In partnership with local philanthropist and businessman Albert H. Small and renowned architect Arthur Cotton Moore FAIA, the National Mall Coalition has developed the innovative National Mall Underground, a multi-purpose flood protection and parking facility that also provides a much-needed Mall Welcome Center with restrooms and food options. Features include (numbered in illustration above):
- Storm water reservoir (lower level of parking garage) able to collect 34 million gallons of flood water (a 200-year storm event such as occurred in 2006)
- Bus and car parking to provide visitor access to Mall museums and cultural activities and relieve congestion and pollution
- Visitor welcome center with public amenities including orientation, restrooms, and food
- Public safety, shelter, and security with first aid, manned security, and shelter-in-place
- Irrigation cisterns collecting rainwater and groundwater for sustainable irrigation of gardens and other landscape elements as well as grey-water use in restrooms
- Automated car garage that accommodates more vehicles at lower cost for construction and operations
- Field of geothermal wells beneath the facility to supply renewable energy to nearby Smithsonian museums and other public buildings while generating revenue and reducing energy costs
- Ground-level entrance pavilions (under development) with visitor orientation and shelter during sudden storms, solar panels, exhaust shafts for garage, and heat pumps for geothermal (candidate for LEED Platinum, to meet Executive Order 13514)
Significantly, the project, to be constructed through a public-private partnership, is largely self-funding due to anticipated revenue from parking, stormwater credits, and the geothermal energy component.
Flooding — During heavy storms, vehicles will be removed from the lower stories to allow flood waters to flow into these areas until they can be pumped out later into the sewer system. Solving the stormwater flooding problem along the Mall and Federal Triangle area could potentially shrink the FEMA flood map flood zone associated with stormwater or interior flooding (shown with blue hatching), and reduce or eliminate the burdens associated with buildings located in that flood area.
Irrigation — Cisterns at each end of the facility will collect rainwater and groundwater flow to be used for Mall irrigation and as grey water for visitor center restrooms.
Bus Parking — With tour buses paying millions of dollars a year in parking tickets, the National Mall Underground will provide ample parking to solve this enduring problem and reduce pollution by eliminating bus idling and circling. A rest area for bus drivers will provide showers and places to rest and relax.
Automated Parking — A mechanical two-story car parking system provides convenient and cost effective equal access for Mall visitors. Automated parking produces 83% less toxic fumes than conventional garages.
Welcome Center — The Underground will feature a Mall Welcome Center with plentiful restrooms, food options, First Aid, and other amenities that are lacking today for visitors on the Mall. An educational exhibit will explain the water resources function of the facility including the recycling of greywater collected in the cisterns for use in the restrooms.
Geothermal — The field of geothermal wells beneath the facility will be able to provide efficient, cooling energy to the nearby Smithsonian museums as well as other public buildings.
Security — The Underground will not only include a security office and a first aid station, but will also provide shelter to Mall visitors during sudden down-pours. Federal agencies charged with national security and public safety have reviewed the project and found no security concerns. Indeed, the Underground will provide new public safety benefits. According to security experts, it can be used in staging such high-profile events such as the Presidential Inauguration and the Fourth of July.