high water table

[dragonkoi]

hi all has anyone encountered a high water table when doing a concrete base and if so how is it best to get round this problem??

Many Thanks

[MikeM]

Dragon, I think there are others better suited to answering your question, but I'll get it started...

If when digging out the pond you go below the water table, you first should decide if you want to keep digging or design your pond to be partially aboveground. For moderating temperatures, etc., the deeper the better. But, there are trade-offs. If your pond goes below the water table there will always be stresses on the structure and these will be severe if the pond is emptied below the water table line.

If you decide to keep digging, then you have to construct a de-watering pit that goes down below the ultimate depth of the pond. In the de-watering pit you place a submersible pump with pipe to take the water to a discharge point away from your project. You have to get rid of the water. The pump has to be sufficiently strong to deal with the head pressure and provide enough volume of flow that you reduce the water table in the vicinity of your pond project. You will want to keep the de-watering "well" in place permanently so that you can monitor the water table depth and lower the water table whenever you lower water in the pond to within, say, a foot of the water table. (A margin of error there!)

As for selecting the right pump, etc., I cannot advise. Need someone more attuned to the hydraulics of this sort of thing.

[dragonkoi]

Thanks Mike good points.

Does the sumbmersible pump stay there even after pond is finished??

many thanks

[MikeM]

I've read of it being done both ways. I think it would be according to what is most convenient in your circumstances. If possible to have a permanent installation without an unacceptable unsightliness problem, I tend to think that would be best. I know I get lazy and would probably delay setting it up if I had to drag a bunch of stuff around.

[luke frisbee]

dragonkoi..you want to get the right info for your area....talk to the local pool builders. in 5 minutes they can tell ya everything and in 30 minutes they can take you to a buld site and show you.
And I like the name for the pump. it is called a deadman's pump...miner's use them to keep the water outta their mines. if thye quit and you're in the mine...the pump's named after you.