Porous Pavements

[cedric]

Porous Streets Work--Even in Rainy Oregon
ERICA BARNETT
JANUARY 30, 2008 4:45 PM

http://www.worldchanging.com/archives/007813.html


Walking along Lake Washington in Seattle recently, we noticed that one of the city's boating centers had repaved its rather large parking lot. What struck us about the paving project was that the city had repaved the lot using impervious black asphalt--surprising for a city that prides itself on being "green" (cf. our recently adopted "zero waste strategy"), but shocking considering the parking lot sits mere meters from a large, heavily used body of water.

What reminded me of that incident was a story in the Salem, Oregon Statesman Journal about a system of porous streets in that city's Pringle Creek Community, a housing development that has gotten national praise (even landing on Natural Home's list of the top 10 "green" housing developments in the US) for its green building and sustainable-design practices. Community members had worried that the system would not be able to stand up to Oregon's wet winters; so far, with February getting underway, residents have been hard-pressed to so much as find a puddle.

Pringle Creek, a 30-acre, 139-lot development, boasts the largest porous street system in the country, although interest has been increasing exponentially, according to the Oregon Asphalt Pavement Association, whose director, Jim Huddleston, told the Portland Journal of Commerce that he looked forward to a day when cities routinely used porous asphalt to pave roads, not just parking lots.

Porous pavement has been around since the 1970s. It consists of regular asphalt from which the smallest particles have been removed, allowing the vast majority of liquid that hits the pavement to pass through. Stormwater drains through the asphalt and infiltrates slowly into the underlying soil. Although it does cost more, it holds up as well as or better than traditional asphalt; a test street in North Portland demonstrated that porous streets can hold up to regular city traffic.

Most importantly, unlike impervious pavement it allows 90 percent of stormwater to infiltrate back into the ground. Impervious pavement, in contrast, gets rid of stormwater in the form of runoff; that in turn leads to more polluted waterways, more frequent and severe flooding, loss of natural storage capacity in plants, wetlands, and soil, and reduced groundwater recharge. Other solutions include reducing the amount of impervious surface in new developments, routing water to areas with soil and grass, building retention basins, and (my favorite!) xeriscaping.

http://flickr.com/photos/eyefruit/51110795

[xchrom]

1. recommend

:applause:

[NNadir]

2. We have a porous sidewalk in front of my house.

It's less than a year old, and pieces are beginning to break up.

[Greyskye]

4. Is your sidewalk asphalt or concrete?

They are different materials. http://en.wikipedia.org/wiki/Permeable_paving

You likely have concrete in front of your house, as opposed to the asphalt talked about in the OP.

[NNadir]

5. It is concrete. When I saw it, I knew it would break up with the first freezes and thaws.

[benld74]

3. We have a World leader with a porous brain, stuff filters in BUT NEVER stays!

[phantom power]

6. I once suggested to my dad that photosynthesizing pavement would be cool.

He looked at me, and said "god no, they'd pave the whole planet."

http://www.aerostich.com/catalog/US/Pave-the-Planet-p-16854.html

Back in the day, there used to be a usenet group called alt.pave.the.planet, where people got together to discuss planet-paving schemes. I'm almost sure it was a joke.