Dammed if you do...

According to this Reuters report, fixes to the New Orleans levee system could actually make matters worse:

Flood defenses meant to protect New Orleans from hurricanes could lock rain in the city and put some areas 5 feet under water during a tropical storm, the U.S. Army Corps of Engineers said on Wednesday [Jul 26].

[..]

The Army released maps on Wednesday [Jul 26] showing new floodgates built to keep out storm surge could disrupt the system for draining rain from low-lying areas.

That has been a major concern of community groups and supporters who argued the Corps' storm barrier plan had a potentially fatal flaw -- not enough pumps.

Most of New Orleans is below sea level and pumps out rainwater beyond the ring of protective levees.

"Large areas of the metro area that may have had minor street flooding before will now have 2 to 3 feet on top of that -- significant home flooding -- because of the Corps' failure to build adequate pumping capacity for this hurricane season," Louisiana Sen. David Vitter said in a statement after the Corps released the maps.

It is interesting to note that the floodgates were delayed because of concerns about getting adequate pumping capabilities installed. This Houston Chronicle report from May quotes the Corps of Engineers:

"We're trying to communicate this to the public because we understand they need to know where we are, but we also need to reassure everyone that we can provide the level of protection we promised," [Col. Lewis] Setliff said Friday.

According to the same article, Sen. David Vitter was critical of the delays at that time:

"This Corps announcement is a huge disappointment," U.S. Sen. David Vitter, R-La., said Friday. "I have been told for months that our system would be considerably stronger this season than the day before Katrina, though we had much more short-term work to do. I no longer have confidence in that being the case. The Corps leadership is completely failed and the Corps process completely broken. I'm in the process of telling President Bush this privately and in excruciating detail."

According to the U.S. Water News, the problem was anticipated in January when the Corps realized they were running out of time to reinforce the levees and proposed the floodgates as a temporary way to control at least one source of flooding:

The U.S. Army Corps of Engineers has decided to proceed with proposed floodgates as a way to prevent storm surge from building up in three of the city's major drainage canals, two of which breached during Hurricane Katrina.

"We just don't have the confidence in the canal levees at this point," Corps spokesman Jim Taylor said.

[..]

"The level of protection is greater if you stop the surge at the lake," Taylor said.

That was what the Corps wanted to do long ago, but the city's sewerage and water board, which is in charge of draining the city, fought that proposal, fearful the gates would interfere with the drainage of rain water.

Even with this, the Corps warned in January that some rainwater flooding could still occur, but that it would be "preferable to the catastrophic flooding from Lake Pontchartrain."

According to the article, the plan called for temporary pumps to move rainwater out of the canals. Engineers recommended that permanent pumps should be installed to allow draining at full capacity, but this would require authorization by Congress.

All of this illustrates one small part of the huge problem facing the Corps of Engineers and the City of New Orleans. There is no quick fix, but hopefully there are smart, or at least smarter, temporary fixes in the interim.