The U.S. Army Corps of Engineers, which periodically inspects California’s Central Valley flood-protection network, released a report card on 10 of the state’s 26 levee systems, rating seven as “unacceptable” and warning some problems would “likely prevent performance in the next flood event.” Issues cited included encroachment, underseepage, vegetation and slope stability. The other three won “marginally acceptable” ratings; they retain eligibility for “active” status in a federal “rehabilitation and inspection” levee safety program and may receive federal aid to repair flood damage. The Corps is using $4.6 million in American Recovery and Investment Act funds to contract with GHT2—a
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.