A deeper look into the levee system on the National Mall
WASHINGTON - As many areas continue to recover from all of the devastation caused by Hurricane Harvey, Irma and Maria, some are wondering if the nation's capital is ready for a major hurricane.
Rolling Stone magazine published a story about how a superstorm in our area could paralyze the government and jeopardize national security.
Along Constitution Avenue at West Potomac Park, there is a stone wall that you may assume is part of a monument. However, this wall is actually a levee placed here by the U.S. Army Corps of Engineers to protect our nation's treasures from a major storm or hurricane. But how much water can this levee handle?
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In the case of a major hurricane making landfall near Virginia Beach, storm surge would be pushed up the Chesapeake Bay and into the Potomac River. In the D.C. area, Reagan National Airport, Joint Base Anacostia-Bollling and Fort McNair could take on massive flooding as a result. As the water makes its way in, the National Mall would be in jeopardy.
"The flooding will continue where the levee is and then that could affect the Washington Monument," said Bilal Ayyub, a professor in the Department of Civil and Environmental Engineering at the University of Maryland. "It could get to the [National] Mall. It could actually get all the way to the backyards of almost the White House."
The part of the levee that crosses 17th Street has to be manually put in place if a storm is approaching. It is roughly ten feet above street level and 19 feet above sea level. If we were to see extreme surge in excess of 13 to 16 feet, the water would begin to loop around essentially leaving the Washington Monument on an island.
"Pretty much if you are taking clockwise around the Washington Monument - that is how the flooding would build up," Ayyub said. "So the levee will stop this, but the water is so high that the water will come from the other side. It would come parallel to South Capitol Street and going to the Mall not far from the [U.S.] Capitol.
The other major threat is severe rainfall. If a storm parked over Washington D.C. much like Harvey did over Houston, storm drains would quickly be overwhelmed. The city's lowest lying areas would be in danger and experts said the Federal Triangle area, home to a number of government agencies, could become ground zero.
"I don't know that there has been comprehensive modeling done and I think that is one of the issues we need to be working towards, and the Corps of Engineers has a study planned for the area, but having that kind of comprehensive look," said Sandra Knight, senior research engineer for the Department of Civil and Environmental Engineering at the University of Maryland Center. "But we know from the 2006 rainfall event that we flooded Federal Triangle area, the Archives building, the IRS."
Large parts of Metro and any underground infrastructure could be compromised as well. There could be potentially billions of dollars in damage.
"I think what needs to be done is more studies to characterize it better and understand it better," said Ayyub.
The U.S. Army Corps of Engineers said there are several new studies concerning flooding and the D.C. region underway right now.
The levee on Constitution Avenue was built to protect against a 100-year flood. There are designs in place to raise it higher, but right now, Congress has not approved the funding for it.