bypassing impervious cover with pervious concrete (Center, Mart: landscaping, construction, university)

[Austin97]

ive been reading about pervious concrete. It has pores which allows water to drain through it. As a result you can bypass typical impervious cover restrictions by using pervious concrete.

Does anyone have any experience with this?

[tfresca]

I imagine this kinda thing is expensive and maintenance heavy.

[Trainwreck20]

You have to make sure the COA agrees that it meets the intent of non-impervious cover. Just because water can seep through it does not mean that it runs through fast enough to prevent excess run off due to the additional cover.

[Austin97]

Originally Posted by Trainwreck20

You have to make sure the COA agrees that it meets the intent of non-impervious cover. Just because water can seep through it does not mean that it runs through fast enough to prevent excess run off due to the additional cover.

cost is about 15% more than standard concrete and the amount of water that can go through is pretty high

From the ecocreto.com website (there are many pervious concrete suppliers)

<< The pavements made with EcoCreto Enhanced Pervious Concrete™, according to the University of Texas research report allow rain water to flow through it at a rate of 4” per minute or 240” per hour! >>

[centralaustinite]

the parking lot of the Ben White Wal-Mart is made with it! (at least parts of it) because it is built in the zone that contributes to Blunn Creek. The neighbors pushed hard for this. It is more expensive. I don't think that CoA would let you pave your lawn with it but if you used it for your driveway you be able to play with the impervious cover percentages in other places on the property. Go down to One Texas Center and ask!

[CptnRn]

I can't find any indication that pervious cover counts as nothing in the impervious cover calculations.

What I did find was this, which suggests it still counts as 80% impervious cover:

http://www.amlegal.com/nxt/gateway.dll/Texas/austin/thecodeofthecityofaustintexas?f=templates$fn=defau lt.htm$3.0$vid=amlegal:austin_tx$anc=

Source: City Code Section 25-8-62; Ord. 031211-11; Ord. 031211-42.

§ 30-5-63 IMPERVIOUS COVER CALCULATIONS.

(A) Impervious cover is calculated in accordance with the Environmental Criteria Manual.

(B) Impervious cover calculations include:

(1) roads;

(2) driveways;

(3) parking areas;

(4) buildings;

(5) concrete;

(6) impermeable construction covering the natural land surface;

(7) for an uncovered wood deck that has drainage spaces between the deck boards and that is located over a pervious surface, 50 percent of the horizontal area of the deck;

(8) interlocking or permeable pavers, except up to 20 percent of the area of the pavers may be excluded in calculating impervious cover if the pavers are approved by the director for recharge enhancement under Section 30-5-151 (Innovative Management Practices); and

(9) the portion of a site used for the storage of scrap and metal salvage, including auto salvage.

(C) Impervious cover calculations exclude:

(1) sidewalks in a public right-of-way;

(2) water quality controls;

(3) drainage swales and conveyances;

(4) ponds, pools, and fountains; and

(5) areas with gravel placed over pervious surfaces that are used only for landscaping or by pedestrians.

Source: City Code Section 25-8-63; Ord. 031211-11; Ord. 031211-42.