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Nitsch Engineering Designing Green Infrastructure Solutions to Serve as Model in D.C.

Nitsch Engineering has been selected to design green infrastructure improvements on Kennedy Street in Washington, D.C., as the winning streetscape entry in the DC Water Green Infrastructure Challenge design competition. After being selected as one of the finalists in the planning and design phase of the competition, Nitsch Engineering’s team refined their design for Kennedy|Greened: A Neighborhood Green Street Project to include a variety of green infrastructure strategies for the 100 Block of Kennedy Street NW. A multi-agency evaluation panel selected the Nitsch Engineering team for demonstrating innovative, cost-effective, constructible, and replicable solutions to alleviate stormwater discharges to combined sewers, thus reducing combined sewer overflows (CSOs) in the Rock Creek drainage area. Combined sewers, which carry both stormwater and sewage, can be found in most older cities in America.

With the goal of designing innovative solutions that absorb stormwater before it enters the combined sewer system, the Nitsch Engineering team proposed streetscape improvements for Kennedy Street that integrate a variety of landscape and stormwater strategies including additional street trees, permeable pavers, landscape infiltration gaps, stormwater curb extensions, grated landscapes, and sub-surface storage/infiltration. Environmental art installations draw attention to these functional stormwater features, raising awareness of stormwater movement, treatment, and storage. The design further promotes “complete street” concepts by using curb bump-outs, sidewalk crossings, and boardwalks to create a streetscape that is safe and comfortable for pedestrians, bicyclists, and motorists.

“We anticipate that our plan for Kennedy Street will eliminate significant amounts of stormwater from entering the combined sewer system annually, improve water quality, and minimize urban heat island effects,” said Nicole Holmes, PE, LEED AP BD+C, Nitsch Engineering’s Green Infrastructure Project Manager. “Just as important, our design will benefit the community by raising awareness and advocacy of green infrastructure, and by creating a shared street that is safer and more pleasant for all roadway users.”

Scott Turner, PE, AICP, LEED AP ND, Nitsch Engineering’s Director of Planning, added, “One of the most exciting things about this project is that the strategies we’re implementing will serve as a model for what can be done anywhere to address CSOs and stormwater in roadways. Our design solutions from this project can be replicated throughout urban corridors across D.C., which will further address the district’s need to alleviate stormwater discharges to combined sewers.”

The team includes Nitsch Engineering as the design engineer and principal consultant; Urban Rain Design and Warner Larson Inc. as landscape architects; Stacy Levy as the environmental artist; EBA Engineering Inc. as the land surveyor, geotechnical engineer, and constructability consultant; McKissack & McKissack as the permitting consultant; and Tina Boyd & Associates as the public outreach and participation consultant. To view a video that summarizes the Nitsch Engineering team’s proposed design, visit

About DC Water

The District of Columbia Water and Sewer Authority (DC Water), created in 1996 by the District government and Congress, is one of the largest water and sewer utilities on the East Coast, serving a regional area of 725 square miles, and providing drinking water and wastewater collection and treatment to residential, commercial, and governmental users in the District of Columbia, Maryland, and Virginia. In 2005, DC Water developed a Long Term Control Plan (LTCP) for Combined Sewer Overflow (CSO) control, highly dependent on a tunnel system for storing and conveying combined sewage for treatment. In 2012, DC Water, US EPA, and the District of Columbia signed the Green Infrastructure Partnership Agreement; the agencies are exploring a revision to the LTCP that incorporates more green infrastructure. The Green Infrastructure Challenge demonstration projects, once constructed, will serve as a model for the green infrastructure implemented within the District.