Shale-gas drilling and its alleged impacts are very much in the news, particularly linked to water quality. Environmental activist groups claim that hydraulic fracturing, or fracking, poses a dangerous risk to drinking-water sources. But pre-existing conditions may be a bigger threat, one that simple home baseline tests may detect.The U.S. Environmental Protection Agency is undertaking a national study to understand the potential impacts of fracking on drinking water. Environmental best practices are necessary to responsibly manage resources and inspire public and regulatory confidence in the industry's ability to conduct safe and clean life-cycle operations in the shale-gas arena. KOHLHAASBaseline water
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.