The largest dam removal and river restoration project in U.S. history moved a step closer to reality last month as the U.S. Dept. of the Interior, Oregon, California, PacifiCorp and about 40 other groups signed agreements that will set into motion the $200-million removal of four dams on the Klamath River and the $1-billion restoration of the Klamath Basin. Photo: Pacificorp The 20-MW concrete dam Copco 1 has lost its efficiency since it was commissioned in 1918. + Image The dams, owned by PacifiCorp, a subsidiary of Warren Buffet’s Mid-American Energy Holdings Inc., Des Moines, Iowa, would continue to produce
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.