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Community and Q&A

Can I build stormwater retention trench so I can park on top of it?

user-5691874 | Posted in GBA Pro Help on

We are building on a small lot, and are required to locate a 10’x10’x2′ stormwater retention trench in a location ideal for parking. I’ve been researching the base prep for permeable paving, and much of it looks similar to the stormwater retention trench: 12″-18″ layers of triple washed gravel, overflow pipes, judicious use of filter cloth. Can anyone point out issues that would arise from doubling the base layer and otherwise building the stormwater retention area as we would a permeable driveway?

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  1. onslow | | #1

    Mr. Fitler, Here are two links to what I think you are trying to do. The methods are somewhat different, but both allow for tire loads to be handled without compromising the water handling feature. I believe that another option might be the grass friendly concrete pavers that look sort of like a waffle that has holes between the bumps. These might offer a do-it-yourselfer lower cost. Not sure where to find them. The idea is to embed them into the turf layer such that grass can grow up and disguise the parking area as well as provide rain runoff absorption. A general search of the term permeable pavers might help you find options. Hope this helps. -

  2. user-2310254 | | #2


    I think what you want to do is possible. Check out this page:

    You also might want to talk with a civil or geotechnical engineer.

  3. gusfhb | | #3

    I would check with whatever body is enforcing that code and see if it is ok with them, or rather ask a general question about what is allowable above it. Parking my squished dinosaur burning SUV over the drainage system can have negative connotations in some circles

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