One of Washington DC’s most striking—but neglected, historical landmarks is the McMillan Reservoir and Sand Filtration Site. Designed and used for the District’s water supply, the site provided water to sustain the District’s growing population from 1902 until closing in the mid-1980s. The site propelled the District into a movement toward a healthier and cleaner city, providing purified water to residents via slow sand filtration. Though the filtration site was once a very necessary component of everyday life, as population increased and purification practices evolved, the District soon outgrew the need for which the site was designed. Since decommissioning and sale to the District in 1987, the historic site remained vacant with disuse rendering it derelict, while the area and edges surrounding McMillan have experienced varying degrees of urban development.

An important tenant of urban redevelopment and placemaking is the integration of a site into its neighborhood; this concept being critical in regards to the McMillan. Reintegrating this particular site into the city is a challenge, but also a great opportunity. How can the project help the site forge a new identity without losing its genus loci? How can McMillan be adapted for a contemporary context, while preserving the richness of its incredibly interesting past?

Today McMillan has been reimagined and reintegrated into a new and ever-evolving urban context; redevelopment will activate the long closed and dormant site. Designed by EE&K / Perkins Eastman, the master plan reconnects the disconnected city grid, while the significance of the past is memorialized in the preservation of topography and historical features and structures. The site will be activated by a mix of uses, including civic, parks and open space, benefiting District residents.

The process of designing the master plan has been an iterative one, and unsurprisingly so. Its historical, architectural and engineering complexities have given way to infinite design opportunities. These opportunities, along with input from the community, regulatory agencies and consultants, have contributed to the creation of design guidelines and goals that are revealed in the urban pattern and architectural scale. Among the guidelines and goals of the master plan is the evocation of a sense of place through historic elements and the provision of greater connectivity to its context.

Preservation of plinth along N Capitol ST

Conceptually, the master plan preserves and reinterprets the history of the site, while proposing ideas that allow for the site to function in a contemporary context. The silos, regulator houses and sand washers will be preserved and adaptively reused, allowing one to experience the structures as historical pieces of architecture, regaining different purpose in a new time. The McMillan site emerges as a plinth out of its adjacent urban context; its flatness a resultant of cavernous vaulted underground cells. Though the vaults have experienced significant structural degradation with the passage of time, some collapsing and others increasingly unstable and prone to eminent collapse, the master plan proposes the preservation and adaptive reuse of two cells (14 & 28). Providing visual connectivity to the site’s past use, the vaulted aesthetic is replicated in features throughout the site such as the community center. The master plan will also preserve the plinth-quality of the McMillan site, while recreating and reopening the historic Olmsted Walk that once traversed its perimeter.

Tripartite Organization of the McMillan site

Two historic service courts, each framed by the historic silos, regulator houses and sand washers, visually physically organize the site in tripartite form (see image to the right). This tripartite organization provides the pattern for the organization of uses on the site. Responding to the large scale architecture adjacent the northern border of the site, healthcare facilities and mixed-use multifamily housing are proposed before transitioning to row houses mediating the shift to the smaller scale architecture of the neighboring residential fabric. Providing a transition to the park and community center, the South Service Court becomes a civic space conducive for community activities, outdoor markets, events, and gatherings. Preserving the existing open plain and topography created by underground vaults, the community park provides passive open space replicating the current scale of the elevated plinth. Connecting the two service courts, three internal streets facilitate the movement and distribution of traffic throughout the site.

The ideals of the late 19th to early 20th century City Beautiful Movement, highly emphasized during the period of McMillan’s origin, are embraced in the sustainable design of the site. From an onsite stormwater management system consisting of rain gardens, a wetland and permeable pavement to help mitigate runoff, to the reuse of onsite resources, the proposed master plan approaches sustainable urbanism in a holistic method. Recognizing this commitment to sustainability and urbanism, the entire McMillan redevelopment will be certified LEED for Neighborhood Development (LEED-ND).

The collaborative process of the past few years has allowed the McMillan Master Plan to respond and evolve into a design reviving an important part of the city’s history through preservation, adaptive re-use and open spaces, while enriching the life of the city by not only reconnecting with the past, but also providing opportunities for the future.