Downspout Drywells

[RobS]

Hey, thanks Scott. Yeah, I pretty much love my little 790. Just got the hoe and I'm very impressed considering it's size. I think it will be perfect for all of the landscaping projects we've got planned for the next several years. I've had it off and on a couple of times now and it gets easier each time.

Our other house had gutters but the downspouts just dumped out onto the ground. Had some basement water problems so I put above ground extensions on. Solved the problem but looked tacky so in the new house I vowed to "do it right". Everything is underground and the water that goes there should stay there.

I should add that our land is essentially flat. If you've got some natural slope and a place for the water to go you may have a different/better solution available /forums/images/graemlins/smile.gif

 

[Rch]

I put three dry-wells in 13 years ago for downspout run off. I'm clay based with an easy down hill setting. I used 55 gal plastic barrels that are easily available. I cut the bottoms out, made a trap door on the top and left the bung holes off. I filled the barrel with rocks and filled around the barrel with rocks. I laid the cut off bottom on the top for added strength. The plastic 4" drain tile enters the side of the barrel about 1/2 up. The barrel is buried with 12- 15" of soil on top. For sure put a heavy-duty or double layer of landscape fabric over the barrel and rocks so the soil doesn't keep caving in.
I put mine 50-60' away from the house and, if I did it over I'd double or triple that. One of them gets kind of mushy that picks up the sump pump, especially in the spring, and I have to skirt it with the lawn mower. That may be because of my clay base. Several times it has rained so hard that the grass has ballooned up about a foot for a diameter of 3' or so right over one of the dry wells that handles a good part of the roof. No apparent damage was done. /forums/images/graemlins/wink.gif
Plant a fast growing tree like a hybrid popular or weeping willow near the dry well- they can suck-up and transfer to the air many tens of gallons a day. Since a willow is such a shedding/dirty tree you want it far from the house, another reason to put the dry well away from the house.
If you live up north, for the sump pump discharge, just angle a PVC pipe into a drain tile sticking out of the ground. My neigbor made a tight connection and with little snow cover this year, the dry well system froze up and he ended up with a wet basement /forums/images/graemlins/frown.gif

 

[scottbrrtt72]

Rob, will you run into any problems during winter? Will those freeze at all? I live in NH and our recommended frost depth is 4'. When our house was built they put drainpipe around the foundation and piped it away from the house. There is water running out of that pipe pretty much all year. I wonder if that will be good enough to take care of any water from the gutters. I have not had any water problems so far and I hope it stays that way.

It looks like you need ROPS extenders for your machine. Did they give those to you when you had the backhoe put on? I took mine off so it would fit in my garage. I have hit my head a few times on the top bar while working with the hoe and ouch!! When I took mine off I made the mistake of removing all the bolts. The metal inserts slid down into the sidebars of the ROPS. I tried getting them out but no luck. Now I need to get new inserts for the extenders.

 

[RobS]

Scott, yes I need ROPS extensions and they are on order. Fortunately, I've only hit my head a couple of times.

I'm not too worried about the drywells freezing. They are down a couple of feet but exposed to air via the overflow. If it's cold enough to freeze there won't be any water flowing in to bother with. I suspect the downspouts/gutters will thaw within days of the drywells. Due to the pitch, there should not be any standing water in the drain lines. I guess we'll see this winter /forums/images/graemlins/smile.gif

 

[Jim_Fisher]

Rob,

Great shots!

How do you determine the number of chambers to use for a given application?

How far did you place them from the building and what size pipe did you use to feed them?

I have a couple of places that I would like to install these and any additional information will be appreciated.

Thanks,


Jim

 

[Anonymous Poster]

Nice pics, thanks for including some of the backhoe frame.

 

[RobS]

Hi Jim, thanks for the kind words. As far as sizing, I did some real seat-of-the-pants engineering. I started with the projected area of the roof draining into each downspout times a typical rain. The math was easy enough but my 1" of rain came to over 700 gallons in one of my drains /forums/images/graemlins/shocked.gif Of course, that calc doesn't take into account the time factor of the rainfall or the percolation rate of the soil.

I then let some practicalities settle in. The way my drains are arranged I have one with a whole lot of roof, two with quite a bit and another two with not much. So I did three chambers on the big one, two each on the middle ones and one each on the light ones. Cost-wise, it worked for me and seems "reasonable". I did recalc and without any percolation I can store over a quarter inch of rainfall.

My gut tells me for the typical rainfall I'll never see the water, which was my goal. In the event that we do get a Florida-like rain (over 15 inches in a week or so?!?) my overflow pipes will take over and the water will just spill out onto the ground like it did before.

I'm sure a civil engineer, soil scientist or such could have done a more accurate calculation for me but I doubt it would have changed my outcome, partly due to my practical considerations.

All the piping is good old, dirt cheap 4" corrugated drain pipe. Distance from the house vary due to driveway etc. but the smallest chambers are closest at about 10' and the others are 20-50' away.

Hope this helps /forums/images/graemlins/smile.gif

 

[Anonymous Poster]

<<<<The pipe sticking out of the ground is the overflow which gets cut off at grade and capped with a drain grate.>>>>

RobS, great job and great photos. A few questions for you, if you don't mind. Where did you purchase the plastic drywells from? Did you have to go to the manufacturer/distributor to pick them up or where they shipped to you?

Is the overflow pipe necessary or was this your idea? I guess you figure (hope) that any overflow will exit at the drywell and not backup at the downspout. /forums/images/graemlins/tongue.gif

 

[RobS]

Thanks Stanley. I got the chambers from a local distributor which I found by contacting Infiltrator . I saw a brochure for a similar product at Menards the other day but (imagine this) nobody there knew anything about it /forums/images/graemlins/shocked.gif

My overflow caps are all below the downspout level due the the grade around the house. If the chambers do fill up they will flow out of the overflow and not back up into the downspouts.

Our builder mentioned a house someone built and routed all the downspouts into a single 3" drain. First heavy rain everything backed up and water was spraying out of the downspout/drain pipe connection severely eroding the foundation. Hopefully, I won't have that problem /forums/images/graemlins/smile.gif

 

[bnixon]

Rod,

Nice pics!

I live on the Texas Gulf Coast and have never heard of anyone doing what you have done for house gutters. Why did you not let the gutter down spouts just drain to the surface?

I am not questioning your solution, I just have never seen this done before and am curious about it.

Thanks,