The District’s Green Alley Projects are designed to reduce the quantity and improve the quality of storm water within the city’s right-of-way (ROW). The District Department of Transportation (DDOT) is implementing these projects in partnerships with the District Department of the Environment (DDOE) with funding from the American Recovery and Reinvestment Act of 2009.

Although alleys constitute a significant portion of impervious surface, most do not have storm water 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 storm water and pollutants entering the sewer system by increasing water infiltration and treatment on site.

DDOT will construct Green Alleys by removing gravel, impervious concrete, or asphalt surfaces and replacing them with a variety of permeable concrete, asphalt or brick paver materials in areas where the storm sewer and sanitary sewers are separated. 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.

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.

The initial Green Alley sites are in the Watts Branch Watershed in Ward 7 in the following blocks:

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

Please contact Meredith Upchurch at meredith.upchurch@dc.gov or (202) 671-4663 with any questions or comments about this program.