It has traveled a long, bumpy path, but a controversial proposal to build a major bridge between Minnesota and Wisconsin has moved a giant step closer to a groundbreaking. Congress has cleared a bill exempting the estimated $626.4-million St. Croix River bridge from the requirements of the Wild and Scenic Rivers Act. The 1968 statute bars federally funded projects that would harm such rivers' scenic qualities.
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.