Firefighters pump water out of lake Tangipahoa at Percy Quin State Park outside of McComb, Miss., on Thursday in an effort to relieve pressure on the dam, which the faced threat of flooding after being inundated with rains from Tropical Storm Isaac. (Associated Press)
Last Modified: Friday, August 31, 2012 8:24 PM
AMITE (AP) — Residents in low-lying areas flanking the engorged Tangipahoa River are reliving a decades-old nightmare after the state ordered mandatory evacuations Thursday because a lake swollen with rain from the remnants of Hurricane Isaac threatened to break through a dam inside a southwest Mississippi park.
The 2,300-foot-long earthen dam — a levee on which a two-lane roadway runs — has not been breached. The plan is to shave away one end for a controlled release of water from Lake Tangipahoa while repairing two 70-foot-wide areas where mud and grass slid off after two days of Isaac's hammering rain, said Ramie Ford, director of Mississippi state parks.
Crews also began pumping water Thursday. The aim is to slowly let about 8 feet of water out of a lake that is 3 to 4 feet higher than normal, reducing stress on the levee.
"The water flow will be controlled by us and not Mother Nature. So no one should be in harm's way," Ford said.
The bank also was being cleared for earthmoving equipment, Ford said. He said the "slides" were on the south side of the levee, which runs along the lake's south end.
Greg Flynn, a spokesman for the Mississippi Emergency Management Agency, said he doesn't know how long the process will take.
Richard Ingram, director of the office of land and water resources for the Mississippi Department of Environmental Quality, said the plan was to dig out part of the bank near the edges of the dam to let water into the spillway.
Preliminary models indicated that a successful controlled release would not significantly affect water levels in the Bayou State, Louisiana Gov. Bobby Jindal said. Even so, he and Parish President Gordon Burgess strongly encouraged Louisiana residents near the structure to heed warnings to evacuate. They ordered the immediate evacuation of Kentwood, a town of about 2,200, after flying over Tangipahoa Parish.
Burgess earlier had asked residents in mostly rural areas along the river, from Kentwood south to Robert, to voluntarily leave because of uncertainties about the dam. The evacuation order did not include the parish's major city, Hammond, which has about 20,000 people and is home to Southeastern Louisiana University.
It will be a few days before evacuees can return, Jindal said. If the dam broke, he said, it could cause a 17-foot crest on the river that would threaten 40,000 to 60,000 people in the parish with flooding. Water levels would be like those in the record flood of 1983, which was caused by a disruption in the floodplain from bridge construction on Interstate 12 and flooded hundreds of homes in and around Robert.
"This would be a significant, significant flooding event for Tangipahoa Parish," Jindal said.
Iris Renee Brown was on the verge of tears as she waited for information at a small cafe in Robert. She lost her home when the town flooded in 1983 and her yard was already covered in a foot of water when she left Thursday.
Brown said she barely had time to pack some clothing before gathering up her family and heading north. "It was devastating in '83. You rebuild, you know?" she said. "Give us a break."
Jindal said data from preliminary inundation maps indicate at least a half-mile area on either side of the Tangipahoa River could flood if the dam fails. Parish officials said a flyover of the area indicated a much larger area would be affected than they initially anticipated.
In Mississippi, fire trucks from around Pike County began pumping lake water into the spillway. The Army Corps of Engineers sent four pumps that each can move 3,500 gallons of water a minute, said Kavanaugh Brazeale, spokesman for the corps in Vicksburg, Miss.
The Mississippi Army National Guard was sending two bulldozers, two backhoes and six sets of lights so work can continue at night, spokesman Tim Powell said. He said it also sent a 38-person evacuation notification team to go to homes and warn residents of potential evacuation.
Louisiana State Troopers and National Guard troops were heading to the state line to be ready if the situation changes.
The park is in an agricultural area. Flynn said any water pouring through would affect no more than 12 homes in Pike County.