Garrison Reservoir Geology, Paleontology, Archeology, History>

The Garrison Reservoir, a major link in the chain of water-control and development projects of the U. S. Army Corps of Engineers along the mainstem of the Missouri River valley, is situated in the northwestern part of North Dakota. The reservoir takes its name from the town of Garrison, in McLean County, near the dam. The name of the town itself was derived from the former garrison of Fort Stevenson, a military post used from 1867 to 1883, the site of which is now covered by the reservoir.

At various periods during geologic time, this portion of the great Missouri valley was covered by vast glacial ice sheets. As the ice melted and retreated, it deposited a heavy earth mantle, particularly to the north and east of the valley, leaving gently rolling, boulder-strewn, fertile soils now characteristically used for wheat-farming. South and west of the main channel, a region little affected by the departing glaciers, the topography is more rugged, with many picturesque river bluffs and buttes, formed by the eroded remnants of more ancient rock and earth deposits. These prominent landmarks frequently bear distinctive local names, among which are Red Butte, Blue Buttes, and Eagle's Nest Butte.

Garrison Reservoir Area, Missouri River, North Dakota. (click on image for a PDF version)

Precipitation on the uplands of the great valley is often variable and erratic, and ordinarily supports only grasses—and now cereal and forage crops—though along the lower parts of the tributary streams and on the bottomlands of the main channel there is abundant timber. Here cottonwood, box elder, and willow are common, with occasional stands of ash, elm, and some juniper. In many areas there are plums, chokecherries, and other wild fruits.

Numerous species of native wildlife, including deer, antelope, and coyote, are still to be seen in the more remote parts of the area, as well as many varieties of upland game birds and waterfowl, the latter especially in the migratory seasons. The eagle can still be seen. Originally, large and more spectacular animals were to be found here, such as bison (or buffalo), and even elk and grizzly bear.