Much of the flooding that devastated New Orleans' Lower Ninth Ward and nearby St. Bernard Parish during 2005's Hurricane Katrina was the fault of the U.S. Army Corps of Engineers, a federal judge has ruled. In a harshly critical 156-page ruling, Judge Stanwood R. Duval Jr. found that the Corps' negligent maintenance of the Mississippi River Gulf Outlet (MRGO) navigational channel created hazardous conditions that allowed Hurricane Katrina's storm surge to penetrate two key Federal levees and flood the low-lying neighborhoods. The suit was brought by just a handful of Louisiana homeowners. But if it holds up on appeal, Judge Duval's decision could expose the U.S. Government to far more extensive legal claims, reports the New York Times (" Ruling on Katrina Flooding Favors Homeowners," by Campbell Robertson): "Though the judge granted six of the plaintiffs in this lawsuit a total of less than $750,000, tens of thousands of other property owners could now try to join class-action lawsuits against the government under the same legal reasoning." The New Orleans suit involves unusual circumstances. Ordinarily, Federal law insulates the Army Corps from any liability connected with flood control systems such as levees. And Judge Duval in 2008 upheld that immunity in an earlier case against the Corps that was based on claims of deficient levee construction. But the MRGO lawsuit, Judge Duval held, is based on negligent operation and maintenance of a shipping channel, not a levee, and he said that the Corps' immunity does not hold in that case. Just as the government would be held to account if a Navy vessel crashed into a levee and caused catastrophic flooding, so, the judge said, should the Corps be liable if one of its canal projects helped to destroy one of its own levees. And it was the Corps' "myopia" in managing the channel that damaged and destroyed the levees, reasoned the judge: "The failure to maintain the MRGO properly compromised the Reach 2 Levee and created a substantial risk of catastrophic loss of human life and private property due to this malfeasance." The Corps is virtually certain to appeal the verdict. Corps spokesman Ken Holder said in a statement, "Until such time as the litigation is completed, including the appellate process up to and through the U.S. Supreme Court, no activity is expected to be taken on any of these claims." And some legal experts expect Judge Duval's limitation of the Corps' immunity to be reversed. Predicted CBS legal analyst Andrew Cohen, "As we get higher up the appellate ladder, the judges are going to intervene and basically save the Army from having to pay this lawsuit and the potential for other lawsuits down the road." CBS News coverage is available in this YouTube video ("Fed's Role in Katrina Flooding," reported by Byron Pitts). The case against the Corps rests largely on the agency's failure to armor the channel's banks against erosion. Originally authorized as a 600-foot-wide and 32-foot-deep channel, MRGO had expanded to as wide as 1900 feet or more because of turbulent waves created by the wakes of passing ships. Continual dredging had also deepened the channel to 75 feet in places. Reports dating back decades showed that the Corps had recognized from the channel's earliest days that erosion was widening the channel and threatening the levees, but took no action, the judge's opinion says: "Thus as overwhelmingly demonstrated at trial, this subsequent erosion resulting in the width of the channel increasing by more than 3 times its authorized width was caused by the Corps’ failure to armor the banks of the MRGO to prevent (1) boat wakes causing erosion of the banks; 2) excavation and maintenance dredging causing bank slumping; and 3) saltwater intrusion killing vegetation and promoting organic decay." As protective banks at the toes of the levees wore away, soft clay under the levees was squeezed outward and the levees themselves sank by several feet per decade, requiring continual rebuilding. The wider canal allowed more "fetch" for the buildup of destructive waves during the hurricane, while the destruction of many square miles of wetlands along the canal and near its seaward mouth removed a critical barrier that would otherwise have slowed and reduced the oncoming hurricane storm surge. In these ways, the judge concluded, MRGO's unchecked sprawl directly caused levee failures and destructive flooding. Whether higher courts uphold Judge Duval's legal analysis or not, they are unlikely to re-examine his assessment of the facts and evidence in the case — an area where trial court judges typically have wide discretion. And whatever happens on appeal, one casualty in the case may be the Corps of Engineers' own battered credibility. Judge Duval took the Corps' expert witnesses to task in blunt terms, accusing some Corps personnel of, in essence, fudging their data to support their wished-for conclusions. The Corps' argument that the levees were overtopped by a high storm surge, rather than eroded from the front by wave action on the shipping channel, depended on some key assumptions about storm surge height and timing — assumptions that the Judge virtually accused the Corps of making up. "While the computer programs used by the Government to prove causation were substantially analogous to those used by plaintiffs, after hearing the testimony and having reviewed the expert reports presented, the Court finds that some of the Corps' models are critically compromised by the use of input data that has been overly 'scaled' to obtain the results," wrote Judge Duval. "The reason for such a finding is that many of the Corps' 'facts' or inputs are controverted by hard evidence presented in this case." Engineer Bruce Ebersole, Chief of the Flood and Storm Protection Division of the United States Corps of Engineers in Vicksburg and the leader of the Corps' analytical team for the lawsuit, came in for particular criticism. According to Judge Duval, Ebersole applied various multipliers to the measured storm surge wave heights in order to arrive at levels that could overtop the levees rather than eroding them from the front. Further, the judge complained, Ebersole became "obstreperous" in avoiding some detail questions. Calling the engineer's testimony "highly equivocal and less than candid," the judge concluded, "Simply put, the Court finds that some of these models were manipulated." Robert Bea, a University of California (Berkeley) engineering professor who testified as an expert witness for the plaintiffs in the case, says the case calls into question levee construction and safety generally, reports the Los Angeles Times (" Effects of judge's Katrina ruling could be huge," by Richard Fausset and Ralph Vartabedian). Bea told the Times, "The American public frequently believes they are protected by these piles of dirt that we call levees, when they are not. I hope this ruling would serve as a wake-up call." But even if it stands, the legal implications of this case are restricted to similar cases. In most cases where a levee is breached, the government's sovereign immunity will remain intact — and citizens who live in a flood plain behind a levee, whether the levee is adequate or deficient, do so at their own risk.