use a well point to draw down water table?
#1
04-24-15, 09:58 AM
use a well point to draw down water table?
our basement foundation footing is pretty much built into the water table. constant flow of water into sump from snow melt through Halloween. pump runs every 2-3 minutes all spring/summer. this is not storm water. heavy rains do not significantly increase the flow into the sump.
i'm thinking of driving a few well points around the foundation to suck out the ground water before it enters the interior sump. just 10-12ft down.
will this work?
I know there are better ways to handle this, but I'm looking for a quick/cheap fix while a plan a long term solution. whatever I end up doing will involve pumps since we do not have sufficient grade to gravity drain the footing drains. drywells are useless due to the high water table.
i'm thinking of driving a few well points around the foundation to suck out the ground water before it enters the interior sump. just 10-12ft down.
will this work?
I know there are better ways to handle this, but I'm looking for a quick/cheap fix while a plan a long term solution. whatever I end up doing will involve pumps since we do not have sufficient grade to gravity drain the footing drains. drywells are useless due to the high water table.
#2
04-24-15, 01:09 PM
Controlling a high water table is almost impossible & I don't know if there are better ways to handle it. I would certainly be interested, if your idea works.
#3
04-24-15, 01:44 PM
my long term idea is to bore an 18" dia hole, 11ft deep, next to the house. line it with 15" PVC. dig down and hook it up to the footing drain tile and drop a pump in it. effectively creating an exterior sump pit and diverting all the water to it. that way at least we don't have to listen to the pump run every couple minutes for 9 months of the year. it's gonna cost some bucks to do this, though. but since I already have shallow well jet pump I figured for a couple hundred $$ i could drive a few points and see what happens.
#4
04-24-15, 02:20 PM
We don't have enough room here for me to tell you all of my stories about people trying to deal with ground water, but very few made any progress.
If you could wave your hand and remove all of the upper layers of permeable soil down to whatever is preventing your ground water from soaking further into the ground you would see your problem and possibly a solution.
In some areas of the country sub soils are well documented and some research might tell you whether you are sitting on a lake or just a pond that has no place to go.
How far down is the head on that shallow well jet pump. A jet pumps is required when you draw from below (testing my memory here) 32'. So your current well may have a head below what you are thinking is the water table.
If you are just sitting on a pond where the below grade water likes to drain to your basement, it might be possible to excavate a trench to the most remote practical corner of your property and let gravity carry that water to where it can sink further into the ground.
Bud
If you could wave your hand and remove all of the upper layers of permeable soil down to whatever is preventing your ground water from soaking further into the ground you would see your problem and possibly a solution.
In some areas of the country sub soils are well documented and some research might tell you whether you are sitting on a lake or just a pond that has no place to go.
How far down is the head on that shallow well jet pump. A jet pumps is required when you draw from below (testing my memory here) 32'. So your current well may have a head below what you are thinking is the water table.
If you are just sitting on a pond where the below grade water likes to drain to your basement, it might be possible to excavate a trench to the most remote practical corner of your property and let gravity carry that water to where it can sink further into the ground.
Bud
#5
04-24-15, 05:30 PM
thanks for the reply.
just to clarify, I have the jet pump itself but the well point is not yet driven. the pump is for wells less than 25'. I should only need to go down about 12'.
I have a picture of the property from 1939. it was farmland - either soy beans or corn fields. the village engineer said this whole area has a high water table and very slow "recharge" - which I think means the soil doesn't percolate well. he said the next neighborhood over some houses have 7 sump pits to manage all the water. within our neighborhood we have the lowest lot, and the corner of our front yard (lowest spot on our property) turns into a lake with heavy rains, and the water just sits there for days. that ponding occurs about 150ft from the house, and about 5ft down grade. if that area would drain then I'd drop a drywell there and dump the footing drain into it. but that won't work in our situation.
a few feet past the back edge of our property there's a shallow ravine. that's where we discharge our sump and a few of the downspouts. still not enough slope to gravity drain the footing drains, though.
I could probably drop a french drain about 6ft deep and dump it into the ravine -- but that wouldn't be deep enough to solve our problem -- footings are about 9-10ft below grade.
just to clarify, I have the jet pump itself but the well point is not yet driven. the pump is for wells less than 25'. I should only need to go down about 12'.
I have a picture of the property from 1939. it was farmland - either soy beans or corn fields. the village engineer said this whole area has a high water table and very slow "recharge" - which I think means the soil doesn't percolate well. he said the next neighborhood over some houses have 7 sump pits to manage all the water. within our neighborhood we have the lowest lot, and the corner of our front yard (lowest spot on our property) turns into a lake with heavy rains, and the water just sits there for days. that ponding occurs about 150ft from the house, and about 5ft down grade. if that area would drain then I'd drop a drywell there and dump the footing drain into it. but that won't work in our situation.
a few feet past the back edge of our property there's a shallow ravine. that's where we discharge our sump and a few of the downspouts. still not enough slope to gravity drain the footing drains, though.
I could probably drop a french drain about 6ft deep and dump it into the ravine -- but that wouldn't be deep enough to solve our problem -- footings are about 9-10ft below grade.
#7
04-24-15, 06:08 PM
In some cases I have simply installed a second sump pump in a much deeper pit. This collects the water before it risks entering the basement itself. In your case it could position the second pump below a sound proof cover and although it would still run often you wouldn't hear it. Installing the driven wells outside doesn't sound like it will reduce the pumping costs so it seems to be only a sound reduction issue.
Your house lot sounds hopeless and as long as you don't plan on finishing that basement, which will apparently always have a moisture concern, then you're all set.
Bud
Your house lot sounds hopeless and as long as you don't plan on finishing that basement, which will apparently always have a moisture concern, then you're all set.
Bud
#8
04-26-15, 04:57 AM
The purpose of having "several" point wells is that each well (pit) protects only a few feet away from it horizontally. You don't want them both close to the house and much deeper than the foundation footings because excavating for them could cause the foundation to collapse. And each has to be sucked dry almost all the time to lower the water table near it.
A perimeter drain at footing level along with one sump pump pit is usually just as effective as four or five well points at selected locations around the house. If one pit cannot keep up with the incoming water, install a second pit and sump pump at the opposite corner.
For noise reduction I would suggest just one point well outside your house and perhaps ten feet away. Provided that you can keep the trench under 18 inches wide at foundation footing depth and only slightly deeper than the footings, you won't have any foundation problems running the (required) gravity flow connecting pipe to the existing sump pump pit or perimeter drain system.. Put the primary sump pump in the new pit (well) and the existing sump pump becomes the backup.
A perimeter drain at footing level along with one sump pump pit is usually just as effective as four or five well points at selected locations around the house. If one pit cannot keep up with the incoming water, install a second pit and sump pump at the opposite corner.
For noise reduction I would suggest just one point well outside your house and perhaps ten feet away. Provided that you can keep the trench under 18 inches wide at foundation footing depth and only slightly deeper than the footings, you won't have any foundation problems running the (required) gravity flow connecting pipe to the existing sump pump pit or perimeter drain system.. Put the primary sump pump in the new pit (well) and the existing sump pump becomes the backup.
Last edited by AllanJ; 04-26-15 at 05:24 AM.
