Bonnet Carré Spillway is opening Friday, Army Corps decides. Here are details.
On top of the novel coronavirus, South Mississippi has a familiar enemy to deal with: the U.S. Army Corps of Engineers expects to open the Bonnet Carré Spillway as early as Friday, Joe Spraggins says.
Spraggins who heads the Mississippi Department of Marine Resources, said he received a call about the opening from the office of Gen. R. Mark Toy. As commander of the Corps’ Mississippi Valley Division and president of the Mississippi River Commission, Toy decides, in consultation with the Corps’ New Orleans district engineer, whether to open the Bonnet Carré.
Spraggins said Toy’s office advised him that 150 to 160 of the spillway’s 350 bays will be opened for three to four weeks.
The trigger point for opening the spillway, established under the 1928 Flood Control Act, is a flow rate of 1.25 million cubic feet per second at the Carrollton gage on the river at New Orleans. Flood stage is 17 feet.
The river is expected to reach a flow rate of 1.35 million cubic feet per second and crest at 17.3 feet on the levees by April 12, the Army Corps says forecasts now indicate. Opening the spillway will allow the swollen river to safely pass New Orleans.
This would be a record-setting third year in a row for the spillway to open. The longest opening in spillway history, in 2019, decimated oyster beds off the Mississippi Coast and is blamed for the deaths of dolphins, sea turtles and other aquatic life.
The 123-day opening poured trillions of gallons of Mississippi River water into Lake Pontchartrain and the Mississippi Sound beyond, dropping salinity levels below the norm.
The prolonged opening over the summer months also allowed blue-green algae to flourish, closing the Mississippi Sound to swimming during the tourist season.
Federal fisheries disasters were declared in Mississippi, Alabama and Louisiana.
Spraggins said he hopes the Bonnet Carré will open for a much shorter time this year. He said damage would not be as bad if the spillway could be closed by the end of April.
If the spillway remains open as the Mississippi Sound grows warmer, he expects problems in South Mississippi.
“We can live through a lot but we can’t live through 120 days,” he said. “If it runs past April, we’ll definitely have a lot of issues.”
Because of COVID-19, the Army Corps is foregoing the usual in-person meeting of stakeholders prior to a spillway opening and instead will schedule an online call-in for Thursday.
“The Mississippi River Levee system protects millions of lives downstream, many of which are currently threatened by the COVID-19 pandemic as the greater New Orleans area struggles against one of fastest growing COVID-19 infection rates in the nation,” an email from the Corps’ New Orleans District says.
“The system safely transported far more water last year than during any previous historic flood on the river (1927, 1937, 1973, or 2011) and will do so again, especially when so much else is at stake. We are committed to work proactively alongside our local levee district partners to ensure its continued success.
This story was originally published March 31, 2020 at 3:52 PM.
