Dimensions - Summer 2014 - 8

vision: innovation
The ﬁrst of its type in the U.S., the National Mall
Underground (NMU) is an innovative infrastructure project
that combines parking, ﬂoodwater storage, irrigation
cisterns, and a visitor center. Dewberry is the civil and
structural engineer for the proposed LEED-Platinum NMU.

Courtesy of Arthur Cotton Moore, FAIA

The National Mall Underground
A Multi-Purpose Solution
National Mall is moving forward for the green space

Reducing Flood Risk
Near National Treasures

between the Smithsonian Institution's Castle building

The National Mall has experienced recurrent ﬂooding.

A vision to create a more sustainable, visitor-friendly

and the National Museum of Natural History in the heart
of Washington, D.C. Dewberry is currently preparing
conceptual civil and structural engineering designs for
the National Mall Underground (NMU), a multi-purpose
project that will address ﬂooding, traffic congestion, air
pollution, and long-term sustainability challenges.
Proposed by Washington, D.C., real estate developer
and philanthropist Albert H. Small, architect Arthur
Cotton Moore, FAIA, and the nonproﬁt National

A 2006 event inundated several public buildings in the
Mall area, including the National Archives, and caused
millions of dollars in damage. A 2011 study proposed the
cistern solution as a way to enhance the Mall's resiliency,
but federal and D.C. agencies lack funding. The sponsors
of the innovative NMU say that parking revenue and
creative public-private ﬁnancing will make this a largely
self-funding facility.

Coalition to Save Our Mall, the NMU is a subterranean

Designing for Sustainable Results

infrastructure initiative that will provide approximately

The NMU is being designed as a LEED®-Platinum

1,000 parking spaces and double as a 34-million-gallon
reservoir for ﬂoodwater during major storm events.
Large cisterns at the perimeter of the three-level structure
will collect rainwater and graywater ﬂow from adjacent
buildings for use in irrigation. The parking will also
provide a much-needed location for tour buses, which
currently idle along roadsides, thereby reducing traffic
congestion and air pollution. The top level will include
a visitor center with restroom and food service. New turf
grass will top the structure as a green roof. Prior to severe
storms, the lower levels of parking would be vacated and
closed, allowing ﬂood waters to be temporarily stored.

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facility. Dewberry is also using the Business Case
Evaluator (BCE) tool for stormwater management.
This tool was developed as a companion to the Institute
for Sustainable Infrastructure Envision™ rating system
to provide value-based and risk-adjusted analysis.
BCE calculates the full impact of economic, social, and
environmental factors of various sustainable strategies and
can map results to several Envision rating system categories.
In addition to Dewberry, design team members
include Arthur Cotton Moore Associates, Clark
Construction, and Gorove/Slade. For more information on
the project, visit http://nationalmallunderground.org.
http://www.youtube.com/watch?v=tGAxAl7dN4Y http://nationalmallunderground.org
Dimensions - Summer 2014

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