March 27, 2004

Gravelpave 2

Category: Urban Planning

Tucson: Among the many thoughtful steps taken in the development of the Milagro Co-Housing project in Tucson, is the installation of a porous surface for their parking lot. A product known as Gravelpave 2 was used in place of traditional asphalt to make this possible.

Why is this significant? Well, in Tucson (and anywhere for that matter) storm water runoff is major problem. Traditional asphalt lots funnel 100% of rainwater to a drain of some kind which ultimately leads to a city system, either the sewer or a special retention structure.

This leads to overloading of the city's infrastructure, washes tremendous amounts of pollutants into local waters, and prevents the natural recharge of groundwater, which is an especially huge issue in the desert.

Gravelpave 2 (and similar products) allow most rainwater to soak right into the ground, letting the groundwater recharge, and eliminating the problem of storm runoff. It also allows pollutants to filter through the ground in small amounts rather than concentrating them at the end of a drainage.

Unlike a standard gravel lot, Gravelpave is reinforced by plastic rings and a permeable membrane which holds it together thus preventing ruts and allowing vehicles as heavy as fire engines to traverse it normally.

Of course it's slightly more expensive than an ordinary lot, which is why incentives ought to be used to convince developers to use it. Given the high costs municipalities face with stormwater issues alone, this ought to be a no-brainer. And even in Tucson, as pointed out by desert permaculture expert Brad Lancaster, the little amount of rain that falls is still more than enough to satisfy the city's needs if it can be captured (as replenished groundwater for example) rather than funneled away.

Posted by Nick at March 27, 2004 5:29 PM