Underground river flooding??

9 years ago

So I built directly on bedrock last summer, and even during some heavy periods of rain, there was never more than a couple puddles sitting on top of the bedrock while we built.

We placed about 12" of clean limestone under our slab, steggo wrap on top of that (it's a very thick plastic), and then poured the basement floor. The footing and exterior ICF walls were covered in a waterproofing membrane that wrapped down over the footings.

Weeping tiles (polymer) were placed around the exterior of the footings and covered with another 12" of clean limestone. A run of weeping tile was also placed in a loop under the basement slab.

Never seen a drop of water in the sump pit, which is carved into the bedrock below the basement floor (had to use a jackhammer).

We got about 70" of rain this past weekend, and Sunday night, the pit had about an inch of water in it, but nothing was coming out of the weeping tile inlets.

Monday afternoon, it was like someone turned on a fire hose down there. All of the weeping tiles are POURING water at an alarming rate, and after 3 continuous days of pumping, we've made no progress. The pit fills almost as fast as we pump it.

Our first thought was that the well pipes broke, but the pressure tank holds its pressure when the pump is off, the pump has no delays in filling the pressure tank when it's empty and even leaving the pump off for 24 hours does not change the flow of the water into the pit.

I should note, that we live 1/2 way up the side of a shallow hill, with a sandy loam soil (25% sand, 25% loam, 25% silt, 25% clay). It's usually really well draining.

Anyone else experience this?? Is it possible that the underground accumulation of water has created a mini "river" along the bedrock base, and our house is right in the middle of it?? Or should I be concerned about the appearance of an underground spring, or some sort of back-up from the well pipe??

Comments (7)

musicgal
9 years ago
Sounds like one of the springs we have in our area... yours, hopefully is seasonal and only activated by an anomalous weather event. The home I am staying in now was found to have a natural spring under the foundation and they had to install a sump with a backup generator, which takes care of the problem for them.

Is 70 inches correct in your description of the rainfall?
musicgal
9 years ago
Sounds like one of the springs we have in our area... yours, hopefully is seasonal and only activated by an anomalous weather event. The home I am staying in now was found to have a natural spring under the foundation and they had to install a sump with a backup generator, which takes care of the problem for them.

Is 70 inches correct in your description of the rainfall?
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Annie Deighnaugh
9 years ago
Our old house was near the top of a hill. When we had very heavy rain enough to raise the water table, we would get water in our basement...and there would be water running down the road in front of our house. Usually the day after the road dried up, our basement would dry up. We ended up putting in curtain draining which solved the problem. Otherwise, there's not much else you can do if it's a water table issue.

Did you mean 70" of rain? or 7"?
Awnmyown
Original Author
9 years ago
Haha, whoops! 70 centimeters!! Wow, that's a huge difference! So about 30" of rain over a couple of days. Poured again yesterday as well. Just no winning this year.
live_wire_oak
9 years ago
I was thinking if you got 70" of rain that it was time to declare the property lake front acreage, sell, and reap the profit!
kg4951
9 years ago
Time to build an ark rather than a house! :-)
kirkhall
9 years ago
I wonder, with all of that limestone, if you didn't attract the water there? Water will flow the path of least resistance. If you have rock, clay, etc, your limestone is nice and easy path to flow through in comparison. Too bad you need an electric pump and not just a gravity flow sump pump though.

It sounds like everything is keeping up so far! Hopefully this is a one-off year and it won't be an issue in the future.