Saturday, May 14, 2011

Mississippi River floodwaters to spread slowly southward after Morganza Floodway opens

The Army Corps of Engineers will begin opening the Morganza Floodway above Baton Rouge on Saturday to allow Mississippi River floodwaters to flow into the Atchafalaya River basin, which will reduce the flow of water — and threat of flooding — along levees in New Orleans and other downstream cities.
The Friday afternoon announcement of the second-ever opening of the emergency floodway came in a three-sentence news release:


“The President of the Mississippi River Commission Maj. Gen. Michael J. Walsh has directed the New Orleans District Commander Col. Ed Fleming to be prepared to operate the Morganza Floodway within 24 hours. The operation will include the deliberate and slow opening of the structure.”

The water will spread slowly south, according to an accompanying map, reaching Melville in six hours, Krotz Springs in 12 hours and Morgan City in three days. At eight days, the floodwaters will have flowed east around Houma toward the eastern side of Timbalier Bay.

In a separate news release, corps officials said they expect to flow less water through the floodway, based on new estimates of floodwaters moving downstream. Instead of putting 300,000 cubic feet per second into the Atchafalaya Basin, as little as 125,000 cubic feet per second might need to be diverted.

That could be good news for some with property in the floodway, although hundreds are still expected to evacuate because of the water threat. The new map indicates water will not flow all the way northwest to Palmetto in St. Landry Parish, and there will be less water in areas near Melville, Krotz Springs and Butte La Rose. But much of the change would occur in sparsely populated areas that would see 10 to 16 feet of water instead of 16 to 20 feet.

In a Friday morning news conference, Gov. Bobby Jindal announced that he has instructed parish governments to begin notifying residents within the areas expected to be flooded in the Atchafalaya River basin to begin evacuations.
“Now is the time to take action. Don’t delay. Don’t hope something will change,” Jindal said.

“They’re not going to open it all at once,” Jindal said during a second news conference in Baton Rouge moments after the corps announcement. “It will be based on the modeling data, the most recent data.

“As of this morning they were telling us 15-30 cubic feet per second is what they expect to start with,” he said Friday. “They expect to start with 2-4 bays out of 125 bays. So it is going to be a gradual opening.

“You’re not going to see a foot of water immediately, there’s not going to be wall of water, but it is going to steadily increase,” he said. “And they’re going to gradually add more capacity.”

Staying under 17 feet in N.O.

The Lower Mississippi River Forecast Center, part of the National Weather Service’s Slidell office, indicated that the Mississippi River’s flow at Red River Landing, across from the Louisiana State Prison at Angola, first reached the corps trigger level of 1.5 million cubic feet per second on Friday at 7 p.m.

Opening Morganza will allow the flow to be kept at 1.5 million cubic feet or less to the south, while the Bonnet Carre Spillway, stretching between Norco and Montz, funnels 250,000 cubic feet per second into Lake Pontchartrain. That should allow the river to rise no higher than 17 feet at the Carrollton Gage in New Orleans.

Without opening Morganza, the river was likely to crest at 19.5 feet in New Orleans, according to the forecast center, only a half-foot below the tops of levees and floodwalls in the city.

If the corps’ prediction of lower flow is incorrect, enough of Morganza’s 125 bays might have to be opened to allow the flow of 300,000 cubic feet per second into the Atchafalaya, which the forecast center says would result in a crest at Morgan City of between 12 and 13 feet, which is 1 1/2 to 2 1/2 feet above the record set in 1973.

North shore sends supplies

St. Tammany Parish on Friday sent equipment and personnel to St. Mary Parish and the Morgan City area to help prepare for the flooding.

A caravan of equipment and personnel from the parish’s Department of Public Works left Friday morning from Covington, according to a news release from parish government. The caravan included sand trucks, front end loaders and sandbagging equipment.

“This is a situation where we all need to work together,” St. Tammany Parish President Kevin Davis said. “Our neighbors in the St. Mary Parish area could be facing some serious flooding, and we want to provide as much help as possible to keep homes and businesses safe. We all have experienced loss in recent years, and whatever we can do to work together and share resources should be done.”

State officials have been preparing for the expected flooding all week.

“We’ve already notified the American Red Cross about making shelter spaces available” for evacuees, Jindal said. Red Cross officials have 22 shelters with 4,758 cots available for evacuees, and local emergency officials have told the state that the expected need is for 3,850 evacuees.

If more space is needed, Jindal said, the state has the ability to open shelters for tens of thousands quickly.

Jindal also has asked the federal Commerce Department to declare a commercial fisheries failure in the state because of the expected disruption from freshwater to oysters, shrimp and crab catches. If approved, individual fishers and commercial and recreational fishing businesses would be eligible for federal financial assistance.

Meanwhile, the Louisiana National Guard is planning for search and rescue operations with Wildlife and Fisheries, State Police, and other agency partners, if they are needed after the floodway is opened.

National Guard and Transportation crews were deployed to help parish and levee board officials build a variety of temporary dams and levees and strengthen existing levees.

Energy firms get ready

Businesses with facilities within the floodway also are gearing up for high water. A number of the 150 oil and gas companies that could be affected are marking well sites and removing loose equipment, said Matt Ross, a spokesman for the Louisiana Oil and Gas Association.

“Companies are probably going to have to shut in some wells in order to make those safety adjustments for any massive flooding incidents,” Ross said. The industry group estimates that more than 2,200 wells, producing 10 percent of the state’s onshore oil production, about 19,000 barrels of crude a day, could be affected.

The state expects to close more than three dozen road segments and bridges affected by floodwaters in eight parishes. No parts of the interstate system were on that list.

Information on road closures is available on the Web from the state Department of Transportation and Development at www.511la.org.

Emergency updates also are available from the Governor’s Office of Homeland Security and Emergency Preparedness at emergency.louisiana.gov, on Twitter at @GOHSEP and on Facebook at http://www.facebook.com/gohsep.

Local vigilance

In the New Orleans area, the decision to open the northern floodway was greeted with cautious relief, as levee officials kept track of a variety of seepage issues.

“Patrols are taking place around the clock, and if any increased risk is identified, the public will be promptly notified,” St. Bernard Parish President Craig Taffaro Jr. said.

East bank residents in New Orleans and Jefferson and St. Bernard parishes can report concerns about levees 24 hours a day to the Southeast Louisiana Flood Protection Authority — East by calling 283.9800. West Bank residents in New Orleans and Jefferson Parish can call the Southeast Louisiana Flood Protection Authority — West at 340.0318.

The Morganza opening should allow the Coast Guard to avoid shutting down deep-draft shipping from Baton Rouge to Boothville, as it threatened to do if the river reached 18 to 19 feet. A number of restrictions on shipping, including requirements that some vessels be accompanied by tugs, remain in effect.

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