Flooding won't hit lake, officials say, but debris will



Posted on May 11, 2011 at 6:20 PM

Doug Mouton / Northshore Bureau Chief

NEW ORLEANS -- Murky water from the opening of the Bonnet Carre Spillway is now entering Lake Pontchartrain, but experts do not expect any flooding concerns.

"With the amount of water coming through the spillway compared to the volume of water that's in Lake Pontchartrain, and that moves in and out of Lake Pontchartrain through the Rigolets everyday, the impacts should be completely insignificant," said St. Tammany Parish Environmental Specialist Brian Fortson.

Fortson described Lake Pontchartrain as an open system, with huge quantities of water moving in an out every day.

"You probably will not even be able to detect any rise in the elevation of Lake Pontchartrain because of the water coming in from the Spillway," Fortson added. "Water coming in from the spillway should not have any appreciable impact on the elevation, and it should in no way even come close to what you see on a daily scale with regard to just the normal tidal action."

That opinion is shared by the U.S. Army Corps of Engineers and the National Weather Service, said St. Tammany Parish President Kevin Davis.

"We don't believe they will be any significant rise in the level of the Lake," Davis said. "No flooding is expected at this time."

In fact, Davis said, Northshore rivers are low because of drought-like conditions, so extra water will not hurt rivers either.

Brian Fortson described the water headed into the Lake as "murky". He said, it will bring a nutrient load that could produce algae blooms.

Some bait fish could also be killed because the salinity of the lake will change as the fresh water arrives.

The most significant effect could come from debris moving in with the spillway water, and it's not just trees and vegetation.

"Because of the flooding that went on up north, and the invasive waters getting into home sites and camp grounds, you can expect anything," said Louisiana Wildlife and Fisheries Sgt. Darryl Galloway.

That debris, according to Galloway, will be floating on the surface and just beneath the surface.

"It's not only the stuff that you can see on top; that's easy," Galloway said. "Anybody can see stuff floating if they're paying attention. The stuff that's under the water that you can't see is what your concerns should be."

Debris could be especially dangerous because of the popularity of small vessels like JetSkis, and because so many boaters enjoying pulling kids on intertubes behind their boats.

With all the debris headed into the lake, Galloway has recommendations: "Reduce speed on your vessel. Be aware that at any point you can strike something in the water."

Plus, he advises anyone standing in the boat should sit down, and everyone should wear a life vest.