In a settlement with the U.S. Justice Dept. and other federal agencies, BP Exploration Alaska Inc. has agreed to pay a $25-million civil penalty for crude-oil spills in 2006, totaling more than 5,000 barrels, from its pipelines on Alaska's North Slope. Under the pact, announced May 3, BP also will put in place an estimated $60-million, pipeline-integrity program to include regular inspections. U.S. investigators found that two 2006 spills, totaling 5,078 barrels stemmed from BP's failure to inspect and maintain the pipeline well enough to prevent corrosion. The firm pleaded guilty in 2007 to a misdemeanor violation of the Clean
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.