Sunday morning, crowds gathered at the massive Bonnet Carre Spillway in St. Charles Parish to watch its official opening. Two cranes moved along the railway tracks that top the flood-control structure and removed some of the structure’s 7,000 wooden “needles,” allowing water from the swollen Mississippi River to bypass New Orleans.
The needles are grouped into 350 linear bays of 20 needles each and the U.S. Army Corps of Engineers removes as many as needed to divert floodwaters. It is unclear how many of the bays will be opened today. In 2008, fewer than half of the Bonnet Carre’s bays were used. But in May 2011, the structure’s most recent use, more than 94 percent of bays were opened.
At its full capacity, the spillway can carry 250,000 cubic feet of water per second away from New Orleans and the lower portion of the river.
The Bonnet Carre’s ceremonial opening today is just one part of the state’s response to unusually early flood conditions on the river.
Corps scientists are monitoring weather and river-level forecasts before deciding to unleash water through the Morganza Spillway, which is located upriver from Baton Rouge and flows into the Atchafalaya River Basin.
Since parts of the basin will flood even if the Morganza doesn’t open, people who own camps and other property in the area have begun carrying away anything valuable and protecting what’s left with sandbags. Power companies in the area are disconnecting electric meters. The Governor’s Office of Homeland Security and Emergency Preparedness also reported on Friday that it had 842,000 sandbags in stock and had already issued 26,000 sandbags to Avoyelles Parish, 13,000 to West Feliciana Parish and 13,000 to the Louisiana State Penitentiary at Angola, which is bounded by the Mississippi River on three sides.
In the days following Gov. Bobby Jindal’s Dec. 30 emergency proclamation, a number of state agencies issued emergency plans due to “an imminent threat of flooding.” On Thursday, the Department of Natural Resources declared an emergency for the state’s oilfields and structures that ordered operators to secure facilities and remove chemicals from sites and pipelines. Also, deer hunting is banned in areas affected by the Bonnet Carre starting 30 minutes after sunset today, to comply with an order issued by the Louisiana Wildlife and Fisheries Commission.
The Bonnet Carre Spillway is located about 28 miles upriver from New Orleans. Built after the great river flood of 1927 as a flood-relief valve, it opens up more than a mile of the Mississippi’s east bank and pulls surging riverwaters into a 5.7-mile floodway that empties into Lake Pontchartrain and, eventually, the Gulf of Mexico.