One bay had closed Tuesday evening and two more bays were closed Wednesday. As of Wednesday afternoon, the structure had 14 bays open with a discharge rate of 140,000 cubic feet per second.
Since opening the Morganza Floodway on May 14, discharge into Morganza Floodway has been reported daily.
The Corps computed the discharge, in cubic feet per second, through the structure.
Beginning on May 18, discharge measurements were taken on site by the Corps of Engineers' federal partners at U.S. Geological Survey to validate the computed measurements.
A significant difference in the computed and measured discharge rates was discovered. After a review of this difference, it was determined that the computed flow understated the discharge from the Morganza Floodway.
Ken Holder, chief of the public affairs office, said the partnership with the USGS gave the Corps better measurement tools.
In addition, water levels continue to be lower than anticipated throughout the Atchafalaya Basin.
Working closely with the USGS, the Corps of Engineers has determined the Morganza Floodway was discharging at a rate of 172,000 cubic feet per second, with 17 bays open, instead of the reported 114,000 cubic feet per second.
Both measurements were below initial estimates of 300,000 cubic feet per second.
This discharge of 172,000 cubic feet per second is well within the water control plan for the structure, which is designed for a 600,000 cubic feet per second capacity.
The discharge measurement has no effect on gate operations at the Morganza Floodway.
The inundation maps were initially developed to reflect 50 percent operation of the Morganza Floodway and based upon a discharge rate of 300,000 cubic feet per second.
Modified inundation maps reflect a Morganza Floodway discharge rate of 150,000 cubic feet per second, with 25 percent operation of the structure.
Operation of the structure is based on flow rates in the Mississippi River at Red River Landing and water stages at the Morganza Floodway structure itself.
The Corps will continue to assess conditions for the Mississippi River and operate the Morganza Floodway and Bonnet Carre Spillway in the interest of public safety.
The Corps will continue to assess water levels and conditions in the Atchafalaya Basin.