Moses Coulee till, up to thick in places. This glacial till, made up of clay, silt, sand, gravel, cobblestones, and erratic boulders, covers most of the upper coulee. Today Moses Coulee supports an excellent example of a shrub-steppe ecoregion. Vegetation includes sagebrush, rabbitbrush, greasewood, hopsage, bitterbrush, bunchgrass, buckwheat and other vegetation once common to most of the Columbia Plateau. The Nature Conservancy has established the Moses Coulee Preserve, which is a contiguous, intact shrub-steppe habitat. It is located south of Jameson Lake near the head of Moses Coulee. It provide habitat for a rich variety of birds (lazuli bunting, common goldeneye, sage
Grand Coulee pumped from the Grand Coulee Dam, into Banks Lake to act as an Equalizing Reservoir and irrigation water source. Evidence of the waterfalls includes a plunge basin where the falls began, immediately south of Coulee City. It contains at least of gravel lower than the open flooring of the land. The river above the falls was shallow and much wider than the gorge. Thus, it wrapped around the lip of the main falls creating lateral falls. These flowed until the recession of the main falls denied them water. Northrup Canyon in Steamboat Rock State Park, contains a dry cataract as