It stood athwart the river seven miles upstream from Missoula for over 100 years accumulating sediments toxic with arsenic, cadmium, lead, copper and zinc, all washed down from mining and smelting that had been going on since the mid-1800s in Butte and Anaconda. Poisoned from practically the headwaters down by the traditional extraction industries that ruled the west, the toxins killed thousands of fish and gradually seeped into the aquifer and started showing up in Missoula’s wells downstream.
Restoration projects have been under way on this 110 mile stretch of river, which forms the largest superfund site in the US. The headwaters were rerouted into holding ponds and bird habitat. Over 6 million cubic yards of tainted mud were removed from the Milltown reservoir’s bottom. The Milltown dam and a 120 year old dam just upstream on the Blackfoot river at a timber mill were removed in the summer of 2011 and the rivers joined again. With the spring flood of 2011, Nature had her way with both rivers for the first time in over a century.
As the water dropped and cleared up through the summer and into the fall, changes to the river became more and more obvious. Recently I snuck through the former reservoir section at the confluence that is still off limits to river travel.
With the removal of the dams, both rivers sped up and cut down 20 to 30 feet into cobble and sediment layers that had not seen substantial current for a century. The cutting of the riverbed on the lower Blackfoot was perhaps the most dramatic. Over about the distance of mile, it completely changed multiple bends, rearranged the river bottom, dropped the water level, undercut banks, and laid bare old bedrock ledges and huge boulders long covered. It unearthed thousands of logs buried from the huge log drives at the turn of the century, where all cut timber was pushed into the river and spring floods transported them downstream to the Bonner mill in gigantic matchsticked log jams filling the river for miles. Buried for all this time, thousands of them reappeared and were pushed up to 60 miles downstream, through and below Missoula along different parts of the banks and underwater.
The stretch of the Clark Fork from above the dam site down into Missoula was transformed as well. Huge new expanses of cobble bars appeared right where the Milltown dam powerhouse, spillway, and concrete rip-rap used to be. Sections of riverbed that had only scoured larger cobbles, thick muddy sediments, or algae-plumes in late summer, were replaced by acres of fine sand and perfectly sorted, multi-colored gravel beds. The river looks like a clean mountain stream instead of the largest EPA superfund site in the US. Paddling along in disbelief, I saw Great Blue Herons, osprey, deer, and a bear drinking in the river, and around one corner, two baby bald eagles shrieking in joy as they learned to fly in the blustery afternoon winds. Before our eyes, the river is reborn.