From the Missoulan:

_At the Milltown Reservoir Superfund site, the river was diverted into a bypass channel two days ago, the last step before the Clark Fork and Blackfoot rivers are released Friday from their century-long confinement behind Milltown Dam.

It will be the first time since 1908 that the rivers have flowed freely, a milestone in the $120 million cleanup, restoration and redevelopment of Milltown Reservoir. . . .

The breaching – which could take anywhere from a few minutes to an hour – will drop the reservoir level 14 feet and unleash 300,000 tons of sediment scoured from the mouth of the Blackfoot River, which is relatively free of toxic wastes.

The muddy surge will kill thousands of fish already weakened by heavy metals.

But the survivors will be able to spawn upstream for the first time in a century and the ecosystem is expected to rebound within five years.

In place of a warm, shallow reservoir where invasive pike gobble up native trout will be a cool, meandering Clark Fork, which is to be restored with native vegetation and redeveloped as a state park._