December 1 2007

Chicago's Pervious Pavement Alleys

A recent article in the New York Times describes the challenges posed to Chicago by the thousands of small alleys snaking through the city. The nearly 2,000 miles of back alley service streets are an important part of the city infrastructure because they alleviate trash and parking problems on the main, frontage, streets. The question raised however is how to deal with a city that has a double density of paved driving area, an area calculated to be equal to five mid sized airports!

The solution being tested, and in fact adopted, is a system of pervious concrete or porous asphalt, gravel beds and sand. The system is designed to allow rainwater to filter through the road surface, to the gravel and finally into the soil below. The water is cleaned as it passes through the materials and is allowed to naturally recharge the groundwater and possibly even flow back into Lake Michigan. The surfaces have also been designed to have the added benefit of reducing heat island effect.

Chicago has thus far completed 46 installations of the porous or pervious materials and judged on the success of those projects has committed to making all new alley renovations "green" from this point forward.

For more information visit the original article.

December 1st, 2007 at 5:00 AM. Posted in Industry + Practice. Share this post.