Development Tracker: McMillan Reservoir

Contributing Writer – Lisa Morris, Planning Associate

Drivers stopped at the corner of Michigan Avenue and North Capitol might wonder about the concrete cylinders that dot the fenced-off green space just east of the McMillan Reservoir. The 25-acre property is the former McMillan Sand Filtration Site. If the city’s plans are realized, those concrete cylinders will soon adorn a new mixed-use development.

The McMillan Sand Filtration Site was developed by the Army Corps of Engineers in 1906 to clean the District’s drinking water through the process of slow sand filtration. The process took place in underground cells, where water filtered through two feet of sand before pipes delivered the clean water to city residents. Meanwhile, the surface served as a park designed by the famous landscape architect Frederick Law Olmstead, Jr., until it was fenced off during World War II in response to concerns about the water supply’s safety. In the 1980s, slow sand filtration became obsolete, and the District purchased the property for redevelopment. Now that idea is moving forward with a master plan that proposes a mix of retail, office and residential uses.

The current plan shows about a 25 percent canopy cover for McMillan post-redevelopment. We would like to see the city set a goal for the project of 30 percent canopy cover to help meet D.C.’s tree canopy goal of 40 percent by 2035. Considering the land uses proposed for the site, this goal would be ambitious yet achievable with the use of best practices such as burying utility lines and installing supported sidewalks to allow for adequate soil volume.

Of the 25 acres, about five are proposed to become permanent open space. While this is a welcome part of the plan, a comprehensive approach that opens both the reservoir and sand filtration site to the public and bolsters green space on both sites would best serve the surrounding neighborhoods. This area already acts as a de facto recreation space despite the lack of access; the water, green space and tree-lined hills attract walkers, runners and cyclists eager for a park-like setting. Restoring access would greatly benefit the community and help connect the surrounding neighborhoods. The District can look to Baltimore and Columbia, Md., where city reservoirs serve as public parks, sometimes with fences around the water rather than the entire site.

New development on the McMillan site is a welcome prospect. With good planning, proper attention to tree spaces and an ambitious canopy goal, this project will not only enliven an underutilized part of the city but also enhance the existing beauty of the green space.

This article was originally featured in The Leaflet. Subscribe to receive our monthly e-newsletter in your inbox the first Tuesday of every month.

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