledgeable and helpful pondmeisters BEFORE water. I am still knee-deep in pushin' dirt, tho there is light at the end of my tunnel. My latest collection of progress reports have morph'd within the thread: Principal Spillway thread
Thanx for the kudos...now back to the issue at hand. Don't freak out yet about the core. Right now, it is meant to be educational as you rationalize. I think we all want to eliminate some particular facet of the engineering and shrink the pool of suspects. Your reaction to not seeing a true core cut is not a disaster by any means...or...it could be a problem. Now, the concern lies with the integrity of the soil below the dam; all the existing soil that was undisturbed. If you gleaned some of the good input from the core thread, you realize that cutting a core is not necessary when the existing soil that will be below the dam, and supporting it, is known to be of a clay content and plasticity index that is suitable. This is where soil borings or samplings would have been helpful before construction. In my mind, I am suspicious (and would like to eliminate) the bond between the bottom of the dam and grade as a suspect for seepage. You will want to take some of this thought process and share it with your contractor for answers and input. How do we know that the integrity of the subsoil below the dam was impervious?
Lastly, as a possible test, you could consider going directly behind the dam and take a couple of borings near or at the bottom of the valley to see what may be considered a representative sampling of what lies some 30 or 40 feet upstream. (my contractor does this with the backhoe...dig straight down and examine the lifts as they come up. He will pinch off a ribbon about 3 inches long without breaking from it's weight and shoot me a smile...this is good) If it is good, consistent clayey soil and your contractor followed good practice by removing the topsoil at the damsite and then scarifying the clayey subsoil for a mechanical bond, finally compacting it (tell us how he did this and with what equipment) then you might feel confident in eliminating this suspect from your dead pool.

The company that just did the engineering study and proposal for the ESS-13 said that core sampling by a geotechnical firm could be done but it would be very expensive.

Now that the pond is built and 2/3 full I think it is a mute point. I don't remeber any compaction equipment other than the smallish dozer the builder used.

He was there for almost 3 months and he felt the number of trips from the back of the pond to the dam at the front with the clay and soil was enough compaction.

From what I have learned here I am leaning towards porous soil, combimed with poor compaction and possibly a dam that is too small has allowed water to leave the pond and reenter downstream into the creek.

So, what is the most cost efective means of correcting this? If I have to drain it and use ESS-13, which I am assured will work, should I also have the dam added onto?

With the ESS-13 they remove 2 feet of dirt from the entire pond bottom, mix with the ESS and then replace. At this point I could insist and make sure that they use a sheepsfoot roller and thoroughly compact the bottom.

If this scenario is correct - problem solved for $63k more. If not then the dam is the problem and I won't know until I do the ESS.

Mark- have you been to the ESS-13 website? I suggest you look it over and contact someone there direct.

http://www.seepagecontrol.com/

Mark, a leaky dam would be the best thing you could hope for. Assuming the terrain in front of the dam is suitable, you can key it and build it up against the existing dam face without losing a drop of water. You end up with a nice wide dam to boot, which is needed anyway if it's a tall dam as you indicate. If the dam is the culprit, your dozer guy should donate at least some of the labor to fix it.

Mark, I get in trouble for being blunt here. Forget you fish for a few years. It is the least of your concerns now. You dam likely used up your best materials. It probably is not leaking, itself. Water is either going below it because it is not keyed. However, your best soils were in the floor, so let's hope it is not going under it. Most likely, due to the poor soils you describe, it is going around the dam and bypassing it entirely. You ES whatever may work. Clay is a better option. Keep in mind, you pond could very well seal itself entirely in a year or two.

Good luck.

BB, Robinson,

You are both right. I need to ask these questions to the builder now that I have been educated on this forum.

As far as the fish, I can afford to wait. However, the pond is the focal point for a custom home I want to build and you drive across the dam and up a small hill to the house which looks out over the pond.

It will be a beautiful setting with a southwest view over the pond with moutains in the background(Shenandoah Nat Park). Right now though, it is an eyesore with partially submerged trees and stumps( cut and layed down).

This is to be our "dreamhome"- thus the impatience as I do not want to cmmit to house construction until( unless) I get this damn pond resolved.

This is to be our "dreamhome"- thus the impatience as I do not want to cmmit to house construction until( unless) I get this damn pond resolved. [/QB][/QUOTE]


It's dammed pond. One of our more humorless and Naziesque moderators might just edit you for that one. :p

A Freudian slip. i meant dam/pond like you said.

Know da feelin bro.

Good news. talked to the excavator and he too is concerned. He is taking a machine to the pond and dig behind the dam to see what he can find. There is a lot to be said for hiring someone you feel is honest and will stand behind their work. His conversation was that this pond should work, he's worked with worse materials and he will figure it out. No mention of money or excuses.

Brettski, he did core it out til it was over the cab and way back into the sidehills- with clay. That's what has him puzzled. His dad would stop by and measure the compaction and said it was 98.

I guess we just start by eliminating the most likely problem and move from there.

Mark, grab yourself your first gold star. You're learnin' to walk the walk, talk the talk. The boss, Donna-ski, and I always joke about learnin' on the fly (and man, we do alot of it)..."we'll start gettin' good at it when we're done".
Guys like you and me take the route of hiring the man for this level and volume of dirt-work. This, in of itself, is not so difficult...the tough part is finding someone with the ability, integrity, and honesty to do it for us the way we want it done. There are others on this forum that have not been so fortunate when they walked a mile in our muddy shoes.
Keep it comin', man. You may not know it, but you are teaching right now. If not a veteran, surely another pond-dreamer.

Amen Mark......

I'm just glad that the builder recognizes that there is something amiss and wants to help instead of deny and run. That is huge when you are talking these kinds of dollars. This is a positive step for sure.

In retrospect I would not build a pond without a plan, an engineering and soil report. Sinking tons of money into a project like this and hoping for the desired results is foolish.

Good luck Mark. Please keep us updated!

Mark,

That is really great news...and the best resource you can get IMO is a local expert person with those characteristics. Like BOBAD said, let us all know how this turns out. I've got a feeling its going to be positive.