the early Colorado Territory, when mining was the basis of the economy. The use of irrigation in the Piedmont starting in the 1860s led to widespread homesteading and cultivation of wheat and sugar beets, as well as cattle and sheep ranching. Much of the irrigation water in the Piedmont comes from shallow wells that tap the layers of Pleistocene gravel. Water diversion projects, locally from the Cache la Poudre and other rivers, as well as the Colorado-Big Thompson Project, also supply needed water to the region. References Further reading Roadside Geology of Colorado; Halka, Chronic; Mountain Press Publishing; 1980. Regions of Colorado Physiographic sections Great Plains Valleys of Colorado