Crews relieving pressure on dam
Workers were creating a small breach in a dam near McComb, Miss., in hopes of lessening pressure that could cause it to fail and flood homes along the Tangipahoa River in Louisiana, Gov. Bobby Jindal said Thursday.
The breach in the dam, in Percy Quin State Park, would release enough water to lower the level of Lake Tangipahoa by 8 feet, the governor said.
Rough modeling indicates the release from the breach would not cause a significant rise of water levels in the river.
Both the lake and river were swollen by rainfall dumped by Hurricane Isaac.
“There is a lot of water in there,” Jindal said of the lake restrained by the dam.
Jindal said Mississippi officials won’t know whether their plan will be effective until they do more work.
The governor, who flew over the dam with other officials, said there appears to be heavy stress on two areas of the dam, but contrary to some reports, it had not breached as of Thursday evening.
If the effort is not successful and there is a complete failure of the dam, water would move down the river quickly, Tangipahoa President Gordon Burgess said.
It would take about 90 minutes for the water to get from the dam to the Louisiana line and would raise water levels to those of the large flood that occurred on the Tangipahoa in 1983. The flooding would likely be severe along the river, which snakes south through the parish east of Interstate 55, said Jeff McKneely, spokesman for the parish.
He said the towns bordering the river, from Osyka, Miss., to Kentwood, Fluker and Roseland all could be affected.
In Tangipahoa Parish, 40,000 to 60,000 people living on either side of the river would face flooding conditions if the dam fails, Jindal said earlier Thursday.
Burgess issued a mandatory evacuation order for those living along the river.
Throughout the afternoon, 314 Louisiana National Guard troops were moved to the area along with 19 boats, 15 ambulances and numerous buses to help with evacuations.
“I strongly advise people to take the parish president’s mandatory evacuation order seriously,” Jindal said.
However, some residents said they plan to stay home.
Christian Wright said she and her family are going to stay home, which is close to the river just south of Tickfaw.
“We have four-wheelers and dirt bikes” to use to escape if the water starts to rise, she said.
Tangipahoa Parish Sheriff Daniel Edwards said that while some people haven’t left their homes, most were in the process of doing so.
He urged everyone in the evacuation zone to get out before dark, when evacuation will become more difficult.
If the dam breaks, the parish could experience its most serious flooding in 22 years. The last time the dam broke in the 1980s, it caused the La. 16 bridge to wash away, McKneely said.
Jindal said the river could rise to 17 feet.
The crisis was threatening two nursing homes and prompting the dispatch of 200 buses to the Ponchatoula area, the governor said.
State Police Col. Mike Edmonson said State Police, the Guardsmen and state Department of Wildlife and Fisheries agents were being posted at the nine state highways that cross the river in Tangipahoa Parish.
“It’s speculation, but we have to at least prepare for it,” Edmonson said of the threat of flooding.
Burgess said southern Tangipahoa Parish already had some storm-surge flooding from Lake Pontchartrain. That flooding affected the Manchac area, where water from the lake topped the railroad line.
Shelters have been established at Hammond West Side Elementary Montessori School, Hammond Junior High Magnet School, Natalbany Elementary School, Nesom Middle School, Amite High School and Kentwood High Magnet School.
McKneely said that the Hammond West Side Elementary and Kentwood High shelters had reached capacity by 7 p.m. Thursday.