Pond Boss Forums POND CONSTRUCTION Building a dam Dam Core Question

Liquid, that is good information. 10" is a pretty narrow trench, but the width of the trench wouldn't matter much as long as the concrete held up. If this truly works, I wonder why most would not use it as their solution to dam leaks? It seems to be the cheaper option, at least in places like Austin where there isn't much clay.

What would 60 mil pond liner cost to line one side of the trench? Excavate, drape into the trench, backfill.

My two cents---- It goes back to what is really leaking and where.

Think hard about this one. If you did this, will it really fix the problem. Are you absolutely sure. How much are you willing to stake on it.

If you fail to intersect where that leak is underground by even 6", it will not help. Compare this to the laying down a complete seal/liner, with clay or such. More expensive, but more of a guarantee. Not to be negative here, just be aware of all outcomes and avenues. If it does work, you just saved a bunch of money.

Have you contacted Otto for advice?

The bid I have on lining the entire pond is over $18,000, the same as building the core out of clay. Ether way, I think I would still have to core the dam. If we dig down below where the dam meets natural grade, I can't see how we could miss the dam leak. I haven't spoken to Otto about it, but I will. If the dam core doesn't solve the problem, then I will have to line the pond with clay.

And essup, I have no idea what what a 60 mil liner would cost, but I would be concerned that it would not reach the bottom of the trench evenly.

I sure hope someone corrects me if I'm wrong, but if the entire pond basin is covered with clay or liner, then there is no need for redoing the core. If the water goes into the "bowl" it can't get to the core, so no need to fix the core at that point. The best fix, but the most expensive.




Water works in mysterious ways... (actually not) - but it can do some pretty amazing stuff. Like being forced downward 20' by the weight of the water and then follow a vein 200' away to come out no where near the pond. If you know where its leaking on the backside I would tend to follow that vein back into the ground/dam and just try to put this trench you are thinking about in that spot. Perhaps a few feet in each direction out from it and downward. That would be the cheapest "gamble". This is just me being cheap... that's not always best.

Might have already been stated, but we always use a dozer's width (around 12') for the core width. That's just because it's easier to build that way. Slope the sides of the core at a 1:1 to get good compaction.

I was thinking if you go the concrete route and hit the leak, there may be enough flow and pressure that the concrete won't set well as it will have too much water pushing into the mixture. You will probably need to get some plastic water barrier down there to prevent water penetration until it sets up. After that, the plastic can degrade, who cares. So any big old roll of plastic like that from the hardware store will probably work to bag it up. However I am uncertain of success since there will be a gap between the plastic and the soil.

One thing about digging the trench, if there is a good leak, you will probably see it while digging, and be fairly certain of making positive progress.

I am having a head-scratcher of a leak problem myself, and would love to get the the bottom of the issue to get it fixed (similar to yours). All was fine and dandy with plenty of inflow, but now that someone turned off the rain faucet, I am seeing some pretty significant drops in level vs. time.