Related Links: U.S. Court of Appeals for D.C. Circuit Aug. 21 ruling In a long-awaited decision, a divided three-judge panel of the U.S. Court of Appeals for the D.C. Circuit has struck down an Environmental Protection Agency rule that aimed to cut powerplants' emissions or air pollutants that move across state lines. The cross-state air pollution regulation (CSAPR) would have required 28 states in the East, Midwest and South to reduce emissions of sulfur dioxide and nitrogen oxide that cross state lines and cause air-quality problems in downwind states. EPA finalized the rule in July 2011, but the court blocked
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.