The report, which was commissioned by the Louisiana Department of Transportation and Development and conducted by a group of engineers and storm researchers called Team Louisiana, now has the Corps defending itself.
The report says that the Corps used obsolete research when designing flood-control structures including the levees that resulted in the structures being built too low. One of the major problems with the levees was that the original plans, which were done up in 1965, used elevation measurements from 1929. However, New Orleans had sunk enough that by the time the plans were drawn up, the levees in the plan were one to two feet too low. By the time of Hurricane Katrina, the levees were up to five feet too low. Additionally, the levees were not properly maintained after they were built, further weakening them.
According to Team Louisiana, the Corps did not use a storm surge model released in 1979 by the National Hurricane Center. The model would have shown the Corps that their levees would not withstand a level three hurricane, which is what Hurricane Katrina was. An engineer who was involved in writing the report noted that the Corps should have known ahead of time that two canals would fail when the water reached 10 feet. This could have been made obvious by a simple calculation and a soil strength analysis.
The researchers reported if the Corps had independent engineers review the plans before building the levees, the Corps would have known of most of the problems with the levees well before any disaster struck.
The Corps has responded by saying that they are not solely to blame for the levee failures. They argue that civil works projects are authorized by Congress and are carried out with cooperation from local, state, and federal agencies.
However, the Corps' credibility has been further weakened by the discovery that they installed defective flood-control pumps last year despite having warnings from an expert that the equipment would fail during a storm. The pumps were installed in order to meet a promise made by President Bush that New Orleans would be protected from storms by the start of the 2006 hurricane season. Problems with the pumps include excessive vibration, overheated engines, and blown gaskets.
Meanwhile the final version of the Interagency Performance Evaluation Task Force (IPET) report said that the flood-control system of levees and canals was a protection system in name only. The report said that the levees were not consistently designed and were planned based on outdated information.
IPET will release more reports, including a current flood-risk assessment for New Orleans that should show how repairs have changed the levee and canal system since Hurricane Katrina. Reported improvements include repairs to wall breaches in canals and new floodgates at the mouths of the canals.
In the meantime it is up to the Army Corps of Engineers to make temporary improvements to levees and flood walls that are too low to protect parts of the area from storm surges. The Corps has a number of options to consider; however they would only be temporary solutions until the Corps has finished raising levees and building permanent gates to protect New Orleans from more storms. Permanent repairs, designed to protect the city from a 100-year storm, that is a storm that has a one in one hundred chance of hitting the city each year, could take until 2011.