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DDOT Issues New Green Infrastructure Design Standards

Tuesday, April 22, 2014

DDOT Issues New Green Infrastructure Design Standards

Standards will Affect Projects Advertised or Permitted After May 1, 2014

Washington, DC - Today, on Earth Day, The District Department of Transportation (DDOT) has released new standards for Green Infrastructure (GI) design, construction and maintenance in the public right-of-way (ROW). Standards have been developed for Low Impact Development (LID) techniques including bioretention, permeable pavement and street tree space design.

Nicknamed the “Green Book”, the Green Infrastructure Standards include supplements to DDOT's Design & Engineering Manual, Standard Drawings and Standard Specifications and new plant lists and maintenance schedules. A companion illustrative guide—“Greening DC Streets: A Guide to Green Infrastructure in the District of Columbia”—summarizes GI opportunities and constraints in the District.

The GI Standards are only available electronically in PDF format.

The development of DDOT's GI standards is part of a nationwide shift in improving the quality of life in cities and the condition of waterways. The draft LID & GI Standards were released for public comment in March 2013 and have been available for public use. The standards have been piloted through several DDOT projects, including RiverSmart Washington and refined based on results.

“Since their initial roll out last year, DDOT has attempted to change the culture of urban stormwater management by applying these standards on all capital improvement and private sector projects in the public space,” said DDOT Chief Engineer Ronaldo T. Nicholson.

These standards are the recommended practices in the ROW to meet the Stormwater Regulations issued by the District Department of Environment (DDOE) in 2013.  The GI standards will help the District achieve the Sustainable DC goal of increasing the use of GI along the public ROW and to use the landscape to capture rainwater. 

GI practices are methods used to restore ecological systems of urban cities.  Paved surfaces such as roads and sidewalks cause significant stormwater runoff and pose difficult growing conditions for urban trees.  LID designs for streets reduce and filter pollutants from stormwater runoff at the source before the water flows into the storm drain system toward area waterways.  Bioretention areas capture and filter stormwater while creating a green streetside amenity. Permeable paving allows water to flow into pavement and through a storage area.  Both types of practices will infiltrate water where the soil conditions are suitable.  Improved tree spaces create larger soil volumes which allow capacity for larger, healthier urban trees.

These Green Infrastructure Design Standards are now standard for all DDOT contracts awarded by the Mayor of the District of Columbia, the Council of the District of Columbia, and/or the Contracting Officer. The GI Standards shall also be used for all design, material control, construction and maintenance of GI within the District’s public space. All Public Space Permit applications submitted after May 1, 2014, must comply with the GI Standards.

These Standard Specifications may be revised or amended in the future, but only to the extent specified under a supplemental specification or special provision included in the specific contract.