The Corps’ Mississippi Valley New Orleans (MVN) began opening bays on the Bonnet Carré Spillway for the second time this year, in an emergency response this afternoon (Friday, May 10, 2019). The MVN opened 60 bays today in order to keep the maximum flow at New Orleans at or below the target flow of 1.25 million cubic feet per second (cfs).
The maximum flow above the Spillway today was 1.248 million cfs as based on the flow measured at Red River Landing, with timing adjusted for downriver at Bonnet Carré.
The MVN estimated a flow of 8,000 cfs yesterday through the flood control structure (seepage through the needles). The present forecast estimates the crest about the Spillway on May 22, 2019, based on the operation of the spillway the maximum flow is forecasted to remain at 17.0 feet until June 4, 2019 as adjusted based on the Spillway’s operation.
BONNET CARRÉ SPILLWAY OPERATION
|Date||Carrollton Gauge (New Orleans)||Bays Opened||Total Number of Open Bays||Spillway Discharge Cubic Feet Per Second (cfs)|
|2/27/19||17.25 feet||60||60||78,000 cfs (estimated)|
The MVN noted the following concerns prompted today’s opening, the original plan was to operate the structure on Tuesday, May 14, 2019, as provided by MVN:
“The sudden change prompting today’s opening was a combination of the flow trigger moving to the left, and river stage concerns due to heavy rainfall over the last 48-hrs in Louisiana and Mississippi. Today’s opening preserved freeboard for our machinery at IHNC lock and some other areas along the Mississippi River Levee Protection System.”