The U.S. Army Corps of Engineers recently awarded a $614.8 million project to build three permanent canal closure and pump stations in New Orleans. They will replace temporary structures built in 2006 at the mouths of three drainage canals connecting to Lake Pontchartrain.
The stations are designed to block surges from the lake caused by a "100-year storm," a strong hurricane that has a 1% chance of occurring in any year.
In 2005, Hurricane Katrina brought a 28-foot storm surge to the area and caused 50 different levee and floodwall failures in the New Orleans area, submerging 80% of the city.
Floodwalls have since been repaired and improved. Corps spokesperson Ricky Boyett says temporary pump stations and gates were installed in 2006 to protect the vulnerable city from the following hurricane season.
The permanent stations will be built at 17th Street Canal, Orleans Avenue Canal and London Avenue Canal. Gates are designed to be lowered to protect from surges while pumps can push drainage waters from the canals into the lake. At the 17th Street Canal, pumps will be able to handle 12,500 cubic feet per second.
"New Orleans is essentially a big bowl and the gates not only need to keep out the surge, the pumps need to pump rainwater from the streets to the canals to the lake," says Boyett.
The stations are also being designed to factor in the lake's water level during the next 50 years from sea level rise by local subsidence and global warming. Pumps are also being positioned so that they can later be lowered should city officials decided to deepen the canals in the future.
The project has been awarded to PCCP Constructors, a joint venture comprised of Kiewit Louisiana Co., Traylor Bros. Inc. and the M.R. Pittman Group LLC.
The structures are parts of the final improvements to the post-Katrina New Orleans levee system. Boyett says the project should take 44 months to complete.