The Colorado Piedmont is an area along the base of the foothills of the

Front Range The Front Range is a mountain range of the Southern Rocky Mountains of North America located in the central portion of the U.S. State of Colorado, and southeastern portion of the U.S. State of Wyoming. It is the first mountain range encountered ...

in north central

Colorado Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of t ...

in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. The region consists of a broad hilly valley, just under 5000 ft (1500 m) in elevation, stretching north and northeast from

Denver Denver () is a consolidated city and county, the capital, and most populous city of the U.S. state of Colorado. Its population was 715,522 at the 2020 census, a 19.22% increase since 2010. It is the 19th-most populous city in the Unit ...

in the valley of the

South Platte River The South Platte River is one of the two principal tributaries of the Platte River. Flowing through the U.S. states of Colorado and Nebraska, it is itself a major river of the American Midwestern United States, Midwest and the American Sout ...

, as well as along the

Arkansas River The Arkansas River is a major tributary of the Mississippi River. It generally flows to the east and southeast as it traverses the U.S. states of Colorado, Kansas, Oklahoma, and Arkansas. The river's source basin lies in the western United Stat ...

valley southward from

Colorado Springs Colorado Springs is a home rule municipality in, and the county seat of, El Paso County, Colorado, United States. It is the largest city in El Paso County, with a population of 478,961 at the 2020 United States Census, a 15.02% increase since ...

. The name Colorado Piedmont also refers to the physiographic section of the Great Plains province.

Description

The Colorado Piedmont elevation is lower than the foothills, but is also slightly lower elevation than the

High Plains High Plains refers to one of two distinct land regions: * High Plains (United States), land region of the western Great Plains *High Plains (Australia) The High Plains of south-eastern Australia are a sub-region, or more strictly a string of adja ...

to the east. According to current geologic theory, the Piedmont was formed approximately 28 million years ago, during the broad bowing of the

North American Plate The North American Plate is a tectonic plate covering most of North America, Cuba, the Bahamas, extreme northeastern Asia, and parts of Iceland and the Azores. With an area of , it is the Earth's second largest tectonic plate, behind the Pacif ...

that lifted the continent between present-day

Kansas Kansas () is a state in the Midwestern United States. Its capital is Topeka, and its largest city is Wichita. Kansas is a landlocked state bordered by Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the ...

and

Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to it ...

to its present elevation of approximately 5000 ft (1500 m). This uplift resulted in increased streamflow and rapid erosion on the eastern side of the

Rocky Mountains The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico in ...

. The erosion scraped away the top layer of

Upper Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', th ...

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...

(which still exists as the top layer on the High Plains), exposing the underlying layer of

Pierre Shale The Pierre Shale is a geologic formation or series in the Upper Cretaceous which occurs east of the Rocky Mountains in the Great Plains, from Pembina Valley in Canada to New Mexico. The Pierre Shale was described by Meek and Hayden in 1862 in th ...

, which had been formed during the Cretaceous, when a

shallow sea An inland sea (also known as an epeiric sea or an epicontinental sea) is a continental body of water which is very large and is either completely surrounded by dry land or connected to an ocean by a river, strait, or "arm of the sea". An inland s ...

covered present-day Colorado. It was during this time that the South Platte River, which had previously flowed eastward across the Plains, rerouted northward along the mountains to join the

Cache la Poudre River The Cache la Poudre River ( ), also known as the Poudre River, is a river in the state of Colorado in the United States. Name The name of the river () is a corruption of the original Cache à la Poudre, or "cache of powder". It refers to an ...

. In some areas of the Piedmont, a loose veneer of

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

gravel overlays older shale and which accumulated during

glaciation A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate be ...

in the mountains, when streams descending onto the Piedmont became overburdened with sediment. The drop off from the Plains to the Piedmont is noticeable to motorists driving southward from

Cheyenne, Wyoming Cheyenne ( or ) is the capital and most populous city of the U.S. state of Wyoming, as well as the county seat of Laramie County, Wyoming, Laramie County, with 65,132 residents, per the 2020 US Census. It is the principal city of the Cheyenne ...

on Interstate 25. At approximately Mile 293 northeast of

Wellington, Colorado Wellington is a statutory town in Larimer County, Colorado, United States. The population was 11,047 at the 2020 census. Geography Wellington is located at (40.702324, -105.005497). According to the United States Census Bureau, the town has ...

, near the Larimer- Weld county line, the road drops noticeably from the Upper Cretaceous sandstone of the Plains to the lower shale of the Piedmont. The transition from High Plains to Piedmont is likewise accompanied by a change in agriculture, from pasture lands on the Plains to cultivated fields in the Piedmont. In the 19th century, the Piedmont region was inhabited primarily by the Southern Arapaho and

Cheyenne The Cheyenne ( ) are an Indigenous people of the Great Plains. Their Cheyenne language belongs to the Algonquian language family. Today, the Cheyenne people are split into two federally recognized nations: the Southern Cheyenne, who are enroll ...

tribes. From the earliest time of white settlement in the middle 19th century, the issue of water has been a controlling force in the economy of the region. The region was not widely settled in the early

Colorado Territory The Territory of Colorado was an organized incorporated territory of the United States that existed from February 28, 1861, until August 1, 1876, when it was admitted to the Union as the State of Colorado. The territory was organized in the ...

, 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.

Description

References

Further reading