Colorado River

Catchment area of ​​the Colorado River

The Colorado Grand Canyon

Colorado River

Horseshoe Bend ( Arizona) of the Colorado River

Hoover Dam

The Colorado (Spanish for colored red or colored) is the largest and most important river in southwestern North America. It is 2333 km long and has a catchment area of 703,132 km ². Agriculture, drinking water and electricity supply in the southwestern United States and in parts of California strongly depend on the water regime of the Colorado River. These were a variety of different size irrigation projects built between the end of the 19th century and the 1980s.


The river rises in the Rocky Mountain National Park in the U.S. state of Colorado, northwest of Denver on the west edge of the North American Continental Divide. It flows from the mountains of the Rocky Mountains to Utah and Arizona, and largely forms the border between Arizona and Nevada and the entire border between Arizona and California. Thereafter, the Colorado flows to Mexico and flows between the states of Baja California and Sonora in the Gulf of California. The Colorado River rises in an area of ​​high water dispensing area and flows as a result a large dry area. In the U.S. states of Utah, Nevada, Arizona and California, he is therefore a so-called stranger flow.

Where the Colorado leaves the Rocky Mountains, the highlands of the Colorado Plateau and thus the middle reaches of the river begins. In this area of ​​Colorado has created with its tributaries by erosion many unique landscapes. At a length of 1600 km of the Colorado River flows through several canyons, including through the Glenwood Canyon in Colorado, the Glen Canyon in Utah, the Marble Canyon and Grand Canyon in Arizona. At the output of the Grand Canyon, now in the dam area of ​​Lake Mead, the lower reaches of the Colorado River begins. Here the river runs first through the high-altitude Mojave Desert and then through the lower Sonoran Desert. The mouth region of the Gulf of California reached the Colorado River no longer throughout the year on the surface. As above the mouth region much water is taken for irrigation, evaporation results in desert climate means that the small, remaining amounts of water seep into the sandy bottom and only underground flow to the Gulf.

At the mouth of the Colorado River are the islands of Montague, Gore and Pelícano.

The headwaters of the Colorado to the confluence with the Green River was formerly called Grand River. Only in 1921 it was renamed at the request of the State of Colorado by the U.S. Congress in Colorado River.


The historical state of the Colorado River is largely unknown. Before the construction of the Glen Canyon Dam, which was completed in 1963, there was no cross- examination. The first wave of systematic research began in 1977 at the suggestion and paid for by the Bureau of Reclamation, which operates the dam.

The ecosystems of the river are very different in the different sections of the river. During the headwaters of the Colorado River can be described as a cold and clear mountain river, it will take through its own erosion and supply of sediment to the proceeds on the Colorado Plateau tremendous amounts of suspended matter. With the inflow of the Gila River in Arizona minerals and salts in particular in the Colorado are entered, change the chemical composition and salinity. In addition, the underflow is flat through water extraction and heated in the desert climate greatly.

The extreme change in the water regime by the construction of dams and the diversion of water has greatly affected the aquatic ecosystems of the central and lower reaches. The reservoirs are deep and the flow rate is reduced to near zero. Below the dams, the absence of sediment causes the river carves and flowing through it faster. So the water is colder and tearing, which in turn, that the Benthic is coarse-grained. Organisms that are dependent on warm shallow water, lose their habitats.

The total number of original fish species in the catchment area of ​​Colorado is typically given as 49, of which four are to be locally extinct. On the other hand, at least 72 non-native species have been introduced into the catchment area, mainly in the interest of sport fishing. Individual voices only accept 36 or even 29 originally native species. All others were afterwards introduced by man, including especially the catfish Ictalurus punctatus and originally from Eurasia carp. Both types have contributed significantly to the decline of native fish because their spawning serves them as food. Among the most endangered species belongs Gila cypha, a carp fish, running to its rescue from 2009 to 2011 a settlement project in Grand Canyon National Park.

In the 1970s, carp accounted for 70-80 % of all fish caught in the middle reaches of the Colorado fish. Since the early 1980s, the proportion decreases massive, studies using the same methods as previously revealed since only about 25% of carp and these only in small schools. The cause of the changes apply through the dam, the first carp preferred strong, but hovered again for about twenty years. Furthermore, make introduced species around 85 % of the stock in the best studied section from within the Grand Canyon National Park.

The insect population in the headwaters of the Colorado is dominated by stoneflies, caddisflies and mayflies. Together with aquatic beetles and some real fly, they account for 95% of the invertebrates. On the Colorado Plateau and in the lower reaches of the river, the insects are greatly reduced by the high level of suspended solids in the water. Little Borster and the amphipod Gammarus lacustirs, as well as a variety of worm make the most of the invertebrates in the middle reaches of the Colorado.

The riparian vegetation is dominated by the different altitude levels and the surrounding ecosystems. Significantly, the tamarisk is as a neophyte. With its high water requirement tamarisk bushes, the riparian zones dominate and displace the natural vegetation. In some of the protected areas on the river the species is therefore combated by mechanical means.

Water regime

The Colorado River is one of the most used by humans rivers worldwide. Although his entire catchment area is inhabited only an average of seven people per square kilometer, every drop will precipitate along the river course as used statistically 17 times for irrigation, power generation or as drinking water.

The Colorado - Big Thompson Project

The Colorado - Big Thompson Project is the largest water diversion project in Colorado. On the west side of the Rocky Mountains, the water at the headwaters of the Colorado in the Grand Lake, Lake Granby and in man-made reservoirs is collected. A large part of the water is passed through the Alva B. Adams Tunnel under the Continental Divide through the east side of the mountains to the Big Thompson River, a tributary of the South Platte River. On his way through the mountains, it is used to generate electricity. On the east side it is used for irrigation of some 290,000 ha of agricultural land and supplied the cities Fort Collins and Greeley, and Colorado State University and several rural communities with water for industry and private consumption. The Colorado - Big Thompson project system extends 240 km in east-west direction and 105 km in the north-south direction. The water deliveries through the system amount to an average of 213,000 acre-feet (about 263 million cubic meters ) per year.

Reservoirs and dams

Along the river there are several huge dams such as the Hoover Dam, which impounds Lake Mead near Las Vegas, and the Glen Canyon Dam on Lake Powell. The reservoirs are drinking water reservoirs and serve to generate electricity.

About channels the waters of the Colorado reaches into the major cities Los Angeles, San Diego, Phoenix and Tucson. Due to the intensive water withdrawal, the river bed is at the mouth now mostly dry.

List of dams and reservoirs on the Colorado downstream:

  • Shadow Mountain Dam impounds Shadow Mountain Lake
  • Granby Dam impounds Lake Granby
  • Glen Canyon Dam impounds Lake Powell
  • Hoover Dam impounds Lake Mead
  • Palo Verde Diversion Dam
  • Imperial Dam
  • Laguna Diversion Dam
  • Morelos Dam


In 2000, the flux due to relatively low rainfall began to cause less and less water. According to the geological survey of the last 800 years presented geologists, however, that it was the reverse came in the last hundred years to above-average rainfall in the western United States. Due to the absence of which would be the entire water and energy supply of the American West, which depends on the Colorado River, at risk. This risk is exacerbated by concurrent fast-growing populations in the area. Lake Powell has since 2000 lost about 60 percent of its water. The volume of Lake Mead has become about 40 percent smaller at the same time. The rainfall in the catchment area of the river is no longer sufficient for a study of 2012 is already sufficient to cover the discharges, so that inventories are shrinking in the dams.

2013, the Colorado River was set to square one of the ten most endangered rivers in the United States.

Tributaries and Places

Among the most important tributaries of the Colorado include ( from north to south ):

Places on the Colorado River include:

  • Glenwood Springs (Colorado)
  • Grand Junction ( Colorado)
  • Moab (Utah )
  • Page (Arizona )
  • Boulder City (Nevada )
  • Lake Havasu City ( Arizona)
  • Yuma ( Arizona)
  • San Luis Rio Colorado ( Sonora )


The landscape around the Colorado River, the Grand Canyon in particular, has inspired many visual artists and musicians to an artistic confrontation with it. Among others, two pieces of music, from classical and rock from the area arisen that have the river and the gorge on the topic:

  • Ferde Grofé: Grand Canyon Suite (1929-1931) with the sets Sunrise, The Painted Desert, On the Trail, Sunset and Cloudburst. Analog recording in vinyl with the London Festival Orchestra conducted by Stanley Black: Liner SPC 21002nd
  • Refugee: Grand Canyon, rock suite on the album Refugee (1973).
  • Johnny Cash: You wild Colorado, folk song on the album Orange Blossom Special (1965).