On February 21, 2020, the “DC Silver Jackets Team,” an interagency group assessing ways to protect the District of Columbia from catastrophic flooding, held a charrette that endorsed the idea of developing floodwater storage under the National Mall, but rejected “ancillary uses such as parking.”
The charrette report does not explain why such “ancillary uses” were rejected, but we understand that there is opposition to car parking based on the belief that driving into and through the downtown should be discouraged in favor of using mass transit.
To accommodate this concern, the National Mall Coalition has begun looking at an alternative to the original National Mall Underground concept, called “Alternative A,” designed to accommodate only tour bus parking.
Figure 1 below is a cross-section of the original plan for the Underground, designed to accommodate 600 buses and 600 cars. Figure 2 is a cross-section of “Alternative A,” which would replace car parking with additional bus parking spots. Figure 3 shows how in both concepts the lower level would serve as a stormwater reservoir during flood events.
Adopting Alternative A would have implications for the Underground’s financing plan; these are currently being analyzed by the Coalition’s financing team.
