The Clarks Fork of the Yellowstone is the most endangered river in North America, reports the environmental group American Rivers. The wild and scenic river, which runs through Montana and Wyoming, is threatened by a proposed gold mine two-and-a-half miles from Yellowstone National Park. The project includes a 90-foot dam designed to hold millions of tons of acid mine waste, but "In the event this tailings pond failed," says Sen. Max Baucus, D-Mont., "... the impact to the greater Yellowstone ecosystem would be cataclysmic and the damage irreversible." Other Western rivers making American Rivers' top 10 endangered list include the Columbia and Snake river system of Idaho and Oregon, where some 90 percent of the wild salmon have been lost to dams and damaged habitat. Also listed was the Rio Grande on the U.S. and Mexican border, whose waters are contaminated by nuclear, sewage and chemical wastes. American Rivers is located at 801 Pennsylvania Ave., S.E., Suite 400, Washington, DC 20003.