RIVER ON THE EDGE.(Yellowstone's Soda Butte Creek)

Old mine wastes threaten Yellowstone's Soda Butte Creek.

ONE OF YELLOWSTONE NATIONAL PARK'S most popular fly-fishing rivers is threatened by mine tailings that, if set free by a heavy spring runoff, could poison and kill the ecosystem that supports its trout. Fly fishers should support the removal of the old mine tailings as part of the New World Mine cleanup settlement arranged in 1996 by President Clinton.

Five miles upstream from the northeast entrance to Yellowstone Park, Soda Butte Creek begins in snow-fed springs that join small, steep tributaries just east of Cooke City, Montana. The stream meanders toward Yellowstone Park through a mix of dense timber and open meadow, sometimes hidden within dark silver-green thickets.

Not far into the Park, Soda Butte Creek cuts its way through deep Ice Box Canyon before spilling onto the sagebrush flats and past the extinct hot-spring cone of travertine for which the stream is named, The stream runs from 20 to 30 feet wide, coursing its way through large gravel, bars, riffles, and pools as it meanders down the sage-and-grass-covered valley to join the Lamar River.

At dusk in late July, with the sweet mingling aroma of sage and evergreen flooding your senses, you cast a Blue Dun to a pool near an undercut bank on a bend below the Soda Butte cone. Suddenly a 16-inch native cutthroat explodes on your fly and the quiet is broken. Moments later, as you release the spotted-black and amber-brown beauty, you look up toward the towering peaks and sheer vertical cliffs that surround you and this gentle valley. The problems and pollution of modern life fade into the dwindling light, and all seems right with the world.

Sadly, the reality, that shatters this magical illusion lies, but inches from your feet. Soda Butte Creek is a stream in peril, the victim of more than 65 years of serious mining pollution near its headwaters outside the park.

What Happened?

FROM 1933 TO 1953, the McLaren Gold Mining Company deposited from 150,000 to 370,000 cubic yards of waste in the floodplain just below Soda Butte Creek's …