COMING TO CHICAGO - GREEN ALLEYS?
PROGRAM WOULD DIVERT MUCH WATER FROM CITY OF CHICAGO SEWER SYSTEM
You might not realize that the City of Chicago has more miles of alley than any city in the world. In all, over 1,900 miles of alleyway parallel the Chicago street system. These alleys serve several important functions. They remove unsightly trash from residential and commercial streets, and reduce traffic from refuse and delivery trucks, thereby lengthening the lives of the surrounding streets.
However, many of the older, concrete alleys do not divert rainwater properly, and they absorb high levels of heat, requiring greater levels of maintenance.
A new "Green Alley" program hopes to address these concerns throughout the city. Started in 2006, the city identified 25 alleys throughout the city that would benefit from a permeable, non-reflective surface that would reduce heat levels, and more effectively divert water. Three types of Green Alleys have been tested: Special concrete or asphalt with high permeability, a surface of paver bricks, similar to those used on high-end walkways and driveways, and a special high-albedo surface designed to absorb far less heat than conventional materials.
Permeable alley surfaces are most effective in areas with sandy soil. In Chicago, such soil is most common closer to the lakefront. However, residents in other areas, with more clay in their underlying soil, can reap many of the benefits from the system with a two-foot permeable "trench", one inch deep, in the center of the alley.
Brian Steele, a spokesman for the Chicago Department of Transportation, applauds to new design. "It helps prevent pooling of water, and keeps ice patches from forming in the winter," Steele said. Many new alleys, however, have to be closely monitored, he said . "Some have the potential to become easily clogged."
However, where installed, initial results are very favorable. According to Chicago Alderman Brian Dougherty, of the 41st Ward on the Northwest Side of Chicago, a stretch of alley on the 7800 block of west Farragut Avenue has effectively diverted rain water away from the back yard and garage of a long-time resident on that block. Prior to alley construction, the resident's back yard and garage were inundated by puddling during moderate rain storms. Since the installation - far less puddling water. The section of permeable alley here consists of a special porous asphalt, with an underlying French drain system.
Currently, the Chicago Green Alley Program is in the development and testing phase. If successful, however, there would be great demand for this new design throughout Chicago, and in other cities.
Stay tuned for more information!
Read more about the Chicago Green Alley Program, along with a diagram of how the system works, in an article written by Andrew Schneider, in the December 20th Edition of the Edison-Norwood Times Review.
DEAN MOSS & DEAN'S TEAM CHICAGO
