Sunday, August 27, 2017

Great Falls

Several years ago, I spent a wonderful early morning climbing the hill above the confluence of the Madison, Gallatin, and Jefferson Rivers near Three Forks, Montana (September 2014). Where the Missouri officially begins. A few hundred miles downstream, after picking a few more tributaries draining the eastern slope of the Rockies, the river reaches Great Falls. Geologically, this section of the river is very young, since the Missouri followed a distinctly different course prior to the last glaciation.

Great Falls gets its name from a series of five falls and intervening rapids that drop the Missouri over 600 feet in 10 miles. This was a significant landmark for native Americans, a major pain for Lewis and Clark making their way upstream in heavy boats in 1805, and a boon to early Great Falls, which was built on local hydropower.

As on so many rivers, great and small, the capturing of hydropower requires eliminating (or severely modifying) the waterfalls, so now their are five dams perched on each of the original falls and very little water is left to cascade over the rocks, since most is diverted to the power houses. This must have been incredibly impressive during spring runoff before the dams were built (much like the falls on the Snake near Twin Falls -- June 2012).

We were staying downtown - the renovated Hotel Arvon (with a great dinner at the completely unexpected Wine by Wednesday). Early Wednesday morning, I rode my bike down the river past Giant Springs on the trail, then revisited with M on the way out of town. Giant Springs is a huge natural spring on the banks of river - probably as significant a geologic feature as the falls themselves.

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