The federal appeals court in New Orleans on Nov. 25 dismissed class-action lawsuits for Hurricane Katrina-related damages against 32 major dredging contractors. Two groups of plaintiffs sued companies that worked under federal contracts in the Mississippi River Gulf Outlet (MRGO), claiming that work damaged protected wetlands and caused an amplification of the storm surge in the New Orleans region during the 2005 hurricane. The 5th U.S. Court of Appeal Circuit in Ackerson v. Bean Dredging LLC, upholding a federal district court’s ruling, applied the principal that public-works contractors duly carrying out projects authorized by Congress have immunity from lawsuits for
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.