The National Weather Service has predicted that at its crest, 1.9 million cubic feet per second of water will flow past the Red River Landing if the floodway is not opened. That would result in a crest of 19.5 feet at the Carrollton Gauge in New Orleans, which is 2.5 feet above official flood stage and just 6 inches below the top of floodwalls
The new corps map assumes that such a high water level could result in multiple failures of earthen levees, floodwalls or other structures along the river, said Walter Baumy, chief of engineering for the corps' New Orleans office. The record high water levels also would cause a dramatic disruption to business in the Port of New Orleans and elsewhere along the river in the New Orleans area, said Bob Turner, executive director of the Southeast Louisiana Flood Protection Authority-East.
That's from 2011. The last time we were talking about opening the spillways. They're going to open Bonnet Carré on Sunday.
The Army Corps of Engineers will begin opening the Bonnet Carre Spillway in St. Charles Parish at 10 a.m. Sunday morning to reduce the level of the Mississippi River in New Orleans, so its flow does not exceed 1.25 million cubic feet per second in New Orleans, corps officials confirmed late Thursday.
The river was at 15.5 feet on Thursday at the Carrollton Gage in New Orleans and is expected to reach 16.4 feet on Sunday morning. The official flood level for the city is 17 feet, which will be reached on Tuesday, according to the National Weather Service's Lower Mississippi River Forecast Center.