“…Large, economic quantities of Cu, Zn, Mn, Pb, Mo, Ag, and Au were produced, leading to the District being known as the “Richest Hill on Earth” . Mining, milling, and smelting activities within the District over a 150-year period generated large quantities of mine waste and tailings that were historically released to nearby surface waters. , Large flood events in the early 1900s washed these materials downstream, contaminating groundwater, soils, , alluvial sediments, and the hyporheic zone. , The extent of this contamination includes Blacktail and Silver Bow Creeks within the City of Butte, 35 km of Silver Bow Creek downstream of Butte, and 380 km of the Clark Fork River. − An estimated 2–4 million m 3 of mine waste has been transported downstream from Butte along this corridor, , adversely affecting riparian vegetation and biota , along the way. The contaminated floodplain, extending from Butte to Missoula, Montana, constitutes the largest Superfund site in terms of areal extent. ,, …”