The San Francisco Public Utility Commission’s $4.6-billion regional water-system improvement program is racing against the clock as the construction team retrofits facilities to withstand a potential earthquake that, according to the U.S. Geological Survey, could come at any time. Set for completion by December 2015, the Water System Improvement Program (WSIP) is a mammoth undertaking, consisting of 86 separate water-supply and storage projects spanning counties in northern and central California. Construction is well under way on some of the projects; others won’t break ground until 2011. Julie Labonte, the commission’s WSIP program director, says that while some of the projects
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.