 In the same period , several private establishments – most notably the Montana Power Company – began to develop the Missouri River above Great Falls and below Helena for power generation . A small run @-@ of @-@ the river structure completed in 1898 near the present site of Canyon Ferry Dam became the second dam to be built on the Missouri . This rock @-@ filled timber crib dam generated seven and a half megawatts of electricity for Helena and the surrounding countryside . The nearby steel Hauser Dam was finished in 1907 , but failed in 1908 because of structural deficiencies , causing catastrophic flooding all the way downstream past Craig . At Great Falls , a section of the Black Eagle Dam was <unk> to save nearby factories from inundation . Hauser was rebuilt in 1910 as a concrete gravity structure , and stands to this day . 
