On 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. 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.

After a ceremony that included a line of officials including 6th District U.S. Congressman and New Orleans Mayor Mitch Landrieu, Major Gen. Michael Wehr, head of the Mississippi River Division of the U.S. army Corps of Engineers, climbed into one of the red cranes to ceremoniously remove the first needles.

The Corps was removing 400 of the needles Sundayday, opening up 20 of the structure's 350 bays. An additional 30 bays could open Monday, depending on river speeds and levels.

Gerald Donaldson, 66, who lives nearby, rode his maroon Raleigh bicycle to the opening to avoid the day's traffic snarls. He's seen the spillway opened several times before, but he still wanted to make the ride Sunday. "It's a lot of water and there's something about water," he said. "It just kinda grabs you."

Anne Landry, 35, a fifth-grade teacher at Rudolph Matas Elementary in Metairie, came to videotape and photograph the event for her class, which has been studying the source and tributaries of the river. Her friend Jennifer Lojszczyk, 38, who teaches at Catherine Strehle Elementary School in Avondale, tagged along for the educational experience but also for what she called "the wow factor."

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 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 Sunday, 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.

Sunday’s opening marks the 11th time the spillway has been used since it was completed in 1931. On Friday, Corps spokesman Ricky Boyett warned that it could remain open for several weeks.

The Morganza has been used more infrequently: an opening this year would be only its third since it was completed in 1954.

Sunday’s Jan. 10 Bonnet Carre opening is one for the record books, marking the earliest calendar opening of the spillway’s 85-year history.

Typically, river levels rise in the spring, after the snow melts in the Midwest. Of the spillway’s previous 10 openings, eight occurred in March or later. But the first opening, in 1937, also was early, on Jan. 28. And in 1950, it was opened on Feb. 10.

But this year, heavy December rainfall in the Midwest caused the Mississippi and its tributaries to overflow, triggering severe wintertime flooding upriver in Illinois and Missouri.

That water is now on its way to New Orleans, where the river’s crest is expected to arrive around Jan. 21.

On Wednesday, when the river reached 15 feet at the Carrollton gauge in New Orleans, the Corps began daily patrols of the river’s levees from Baton Rouge south to Venice. On Friday, at a Unified Command Group meeting in Baton Rouge, the Corps reported that it was tracking some deficient areas in the levees, including broken pavement, animal burrows, erosion, shrinkage cracks and “an area of slides” just south of the Algiers Lock. Until the high-water subsides, any construction projects within 1,500 feet of the river are shut down. Vehicle and pedestrian traffic is also barred along the levee system.

Sunday morning at 4 a.m., the river stood at 16.24 feet in New Orleans, up only slightly from 15.8 feet on Saturday but far above than the 7-foot levels seen here as recently as Dec. 1, before the surge of Midwestern floodwater reached this part of the river.