At FrontPage Magazine, Michael Tremoflie tells of a flood control project that was stopped by the environmentalist lobby
In the 1970s, the U.S. Army Corps of Engineers' Lake Pontchartrain and Vicinity Hurricane Barrier Project planned to build fortifications at two strategic locations, which would keep massive storms on the Gulf of Mexico from causing Lake Pontchartrain to flood the city. An article in the May 28, 2005, New Orleans Times-Picayune stated, "Under the original plan, floodgate-type structures would have been built at the Rigolets and Chef Menteur passes to block storm surges from moving from the Gulf into Lake Pontchartrain."
"The floodgates would have blocked the flow of water from the Gulf of Mexico, through Lake Borgne, through the Rigolets [and Chef Mentuer] into Lake Pontchartrain," declared Professor Gregory Stone, the James P. Morgan Distinguished Professor and Director of the Coastal Studies Institute of Louisiana State University. "This would likely have reduced storm surge coming from the Gulf and into the Lake Pontchartrain," Professor Stone told Michael P. Tremoglie during an interview on September 6. The professor concluded, "[T]hese floodgates would have alleviated the flooding of New Orleans caused by Hurricane Katrina."
So what happened?
Why was this project aborted? As the Times-Picayune wrote, "Those plans were abandoned after environmental advocates successfully sued to stop the projects as too damaging to the wetlands and the lake's eco-system." (Emphasis added.) Specifically, in 1977, a state environmentalist group known as Save Our Wetlands (SOWL) sued to have it stopped. SOWL stated the proposed Rigolets and Chef Menteur floodgates of the Lake Pontchartrain Hurricane Prevention Project would have a negative effect on the area surrounding Lake Pontchartrain. Further, SOWL's recollection of this case demonstrates they considered this move the first step in a perfidious design to drain Lake Pontchartrain entirely and open the area to dreaded capitalist investment.
Oddly, the enviros appear to have sided with a plan that harms the wetlands even more than the floodgate project allegedly would have:
Worse yet, the environmentalists' ultimate decision to reinforce existing levees may have actually further harmed the Big Easy. There is at least one expert who claims the New Orleans levees made no difference – in fact, they contributed to the problem. Deputy Director of the LSU Hurricane Center and Director of the Center for the Study Public Health Impacts by Hurricanes Ivor van Heerden said, "The levees 'have literally starved our wetlands to death' by directing all of that precious silt out into the Gulf of Mexico."
The Commissar has some posts on the impact of levees on the environment and the gradual sinking of New Orleans - see here and here. This post displays an elevation map of the city and a little info on how flooding affects rivers.