First bays of spillway opened

Published 12:00 am Wednesday, May 11, 2011



NORCO – For only the 10th time in its nearly 80-year history, the Bonnet Carre Spillway in St. Charles Parish was opened Monday in an effort to divert water from the swollen Mississippi River into Lake Pontchartrain and ease pressure on levees further downstream.

A crowd of hundreds from across the region turned out to witness the event as a pair of crews from the U.S. Army Corps of Engineers used cranes to painstakingly remove the first wooden “pins” from the flood control structure. The corps opened 28 of the spillway’s 350 bays Monday and an additional 44 were opened Tuesday. There are about 20 pins per bay.

“It is pretty amazing to watch the water progressively get faster and faster as more of it gets opened,” said onlooker Franklin Madere of Norco. “I missed it the last time it was opened, so I felt like I had to see this one.”

Although the crowd was not nearly as large as the crowd that came out in 2008 when the spillway was last opened, there were still scores of residents who showed up with lawn chairs, umbrellas and coolers. Others were armed with binoculars, cameras and video equipment to document the occasion. Some even took off of work and school to see the event live.

“It does not happen very often, and it is something right in our back yard,” said New Sarpy resident Charles Allen. “I hope that this helps prevent a disaster we do not need right now.”

A representative from the corps said all 350 bays would eventually be opened, diverting the murky water about six miles through an uninhabited area and into Lake Pontchartrain. Opening the spillway relieves strain on levees throughout the Mississippi River Valley, which has experienced weeks of record rainfall and snowmelt.

“We are seeing historic flows and historic stages in the Mississippi River,” said Col. Ed Fleming, commander of the corps’ New Orleans District office. “We’re trying to reduce the pressure on the levees so we don’t have a catastrophic failure.”

Bonnet Carre Spillway Project Manager Christopher Brantley said the flood control structure is capable of diverting up to 250,000 cubic feet of water per second from the normal flow of the river when all bays are opened. He said that number translates to roughly 20 percent of the river flow through the area.

In addition to controlling quantity, the spillway also has the ability to control the speed at which the river continues downstream into the Gulf of Mexico. Brantley said the corps is trying to keep the flow from exceeding 1.25 million cubic feet per second.

According to the National Weather Service’s Lower Mississippi River Forecast Center in Slidell, even with the spillway opening Monday, river levels in some areas still registered at about 17 feet, an official flood level. With all bays of the Bonnet Carre Spillway opened, the river is still expected to crest south of the spillway at 19.5 feet on May 23, just half a foot below the top of floodwalls in New Orleans.

The expected river heights are prompting state officials to request permission to also open the Morganza Spillway north of Baton Rouge, which diverts water into the Atchafalaya Basin. That structure has not been opened since 1973.

With the river continuing to swell throughout the region, the corps will conduct daily monitoring of the levees to check for weaknesses or leaks. The corps has also issued a series of mandates pertaining to activity near and on river levees in an effort to maintain the structural integrity. Residents have been asked to refrain from parking and driving unauthorized vehicles on the levee top. There is also a ban on digging, trenching, excavating and pile driving within 1,500 feet of the levee.

The high water has also prompted the closure of the Reserve/ Edgard ferry until further notice. Parish spokesperson Paige Braud said the ferry operates on a floating landing, but the access road to the landing is currently underwater.

Braud said Monday the parish is in regular contact with the Army Corps of Engineers and added there is no threat of flooding in the region.

“People have called us with concern because the news mentions flood stages in Reserve,” Braud said. “We want the public to understand that it does not mean levees will be overtopped in any areas of the parish. Reserve has a river gauge used by the National Weather Service.”