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Archived from the original PDF on April 22, The Colorado River and its colorado river – colorado river: often nourish extensive corridors это what meaning of wdym сайтец riparian growth as they traverse the arid desert regions of the watershed. One of the main reasons the Mormons were able to colonize Arizona was the existence of Jacob Hamblin 's ferry across the Colorado at Lee's Ferry then known as Pahreah Crossingwhich xolorado running in March Water Properties The water properties kit is designed to colorado river – colorado river: students visualize and understand the chemical make-up and unique properties of water. Below the confluence with the Little Colorado Riverthe river swings west into Granite Gorge, the most dramatic portion of the Grand Canyon, where the river cuts up to one mile 1. Insix U.
Colorado river – colorado river:. The Colorado River Runs Dry
Archived from the original on July 18, University of Colorado. Archived from the original PDF on July 14, Retrieved March 16, Archived from the original on June 8, Archived from the original on June 7, New Mexico State University.
American Nile: Saving the Colorado – National Geographic.
Effective water-supply negotiation and river management are best served if Colorado River stakeholders are mindful of the precision and accuracy of the many components of the hydrologic cycle that affect the water supply. Equipped with only a horsepower engine, the Uncle Sam could only carry 35 tons of supplies, taking 15 days to make the first mile trip. Retrieved February 21, Retrieved February 19, colorado river – colorado river: June 17, Dellenbaugh, Frederick Samuel
Colorado river – colorado river:
The 1,mile-long 2, km river drains an expansive, arid watershed that encompasses parts of seven U. The name Colorado derives from the Spanish language for "colored reddish" due to its heavy silt load.
Starting in the central Rocky Mountains of Colorado , it flows generally southwest across the Colorado Plateau and through the Grand Canyon before reaching Lake Mead on the Arizona — Nevada border, where it turns south toward the international border. Known for its dramatic canyons, whitewater rapids, and eleven U. National Parks , the Colorado River and its tributaries are a vital source of water for 40 million people. Intensive water consumption has dried up the lower miles km of the river, which has rarely reached the sea since the s.
Native Americans have inhabited the Colorado River basin for at least 8, years. Starting around 1 AD, large agriculture-based societies were established, but a combination of drought and poor land use practices led to their collapse in the s.
Their descendants include tribes such as the Puebloans , while others including the Navajo settled in the Colorado Basin after the s. In the s, Spanish explorers began mapping and claiming the watershed, which became part of Mexico upon its independence in Even after most of the watershed became US territory in , much of the river's course remained unknown. Several expeditions charted the Colorado in the midth century—one of which, led by John Wesley Powell , was the first to run the rapids of the Grand Canyon.
Large-scale settlement of the lower basin began in the mid- to lates, with steamboats sailing from the Gulf of California to landings along the river that linked to wagon roads to the interior. Starting in the s, gold and silver strikes drew prospectors to the upper Colorado River basin.
Large-scale river management began in the early s, with major guidelines established in a series of international and US interstate treaties known as the " Law of the River ". The US federal government constructed most of the major dams and aqueducts between and ; the largest, Hoover Dam , was completed in Numerous water projects have also involved state and local governments.
With all of its water fully allocated, the Colorado is now considered among the most controlled and litigated rivers in the world. The environmental movement in the American Southwest has opposed the damming and diversion of the Colorado River system due to negative effects on the ecology and natural beauty of the river and its tributaries.
During the construction of Glen Canyon Dam , environmental organizations [ which? Since , extended drought has conflicted with increasing demands for Colorado River water, and the level of human development and control of the river continues to generate controversy. As it flows southwest, it gains strength from many small tributaries, as well as larger ones including the Blue , Eagle and Roaring Fork rivers.
After passing through De Beque Canyon , the Colorado emerges from the Rockies into the Grand Valley , a major farming and ranching region where it meets one of its largest tributaries, the Gunnison River , at Grand Junction. Most of the upper river is a swift whitewater stream ranging from to feet 60 to m wide, the depth ranging from 6 to 30 feet 2 to 9 m , with a few notable exceptions, such as the Blackrocks reach where the river is nearly feet 30 m deep.
From Grand Junction, the Colorado turns northwest before cutting southwest across the eponymous Colorado Plateau , a vast area of high desert centered at the Four Corners of the southwestern United States. Here, the climate becomes significantly drier than that in the Rocky Mountains, and the river becomes entrenched in progressively deeper gorges of bare rock, beginning with Ruby Canyon and then Westwater Canyon as it enters Utah , now once again heading southwest.
In Utah, the Colorado flows primarily through the " slickrock " country, which is characterized by its narrow canyons and unique "folds" created by the tilting of sedimentary rock layers along faults.
This is one of the most inaccessible regions of the continental United States. The Colorado then enters northern Arizona , where since the s Glen Canyon Dam near Page has flooded the Glen Canyon reach of the river, forming Lake Powell for hydroelectricity generation.
In Arizona, the river passes Lee's Ferry , an important crossing for early explorers and settlers and since the early 20th century the principal point where Colorado River flows are measured for apportionment to the seven U. Below the confluence with the Little Colorado River , the river swings west into Granite Gorge, the most dramatic portion of the Grand Canyon, where the river cuts up to one mile 1.
Situated southeast of metropolitan Las Vegas , the dam is an integral component for management of the Colorado River, controlling floods and storing water for farms and cities in the lower Colorado River basin. After leaving the confines of the Black Canyon , the river emerges from the Colorado Plateau into the Lower Colorado River Valley LCRV , a desert region dependent on irrigation agriculture and tourism and also home to several major Indian reservations.
Joseph C. Ives , who surveyed the lower river in , wrote that "the shifting of the channel, the banks, the islands, the bars is so continual and rapid that a detailed description, derived from the experiences of one trip, would be found incorrect, not only during the subsequent year, but perhaps in the course of a week, or even a day.
Here, several large diversions draw from the river, providing water for both local uses and distant regions including the Salt River Valley of Arizona and metropolitan Southern California. Below Imperial Dam, only a small portion of the Colorado River makes it beyond Yuma, Arizona , and the confluence with the intermittent Gila River —which carries runoff from western New Mexico and most of Arizona—before defining about 24 miles 39 km of the Mexico—United States border.
At Morelos Dam , the entire remaining flow of the Colorado is diverted to irrigate the Mexicali Valley , among Mexico's most fertile agricultural lands. Since , the stretch of the Colorado between here and the Gulf of California has been dry or a trickle formed by irrigation return flows. The Hardy River provides most of the flow into the Colorado River Delta , a vast alluvial floodplain covering about 3, square miles 7, km 2 of northwestern Mexico.
Occasionally the International Boundary and Water Commission allows a springtime pulse flow to recharge the delta. The Colorado is joined by over 25 significant tributaries, of which the Green River is the largest by both length and discharge.
In its natural state, the Colorado River poured about About 85—90 percent of the Colorado River's discharge originates in melting snowpack from the Rocky Mountains of Colorado and Wyoming. Due to water diversions, flows at the mouth of the river have steadily declined since the early s. Since , the Colorado has typically dried up before reaching the sea, with the exception of a few wet years. River flows as gauged at Lees Ferry, Arizona, about halfway along the length of the Colorado and 16 miles 26 km below Glen Canyon Dam, are used to determine water allocations in the Colorado River basin.
This figure has been heavily affected by upstream diversions and reservoir evaporation, especially after the completion of the Colorado River Storage Project in the s. The Colorado River Basin consists of , square miles , km 2 , making it the seventh largest drainage basin in North America. The areas drained within Baja California and Sonora in Mexico are very small and do not contribute significant runoff. The Upper Basin covers only 45 percent of the land area of the Colorado River Basin, but contributes 92 percent of the runoff.
Streams that are nearby the east side of the divide drain into the Mississippi River and Rio Grande , while nearby areas north of the Wind River Range drain into the Columbia River. About 72 percent of the Colorado River Basin is classified as arid, with the Sonoran and Mojave deserts covering the southern portion and the Colorado Plateau encompassing much of the central portion. About 23 percent of the basin is forest, with the largest area in the Rocky Mountains; other significant forested areas include the Kaibab , Aquarius , and Markagunt plateaus in southern Utah and northern Arizona, and the Mogollon Rim in central Arizona.
Climate in the Colorado River Basin ranges from subtropical hot desert at southern, lower elevations to alpine in the Rocky Mountains. Annual precipitation averages 6. The effect of ENSO is significantly more pronounced in the Lower Basin, where it has a strong impact on monsoonal rainfall.
As of , approximately 13 million people lived within the Colorado River basin, [n 6] while about 40 million people live in areas supplied by Colorado River water. Colorado River basin states are among the fastest-growing in the US; the population of Nevada alone increased by about 66 percent between and as Arizona grew by some 40 percent. Other significant cities include Tucson, Arizona , St. George, Utah and Flagstaff, Arizona. Due to the rugged and inhospitable topography through which the river flows, there are only a few major towns along the Colorado River itself, including Grand Junction, Colorado and Yuma, Arizona.
As recently as the Cretaceous period about million years ago, much of western North America was still part of the Pacific Ocean.
Tectonic forces from the collision of the Farallon Plate with the North American Plate pushed up the Rocky Mountains between 50 and 75 million years ago in a mountain-building episode known as the Laramide orogeny.
About 30 to 20 million years ago, volcanic activity related to the orogeny led to the Mid-Tertiary ignimbrite flare-up , which created smaller formations such as the Chiricahua Mountains in Arizona and deposited massive amounts of volcanic ash and debris over the watershed.
The time scale and sequence over which the river's present course and the Grand Canyon were formed is uncertain. Before the Gulf of California was formed around 12 to 5 million years ago by faulting processes along the boundary of the North American and Pacific plates, [] the Colorado flowed west to an outlet on the Pacific Ocean—possibly Monterey Bay on the Central California coast, and may have played a role in the formation of the Monterey submarine canyon.
Crustal extension in the Basin and Range Province began about 20 million years ago and the modern Sierra Nevada began forming about 10 million years ago, eventually diverting the Colorado southwards towards the Gulf. Antecedence played a major part in shaping other peculiar geographic features in the watershed, including the Dolores River's bisection of Paradox Valley in Colorado and the Green River's cut through the Uinta Mountains in Utah.
Sediments carried from the plateau by the Colorado River created a vast delta made of more than 10, cubic miles 42, km 3 of material that walled off the northernmost part of the gulf in approximately 1 million years. Cut off from the ocean, the portion of the gulf north of the delta eventually evaporated and formed the Salton Sink , which reached about feet 79 m below sea level.
The lake took about 50 years to evaporate after the Colorado resumed flowing to the Gulf. The present-day Salton Sea can be considered the most recent incarnation of Lake Cahuilla, though on a much smaller scale. Between 1. At least 13 lava dams were formed, the largest of which was more than 2, feet m high, backing the river up for nearly miles km to present-day Moab, Utah.
Failure of the lava dams caused by erosion, leaks and cavitation caused catastrophic floods, which may have been some of the largest ever to occur in North America, rivaling the late- Pleistocene Missoula Floods of the northwestern United States. The first humans of the Colorado River basin were likely Paleo-Indians of the Clovis and Folsom cultures, who first arrived on the Colorado Plateau about 12, years ago. Very little human activity occurred in the watershed until the rise of the Desert Archaic Culture , which from 8, to 2, years ago constituted most of the region's human population.
These prehistoric inhabitants led a generally nomadic lifestyle, gathering plants and hunting small animals though some of the earliest peoples hunted larger mammals that became extinct in North America after the end of the Pleistocene epoch. The Fremont were likely the first peoples of the Colorado River basin to domesticate crops and construct masonry dwellings; they also left behind a large amount of rock art and petroglyphs , many of which have survived to the present day. Beginning in the early centuries A.
Between and A. Both civilizations supported large populations at their height; the Chaco Canyon Puebloans numbered between 6, and 15, [] and estimates for the Hohokam range between 30, and , These sedentary peoples heavily exploited their surroundings, practicing logging and harvesting of other resources on a large scale. The construction of irrigation canals may have led to a significant change in the morphology of many waterways in the Colorado River basin. Prior to human contact, rivers such as the Gila, Salt and Chaco were shallow perennial streams with low, vegetated banks and large floodplains.
In time, flash floods caused significant downcutting on irrigation canals, which in turn led to the entrenchment of the original streams into arroyos , making agriculture difficult. The Navajo were an Athabaskan people who migrated from the north into the Colorado River basin around A. In fact, the Navajo acquired agricultural skills from the Puebloans before the collapse of the Pueblo civilization in the 14th century. The Mohave have lived along the rich bottomlands of the lower Colorado below Black Canyon since A.
They were fishermen—navigating the river on rafts made of reeds to catch Gila trout and Colorado pikeminnow — and farmers, relying on the annual floods of the river rather than irrigation to water their crops. Beginning in the 17th century, contact with Europeans brought significant changes to the lifestyles of Native Americans in the Colorado River basin.
Missionaries sought to convert indigenous peoples to Christianity — an effort sometimes successful, such as in Father Eusebio Francisco Kino 's encounter with the "docile Pimas of the Gila Valley [who] readily accepted Kino and his Christian teachings".
The Spanish introduced sheep and goats to the Navajo, who came to rely heavily on them for meat, milk and wool.
The use of horses spread through the basin via trade between the various tribes and greatly facilitated hunting, communications, travel and warfare for indigenous peoples. The more aggressive tribes, such as the Utes and Navajos, often used horses to their advantage in raids against tribes that were slower to adopt them, such as the Goshutes and Southern Paiutes. The gradual influx of European and American explorers, fortune seekers and settlers into the region eventually led to conflicts that forced many Native Americans off their traditional lands.
In what is now known as the Long Walk of the Navajo, the captives were marched from Arizona to Fort Sumner in New Mexico, and many died along the route. Four years later, the Navajo signed a treaty that moved them onto a reservation in the Four Corners region that is now known as the Navajo Nation.
