District First Green Alley Pilot Project Now Underway

(Washington, DC) Today the District Department of Transportation (DDOT) launched its first Green Alley Pilot Project, initiating construction in an alley in Northeast Washington. The Green Alley Pilot is aimed at reducing the quantity and improving the quality of stormwater run-off within the District’s right-of-way (ROW). The program is being implemented in partnership with the District Department of the Environment (DDOE) with funding from the American Recovery and Reinvestment Act of 2009.

“Our green alley program demonstrates how we are continuously evolving to ensure that our infrastructure and operations remain sustainable, said DDOT Director Terry Bellamy. “The green alley concept has the potential to shape how we design our right-of-way beyond our alleys.”

Although many alleys include a significant amount of impervious surface, most do not have stormwater controls, such as water quality catch basin or grate inlets. To mitigate this, green alleys use sustainable design and Low Impact Development (LID) techniques that reduce the amount of stormwater and pollutants entering the sewer system by increasing water infiltration and treatment on site.

Throughout the United States, Green Alley projects are being used as an effective and innovative way to manage storm water runoff and pollution. In Chicago, for example, more than 80 green alleys have been successfully completed since 2006.

Needless to say, DDOE is pleased with the Green Allley projects,” says Christophe A.G. Tulou, director of the District Department of the Environment. “It is important that we investigate and implement ways in which we can make manage and make good use of storm water so that we can continue to improve our waterways. DDOE will continue to invest and support projects that do that.”

Three initial Green Alley sites are included in DDOT’s pilot program. The sites are located along the Watts Branch Watershed in northeast Washington at the following blocks:

• Alley between 54th Street, Blaine Street, 55th Street, & Clay Street
• Alley between 56th Street, Eads Street and 57th Street
• Alley between 58th Street, Dix Street, 59th Street and Clay Street

DDOT will construct Green Alleys by replacing gravel, impervious concrete or asphalt surfaces with permeable concrete, asphalt or brick paver materials. Permeable pavement has pores or openings that allow water to pass through the surface, then percolate down through a gravel layer and into the soil below rather than running off into sewers.

DDOT estimates it will take approximately two months to complete each alley. Upon completing the work DDOT will monitor these four sites to determine the effectiveness and durability of the materials.