The Army Corps of Engineers needs to armor all levees in the area as soon as possible, update models used to establish storm threats to the region -- and rein in top officials who are issuing assurances the region will be safe by June 1, engineers monitoring reconstruction of New Orleans' hurricane protection systems said Monday.
In a progress report, the External Review Panel of the American Society of Civil Engineers said the corps' ongoing examination of the massive failure has been generally satisfactory. But it offered a number of recommendations that chairman David Daniel of the University of Texas called "urgently important."
The most immediate concern is to address the threat to levees posed when water overtops them, triggering rapid erosion and possible collapse.
The corps has determined that much of the flooding from Katrina was caused when overtopping led to the disintegration of large sections of levees, most notably along the Mississippi River-Gulf Outlet. Overtopping also caused failures of the Industrial Canal floodwall by scouring the inland side of the levee supporting that structure, the corps said. Other failures, notably along the London Avenue and 17th Street canals, appear to have occurred even without overtopping.