Located at the meeting of the National Mall and the Capitol grounds, Union Square is a focal point in Washington’s monumental urban plan and the setting for some of our nation’s most powerful shared memories. As an iconic public space, it has been a place of engagement for hundreds of thousands of visitors. Our competition-winning proposal re-imagines Union Square’s current configuration to enhance the experiences it offers and its place in our national consciousness.
This competition-winning plan selected by the Trust for the National Mall re-envisions Union Square with a complexity and richness of experience and potential that addresses who we are today. Union Square is a focal point in L’Enfant’s plan for the United States Capitol. It is the ground on which we gather during moments of national crisis and celebration. As a nation and as individuals, this is where we express our unity. Situated between the Mall and the Capitol, Union Square both literally and symbolically presents an opportunity to question who we are as a nation and how we relate to our leaders. Despite this significance, the site today is a broad and un-modulated plane of water and lawn that disrupts the Mall and the Capitol as well as L’Enfant’s larger urban plan.
This project presents an opportunity not only to reconnect and reinterpret the vision of L’Enfant and the clarity of his plan, but also to overlay and enrich this plaza with spaces for informal activities; features and textures that respond to the underlying natural landform of the site; the day-to-day patterns of movement through the city; and the diverse needs and desires of the people who visit this place throughout the year. The competition design emphasized two aspects—the monumental and the daily lived experience—which are essential components of a healthy and engaged public.
The design team rooted its process in historical analysis to ground the design and the presentation in the legacy of the place. This was essential to build confidence that the plan was a seamless fit for such a highly-scrutinized and nationally-significant site. In-depth investigation of existing conditions and operational requirements by the multi-disciplinary team also shaped a design that addresses the concerns and priorities of the diverse stakeholders. The structure of the design competition engaged a group of technical stakeholders throughout the design process. This group included historic preservationists, the National Parks Service, the Capitol Police, the Smithsonian Institute, and others interests whose support will be critical in future stages of the project. At the mid-competition stakeholder review the team presented a series of strategies and scenarios for program and site modifications rather than a specific draft design in order to reach consensus on key issues and strategies rather than design specifics. This approach provided critical feedback and support that played a central role during further development of the plan.
Communicating this breadth of analysis was a key part of the competition boards and jury presentation. The strong support of the technical stakeholder group and the competition jury speaks to the design’s incorporation of these important opinions and the potential for the site and the planning process to provide a forum for discussion, debate and common ground.
The design extends the formal axis of the Mall into Union Square as a pool, plaza and additional pathways. This collective central space is framed by a series of outdoor rooms designed for daily exploration and relaxation. Subtle changes in grade are used to form terraces and low retaining walls that provide seating and views into the central plaza. Native and culturally significant planting and paving establish further variety and definition to the spaces within, leveraging the existing mature trees and historic sculptures on the site and connecting to the material and spatial language of the surrounding civic landscape.
Key to its role as a place of national identity is the ability of Union Square to accommodate large gatherings for special events such as first amendment uses, festivals, concerts, and inauguration of the President. The design creates a series of comfortably-scaled every day spaces that combine to create larger flexible spaces for assembly. For the largest events, sub-basins of the reflecting pool can be drained in a variety of configurations depending on the scale and orientation of the activity.
The timeless design for Union Square is founded on principles of sustainability. To mediate the environmental impact of the large reflecting pool, we explored efficient uses of water and energy for the site. Grading is designed to increase storm water retention and achieve zero discharge into the city sewer system. The iconic new pool was conceived with a holistic strategy with regard to water conservation, energy use, visual appearance and programmatic function. Due to the minimal water depth, achievable by precise engineering, the new pool's water volume will be less than 10% of existing, and will be supplied by harvesting, filtration and storage of rain water.