State Plan Calls for New River Channel and Native Plant Revegetation

By the end of this year, cleanup will be mostly finished and restoration activities will take center stage. The work, funded and managed by the State of Montana’s Natural Resource Damage Program with money from the successful lawsuit against ARCO, dovetails with the cleanup and will soon play a more prominent role.

Under the state’s restoration plan, a new channel for the river will be built from scratch through the reservoir area using native gravel and cobbles that have been buried by reservoir mud for the past 100 years. The newly exposed tree stumps and old mill logs recovered from the Blackfoot River will be placed to help stabilize the channel until native vegetation takes root. (With the advent of spring, native plants have apparently sprouted from seeds buried for more than a century.) The restoration program will create a new floodplain and terrace for the channel, complete with side channels and wetland swales. Native vegetation including trees, shrubs, and grasses will be planted according to site; for example, Ponderosa pines on the drier uplands, willows and wetland grasses closer to water.

Restoration work to date has been mostly planning and preparation, but work is occurring out on the ground too. Old mill logs have been removed from the Blackfoot River and stockpiled for use in river restoration. Weed control is ongoing, and a U-shaped structure made of large boulders was built into the riverbed where the dam’s spillway used to stand. The goal is to keep the river’s elevation stable at this location, preventing headward erosion on the Blackfoot or Clark Fork Rivers. The structure will be underwater most of the time, with boulders closest to the bluff visible during low flows.

Upstream of the cleanup area, crews have removed more than 87,000 cubic yards of sediment, some of it contaminated, to prevent erosion and river pollution during runoff this year. Restoration in the reservoir area will start this summer, and by 2012 the river will be turned into its new channel.