I’m trying to wrap my mind around how to fix my leaking pond. Could use some help from a hydrologist. Is it possible to block off a water source so it doesn’t follow its natural course under ground?

Here’s a little history from my prior posts. Had the pond dug in August 2006. I asked the excavator to dig down 12 feet from the surface at the deepest point. He hadn’t hit water so decides to go to 15 feet. He strikes ledge and opens a hole that releases water into the digging.

First water enters digging through a coffee can sized hole in the rock.

I was overjoyed with the water entering the dig. The pond is completed and then water begins to recede. By September there is a 10 foot area with the remaining water.



I contact another excavator to deepen the pond in the shallow area and move the dirt to fill up the deepest part of the pond, where I believe the leak was located. The fall rains fill the pond and winter freezes the pond over. Mid winter the ice collapses, indicating the water has drain from the pond again.

Spring brings more rain and refills the pond, but by June the water has receded. I pump out the remaining water and purchase 20 bags of Bentonite clay. I also bring in four half ton truck loads of blue clay and hand spread it over the deepest part of the pond. Then I mix in the Bentonite with a tiller and compact the basin.


During the compaction, with a Jumping jack machine, the area that I’m trying to seal becomes like mush. The compactor sinks into the mud. I then use my tractor to complete the compaction of the basin. The area has a rubbery bounce to the surface. About this time I’m feed up with working on the pond. So with fingers crossed I begin to fill the basin by pumping water from the well.

The fall rains come and fill the pond. The winter snows cover the pond ice and it holds water all winter. In the spring the pond is full and going out the outlet. Now in June the pond has dropped almost four feet, in spite of adding water from the well adjacent to the pond.

Since hydraulics of the water from the ledge is affecting the water height. Is it possible to seal the ledge to keep water from exiting the pond?

I thought of digging out the filled area during the summer and back filling it with cement, hoping to seal the leak. But the hydraulic pressure during the wet months might reopen the sealed area.

Anyone been through this before on the board?

Scruffy...

I am sorry to hear about the trials that you are going through. What size pond are you dealing with here? Have you considered a liner? It would be a sure-fire fix and might be cheaper than keep renting equipment and having people come out. If I remember correctly, somebody posted here that you can get liner for somewhere around 40 cents a square foot or something like that.

The pond is 80'x50'x8'deep. I'm not sure a liner will would work, when the water table is high the pond is full. I'm thinking the back pressure under the liner might open a seam? Also the irregular shape of the pond may be a challenge.

I'd like to hear from someone that has solved a leak by using a liner.

80x8x2=1280
80x50=4000
50x8x2=800

That is roughly 6080 square ft if it was a perfect box. Since it is obviously not, you could probably go with less. You can get a one piece liner in this size I am sure, which would alleviate your concern over the seam. The cost at 40 cents per square ft would be around $2400 plus shipping. As far as the water pressure goes, as long as the pond level is higher than the water table, there shouldn't be enough pressure to lift the liner off the bottom. I think this may be your solution if you don't mind the cost.

I did a web search and found EPDM liners for as little as 35 cents with free delivery. But, the witdh only went to 50 ft. I'd have to seam the liner and contract a crew to help place it.

Cost would be a big factor as I'm out of funds, that could used for the pond. A kid in college and energy prices are digging into my pockets, not to mention the coming northeast winter. If it's like last year it's going to be expense.

A liner may be your best bet. Ask the liner people about a valve in the bottom of the liner that will allow water to seep in if it needs to.
Colorado Linning has some info on that. That may not be need but you need to check.

OttO

Mike,
Can you describe this valve? Also, the need to allow seepage beneath the liner?

Otto,
Thanks for the input. As asked above why a inlet valve?

The valve is installed in the linner. It will let water or gas that is below the liner in so the winner will not be bushed to the surface. When a liner is allowed to be bushed up it looks like a whale in the water.
The valve looks kind of like a flap that will open when pressure is applied but will not let water out.

You may not need this. Check with the people who sell the liner tell then your situation and then make the decision.

THIS MAY NOT BE CORRECT BUT THIS VALVE COST LESS THAN 100 DOLLARS

If the liner company does not know about this get a second opinion

OTTO

I also have a leaking problem with my pond other than a liner is their any thing else that can be done to stop the leakage.

Quarterman,

I've been fighting this leak going on my third year. Broke into a ledge water seam, now what comes in also goes out.

Do a search, lots of good information on this site. I'm working my way through the fixes and haven't found the solution yet that fits my wallet.

Otto,
A flap type valve I would have concerns with getting debire stuck that would hold it open. I'm thinking a duck bill style valve might work better. I see your point about the water pressure from below causing problems. I think you have pointed out what could happen with my type of leak.

I sent a couple of emails to liner people with no respounce. All my searches came up with companies west of the Mississippi, no dought my project is to small for their interest.

I'm also thinking the only other solution would to be have a well dug above the pond to tap into the water source before it gets to the pond. Pro's; cold fresh water, water fall, good areation. Con's costly to dig, pump costs, electrical costs, location difficult to get equipment into.

About 19 years ago I built a bout a 3 acre pond for a local man the soil did not look good but it sure did not look bad.
This thing filled up and went dry faster than you could have pumped it out. Walked behind the Dan all over the bottom of the lake. the local man added some bentonite on his own. By now we where not talking very much.On the 3 of July at the tire store we ran into each other and I had to at least ask if the pond ever got any better KNOWING IT HAD TO BE DRY. He said it was about 6 inches low but really holding well.

He fed his livestock in the bottom and it started holding water it has not been a problem since.
OTTO

Mike, I've heard of that but never really believed it. OK, I guess it is possible.

I've seen it with my own eyes. When worked, rolled over, or trodden on, mild mannered clay turns into "puddled clay". It gets so hard that when you bulldoze it, it comes up in hard slabs.

BTW, a fair sized calf has a higher weight per square inch on the soil than a dozer.

Otto,
After nineteen years? I can't wait that long. I'm planning on sellling the place after my daughter finishes college in about three years. Need to down size,the energy prices are going to be insane in NH this winter.

Hey Scruffy,
Sorry to hear your still having problems with that leak. It seems like a liner is your only solution, hope you can find one at a reasonable price.
I agree fuel prices are going to be insane, but a good alternative is an automatic coal stove. I took out my wood stove, and got a coal stove this spring. 3 tons of rice coal should get me thru the next winter for $840. Good luck with your pond.

Scruffy,
Did you check out the company called just liners, they're down in Tenn.

AP,
Got one quote out of three inquires. Price per sqft was 51 cents.
Total cost for liner was over $4,000 with delivery etc. I'll look into just liners also. Thanks,

Ordered a wood pellet stove this weekend, figured I'd use about 4 tons of pellets. Still expense but not like oil. Have about 4 cores of wood with two that need spliting but the wife doesn't want me to tackle that project,she saids the house comes first.

The man who fed his cattle in the leaking pond did not do it for 19 years only 1 season...I DODGED HIM FOR 19 YEARS

OTTO

banks our not compacted properly and as you notice in your picture after drain down minimal clay sediment at bottom.It will take time for this to seal lot of rock.
Bentonite will only work if you knit down 12 to 18 inches if a spring is present approx 3 pallets with unwashed sand.
Your photo shows a top soil and loam cover was this removed down h pan before install of dam

If you use a liner a gravel trench at bottom and vented with 4 inch pvc exiting the top of the dam for inspection with 1 1/2 pvc bleed off 3 foot below grade to elimanate ground water air will discharge at top vent on dam

If you do the liner you need a complete reconstuction on your inside slopes also with all that rock a good prayer and liner cushion

SCOTT
Tell us some more about the gravel trench and the vent you are talking about.

OTTO

Same principal as when they poured the footings on the world trades center to expel trapped bentonite slurry and air a mechanical valve would require service and fail because of debris so by installing pref pipe in bottom in gravel and coming up solid to suface hance air and water relief.For northern ponds a frost bleed off is suggested. I have only done three liner ponds which were small and came up with this method because I could not bring myself to the point of cutting a hole in a $7000.00 liner to put in a burp valve and wondering if it was in the right location or if the liner would seal to the soil from runoff clay. This was evident when we had the liner delivered it sat on some clay on shore for two weeks and when Jim went to lift into pond the clay stuck to the liner
Then the next hammer in the bag was what if the pond went down winter frost came and liner froze to the soil thermal reserve from the pond yes should warm the dam but had a doubt so we installed the bleed pipe

If you look at the construction data of your new stadium down there they have applied this to geo thermal.

THINK OF A WELL TANK Iwould think a gravel key from the bottom up might work would you exit it on the dam deck past the liner or would it fill with silt over time pipe is bettr i think

Scott
Thanks for the info. Lots to think about, It makes sense.

Not for sure I understand about the LINER SEAL TO THE SOIL FROM RUNOFF CLAY.

keep THE INFO COMMING.

OTTO