Civil engineering and infrastructure repair in New Orleans after Hurricane Katrina
Though Hurricane Katrina did not deal the city of New Orleans a direct hit on August 29, 2005, the associated storm surge precipitated catastrophic failures of the levees and flood walls.
Hurricane Rita brushed the city nearly a month later, causing reflooding of some areas, most significantly from water flowing through incompletely repaired levee breaches.
Congress removed responsibility from the state and mandated that the US Army Corps of Engineers have sole authority over the design and construction of the New Orleans area flood protection, although local cooperation was stipulated.
[4][5][6] In 2001, the Houston Chronicle published a story which predicted that a severe hurricane striking New Orleans, "would strand 250,000 people or more, and probably kill one of 10 left behind as the city drowned under 20 feet (6.1 m) of water.
Furthermore, the region's natural defenses, the surrounding marshland and the barrier islands, have been dwindling in recent years due to human interference.
[10] On Saturday, August 27, while Katrina was a Category 3 storm gathering strength in the Gulf of Mexico, the Army Corps of Engineers Mississippi Valley Division was preparing and posturing elements from as far as Hawaii.
[11] On August 29, 2005, as Katrina made its second and third landfalls on the Louisiana-Mississippi coast, Corps District Commander, Col. Richard Wagenaar, and a team worked out of an emergency operations shelter in New Orleans.
[12] Corps' engineers initially believed that water in the 17th Street Canal overtopped the floodwall, scoured behind the wall, and caused it to collapse.
The Corps began operating on an initial hypothesis that the force of the water overtopped the floodwall and scoured the structure from behind and then moved the levee wall horizontally about 20 feet (6.1 m).
The 3,000 pound sandbag operation at the 17th Street Canal was postponed early in the day when U.S. Army Chinook helicopters were diverted for rescue missions.
The Industrial Canal Lock needed repair, and its lockmaster raised the St. Claude Avenue bridge, but lowered it because of hostility from civilians wanting to cross on both sides.
Sewer & water board, electric utility and the 249th Engineer Battalion (Prime Power) were completing pump house inspection.
It was decided to use sheet pile closure to stop water flow at the London Avenue breach, similar to what was done at 17th Street Canal.
Pump station 8, located in St. Bernard Parish in the vicinity of St. Mary, was running at full capacity at 837 cubic feet per second (24 m³/s).
[20] However, officials were wary of operating the pumps at full capacity because of the possibility of damaging newly repaired levees and of losing corpses.
Texas Army National Guard Chinook and Blackhawk helicopter crews had placed an average of 600 7,000-pound sandbags each day into the breaches.
Operations at Pump Station 3 were immediately stopped and a few sheet piles were removed to allow the canal water level to equalize.
Contractors maintained cranes at the sites to regulate flow levels by adjusting sheet pile walls at the mouths of the canals into Lake Pontchartrain.
[24] The U.S. Army Corps of Engineers performed a detailed assessment of about 350 miles (560 km) of hurricane levee and developed a comprehensive, prioritized plan to repair it and the pumping stations that support New Orleans and surrounding areas.
"The system in its present condition does not ensure that the city will be protected from flooding resulting from storms or hurricanes," stressed Col. Duane Gapinski, Task Force Unwatering commander.
Gapinski said that residents could be placing their lives and property at risk by re-entering flooded areas until additional emergency levee repairs are made.
Second, to provide an interim level of protection to get the city through hurricane season and later high water, and over the long-term, to return the system to pre-hurricane conditions.
Additional traffic in the city in the past three days had caused some delay in traveling to work sites and moving emergency repair equipment.
[25] By September 21, 2005, the Army Corps of Engineers had begun closing two damaged canals at noon in preparation for storm surges associated with Hurricane Rita.
By September 23, 2005, although high water caused by Hurricane Rita flowed over the temporary closure on the Industrial Harbor Navigation canal, the structure remained intact.
By January 2006, the Army Corps of Engineers announced that temporary repairs of the Industrial, London Avenue, and 17th Street Canals had been finished.
In January 2007, the Army Corps of Engineers, after having visited the extensive "Delta Works" levee system in the Netherlands, awarded a $150 million contract to a group of Dutch engineering companies for the evaluation, design and construction management of levees and floodwalls, special closure structures for protection of the communities adjacent to the Inner Harbor Navigation Canal, major pumping facilities and planning studies for improved levels of flood protection for New Orleans and southern Louisiana.
[29] On Monday, September 5, 2005, electrical power began to be restored to buildings in the central business district of New Orleans on a priority basis.
Officials awarded a $30.9 million contract to repair the, "twin spans" I-10 bridge to New Orleans to Boh Brothers Construction Co. on September 12, 2005.
On Tuesday, September 13, 2005, the Mississippi River upstream of Head of Passes was declared open by the United States Coast Guard.
