District Appeals Widening Of Downtown Flood Zone

Officials have said projects such as the expansion of the Department of Commerce building and the construction of the Smithsonian's National Museum of African American History and Culture would have to be reviewed if the map changes are adopted because they would be partly in the new hazard zone.

The proposed new flood zones were drawn up after the U.S. Army Corps of Engineers reported last year that the so-called Potomac Park levees, which are designed to protect downtown Washington from Potomac River flooding, are inadequate. If the levees were brought up to standard, the map would be redrawn to shrink the size of the hazard zone. That, in effect, would minimize the number of residents who must get flood insurance.

The levee system consists of temporary and permanent barriers at four locations _ three on or near the Mall, and one near Fort McNair.

The corps objected mainly to the temporary levee erected across 17th Street near the National World War II Memorial.

That levee, which has been used only six times since the 1940s, consists of sandbags and Jersey barriers covered with a plastic membrane.

In a worse case, however, plans call for building an eight-foot-high earthen dike there made of dirt excavated from the grounds of the Washington Monument. That plan has never been implemented.

The corps, which designed the system decades ago, decided after a 2006 inspection that, especially at 17th Street, it wasn't reliable.

"We don't believe that the earthen dike is a dependable closure structure," said Tony Videl, head of levee safety programs for the corps' Baltimore district, which includes Washington.

"We believe that's a high-risk thing to do during a storm event," he said in a recent interview. "We've always wanted a permanent structure there."

Consequently, the corps declined to certify the reliability of the levees.

Corps officials said repair of the levees would have to be paid for by Congress, which in the past has authorized $7.2 million for part of the project but never made the money available. No one knows what the total cost would be.

Videl said a more sophisticated "post and panel" barrier across 17th Street, which could be erected during a flood, would up the cost. The barrier is created when panels are lowered into place between posts that are inserted into holes dug in the street.

FEMA, meanwhile, is in the process of reexamining flood maps across the country in the wake of Hurricane Katrina. As a result of the corps' findings, FEMA drew up new flood maps for the District as if the levees didn't exist.

The maps were unveiled last fall, but they were not widely publicized until they were discussed at a Jan. 3 meeting of the National Capital Planning Commission. The commission wrote to the city suggesting an extension of the appeal period, which expired that day.

The District Department of the Environment, the city's point agency on the issue, wrote to FEMA on Jan. 10 requesting the extension.

"The consequences of these proposed changes are extensive and will substantially affect many stakeholders throughout the City, both commercial, private, Federal Government and the District Government," wrote George S. Hawkins, the department director.

"While we appreciate the need to modernize and make more accurate the actual flood zones, we need this process to occur within a longer timeframe and a more inclusive process," he wrote.

FEMA agreed to the extension the next day.