A flood warning was issued Monday morning for the segment of the Mississippi River passing through New Orleans, as the river is forecast to reach 17 feet, its official flood stage, on Saturday (March 9), according to the National Weather Service. The warning will be in effect until March 23.
On Monday, the river was at 16.5 feet at the Carrollton Gage, which is adjacent to the Army Corps of Engineers New Orleans District office on Leake Avenue in the Riverbend area.
Floodwalls officially protect the city of New Orleans to a water level of 20 feet.
At 17 feet, the river level will continue to make navigation and docking difficult. On Feb. 27, an oil tanker’s lighting mast hit the Huey P. Long Bridge, closing it to traffic for three hours while engineers determined no significant damage had occurred.
The corps began opening bays in the Bonnet Carre Spillway on Feb. 27 to funnel part of the Mississippi’s flow into Lake Pontchartrain, in an effort to keep the flow of water to below 1.25 million cubic feet per second, which is equivalent to the 17-foot flood level. On Monday, 108 of the structure’s 350 bays were open, with at least 40 more bays scheduled for opening during the day.
It’s the 13th time the spillway has been opened since it was built after the 1927 Mississippi River flood, and the third time in the last four years.
“We will continue to open bays at Bonnet Carre to match the river as it crests,” said Matthew Roe, a corps spokesman. “The 28-day forecast shows the river remaining high throughout, so Bonnet Carre will be in operation through the rest of March.”
However, while officials initially thought as many as 200 bays would have to be opened, the present forecast indicates that only 170 bays will be opened, he said.
Roe said the forecast of the river rise still has not hit the trigger points necessary to operate the Morganza Floodway upriver of Baton Rouge, which would funnel part of the Mississippi’s flow into the Atchafalaya River Basin.
River levels in the New Orleans area have been high enough to trigger corps and local levee district “flood fight” requirements, including increased inspections and restrictions on and near levees, since November. Those restrictions have been backed up by an executive order from Gov. John Bel Edwards that also prohibit activities on or near levees, unless special permits are provided by local levee districts.
As of Monday, inspectors had identified 164 locations along the river that require monitoring, including four that it listed as medium priority.
There were 68 locations with seepage, including 22 in the New Orleans area. Officials say they are not allowed to release the exact locations of issue areas because of security concerns.
Flood warnings remain in effect for segments of the river between Baton Rouge and New Orleans.
At Baton Rouge, the river was at 42.4 feet on Monday, and “major” flooding was occurring. The official flood stage in Baton Rouge is 35 feet, and the river will rise to near 43.5 feet by Sunday, and not drop below flood stage until March 28.
At 43 feet, shipping and industrial activities along the river are significantly affected, according to the weather service warning. Unprotected low-lying areas along the river will be flooded and agricultural operations will be impacted on the west bank. The City of Baton Rouge remains protected by levees at the predicted high water level.
The present water level already has meant that older segments of the Louisiana State University campus have been seeing soggy soil conditions, including the area around the Veterinary Medicine building and annex, the football stadium and ball fields.
At Donaldsonville, the river was at 30.9 feet on Monday, with flood stage at 27 feet. The river is expected to reach 33 feet by March 17, and not fall below flood stage until March 31.
At 33 feet, river barge traffic becomes dangerous, especially while navigating sharp turns on this stretch of the river, the Donaldsonville warning said.
At Reserve, the river was at 23.2 feet, just above the flood stage of 22 feet. The river is expected to rise to near 23.5 feet by March 13, and fall below flood stage on March 25.
At 22 feet, marine and industrial interests along the river and upstream barge operators are impacted, according to the warning.