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The Green Alley Program is a new approach to CDOT’s existing alley program. Alleys provide a great benefit for the City, but like all infrastructure, they also require maintenance and periodic reconstruction. Flooding is often an issue in alleys because many alleys in the City were built without a connection to the City’s combined sewer and stormwater system. While one solution to this problem is to install expensive connections to the City sewer system, the Green Alley Program also looks at other more sustainable solutions. In particular, where soil conditions are appropriate, water
is allowed to infi ltrate into the soils through permeable pavement or infi ltration basins, instead of being directed into the sewer system or onto adjacent property. This not only solves a persistent problem, but it also provides an environmental benefi t by cleaning and recharging the ground water. Furthermore, by not sending additional
water to the combined sewer system a green alley can help alleviate basement and other flooding issues. You, the adjacent property owner, can make a difference by instituting other best management practices (BMPs) on your property. These can range from recycling to installing your own rain garden, which can help alleviate flooding even further.
With approximately 1,900 miles of public alleys, Chicago has one of the most extensive and important pieces of
infrastructure of any city in the world. That’s approximately 3,500 acres of paved impermeable surface that provides an
opportunity to better manage our resources and improve our environment.
Imagine if all of the alleys in Chicago were green alleys. Up to 80% of the rainwater falling on these surfaces throughout the year could pass through permeable paving back into the earth, thereby reducing localized flooding, recharging groundwater and saving taxpayer money that would otherwise be spent treating stormwater. Imagine if all the alleys had a light, reflective surface (high albedo) that reflected heat energy, staying cool on hot days and thereby reducing the “urban heat island effect”, a condition where dense urban areas become several degrees warmer due to the density of buildings and amount of heat- absorbing paved areas. Imagine if all of the alleys were constructed with recycled materials, thereby reducing the amount of construction and industrial waste hauled to landfills and reducing the burden on our natural resources.
Energy Conservation and Glare Reduction is another,Imagine if the thousands of light fixtures that provide a safe environment in the alleys were energy efficient and reduced glare and light pollution to the point where you could see the stars at night. Ally's with impermeable pavement and poor drainage. |
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