National Mall Flood Solutions Will Have to Wait

By Judy Scott Feldman, PhD, Chair of the National Mall Coalition

Stormwater flooding in the National Mall and Federal Triangle area is a well-recognized existential threat to our Smithsonian museums and national treasures as well as government buildings lining Constitution Avenue. To judge by the November 3rd monthly meeting of the National Capital Planning Commission, it’s a problem that will not be solved any time soon.

Watch the NCPC video (begins at 39:32).

Read the NCPC summary of the presentations.

Addressing DC’s “Monumental Core Stormwater Flood Risk Management,” NCPC’s Julia Koster briefed Commissioners on the steps government agencies, including the inter-governmental “DC Silver Jackets” flood team, have taken to identify potential solutions since the devastating stormwater flood of 2006. The results are inconclusive.

The National Mall Coalition then presented our National Mall Underground stormwater reservoir-geothermal-tour bus parking project. I described how since 2013 the project has been modified in response to concerns by the public and government bodies, and favorably reviewed by the US Army Corps of Engineers. I noted that the Underground is the only proposal designed specifically to deal with stormwater flooding in the Mall area in a comprehensive way, while also providing additional benefits including geothermal renewable energy, water for Mall irrigation, bus parking, and visitor amenities.  I tried to correct inaccuracies in agency statements about the Underground and asked that NCPC not reject the project out of hand but instead include it as one option in a full and open public consultation review of potential flood solutions. Read my testimony here.

Judy Scott Feldman presenting for the National Mall Coalition

Next up was Nicholas Bonnard of DC’s Department of Energy and Environment representing the DC Silver Jackets, a consortium of federal and DC agencies addressing flooding in the National Capital region. The Silver Jackets, Mr. Bonnard said, looked at five potential stormwater flooding solutions for Mall area stormwater flooding, including the National Mall Underground. Their preferred solution is a pumping station near the Mall. Second choice is an underground Mall reservoir – but without parking. The Silver Jackets analyses focused on questions of flood mitigation; the Underground’s clean energy and other benefits were not evaluated or considered relevant. (View at 5:50 mark)

But after identifying the preferred solution, Mr. Bonnard mentioned a complicating factor. The pumping station “would discharge [the stormwater] into the Potomac River requiring upgrades and new tunnels.” (View at 5:56 mark)

This is the first public recognition, to our knowledge, that the pump option would require complicated, disruptive, and costly additional components.

In other words, the pumping station analyzed these past four years – and still promoted by NCPC, DDOEE, and the Silver Jackets as the preferred solution – is not a solution unless modified substantially and at great extra expense?

But, more importantly, is the preferred pumping station a solution at all, even if funding for the tunnel were available? Do we seriously entertain a solution that calls for pumping 24 million gallons (the volume of the 200-year flood in 2006) of contaminated stormwater directly into the Potomac River? Did EPA agree to that idea, further polluting the Potomac River?

The potentially huge costs of constructing tunnels to pump stormwater may explain the Silver Jackets’ surprising “Takeaway” in its “Damage and Impact Assessment” that “Given current information a system-wide solution would not be economically justified.” (The only system-wide solutions studied were the pumping station and the Mall underground reservoir.) This dismisses or ignores the revenue-generating potential of the multi-purpose National Mall Underground, which financial experts say could be built at minimal public expense. The only other alternatives considered – “floodproofing individual facilities” – have already been rejected by the Silver Jackets as inadequate to meet the threat to our national museums and treasures. Does this mean we should accept a repeat of the 2006 flood and the destruction and restoration costs that will bring? (On December 8, 2022, the Coalition received a letter from NCPC Chair White, dated November 18, stating that current NCPC flood mitigation efforts are still preliminary and that there “are currently no funded proposals by a federal agency to conduct further studies.”)

Nicholas Bonnard of DC’s Department of Energy and Environment representing the DC Silver Jackets, a consortium of federal and DC agencies addressing flooding in the National Capital region.
Slide from Nicholas Bonnard’s presentation

Chair White ended the testimony phase of the meeting by asking if Commissioners had any questions for the three presenters; they did not.

She then opened the floor to comments, starting with Peter May of the National Park Service who expressed his exasperation that NCPC should be even considering the National Mall Underground after the Park Service has repeatedly rejected the concept. He reiterated his objections to all aspects of the project.

Other Commissioners had no comment or commiserated with Mr. May’s objections.

Why was there no concern by Commissioners at the Silver Jackets’ and NCPC staff’s dismissal of a system-wide flood solution, at their seeming lack of urgency, at the revelation that the preferred pumping station they continue to promote is not a viable solution at all without major modifications that include a new tunnel component, and that the pump station would pump contaminated stormwater directly into the Potomac River ?

Ms. Koster provided one key. She made clear that NCPC staff consider the Mall solely the domain of the Park Service, not the NCPC, and certainly not civic-minded members of the public. “This is a project idea from an outside organization that advocates for one solution,” she said. “Any proposal on the National Mall would require the consent of the Park Service which has not occurred.” (View at 0:57 mark)

And what is the reasoning behind the Park Service’s angst? Mr. May stated that the Park Service has rejected parking beneath the Mall since the 1960s and so rejects outright the Underground, whatever its flood control or other benefits, because he characterizes it as a “parking garage.” May said, “The fact that certain bells and whistles have been added to it don’t (sic) really change the essential picture of this as a parking garage. Adding storm water retention has some benefit. I think geothermal wells has some benefit as well. Having water for irrigation, again, that has some benefit. But . . .” (View at 2:30 mark)

“But” in Mr. May’s mind it’s still a parking garage, and allowing parking on the National Mall – even under it, and even only by tour busses, is unthinkable.

The takeaway from the NCPC session? If the Park Service doesn’t like parking, and the Silver Jackets can’t find any viable solution to flooding other than the Coalition’s unacceptable idea, then the Mall and Federal Triangle will simply have to flood again.

The Coalition’s testimony made only two requests. Not that NCPC sign on to our proposal, but that the NCPC include the Underground as part of an open and public consultation process for flood solutions. Within that context, the renewable energy and bus parking components could be seriously evaluated as more than “bells and whistles.” Also, that NCPC tell Congress that it’s time for a new McMillan-type commission, now 120 years after the last comprehensive Mall plan (the 1901-2 McMillan Plan), to address the existential threats to the Mall, not only flooding but also climate change, need for sites for new museums and monuments, improved visitor amenities, and improved open spaces for educational and cultural events.

The contradictory and inconclusive outcome of this NCPC meeting makes the case, we believe, for Congress to act on both requests.

Even Mr. May, in his concluding remarks, acknowledged the need for Congressional intervention if the Underground is to receive a fair hearing. He said, “This is National Park land and there is not an existing authority that we have to be able to permit, authorize in any way something like Ms. Feldman has proposed. If this were to happen, it would require an act of Congress.” (View at 12:00 mark)

Exactly. In the face of agency inaction, Congress needs to take the initiative.