.. flood control, the spillway is prime ground for sand excavation and recreational activities.

The Bonnet Carré is built on what is called a controlled-levee crevasse, says Brantley. Before the French built the first levees in the area in 1718, the Mississippi routinely overflowed its banks and meandered back and forth across the floodplain. After the levees were constructed, flooding that broke through created cuts, or crevasses, as the river tried to meander from its primary path. Between 1849 and 1882, several crevasses developed at Bonnet Carré, depositing a fan of sediment on the east bank of the river. The spillway was constructed on the accreting bank a couple of miles north of the largest crevasse, Brantley says.

Angelle Bergeron

Angelle Bergeron Spillway has 350 bays. Brantley is preparing to open them.

Once authorized after the 1927 flood, construction of the Bonnet Carré structure proceeded at a phenomenal pace, he says, a fact that encourages Brantley about the Corps’ ability to complete its current assignment to bring the Hurricane and Storm Damage Risk Reduction System to 100-year levels by 2011. “In May 1928, legislation was passed for the Flood Control Act, and by June surveyors were out at Bonnet Carré,” Brantley says. “By December 1928, the Corps had developed a 25-page document of plans and specifications. Construction began in 1929, and two years later it was finished.”

Brantley says he has no doubt the Corps can deliver the 100-year levels of protection, including the Inner Harbor Navigational Canal storm-surge barrier, by 2011. “We’ve done it here,” he says.

The surge of civil work in the area is also sure to generate a lot of beneficial technology, if the Bonnet Carré experience is any guide. During its construction, the Corps built a temporary hydrology lab to study a 20% scale model of the spillway. “That lead to the Waterway Experiment Station, which became ERDC [Engineer Research and Development Center] in Vicksburg,” Brantley says. The Bonnet Carré also marked the “first time they drove 70-ft, untreated piles and found out they wouldn’t rot,” Brantley says. “They also developed 5,000 psi concrete here.” The highest strength at the time was half that, he says.

Bonnet Carré was first operated during the flood of 1937 and again in 1945, 1950, 1973, 1975, 1979, 1983 and 1997.

Brantley remembers coming to the spillway openings in the 1970s to crayfish with his father, who was a civil engineer with the Corps. “One of the reasons I took this job was to see it open,” he says. “If we do open it, the first bay we open will be bay 349 the second one because it makes a big show at the access end for the media and the public. Then everyone goes home, and we spend the next 36 hours opening the rest of the bays.”