D.C. Devises How to Stay Dry During Future Floods

"The Mall is where people mean when they say Washington was built on a swamp — or more precisely, malarial marshland," observes Jennifer Ludden. "Constitution Avenue was once a boggy creek. So you can easily imagine water rushing over manicured lawns, pouring into marble lobbies, threatening the national treasures within — just like in one of those D.C. disaster movies that Hollywood loves."

"Except it already happened [PDF] — in 2006, [Amy Tarce, a federal urban planner with the National Capital Planning Commission] says, after a week of continuous rain."

"There's a very interesting discussion always about how bad is it going to get in 50 years," says Brendan Shane, chief of the Office of Policy and Sustainability for the District of Columbia's Department of the Environment. "Well, the problem is, it could get really bad already."

Flood barriers, automatic flood gates, green roofs, and a huge underground pumping station are among the defense measures being considered and built to keep the flood waters away.