Researchers predict spillway effects on Lake Pontchartrain

Wednesday, May 25, 2011 - 5:21pm

A group of LSU researchers is keeping a close eye on Lake Pontchartrain now that the Bonnet Carre Spillway is open. They did a study on the lake's ecosystem back in 2008 when the spillway was last opened.

 When the spillway was opened in 2008, the impact was fairly small. "Forty percent of the lake never even saw river water," says Professor John White.

This year, there's a lot more water rushing through the New Orleans lake. "The plume has taken about 80% of the lake," he says. That's an increase in algae, thanks to nutrients usually found just in the river. Normally, algae is good for the lake's ecosystem.

"More algae means more animals," says phytoplankton expert Dr. Sibel Bargu.

This time around, however, the conditions have changed. "We can't really compare because there are different levels of nutrient enrichment in the lake and the duration and the time is a little different," explains Bargu.

She says the timing of the spillway opening is critical. "This time, they opened it a little late," says Bargu. "The temperature already started to get warmer."

Warm weather could bring an increase in harmful algae. "If it's too much, you end up having toxic bacteria species. They they contaminate the entire food web," she says.

That's the worst case scenario. More than likely, the impact won't be that bad. "It's not an event that seems to cause the stress that you might expect low oxygen or those types of problems," says White.

Researchers are monitoring the lake right now, and they'll keep doing it, even after the spillway closes.

Due to a technical difficulty, we were not able to attach the research documents to the story. However, if you would like to review a copy, please shoot us an email  at and we'll be sure to send you a copy.

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