Drastic improvements to East Bank levee make for safer hurricane season
Jonathan Menard - Jul 19, 2012
While hurricane season is always a cause for concern for Louisiana residents, those living on the East Bank of St. Charles Parish have been able to breathe a sigh of relief now that they are under protection from a 100-year storm event.
Recent levee work on the East Bank of St. Charles Parish consisted of 13 contracts, including the enlargement of nine miles of levees, constructing new concrete floodwalls, building a railroad gate and replacing four drainage structures. All structural features in the area were built to an elevation of 16.5-feet above sea level. The total construction cost for projects on the East Bank of St. Charles Parish was approximately $100 million, according to the Army Corps of Engineers.
"With all the improvements completed through a team effort of the Pontchartrain Levee District, Corps of Engineers and St. Charles Parish, we feel as if the area is 60 to 65 percent improved compared to the situation previous to Hurricane Katrina," parish spokeswoman Renee Simpson said. "With the levee now at approximately 16.5 feet, Cross Bayou pump station online and improvements at multiple control structures, we’re looking at better height, strength and pumping capacity; all factors critical to efficient levee function in south Louisiana."
The project now includes 8.5 miles of levee located north of Airline Highway that runs from the Bonnet Carré Spillway eastward to the foot of the east-west runway of the Louis Armstrong International Airport.
There are five drainage structures located at waterways that intersect the levee and floodwalls have been built to accommodate three pipeline crossings. One floodwall was also built underneath I-310 where the bridge supports did not allow for the construction of an earthen levee. A substantial floodgate was also built across the Canadian National Railroad at the end of the east-west runway.
The parish didn’t have to pay for any of the upgrades. Instead the Pontchartrain Levee District used credits to complete their portion of the project. Upgrades to every floodwall were also fully funded by the federal government.
The nearly $19 million pump station at Cross Bayou near Airline Drive in Destrehan has been one of the most important upgrades for the parish. The pump station, which is located on the East Bank Hurricane Protection Levee, is designed to pump 1,350 cubic feet of water per second.
"The first real test of the station came during Tropical Storm Lee in September when two of the eight pumps at the station were put to use," Simpson said. "The area received up to 16 inches of rain over four days, in sometimes extremely heavy downpours. Airline Highway stayed dry."
Simpson said that represents a huge difference in drainage efficiency since water will no longer be able to stack up in that area and prevent the drainage of other parts of the Ormond/Destrehan area.
The pump station is a joint venture between the levee district and the state Department of Transportation. Motiva and Shell also contributed a combined $5 million to the project.
A second pumping station, the Trepagnier pump station at the Spillway East Bank Guide Levee, is designed to pump 800 cubic feet of water per second. It features three diesel 60-inch pumps and one 30-inch electric pump.
"In 2011, parish crews cleared an area of vegetation about the size of a city block due to the effectiveness of the automatic bar screen cleaner at the intake," Simpson said. "They also removed a portion of a berm in the same area to help water more easily flow to the station down Engineer’s Canal."
The construction of the pump station, which went online in 2004, was funded in part by Motiva and Shell. Both pump stations can also be controlled and monitored remotely via telemetry 24 hours a day, seven days a week.
While the East Bank levee has reached 100-year storm protection status, Simpson said there are still areas that are in need of improved pumping capacity, especially on the eastern end of the levee toward St. Rose.
"While the levee has been completely raised to 100-year protection, there is always ongoing maintenance and planning for future projects, including additional pump stations," Simpson said.
A 100-year level of protection actually means reducing risk from a storm surge that has a 1 percent chance of being equaled or exceeded in any given year.
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