The U.S. Environmental Protection Agency is seeking comment through Nov. 10 on the agency’s new strategy for cleaner remediation of Superfund sites. EPA says the strategy, released on Sept. 8, is an initial effort to outline key activities that will reduce greenhouse-gas emissions and other negative environmental impacts that might occur from processes and equipment used in cleaning up hazardous-waste sites. EPA says it intends to modify and refine the document, the culmination of a year’s worth of work by the agency’s Office of Superfund Remediation and Technology Innovation, as more becomes known on the issue. The current version of
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.