Do you guys do drainage questions?

[leejosepho]

The one Redwood mentioned above would be the best solution, but I don't know what your driveway would look like afterwords.

Yes, I believe a drywell directly under the driveway might be simplest and best. I would probably do something shaped somewhat like a starfish, with rock-filled trenches feeding water into a drywell in the center. Depending upon the percolation rate of earth below, a 1000-gallon drywell would easily accept 1" of rain per hour over a 30' X 50' area, and probably for at least two hours or so, sans pump.

[Redwood]

Another possiblity would be to use infiltrator chambers.

[leejosepho]

Another possiblity would be to use infiltrator chambers.

Yes ... but they might not be best directly under a stone driveway that would first have to be covered by stones spread from a large truck! Personally, and even though I like chamber systems, I believe a thick drywell lid would be much stronger.

[Redwood]

You are correct Lee...

In fact I wouldn't put either a drywell or infiltrator chambers under the driveway. I would put them in the lawn to the side.

Sometimes if these guys need to pull into your driveway they don't ask whether you have unwittingly put a drywell under the driveway.

[RCraig]

THanks so much for these ideas and advice. If I understand correctly, a dry well might be the best idea. Thanks so much for the picture so I can visualize this. I am still having a bit of difficulty understanding what would have to be done and how the dry well would work.

I am guessing that I would dig a hole (?maybe a foot deep or so) next to my driveway.
I would insert the white thing you kindly included to show me what a dry well is.

One thing that is confusing me is that the white dry well in the picture has a hose attached to it. I am confused as to whether this hose is for water flowing into the dry well or water flowing out of the dry well. Sorry, my ignorance in this regard in legendary! Also in my mind is the question of where the other end of this hose would go to?

I am guessing that process stone means some type of gravel-like stone. So I would put that into the hole around the dry well. Then I guess I would cover it up with dirt and replant grass on top.

Another thing that is not clear to me is what the dry well actually does. I am thinking that it doesn't actually absorb water, but that is another question in my mind. If it is next to my driveway and doesn't somehow absorb water, I am fearing that it won't drain that well as it will be in an area that is also saturated by the rain. Also, New Hampshire clay soil, I am not sure that the water will percolate away that well.

At the same time, leejosepho mentioned a 1000 gallon dry well. This might take a much larger hole than I was envisioning. Is the idea that the water accumulates in the dry well during the rainstorm, and then percolates away later on when things are drying out? A final worry is that I don't think that the drywell, at least as I am envisioning it, will get the water to the storm drain which is very close by. At the moment, the water only gets to the storm drain if I pump it over this very gentle mound, really only a couple inches of height to get over, then off it goes, problem solved until the next precipitation.

Many thanks for all you help. Ruth

[leejosepho]

I am guessing that I would dig a hole (?maybe a foot deep or so) next to my driveway. I would insert the white thing you kindly included to show me what a dry well is.

The drywell you would need (like the one in that picture) would likely need a hole about 10 feet deep and as big around.

One thing that is confusing me is that the white dry well in the picture has a hose attached to it. I am confused as to whether this hose is for water flowing into the dry well or water flowing out of the dry well. Sorry, my ignorance in this regard in legendary! Also in my mind is the question of where the other end of this hose would go to?

That is actually a pipe, and the flow of water could be going either way. A first pipe (or even possibly several) would be letting water from a feeder trench into the drywell, and a second could be letting water pass on through to any other part of the overall system.

I am guessing that process stone means some type of gravel-like stone. So I would put that into the hole around the dry well. Then I guess I would cover it up with dirt and replant grass on top.

Yes.

Another thing that is not clear to me is what the dry well actually does ...

Is the idea that the water accumulates in the dry well during the rainstorm, and then percolates away later on when things are drying out?

Yes, and with size and soil determining its ability to handle a given volume.

A final worry is that I don't think that the drywell, at least as I am envisioning it, will get the water to the storm drain which is very close by ...

An overflow pipe into the storm drain might be possible. Or, maybe you could skip the drywell altogether and just have an extension of the storm drain placed under a grating in your driveway.

[Redwood]

Ruth,
The drywell in the picture is actually quite a bit larger than you are thinking.
That little hose is actually a 4" diameter pipe!

[RCraig]

My thinking was off by a scale factor of 10-fold or more. I am thinking that some way of hooking up to the storm drain that is just a bit down from the driveway might be easier. I think my husband would definitely notice if I dig a 10 foot hole in the front lawn to put the drywell in. The idea of some type of grating, I have to think more about this. Seems as if it should work. No matter which way turns out to be optimal, it is clear to me that this is going to require quite a bit of money.

Thank you so much leejosepho and Redwood for your helpful explanations. At the moment, the whole place is getting covered by snow and I may not have to think about any of it turning to liquid for quite some time! Ruth

[Redwood]

It might be hanging around in its present state for a while....

We've been getting hammered with the white crud since about noon...

[RCraig]

Thanks again for all the great advice. Best wishes to all for happy plumbing in the new year. Ruth