Warm Springs Ponds

Warm Springs Ponds: How Contamination Started

After a massive flood in 1908 washed Butte’s mining waste down Silver Bow Creek and into the Clark Fork River, the Anaconda Copper Company built the first Warm Springs Pond in 1911 to catch mine tailings before they spread further. Two more ponds were added in 1916 and 1959. Together, they’ve collected around 19 million cubic yards of tailings and contaminated sediment.

Cleanup Actions

In the early 1990s, the EPA approved a temporary cleanup plan while work continued upstream. As part of this plan, the EPA ordered several key actions: upgrading pond berms to prevent leaks, removing some tailings, treating Silver Bow Creek water with lime to neutralize acidity, and rebuilding the Mill-Willow Bypass—an important channel that runs along the ponds’ western edge.

Future Plans

A final cleanup decision will be made after all upstream work is complete. In the meantime, the ponds continue to play a critical role in trapping contaminated sediment and helping improve water quality downstream. For updates and more details, you can visit Warm Springs Ponds – MT DEQ

Warm Springs Ponds: Then & Now