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Where to send basement water with a small, flat lot

pjderosa
January 6, 2019

Hi all,

I've got water table problems with the finished basement in my newly build house (backstory: https://www.gardenweb.com/discussions/5578963) and have been researching sumps and drainage systems. My problem now is the last part of the problem of where to send the water, which I find a bit less written about - so looking for ideas.


I have a small (.16 acre), very flat lot in a village center, not much more room than the ~20 ft setbacks and the detached garage in back. We put in a sump this year after discovering the problem, but when the water table rose it flooded the side yard where it exits onto the lawn 15' from the house, ran away from the house (good) to the road where it then flooded about 1/3 the width of the road a couple hundred feet to the closest storm drain. This might not have been a terrible result, but unfortunately it's also below freezing sometimes at night in flood season and the town came by to say we couldn't do that due to the freezing danger on the road.


This leads us to ask the question of what options we might have given it seems unlikely that there is anywhere within our lot lines that we could channel this much water (thinking drywell, etc.) when the water table is up without having it eventually overwhelm the pumps since they're probably running anywhere from 2-12 weeks depending on the water levels that year.


Anyone have any similar situations?

Any chance the town might help us out with storm drain placement, or are they most likely going to say that we made our bed and now we have to lie in it?

Any chance digging the biggest drywell(s) we can in the furthest corner(s) of our small lot might help at all, or are we just direct sending that water back to the basement?


Thanks!

Comments (8)
  • PRO
    Virgil Carter Fine Art

    Sorry you are having this problem. Your comments, however, are not exactly clear.


    Where and how does your domestic water drain?


    How does surface run-off water drain during and after rain storms?


    What does your local jurisdiction say about your drainage options? Are you saying you've been told by your local jurisdiction that your surface runoff cannot run across the road to the closest storm drainage because the water may freeze?


    Does water elsewhere in the community freeze on the roads? What do you pay taxes for?


    Are you also saying your site's water table rises and creates surface ponding or drainage, separate from flooding your basement? What sort of waterproofing and drainage system does your basement have?



    pjderosa thanked Virgil Carter Fine Art
  • PRO
    Mark Bischak, Architect

    Talk to your local municipality.

    pjderosa thanked Mark Bischak, Architect
  • dan1888

    In other words you can contact the city about discharging your sump output into the household sewer system

    pjderosa thanked dan1888
  • PRO
    maecom technology

    Contact your local or regional statutory organization/municipal.

    pjderosa thanked maecom technology
  • pjderosa

    Thanks for your input all. Additional info:

    I have municipal sewer, but sump connections are not allowed as I understand it. I’m not sure if exceptions are ever made.

    Surface runoff does not pool on my property much. Mostly would be running to street I suppose. An apartment building all along the back of my flat lot. I do have a drywell in back for gutter discharge from the back side of the house.

    i haven’t clarified with the town yet. They said sumps can’t discharge directly into the street, but not sure what happens if it discharges to the lawn 15 ft from the street, then pools, then runs into the street.

    No other pooling or flooding on site really. Basement seems to have a seasonal high water table and have post-build installed a sump. Perimeter drainage in floor is actually coming from what was supposed to be a radon collection system pipe (ie I’m pumping that water into my sump when water rises to floor level to keep up).

    I am making inquiries with the town to see if they have any options for me. My best thought is to ask about locating a storm drain by my house or otherwise tapping into that system (which I assume is preferable to the sewer).

  • gardengal48 (PNW Z8/9)

    It would help to know where you are located but I'd seriously consider getting a landscape designer involved and creating a rain garden. This is an excellent method of dealing with stormwater run off, whether it comes from gutter overflow, excessive impermeable surfaces, funky grading or from a basement sump pump.

    pjderosa thanked gardengal48 (PNW Z8/9)
  • PRO
    Yardvaark

    Even what appears to be flat land must have some grade for drainage. If you can't detect it visually, you might take a carpenters level (placing it on top of an 8' 2x4) and see if you can find some degree of slope for the overall lot by measuring different sections of the yard. You'll want drainage to continue in the direction that is already established. You need to get the sump water far enough away from the house that it continues in the direction of grade, though movement will be slow on account of flatness. If you can get it to a place in your yard where it will continue on it's own (to run off of your property to the street, that should be sufficient. There are typically restrictions about directing a concentrated flow of water off of your property on to anyone else's property (including city), so the water will need to spread out first to resume the form of natural sheet flow (which is expected to flow from one property to another as that's how drainage through a neighborhood works.

    pjderosa thanked Yardvaark
  • RES

    You will probably need to hire a civil engineer to test the soil and design a stormwater control system that usually involves an underground structure that distributes the water.

    I'm surprised you didn't have to submit evidence to the local engineering dept that your site could handle the stormwater runoff from your new roof and driveway.

    The house below was on a flat site across the street from a river and the stormwater control system was required by the city just for the addition.







    pjderosa thanked RES

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