Judge Stanwood R. Duval Jr. of the US Eastern District of Louisiana ruled again Friday that the US Army Corps of Engineers cannot claim immunity from suit in connection with damages suffered by plaintiffs by virtue of alleged defects in the Mississippi River-Gulf Outlet (MRGO). Duval said that the outlet was a shipping channel and not a flood control outlet in connection with which the Corps would have been properly immune in tort. He rejected the Corps' argument that the MRGO was nonetheless part of a larger flood control system in the New Orleans area.

Duval made a similar ruling in February 2007 in the context of an earlier motion to dismiss. Three months before Hurricane Katrina struck New Orleans, an expert at the LSU Hurricane Center predicted that the MRGO could amplify storm surges by 20-40 percent. After Katrina, the center determined through computer modeling that the presence of the MRGO also increased the speed of the surge, causing an even greater detrimental effect.