No plans to open Bonnet Carre Spillway

Published 12:00 am Wednesday, May 27, 2009


NORCO — Although heavy rains and snow melt-off from the northern states have caused the Mississippi River to swell near flood stages in the River Parishes area, officials with the Army Corps of Engineers said this week they still have no plans to open the Bonnet Carre Spillway to relieve pressure.

The National Weather Service has forecasted that the river will crest Wednesday at 16.2 feet, just a few inches short of the flood stage of 17 feet. The corps has announced that it has activated Phase II of its flood fight procedures, which includes daily assessments of river levels and flood protection levees along the Mississippi and Atchafalaya Rivers. Those reports are forwarded to the Governor’s Office of Homeland Security and Emergency Preparedness and the corps’ Mississippi Valley Division. The commander of the Mississippi Valley Division makes the final call on opening the spillway.

Flood conditions last spring on the river prompted a partial opening of the spillway for 27 days in April to lower the volume of water flowing through the area from 1.28 million cubic feet per second to 1.25 cubic feet per second. At the peak of the opening, 160 of the spillway’s 350 bays were opened.

Even though there are still no set plans to open the structure, a successful test opening last week proved that the corps would be ready if the need should arise in the next few days.

As part of an annual drill to give crews experience in opening the grates of the flood control structure, corps employees carefully removed all of the wooden “needles” from one of the bays of the structure so that new members of the team know what to do should the need for an opening arise.

“The test is typically done when the river is high so that the crew can get a feel for removing the needles under extreme conditions,” said Chris Brantley, manager of the Bonnet Carre Spillway. “The test is done on one of the lower bays of the structure, since it has the longest needles and the most water flowing through it.”

Brantley said operations on the spillway are very labor intensive. He said it takes employees about an hour to lift all 20 needles from one bay. When all 350 bays of the structure are opened, as much as 250,000 cubic feet of water per second is steered out of the river and into Lake Pontchartrain to reduce the strain on levees in St. Rose, Kenner and the New Orleans area.

Although the fresh water from the river can be a shock to some plant and animal life in the salty lake, Brantley said the seasonal flow of water through the spillway is a good thing for the environment.

“It adds nutrients to areas of the spillway, influences grass growth and improves the fish, crab and crawfish populations.”