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Colorado River

2007 Schools Wikipedia Selection. Related subjects: North American Geography

                    Colorado River
   Map of the Colorado Watershed

                        Map of the Colorado Watershed

   Mouth            Gulf of California
   Basin countries  United States, Mexico
   Length           2,330 km (1,450 mi)
   Source elevation ~2800 m (~9000 ft)
   Avg. discharge   1206 m³/s (42,600 ft³/s)
   Basin area       629,100 km² (242,900 mi²)
   The Colorado River from the bottom of Marble Canyon, in the Upper Grand
   Canyon
   Enlarge
   The Colorado River from the bottom of Marble Canyon, in the Upper Grand
   Canyon
   Colorado River in the Grand Canyon from Desert View
   Enlarge
   Colorado River in the Grand Canyon from Desert View
   The Colorado River from Laughlin
   Enlarge
   The Colorado River from Laughlin

   The Colorado River is a river in the southwestern United States and
   northwestern Mexico, approximately 1,450 mi (2,330 km) long, draining a
   part of the arid regions on the western slope of the Rocky Mountains.
   The natural course of the river flows into the Gulf of California, but
   the heavy use of the river as an irrigation source for the Imperial
   Valley has desiccated the lower course of the river in Mexico such that
   it no longer consistently reaches the sea.

   The Colorado River drains 242,900 sq mi (629,100 km²). Total flows of
   the river range from 20,000 cubic feet per second (570 m³/s) in
   droughts to 1,000,000 ft³/s (28,000 m³/s) in severe floods. With the
   construction of massive power dams on the lower course of the river,
   floods of over 70,000 ft³/s (2000 m³/s) are rare. The mean flow of the
   total river before diversion is 42,600 ft³/s (1206 m³/s). At full flow
   more runoff volume exists in this river than any other in North America
   except the Mississippi and the Columbia.

Course

   The Colorado River's headwaters are located in Rocky Mountain National
   Park, just west of the Continental Divide. (There is some authority for
   considering the headwaters of the Colorado River, and its main source,
   to be the Green River which rises in Sublette County, Wyoming. The
   Green River is practically the same size as the Colorado, formerly
   known as the "Grand" River at their confluence near Moab, Utah).
   Following Rocky Mountain National Park, the river then follows the
   Kewuneeche Valley to Shadow Mountain Reservoir, near the town of
   Granby, then flows into Lake Granby. The river then roughly parallels
   US Highway 40 to the town of Kremmling, then enters Gore Canyon.
   Shortly thereafter the river meets the Eagle River and parallels I-70
   through Glenwood Canyon and then passes through the city of Glenwood
   Springs where it is joined by the swift flowing Roaring Fork River.
   West of Glenwood Springs the Colorado runs through the Grand Valley to
   Grand Junction, where it is joined by the Gunnison River; from there it
   flows towards the Utah border and Westwater Canyon. The Colorado here
   ranges from 200 to 1200 feet wide (60 to 370 m) and from 6 to 30 feet
   in depth (2 to 9 m) with occasional deeper areas.

   Once inside Utah, the river turns south partially forming the southern
   border of Arches National Park near Moab, Utah, then passes by Dead
   Horse Point State Park and through Canyonlands National Park where it
   is met by one of its primary tributaries the Green River. The river
   then flows into Lake Powell, formed by the Glen Canyon Dam. Below the
   dam, water released from the bottom of Lake Powell makes the river
   clear, clean, and cold. Just south of the town of Page, Arizona, the
   river forms the dramatic Horseshoe Bend, then at Lees Ferry is joined
   by another tributary, the warm, shallow, muddy Paria River, and begins
   its course through Marble Canyon. Here, the Colorado ranges from 300 to
   2000 feet in width (90 to 610 m) and 9 to 130 feet in depth (3 to 40
   m).

   At the southern end of Marble Canyon, the river is joined by another
   tributary, the Little Colorado, and the river then turns abruptly west
   directly athwart the folds and fault line of the plateau, through the
   Grand Canyon, which is 217 miles long (349 km) and from 4 to 20 miles
   wide (6 to 30 km) between the upper cliffs. The walls, 4000 to 6000
   feet high (1200 to 1800 m), drop in successive escarpments of 500 to
   1600 feet (150 to 490 m), banded in splendid colours toward the narrow
   gorge of the present river.

   Below the confluence of the Virgin River of Nevada the Colorado
   abruptly turns southward. Hoover Dam, built during the Great
   Depression, forms Lake Mead, a popular recreation site, as well as the
   supplier of most of the water for the city of Las Vegas. From Hoover
   Dam, the river flows south and forms part of the boundary between
   Arizona and Nevada, and the border between Arizona and California.
   Along the California-Arizona reach of the river, two additional dams
   are operated to divert water for agricultural irrigation supplies: Palo
   Verde Diversion Dam and Imperial Dam. Here, the Colorado River ranges
   in width from 700 to 2500 feet (210 to 760 m) and from 8 to 100 feet in
   depth (2 to 30 m).

   Below the Black Canyon the river lessens in gradient, and in its lower
   course flows in a broad sedimentary valley's distinct estuarine plain
   upriver from Yuma, where it is joined by the Gila River. The channel
   through much of this region is bedded in a dike-like embankment lying
   above the floodplain over which the escaping water spills in time of
   flood. This dike cuts off the flow of the river to the remarkable low
   area in southern California known as the Salton Sink, Coachella Valley,
   or Imperial Valley. The Salton Sink is located below sea level;
   therefore, the descent from the river near Yuma is very much greater
   than the descent from Yuma to the gulf.

   The lower course of the river, which forms the border between Baja
   California and Sonora, is essentially a trickle or a dry stream today
   due to use of the river as Imperial Valley's irrigation source. Prior
   to the mid 20th century, the Colorado River Delta provided a rich
   estuarine marshland that is now essentially desiccated, but nonetheless
   is an important ecological resource.

Elevation summary

   Approximate heights above sea level at several key locations:
   Feet Meters Location
   9000   2750 Colorado headwaters (Rocky Mountains)
   6100   1850 midway to Colorado- Utah border
   4300   1300 Colorado- Utah border
   3850   1170 midway to Utah- Arizona border
   3700   1130 Utah- Arizona border ( Wahweap Bay)
   3000    900 midway to Grand Canyon ( Rider Point)
   2800    850 Grand Canyon North Rim
   2500    760 Grand Canyon South Rim
   1200    365 Lake Mead
    600    183 after Hoover Dam
    485    150 California- Nevada- Arizona border
    100     30 California- Arizona-Mexico border

   Note that the significant difference between the present height of the
   rim of the Grand Canyon (about 8000 ft; 2440 m) and the levels at which
   the river enters/exits it gives rise to the geologic theory that its
   upheaval must have begun around the same time the river began flowing
   through it and eroding it (since rivers do not run uphill, it would
   have followed some other path around the upheaval). Estimates for the
   beginning of this erosion/upheaval process range from 5 to 70 million
   years ago.

Engineering

   Glen Canyon Dam and Lake Powell
   Enlarge
   Glen Canyon Dam and Lake Powell

   In the autumn of 1904, the river's waters escaped into a diversion
   canal a few miles below Yuma, Arizona. The river, taking the canal as a
   new channel, re-created in California a great inland sea in an area
   that it had frequently inundated before, for example, in 1884 and 1891,
   when it had for a time practically abandoned its former course through
   Mexican territory to the Sea of Cortez. But it was effectively dammed
   in the early part of 1907 and returned to its normal course, from
   which, however, there was still much leakage to the Salton Sea. In July
   1907, the permanent dam was completed. From the Black Canyon towards
   the sea the Colorado normally flows through a desert-like basin.
   From the Hoover Dam
   Enlarge
   From the Hoover Dam

   The Colorado River is a major and in some cases life-sustaining source
   of water for irrigation, drinking, and other uses by people living in
   the arid American southwest. Allocation of the river's water is
   governed by the Colorado River Compact. Several dams have been built
   along the Colorado River, beginning with Glen Canyon Dam near the
   Utah-Arizona border. Other dams include Hoover Dam, Parker Dam, Davis
   Dam, Palo Verde Diversion Dam, and Imperial Dam. Since the completion
   of the dams, the majority of the river in normal hydrologic years is
   diverted for agricultural and municipal water supply. The Colorado's
   last drops evaporate in the Sonoran Desert, miles before the river
   reaches the Gulf of California. Almost 90% of all water diverted from
   the river is for irrigation purposes. The All-American Canal is the
   largest irrigation canal in the world and carries a volume of water
   from 15,000 to 30,000 ft³/s (420 to 850 m³/s), making it larger in
   volume than New York's Hudson River. The canal's waters are used to
   irrigate the parched but fertile Imperial Valley, where several years
   can pass between measurable rainfalls. Hydrology transport models are
   used to assess management of the river's flow and water quality.

   Hoover Dam (originally Boulder Dam, and the first dam of its type) was
   completed in 1936. Its impoundment of the river in the Mojave Desert
   creates Lake Mead, which provides water for irrigation and the
   generation of hydroelectric power.

   Several cities such as Los Angeles, Las Vegas, San Diego, Phoenix and
   Tucson have aqueducts leading all the way back to the Colorado River.
   One such aqueduct is the Central Arizona Project ("CAP") canal, which
   was begun in the 1970s and finished in the 1990s. The canal begins at
   Parker Dam and runs all the way to Phoenix and then Tucson to
   supplement those cities' water needs.

   The Colorado is navigable by moderate sized craft throughout most of
   its length. The lower river from Davis Dam to Yuma is navigable by
   large paddlewheel boats and river barges, but commercial navigation on
   the river is unimportant because the river is cut off from the sea and
   other means of transportation are more efficient in the region. Before
   the railroads arrived, the Lower Colorado River from the Sea to near
   present day Laughlin, Nevada was an important source of transportation
   via large steamers.

Wildlife

   The Colorado River basin is home to fourteen native species of fish.
   Four are endemic and endangered: Colorado pikeminnow (formerly Colorado
   squawfish), razorback sucker, bonytail chub, and humpback chub. The
   Upper Colorado River Endangered Fish Recovery Program is an effort by
   the US Fish and Wildlife Service, in conjunction with various state
   agencies, to recover these endangered fish. The program has been met
   with controversy, however.

Moab, Utah uranium tailings

   Atlas Corporation operated a uranium mine in the area of Moab, Utah,
   just under three miles from downtown Moab. As a byproduct of mining
   activities, a ten-million-ton pile of radioactive tailings exists. The
   pile is located about 700-800 feet from the Colorado River. Although no
   pollution has been detected, proximity of the material to the watershed
   has been a concern. The Senate has authorized the US Department of
   Energy to budget $22.8 million in 2007 to begin the project of moving
   the uranium tailings further from the river. The plan is to move the
   pile 15-20 miles north and away from the river. The project is expected
   to be completed by 2017.

   Retrieved from " http://en.wikipedia.org/wiki/Colorado_River"
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   with only minor checks and changes (see www.wikipedia.org for details
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