Reservoirs occur on the Missouri river. Fire, insects, and disease are the primary natural disturbances. Most of the area is in farms or ranches, with limited urban expansion. About 50 percent of the area is in dry crops. Grazing is common, especially on the Dakota-Nebraska Tableland.
Irrigation occurs along the Missouri River.
Compiled by Rocky Mountain Region. Gently sloping loess-mantled narrow ridgetops are separated by steep slopes bordering drainage ways. Some stream valleys with nearly level flood plains and large stream terraces exist. Dissected plains with broad rolling ridgetops and moderately steep valley sides occur. Valleys are usually narrow with broad flood plains and terraces, and hilly dissected plains.