The Coast Guard, bracing as Mississippi River floodwaters spread south, was preparing Friday to restrict vessel traffic at the Port of New Orleans if the river rises another half-foot at the city, but operations at the port had not been affected.
Deep-water vessel traffic on some 240 miles of river between Baton Rouge and Boothville, La., near the river’s mouth, will be put into place when the river rises to 17.5 feet at the Carrollton Gauge in New Orleans, said Coast Guard Port Capt. Edwin Stanton.
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Those restrictions would include daylight-only travel, required tug assistance around the 90-degree bend at Algiers Point opposite the French Quarter, and a requirement that captains remain aboard their vessels. The Coast Guard may ban most deepwater traffic if the river reaches 18 feet on the gauge, Stanton said.
The river has been at about the 17-foot mark for several days. The gauge is a measure of water levels above the river’s normal banks and is not an indicator of the river’s depth. Vessels can transit the river’s mouth with fresh-water drafts of as much as 45 feet but excess silting could cause draft restrictions if dredges can’t keep pace.
Port officials said they hoped the Army Corps of Engineers’ efforts to shunt floodwater through two upriver spillways will keep river levels at New Orleans low enough to avoid triggering restrictions on navigation.
Mississippi River ports dominate U.S. grain exports, are an important conduit for steel and other commodities, and serve refineries that account for more than 10 percent of U.S. domestic capacity.
“We believe the Corps’ goal is to not let the Carrollton gauge reach 18 feet and we are confident they have the controls and the mechanisms in place to achieve that goal,” port CEO Gary P. LaGrange said in a statement.
The Corps has opened part of the Bonnet Carre spillway, which will divert 250,000 cubic feet of water per second into Lake Pontchartrain about 30 miles upriver from New Orleans. State and local officials are preparing for extensive flooding in Louisiana’s Atchafalaya River basin from the likely opening of a second spillway, the Morganza Floodway above Baton Rouge.
Without the Morganza Floodway opening, water levels at the New Orleans gauge could hit 19.5 feet around May 23, according to the Mississippi River Forecast Center. Such a level would threaten levees protecting the city.
This year’s Mississippi River floods provoked comparisons with the disastrous 1927 floods that led to federal efforts to control the river, and have already disrupted barge traffic farther upstream.
The Corps of Engineers said seven locks on the Ohio River, the Green River in Kentucky and the McClellan-Kerr Arkansas River system are closed due to flooding. In addition, the Coast guard imposed commercial navigation safety zones and restrictions on the lower Mississippi River and the Missouri River.