A dam on the Green River in western Washington state remains one of the nation’s most unsafe, despite $15 million of work that has been completed over the past year. But the Army Corps of Engineers told local officials on March 18 that an additional $44 million in upgrades is needed to lower the structure’s failure risk to acceptable levels. Photo: Seattle District, U.S. Army Corps of Engineers Leaks in the Hanson dam landed it on the Corps’ danger list. The Corp says it needs a $44-million repair. “We can manage the risk at the dam, but doing so puts
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.