The Corps’ Mississippi Valley New Orleans (MVN) did not open any bays on the Bonnet Carré Spillway (Mile 128.8 to 127.3 Above Head of Passes [AHP]) today (Wednesday, May 29, 2019). The maximum flow above the Spillway today was 1.27 million cubic feet per second (cfs) based on the flow measured at Red River Landing (Mile 302.4 AHP), with the calculations and timing adjusted for downriver at Bonnet Carré.
The operation of the Morganza Spillway (Mile 280 AHP) is confirmed with a scheduled opening on Sunday, June 2, 2019:
“Preparations are underway for the confirmed opening of the Morganza Floodway starting on 2 June (slow opening), based on very high stages predicted at the structure, coupled with the potential for even higher stages/river flow over the longer term. A minimum of 2-weeks Morganza operations are predicted.”
The MVN operated the Bonnet Carré Spillway from February 27 to April 11, 2019, prior to 2019 the Spillway had never been operated in back-to-back years (2018 and 2019). The required opening of the flood control structure twice in the same year represents another historic first.
BONNET CARRÉ SPILLWAY SECOND OPERATION 2019
|DATE||CARROLTON GAUGE (NEW ORLEANS)||BAYS OPENED TODAY||TOTAL NUMBER OF BAYS OPEN||TOTAL NUMBER OF BAYS CLOSED||SPILLWAY DISCHARGE CUBIC FEET PER SECOND (cfs)|
|5/10/19||17.25 feet||60||60||N/A||78,000 cfs|
|5/11/19||16.80 feet||10||70||N/A||82,000 cfs|
|5/12/19||16.80 feet||0||70||N/A||79,000 cfs|
|5/13/19||17.00 feet||58||128||N/A||116,000 cfs|
|5/14/19||16.75 feet||10||138||N/A||127,000 cfs|
|5/15/19||16.70 feet||0||138||N/A||127,000 cfs|
|5/16/19||16.60 feet||0||138||N/A||122,000 cfs|
|5/17/19||16.60 feet||0||138||N/A||122,000 cfs|
|5/18/19||16.80 feet||0||138||N/A||127,000 cfs|
|5/19/19||16.90 feet||10||148||N/A||142,000 cfs|
|5/20/19||16.80 feet||0||148||N/A||148,000 cfs|
|5/21/19||16.80 feet||20||168||N/A||161,000 cfs|
|5/22/19||16.80 feet||0||168||N/A||161,000 cfs|
|5/23/19||16.80 feet||0||168||N/A||158,000 cfs|
|5/24/19||16.70 feet||0||168||N/A||155,000 cfs|
|5/25/19||16.70 feet||0||168||N/A||155,000 cfs|
|5/26/19||16.60 feet||0||168||N/A||152,000 cfs|
|5/27/19||16.60 feet||0||168||N/A||157,000 cfs|
|5/28/19||16.60 feet||0||168||N/A||157,000 cfs|
|5/29/19||16.60 feet||0||168||N/A||149,000 cfs|
The stages below the Spillway will be artificially controlled by the flow diverted form the Mississippi River through the open flood control structure and into Lake Pontchartrain.
The MVN manages the opening and closing of bays on the flood control structure to ensure the maximum flow at New Orleans remains at/or below the trigger point flow of 1.25 million cubic feet per second (cfs) in accordance with the approved Bonnet Carré Spillway Water Control Manual. The river stages are expected to remain steady at approximately 16.7 feet with a predicted crest above the Spillway forecast from June 6 to June 18 (2019) based on anticipated rainfall.
The operation of the Spillway structures for flood control is expected to continue through mid- to late-June.