Colorado Geography: The Land

Geography and Landforms of Colorado

Colorado is located in the center of the western half of the continental United States and is the eighth largest state. Its average elevation of 6,800 feet is the highest of any state in the nation. The Great Plains region covers, roughly, the eastern 2/5 of the state.

Colorado is made up of these Physiographic Areas

Central Shortgrass Prairie

The Central Shortgrass Prairie Physiographic Area covers much of eastern Colorado and smaller portions of western Kansas, southwestern Nebraska, and southeastern Wyoming.

The region contains flat to gently rolling topography, with occasional canyons and bluffs. Elevations within Colorado range from about 975 m (3,200 ft) in Prowers County to about 1800 m (6,000 ft) around Limon and near the foothills of the Rockies. Principal rivers include the South Platte, Arikaree, Big Sandy, Republican, and Arkansas. Precipitation is low, less than 50 cm (20 in) per year with most of that falling in spring and summer; total precipitation varies greatly between years at a given location and varies significantly more than in mixed grass or tallgrass systems (Wiens 1972). Mean monthly temperatures range from -12¡C (10¡F) in winter to 38¡C (100¡F) in summer. Localized severe weather is not uncommon, and blizzards, hailstorms, and tornadoes occur in most years.

The dominant habitat in this physiographic area is shortgrass prairie. Shortgrass is dominated by two low-growing warm-season grasses, blue grama and buffalo grass; western wheatgrass is also present, along with taller vegetation including widespread prickly-pear cactus and yucca, and cholla in the south. Sandsage prairie is found where sandy soils occur, and is dominated by sand sagebrush and the grasses sand bluestem and prairie sand-reed. Mixed grass (needle-and-thread, side-oats grama) and tallgrass (big bluestem, little bluestem, switchgrass) communities occur locally

Colorado Plateau

The Colorado Plateau is centered on the four corners area and extends into Colorado, Utah, Arizona, and New Mexico. It is an area of tablelands with moderate to high relief dissected by narrow and widely-spaced stream valleys. The Colorado Plateau is characterized by limited precipitation, cold winters and hot summers. Lowest elevations are covered with arid shrublands with grass interspersed. Sagebrush is dominant over large areas, with cottonwoods along perennial water courses. At moderate elevations, woodland vegetation is dominated by pinyon pine and juniper, with various shrubs intermixed. Montane forest is in high elevations, with ponderosa pine and Douglas fir dominant to the south and lodgepole pine and aspen farther north.

Mesa and Plains

This physiographic area is located almost entirely in central New Mexico. Major landforms are valleys, lowlands, outwash plains, and alluvial fans and terraces. The middle reach of the Rio Grande is found here. Grama and galleta grasses and four-wing saltbush occur along with sand sage at lower elevations, pinyon-juniper at higher elevations, and conifers are in the scattered mountain ranges. Riparian strips along water courses have cottonwood-willow and non-native salt cedar.

Southern Rocky Mountains

Central Colorado makes up the bulk of the Southern Rockies, which extend into northern New Mexico and southern Wyoming. Steep, rugged mountains cover this region, and vegetation varies greatly on the basis of elevation and aspect. Alpine tundra gives way to various coniferous forests often with aspen intermixed. Ponderosa pine is at lower elevations, pinyon-juniper below that, and grasslands in the lowest areas. Because of topography, weather, avalanches, fire, insect outbreaks, and disease, forests in the Southern Rocky Mountains tend to be patchier than in many other areas. The landscape is thus a complex mosaic of open meadows and forest stands of varying age and species composition.

Wyoming Basin

As its name suggests, the Wyoming Basin is primarily in Wyoming but also extends into northern Colorado, southern Montana, and very small parts of northeast Utah and southeast Idaho. The area consists of broad intermountain basins interrupted by isolated hills and low mountains that merge to the south into a dissected plateau. It is basically a shrubsteppe, dominated by sagebrush and shadscale, interspersed with areas of shortgrass prairie. Higher elevations are in mountain shrub vegetation, with coniferous forest atop the highest areas.

Colorado Landscape and Landforms:

Colorado Plateau

The Colorado Plateau covers most of the western portion of the state. It is a region of high plateaus and deep canyons carved by the Colorado, Gunnison, and other rivers. It runs along the western 1/5 of the state and a small area known as the Intermontane Basin lies in the northwest corner of Colorado. The Intermontane Basin, characterized by rolling forested hills, plateaus and plenty of sagebrush, is the smallest land area in Colorado.

Rocky Mountains

The central portion of the state is covered by the Rocky Mountains. Because of the presence of the high peaks in this range, Colorado has been given the nickname "Roof of the World." The state has 51 out of the 80 peaks in North America over 14,000 feet. Colorado's highest point, Mount Elbert (14,431 feet) is found here. The headwaters of 6 major rivers originate in the mountains of this region – the Colorado, the North Platte, the South Platte, the Arkansas, the Republican, and the Rio Grande. Five mountain ranges make up the Colorado Rocky Mountains; the Front Range, the Sangre de Cristo Mountains, the Park Range, the Sawatch Range and the San Juan Mountains.

Continental Divide

The Continental Divide runs through the Colorado Rockies. Rivers east of the Divide flow toward the Mississippi River; those to the west flow toward the Pacific Ocean.

Great Plains

To the east, Colorado has high plains and rolling prairies that rise westward to the Rockies. Livestock production and the farming of both irrigated and dry land takes place in this Great Plains region. It is part of the Interior Plain of North America that runs from Canada in the north, through the United States, to Mexico in the south. The Great Plains region covers, roughly, the eastern 2/5 of the state. The land is flat and dry, sloping gently upward from east to west to meet the Rocky Mountains.