Bills dealing with air-pollution regulation have met different fates in the House and Senate. The Republican-controlled House on April 7 passed a bill to bar the Environmental Protection Agency from moving ahead with greenhouse-gas rules. But in the Senate, where Democrats have a majority, four air-pollution-related measures, including one identical to the House-passed bill, on April 6 failed to win the 60 votes needed to advance.
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.