Five Dams: The Missouri River Put to Work
Near Great Falls, Montana
The Missouri River drops more than six hundred feet through a ten-mile canyon above Great Falls, and for most of human history that energy simply tumbled into the plains and dispersed. Then, between eighteen ninety and nineteen fifty-eight, five dams were built across that stretch: Black Eagle, Colter, Rainbow, Ryan, and Cochrane, harnessing what the river had been doing for free since the last ice age.
Black Eagle Dam came first, in eighteen ninety, the first hydroelectric dam ever built in Montana and the first on the Missouri anywhere. Ryan Dam followed in nineteen fifteen, built directly across the Great Falls itself, the eighty-seven-foot cascade that Lewis had called the grandest sight he ever beheld. The dam stands sixty-one feet high and produces sixty megawatts. Morony Dam, completed in nineteen thirty, was built specifically to power Anaconda's zinc refinery downstream.
The dams erased four of the five original waterfalls. Rainbow Falls went first, behind Rainbow Dam in nineteen ten. The Great Falls itself vanished behind Ryan Dam in nineteen fifteen. Colter Falls disappeared under the same reservoir. Only Crooked Falls, also called Horseshoe Falls, remains in a natural state: a nineteen-foot cascade the expedition noticed but did not name first.
Great Falls called itself the Electric City, and the name was honest. The river powered the smelter, the flour mills, the refineries, the whole industrial complex that Gibson had imagined from the riverbank in eighteen eighty. The city was, in an entirely literal sense, built on falling water. Today those five dams still produce power for the region, the Missouri doing quietly what no one can see from the highway.
