Overview
The Milltown Dam 46°52′18″N 113°53′33″W / 46.87167°N 113.89250°W / 46.87167; -113.89250 was an earth-fill gravity-type hydroelectric dam on the Clark Fork river in Missoula County, in the western part of the U.S. state of Montana. The dam was located about seven miles east of Missoula, Montana, at the confluence of the Blackfoot River with the Clark Fork. Built in 1908 by copper mining tycoon William A. Clark, it was meant to supply hydroelectricity to his sawmills in nearby Bonner, Montana. Clark's sawmills supplied the giant timbers used to shore up the walls of the mine shafts in Butte. Since the 1870s, the Anaconda and Butte areas had been mined as one of the richest deposits of copper sulfate ever found in North America. With the dam just months old, however, a record flood on the Clark Fork washed tons of toxic mining sediment downstream, where it settled at the base of the dam to remain until remediation began, with a cumulative total of around 6.6 million cubic yards of sediment contaminated with arsenic, lead, zinc, copper, and other metals in the former reservoir bed.
Read more about this topic: Milltown Reservoir Superfund Site