Siting Green Infrastructure within the Nation’s Capital - Process and Considerations


  • Bethany Bezak PE, LEED AP, Caitlin Feehan PE, Laura Bendernagel PE, Felicia Glapion PE, Matthew Jones PhD, PE

The goal of the program is a 96% reduction in combined sewer overflows.

A sampling of the GI solutions that will be implemented in various locations in the project area.

An important consideration of design is proper siting, which includes site visits to observe sedimentation/pavement conditions.

The design should also meet stakeholder requirements and expectations. Input, such as that from site visits by stakeholders, is critical to garner public support.

DC Water is in the process of implementing green infrastructure (GI) in the nation’s capital as part of its Long Term Control Plan (LTCP) to reduce combined sewer overflows (CSOs). The proposal to implement GI under the LTCP was approved in January of 2016 via a modification to the 2005 Consent Decree between the US Environmental Protection Agency, US DOJ, the District of Columbia and DC Water. Under the modified consent decree, DC Water will design and construct GI facilities to manage 1.2” of rainfall on 498 impervious acres between now and 2030. The implementation of GI in Washington, DC (the District) will be phased over a total of eight projects. The first two GI projects are currently in design with construction scheduled to begin in 2017.

This presentation will provide an overview of this relatively new program, and will dive more specifically into the development of DC Water’s approach to siting GI in the District. DC Water’s path to establishing Siting Guidelines to arrive at viable plans for the first two GI projects has been iterative as the program develops, and provides insight into the various factors and challenges municipalities must address to implement cost-effective green infrastructure, especially at larger scales. These challenges, some unique to the District and others commonly found in urban areas, include surface features, subsurface features, land ownership, contamination, historic buildings and streets, and cultural and archaeological resources. In some cases, non-physical barriers, such as acceptance by other agencies and the community, the need to maintain the character and feel of a neighborhood, and cost limitations also impacted where green infrastructure could be sited. DC Water’s siting approach seeks to address these challenges while balancing effective stormwater management, cost, and deadlines to meet Consent Decree milestones. The approach will continue to evolve to meet the unique requirements of the District’s streetscape and communities, but to-date, already offers a unique look at the considerations and challenges to siting GI, and strategies to overcome these obstacles.

For more information, please contact the author at

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Horizons showcases significant water, wastewater, reuse, and stormwater projects and innovations that help our clients to achieve their goals, and can help you achieve yours. Articles are written by top engineers and process group leaders, demonstrating and explaining the beneficial application of a variety of technologies and tools.

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