I have a one year old pond constructed to have a maximum surface area of about two acres and a maximum depth of 30 feet. It was constructed at the site where years of runoff had eroded a deep channel. A test dig hit the water table at 15 feet. As work progressed, as I recall, clay was packed below the 15 foot level. Water also seeped the from inflow side of the pond, a few feet above the level of the water table. The contractor suggested that it was a "stream" that might help fill the pond. None the less, the contractor trenched and back-filled with clay above the "stream." He assured me, and I believe he meant it, that the pond wouldn't leak.
Still, from the beginning to the end of the construction, there was always water seeping into the site from underground. That is, at no time was the "hole" dry. We have had several good runoffs into the pond since it was constructed. The pond has never filled to a depth greater than 15 feet, which I believe is due to leaking between rains. Following each rain the water level drops more and faster than another pond I have nearby. I know this isn't necessarily a fair comparison. Still, at this point, particularly considering my research here on the forum, I'm pretty much convinced that the water is seeping back into the water table and/or spring. I could kick myself for not realizing this would happen, that water would go out just as easily as it comes in. I thought that since water was already there, it would somehow cause a "back pressure," preventing flow in the other direction.
My question is this: If the pond communicates with the ground water or a stream, how is that communication best sealed off? Do you just pack more clay until you get a dry floor, or is that even possible? Likewise, will a liner help? I've read much on this site about fixing leaks, but I'm not clear which method(s) are best suited for my problem. If I just let the pond water level stabilize with the ground water table I'll just have a few feet of water in a really big bowl.
GB Mayes

Welcome to the Pond Boss forum GB!

It's almost never desirable for your pond to communicate with the water table. The exception would be if your pond is lower than the surrounding land.

You'll have to keep filling with good clay and packing (probably with a sheepsfoot roller)until water stops seeping in. If water can be kept from seeping in, it can be kept from seeping out. A wheeled tractor or truck is also good for packing. A dozer or excavator is the worst thing for packing, they just don't have enough ground pressure.

Good luck and keep us posted.

Bobad:

Thanks for your quick reply to what must be a tiring question for regulars on this board. There was no compaction other than the bulldozers. Much that was taken out was reported as good clay and I have lots of it left over as I had them pile it up into a "hill."

(user error in premature post above)
I guess what I need to do is wait till the pond goes down further, during the hot Texas summer, drain what's left, and get it repacked.From your post I assume a liner wouldn't solve the problem.
GB

I agree with bobad, packing a 2' thick liner of clay, compacting with a sheepsfoot roller in 6" lifts should do it. A liner might work, but how does one keep the water from puddling up under the liner before the pond is filled?

Dozers or other tracked vehicles don't put the pounds per square inch of pressure on the ground that a sheepsfoot roller does. You could use a dozer to drag the roller around, but the roller is doing the work.

A friend had his 35ton excavator at my place when we renovated my pond. He tracked right across a damp area, and when I went to walk across the same area in his tracks, I sunk to my knees. I may be fat, but I sure don't weigh anywhere near what the excavator does! PSI to the ground is what really matters.

I feel your pain, I have a groundwater based pond that fluctuates with the water table. I have sandy soil, and not enough clay locally to pack in. So, I have to live with it if I want a pond. Luckily, the water table is pretty high here.

Thanks esshup:
I suspected a liner might not be the way to go from other threads I've reviewed.

I looked into doing a lined pond, and after reviewing the costs and pitfalls of a large lined pond I decided to live with fluctuating water levels. I'd still be $$ ahead if I were to drop a dedicated well just for the pond, including utility costs.