Congress has approved a three-month extension of airport construction grants and other Federal Aviation Administration programs. The bill, which would authorize FAA programs through March 31, next goes to the White House for President Obama's expected signature. Final congressional action came on Dec. 18 when the Senate approved the measure by unanimous consent. The House had passed the bill on Dec. 2. The new stopgap is the 17th FAA extension since Sept. 30, 2007, when the last multi-year aviation authorization expired. The current extension�stopgap number 16�expires Dec. 31.
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.