Drainage on a slope issue-

[Heathbar]

So I feel as if Ive run into a major problem. I'm currently digging my hole and have ground water accumulation in the hole. This isn't the water table- I'm on a hill, next to a ravine. This is just water running down a natural slope through the clay VERY slowly. I don't think a french drain is possible as I would have to go through tons of clay to get a downward grade. I really don't have room for a vertical culvert. Is there anyway I could do a french drain bed with an upwards diagonal shaft to drain/pump any water that might lift my liner? I may be totally wrong here, but I was thinking the pressure from the 4' of water over the drain bed would push the water up some, and then I could use a sump pump to make sure water doesn't accumulate under my liner. Any thoughts, ideas are greatly appreciated. I am obviously not a professional pond builder, nor a hydrostatic engineer so Im just trying to work the problem.

 

[Mmathis]

I hear you! We have clay, but our problem is high water table seepage, but without the downhill flow. Ours wasn’t that bad, though, and it was enough for me to combat the water simply by having the pond a few inches above ground level — that way, the pressure on top of the liner acted against the ground water.

I’m sure others will chime in. I have read where some people have dug something like a sump chamber next to the pond where they place a sump pump. I’ve never had to do that, so will let them explain the process.

Yes, I can see where a French drain would be an issue. Is there a particular level of the excavation where you notice more water coming through....or is it at all levels?

 

[Heathbar]

Thanks for the reply Mmathis. I am doing a block edge so will probably end up 6 inches above my current topsoil. I dont notice any particular place seeping, its just a gradual filling of my hole to about 6 inches, which is 3.5 feet from my top edge. I've read where people can overcome the hydrostatic pressure with water above grade, im just concerned i won't, and then I'm screwed

 

[GBBUDD]

You may not be a pond builder or an engineer but your on the right thought process. Water is like most everything in nature as it takes the path of least resistance. So that equals where you want to give water a place to go that's easier to move then it is for the water to have enough pressure to lift your liner. In other words making the French drain at the underside of the pond. But in stead of French drains that run only horizontal. This one runs horizontal across the bottom but then has the pipes run up along the side in its own trench vertical so the water as pressure builds has somewhere to go and that being your stone trench with open pipes perforated across the bottom but closed running up the sides.

If you have that much water in a heavy clay area you may be better off working with and not doing a liner at all.

 

[Heathbar]

Thats what I was thinking Gbbudd. It wont really drain, but it wont accumulate either, and if I think I need to, I have a spot I can pump out. I do have heavy clay- But here in Iowa the wa
ter is hit or miss- so no way I can plan on my ground being as saturated as it is now, in the spring. This summer it could be sucking water 24/7. So I for sure want a liner- just want to start my forever pond off as good as possible,

 

[GBBUDD]

Depending on the size of your pond you may need several.