A battle royal may be brewing as opposition to the Environmental Protection Agency’s proposed regulation of greenhouse-gas emissions mounts. Recently, three states, along with several industry groups, filed lawsuits challenging the EPA’s December “endangerment finding,” which said greenhouse gases pose a threat to public health and welfare. Meanwhile, the EPA says it is confident the finding will withstand legal challenge, and 16 states and New York City say they may intervene on behalf of the EPA. On Feb. 16, Texas Gov. Rick Perry (R) announced that Texas, which emits more carbon dioxide than any other state, filed suit in the
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.