Is DC Prepared For a 500-Year Storm?

  • October 20th 2017

by Nena Perry-Brown

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Is DC Prepared For a 500-Year Storm?: Figure 1
Potomac River flooding near the Jefferson Memorial in 1985.

Last month, Rolling Stone published an article asserting that DC is woefully underprepared for a “superstorm”, citing its coastal location and inadequate levy system.

“Any breakdown in DC’s ad hoc flood-defense system would unload a sizable portion of the pent-up Potomac on downtown DC,” the article warns. “If the [Potomac River] broke through the levee system at 17th Street, or at the low points near the Lincoln Memorial or Constitution Gardens, a wall of water would spill down Constitution Avenue and rush east into the Federal Triangle.”

In the aftermath of a particularly devastating hurricane season, more metropolitan jurisdictions are facing the question of emergency preparedness and resilience — and the District is no exception. At a recent discussion at the National Building Museum, experts attempted to clarify how the city is addressing flood risk.

Is DC Prepared For a 500-Year Storm?: Figure 2
The Martin Luther King, Jr. Memorial; the blue line marks the 100-year floodplain.

While it may not be apparent, the regional and federal agencies have been thinking about flood risks for over a century. Jeffrey Gowen, branch chief for the National Mall and Memorial Parks at the National Park Service, noted that while 70 percent of DC’s square footage is in the coastal plain, the monument corridor is the most susceptible to flooding. Because much of the Mall and Constitution Avenue and Second Street used to be part of the river, “it’s not a matter of if, but when it is going to flood,” he acknowledged.

Is DC Prepared For a 500-Year Storm?: Figure 3
The World War II Memorial; the blue line marks the 100-year floodplain.

Stephen Walz, director of the Department of Environmental Programs for the Metropolitan Washington Council of Governments, noted that the most important aspect of flood preparedness is avoiding “cascading failures”, or a domino effect of catastrophes. Not only should the city be preparing for tidal flooding of and storm surges from the river basin, other over-land types of flooding could also converge with the rising water levels due to poor drainage systems — an issue that DC Water has been attempting to address through recent infrastructural projects.

Is DC Prepared For a 500-Year Storm?: Figure 4
The regional flood risk levels.

Walz also explained that because any devastating events in DC would also impact national security and the operations of the federal government, the city is likely far more prepared than people realize; it’s just a matter of improving cooperation between local and federal government, as well as throughout the region.

The conversation on Wednesday night comes at an interesting time, just a week after the first phase of The Wharf revitalization was unveiled.

“Waterfront development had long been a priority for the District,” DC’s chief resilience officer Kevin Bush noted, stating that the Office of Planning considered flood risks when evaluating the plans for The Wharf. However, Walz shared that the city wouldn’t want to construct floodwalls along the waterfront because that would change the culture of the locale by cutting people off from the river.

To Bush, the city should educate its residents and make water a more salient part of the city’s life, even incorporating innovative architecture like recessed parks that provide recreational space throughout most of the year while serving as a retention basin for floodwaters whenever needed.

Bush also said that there needs to be a comprehensive and interdisciplinary approach to city planning to ensure DC can withstand moments that sudden “acute shocks” intersect with ongoing “chronic stresses”. DC in particular must also consider issues of income inequality, affordable housing and increasing population as part of any future planning strategies, using an example of a long-time resident who is unable to repair or replace a broken air conditioning unit and is therefore vulnerable during a heat wave.

See other articles related to: climate change, flooding, flooding in dc, floodplain

This article originally published at https://dc.urbanturf.com/articles/blog/is_dc_prepared_for_a_500_year_storm/13149.

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