During the dismantling of Gold Ray Dam, a 106-year-old timber cofferdam and 70-year-old concrete dam near Medford, Ore., the Rogue River blew through a sand spit, changed course and ran freely for the first time in more than a century. Photo: River Design Group Oregon’s Gold Ray Dam is razed two weeks ahead of schedule after an unexpected breach. Scott Wright, project manager for the Corvallis, Ore., office of design-build contractor River Design Group, says the entire process actually sped up the crew’s work by almost two weeks. Crews built two temporary sand-and-gravel cofferdams—one in the river and one in
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.