The Intermountain West , or Intermountain Region , is a geographic and geological region of the Western United States . It is located between the Rocky Mountain Front on the east and the Cascade Range and Sierra Nevada on the west.
107-697: The Old Trails Bridge is a historic bridge over the Colorado River in San Bernardino County and Mohave County in the United States, that is listed on the National Register of Historic Places (NRHP). It has also been known as Topock Bridge and as Needles Bridge . The bridge carried a now-abandoned section of the former U.S. Route 66 across from southeast of Needles , California to south of Topock , Arizona. It
214-608: A property in Arizona on the National Register of Historic Places is a stub . You can help Misplaced Pages by expanding it . This article about a property in San Bernardino County, California on the National Register of Historic Places is a stub . You can help Misplaced Pages by expanding it . This article about a bridge in Arizona is a stub . You can help Misplaced Pages by expanding it . This article about
321-695: A bridge in California is a stub . You can help Misplaced Pages by expanding it . Colorado River The Colorado River ( Spanish : Río Colorado ) is one of the principal rivers (along with the Rio Grande ) in the Southwestern United States and in northern Mexico . The 1,450-mile-long (2,330 km) river, the 5th longest in the United States , drains an expansive, arid watershed that encompasses parts of seven U.S. states and two Mexican states. The name Colorado derives from
428-464: A few decades before collapsing or being washed away. 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. Mapping of flood deposits indicate that crests as high as 700 feet (210 m) passed through
535-580: A few notable exceptions, such as the Blackrocks reach where the river is nearly 100 feet (30 m) deep. In a few areas, such as the marshy Kawuneeche Valley near the headwaters and the Grand Valley, it exhibits braided characteristics. From Grand Junction, the Colorado turns northwest before cutting southwest across the eponymous Colorado Plateau , a vast area of high desert centered at
642-577: A large system of irrigation canals making use of the Salt River . Both civilizations supported large populations at their height, with 6,000–15,000 in Chaco Canyon and as many as 30,000–200,000 Hohokam. Puebloan and Hohokam settlements were abruptly abandoned in the 1400s CE, due both to over-exploitation of natural resources such as timber, and severe drought that made it impossible to maintain irrigation systems. Many Puebloans migrated east to
749-693: A military advantage over Goshutes and Southern Paiutes that were slower to adopt horses. The Navajo also adopted a culture of livestock herding as they acquired sheep and goats from the Spanish. Juan Bautista de Anza in 1774 was the first Spaniard to reach Yuma Crossing, where he established friendly relations with the Quechan people and opened the Anza trail between Arizona and the California coast. The Spanish soon founded Mission Puerto de Purisima Concepcion and Mission San Pedro y San Pablo de Bicuner along
856-694: A mountain-building episode known as the Laramide orogeny . The Colorado River first formed as a west-flowing stream draining the southwestern portion of the range, and the uplift also diverted the Green River, once a tributary of the Mississippi River , west towards the Colorado. 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
963-481: A route for a proposed railroad through the canyon, which was never built. We are now ready to start on our way down the Great Unknown. Our boats, tied to a common stake, are chafing each other, as they are tossed by the fretful river. They ride high and buoyant, for their loads are lighter than we could desire. We have but a month's rations remaining… The lighting of the boats has this advantage: they will ride
1070-490: A short run south, the river turns west below Grand Lake , the largest natural lake in the state. For the first 250 miles (400 km) of its course, the Colorado carves its way through the mountainous Western Slope , a sparsely populated region defined by the portion of the state west of the Continental Divide . As it flows southwest, it gains strength from many small tributaries, as well as larger ones including
1177-474: A significant distance from the river. The Puebloan people built many multi-story pueblos or "great houses", and developed complex distribution systems to supply drinking and irrigation water in Chaco Canyon in northwestern New Mexico and Mesa Verde in southwest Colorado. The Hohokam , present in the modern Phoenix area since about 0 CE, experienced prolific growth around 600-700 CE as they constructed
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#17327985649981284-569: Is a brace-ribbed through arch bridge that was built in 1915–1916. It served as a highway bridge until 1947 when the Red Rock Bridge , formerly a railroad bridge, was modified for highway use. The Old Trails Bridge was later converted to a pipeline bridge . It was listed on the NRHP on September 30, 1988. The bridge has been seen in a number of blockbuster films including The Grapes of Wrath and Easy Rider . This article about
1391-538: Is at Imperial Dam , where over 90 percent of the river's flow is moved into the Gila Gravity Canal and Yuma Area Project, and the much bigger All-American Canal to irrigate California's Imperial Valley , the most productive winter agricultural region in the United States. Below Imperial Dam, only a small portion of the Colorado River makes it beyond Yuma, Arizona , and the confluence with
1498-476: Is estimated at 14.7 million acre-feet (18.1 km ), or an annualized discharge of 20,300 cu ft/s (570 m /s), for the 1906–2023 period. River flows at the Lees Ferry stream gauge, 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. Flows originating above Lees Ferry represent
1605-796: Is now known as the Long Walk and while enduring appalling conditions at Fort Sumner. After the failure of the Army to maintain the reservation there, the Treaty of Bosque Redondo established the Navajo Nation in the Four Corners, where the Navajo were allowed to return in 1868. Gold and silver were also discovered in the Upper Basin, beginning with the 1859 Blue River strike that led to
1712-758: Is only 2–3 percent of the entire basin. Urban areas cover less than 1 percent. Climate in the Colorado River Basin ranges from subtropical hot desert at southern, lower elevations to alpine in the Rocky Mountains. Mean monthly high temperatures are 25.3 °C (77.5 °F) in the Upper Basin and 33.4 °C (92.1 °F) in the Lower Basin, and lows average −3.6 and 8.9 °C (25.5 and 48.0 °F), respectively. Annual precipitation averages 6.5 inches (164 mm), ranging from over 60 inches (1,500 mm) in some areas of
1819-589: Is owned by Union Pacific . As late as 1921, the Colorado River upstream from the confluence with the Green River in Utah was still known as the Grand River. For over a decade, U.S. Representative Edward T. Taylor of Colorado had petitioned the Congressional Committee on Interstate and Foreign Commerce to rename the Grand River as the Colorado River. Representatives from Wyoming, Utah, and
1926-533: Is practiced in the region as well. Cultivated crops include corn , potatoes , sugar beets , grass hay , and alfalfa , the latter two crops are used for livestock feed. For thousands of years the Intermountain West has been the homeland for many Native American cultures, tribes, and bands. The 18th-century fur trade (northern areas), and 19th-century westward expansion of the United States brought irreversible cultural changes. The completion of
2033-571: Is significantly more pronounced in the Lower Basin, where it has a strong impact on monsoonal rainfall. Runoff patterns across the Colorado River Basin reflect this; most of the perennial tributaries originate in the Upper Basin, while tributaries in the Lower Basin are either ephemeral (such as the Little Colorado River) or highly seasonal (such as the Gila and Salt rivers). As of 2010, approximately 13 million people lived within
2140-544: Is the second longest and drains a greater area than the Green, but has a significantly lower flow because of a more arid climate and larger diversions for irrigation and cities. Both the Gunnison and San Juan rivers, which derive most of their water from Rocky Mountains snowmelt, contribute more water than the Gila contributed naturally. The Colorado River Basin consists of 246,000 square miles (640,000 km ), making it
2247-735: Is unknown. The Grand River above the confluence with the Gunnison River was also called the Bunkara River, the Blue River, or the North Fork of the Grand River until the 1870s. By the early 1900s the name "Grand River" had been attached to the entire stream as far as Grand Lake, which was then considered its official source. Although the Grand River was renamed the Colorado in 1921, its name survives in numerous places such as Grand County and Grand Junction, Colorado. In 1848
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#17327985649982354-585: The Baja California – Sonora border. Since 1960, 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 3,000 square miles (7,800 km ) of northwestern Mexico. A large estuary is formed here before
2461-606: 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 200 to 500 feet (60 to 150 m) wide, the depth ranging from 6 to 30 feet (2 to 9 m), with
2568-556: The Chiricahua Mountains in Arizona and deposited massive amounts of volcanic ash and debris over the watershed. The Colorado Plateau first began to rise during the Eocene , between about 55 and 34 million years ago, but did not attain its present height until about 5 million years ago, about when the Colorado River established its present course into the Gulf of California. The time scale and sequence over which
2675-659: The Colorado River Indian Tribes . As the American frontier expanded into the Colorado Plateau, an effort to expel the Navajo from the Four Corners region was begun by General James Henry Carleton , who in 1864 enlisted mountain man Kit Carson to lead a campaign against the Navajo. Carson, with the help of the Navajo's Ute enemies, captured more than 8,000 Navajo and forcibly marched them to Fort Sumner , New Mexico. Hundreds died during what
2782-604: The Columbia River and Colorado River . Other regional rivers and streams are in endorheic basins and cannot reach the sea, such as the Walker River and Owens River . These flow into brackish or seasonally dry lakes or desert sinks . Portions of this region include: The climate of the Intermountain Region is affected by location and elevation. The sub-regions are in rain shadows from
2889-573: The First transcontinental railroad through the region accelerated non-native settlements and development. Historically, the Intermountain West area centered in Utah is associated with Latter-day Saint (Mormon) settlements, and the region has the highest percentage of LDS members in the United States currently. That region is also known as the Mormon Corridor . The intermountain states are generally considered to be Nevada , Utah , Idaho ,
2996-627: 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. Farther downstream it receives the Dolores River and defines the southern border of Arches National Park , before passing Moab and flowing through "The Portal", where it exits
3103-556: The Fremont culture period (0–1300 CE). The Ancient Puebloan culture, also known as Anasazi or Hisatsinom, were descended from the Desert Archaic culture and became established in the Four Corners region around 1000 CE. While there is much evidence of ancient habitation along the Colorado River, including stone dwellings, petroglyphs and pottery in places such as Glen Canyon, the first major agriculture-based societies arose
3210-799: The Grand Mesa ; the Weenuchiu lived along the San Juan River, and the Parianuche and Yamparika lived in the Yampa, White and Duchesne River valleys. The Ute ranged as far as the river’s headwaters; one Ute story recounts a battle with the Arapaho at Grand Lake, which they believe still hosts the spirits of the deceased. Starting in the 1500s, the Spanish began to explore and colonize western North America. Francisco de Ulloa may have been
3317-627: The Great Salt Lake and Sevier Lake watersheds. To the south, the Colorado River Basin borders several watersheds in Mexico draining into the Gulf of California, including the Sonoyta , Concepción , and Yaqui rivers. Much of the basin is at high elevation; the mean elevation is 5,500 feet (1,700 m). Lees Ferry, more than halfway along the Colorado River from its source, is 3,150 feet (960 m) above sea level. The highest point in
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3424-478: The Intermountain West . Intensive water consumption has dried up the lower 100 miles (160 km) of the river, which has rarely reached the sea since the 1960s. Native Americans have inhabited the Colorado River basin for at least 8,000 years. Starting around 1 CE, large agriculture-based societies were established, but a combination of drought and poor land use practices led to their collapse in
3531-627: The Mogollon Rim in central Arizona. These high plateaus and escarpments, often exceeding 9,000 feet (2,700 m) in elevation, form the northern and southern edges of the Colorado Plateau geological province. Developed land use in the basin is mostly irrigated agriculture, chiefly in the Grand Valley , the Lower Colorado River Valley , and the Salt River Valley , but the total area of crop and pasture land
3638-531: 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. As the Colorado Plateau continued to rise between 5 and 2.5 million years ago, the river maintained its ancestral course (as an antecedent stream ) and began to cut
3745-690: The Pacific Ocean and Mexican Plateau . The flora at lower elevations includes deserts and xeric shrublands and temperate grasslands and shrublands biome vegetation. Higher elevation montane habitats include temperate coniferous forests biome vegetation, including groves and forests of various species of pine , cedar , juniper , aspen , and other trees, and understory shrubs , and perennials . Intermountain West ecoregions include: Some sections are agriculturally cultivated with water diversions for irrigation systems . Cattle ranching
3852-546: The Southern Paiute ) and the Kumeyaay inhabited the desert to the river’s west. Those living along the lower Colorado River depended more on fishing and floodplain agriculture than on irrigation, and mostly did not live in permanent settlements. The site of modern-day Yuma has been an important river crossing since ancient times, as the channel here is much narrower compared to the expansive, swampy river bottoms to
3959-504: The United States Geological Survey objected, noting that the Green River was longer and drained a larger area. Taylor argued that the Grand River should be considered the main stream, as it carried the larger volume of water. Taylor felt “slighted” that the Colorado River, as named, did not begin in the state of Colorado, and “he wasn’t going to let Utah or Wyoming lay claim to the river’s headwaters, despite
4066-614: The 1300s. Their descendants include tribes such as the Puebloans , while others including the Navajo settled in the Colorado Basin after the 1000s. In the 1500s, Spanish explorers began mapping and claiming the watershed, which became part of Mexico upon winning its independence from Spain in 1821. Even after most of the watershed became US territory in 1846, much of the river's course remained unknown. Several expeditions charted
4173-526: The 1500s. Navajo Mountain and Rainbow Bridge in the Glen Canyon area came to hold particular religious significance for the Navajo, and the nearby confluence of the Colorado and San Juan River is regarded as the birthplace of clouds and rain. The Ute also became established in the Colorado Plateau around 1500 CE, although they had inhabited more northerly parts of the Colorado basin (modern Wyoming and northern Colorado) since at least 0 CE. They are
4280-679: The Arizona–Nevada and Arizona– California borders. 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 . The river widens here to a broad, moderately deep waterway averaging 500 to 1,000 feet (150 to 300 m) wide and reaching up to 0.25 miles (400 m) across, with depths ranging from 8 to 60 feet (2 to 20 m). Before channelization of
4387-537: The Army had driven out the remaining pockets of Ute resistance on the Western Slope, officially opening the Grand River country to settlement, and the town of Grand Junction was incorporated a year later. The Denver and Rio Grande Western Railroad (D&RGW) quickly expanded into this area to serve mining boomtowns, crossing the Rockies to the south via the Black Canyon of the Gunnison River . By 1883
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4494-407: The Cascade or Sierra Nevada ranges that block precipitation from Pacific storms. The winter weather depends on latitude . In the southern portion, winters are shorter, warmer and have less winter precipitation and snow. In the northern portion, winters are cold and moist. All areas have hot summers. North American Monsoon storms can occur in the region during the mid-summer, coming northeast from
4601-435: The Colorado River Basin is 14,321-foot (4,365 m) Uncompahgre Peak in Colorado's San Juan Mountains , while some water from the river drains via irrigation run-off into California's Salton Sea , 236 feet (72 m) below sea level. 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
4708-401: The Colorado River Basin. 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 . The unimpaired annual runoff of the Colorado River at Lees Ferry, Arizona
4815-408: The Colorado River Delta almost entirely dry except for small amounts of agricultural wastewater. As recently as the Cretaceous period about 100 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
4922-549: The Colorado River Delta prior to the early 20th century. Up to 90 percent of the river's flow originates as snowmelt from the Rocky Mountains and other smaller mountain ranges of the Colorado Plateau. Natural seasonal flows at its mouth varied widely, often exceeding 100,000 cu ft/s (2,800 m /s) in the spring melt and falling as low as 2,500 cu ft/s (71 m /s) in winter. Snowmelt typically begins in April, peaks in May or June, and can extend into August in wet years. Monsoon rainstorms often occur in
5029-405: The Colorado River Delta, the basin extends into Sonora at a few locations further east, including the headwaters of the Santa Cruz River and San Pedro River (both tributaries of the Gila River). For hydrological management purposes, the Colorado River Basin is divided into the Upper Basin (the drainage area above Lees Ferry), and the Lower Basin . The Upper Basin covers only 45 percent of
5136-424: The Colorado River basin, 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 1990 and 2000 as Arizona grew by some 40 percent. Phoenix, Arizona , Las Vegas, Nevada and Mexicali, Baja California are the largest cities by population within
5243-425: The Colorado River near the junction with the Dolores River , naming the larger river “Rio San Rafael”. They later forded the Colorado in southeastern Utah at Crossing of the Fathers , now submerged in Lake Powell. In the 1820s, American fur trappers along the upper Green River in Wyoming (known to them as the "Seedskeedee" or variants thereof), seeking a route to export furs to the coast, surmised that this and what
5350-482: The Colorado and the neighboring Rio Grande are now considered among the most controlled and litigated river systems in the world. Since 2000, 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. The Colorado begins at La Poudre Pass in the Never Summer Mountains in Rocky Mountain National Park , 10,184 ft (3,104 m) above sea level. After
5457-485: The Colorado empties into the Gulf about 75 miles (120 km) south of Yuma. Occasionally the International Boundary and Water Commission allows a springtime pulse flow to recharge the delta. Before 20th-century development dewatered the lower Colorado, a major tidal bore was present in the delta and estuary; the first historical record was made by the Croatian missionary in Spanish service Father Ferdinand Konščak on July 18, 1746. During spring tide conditions,
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#17327985649985564-416: The Colorado enters Cataract Canyon , named for its dangerous rapids, and then Glen Canyon , known for its arches and erosion-sculpted Navajo sandstone formations. Here, the San Juan River , carrying runoff from the southern slope of Colorado's San Juan Mountains , joins the Colorado from the east. The Colorado then enters northern Arizona , where since the 1960s Glen Canyon Dam near Page has flooded
5671-434: The Colorado in the 20th century, the lower river was subject to frequent course changes caused by seasonal flow variations. Joseph C. Ives , who surveyed the lower river in 1861, 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
5778-405: The Colorado in the mid-19th 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 late-1800s, with steamboats sailing from the Gulf of California to landings along the river that linked to wagon roads to the interior. Starting in the 1860s, gold and silver strikes drew prospectors to
5885-400: The Continental Divide, but ran out of money before even reaching Utah. In 1931 the D&RGW completed the "Dotsero Cutoff" linking Glenwood Springs to the D&SL route at Bond, Colorado , finally completing the direct Denver–Salt Lake link with its acquisition of the bankrupt D&SL. The Gunnison River route was eventually abandoned in favor of the shorter Colorado River route, which today
5992-413: 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.S. and two Mexican states in the basin. Downstream, the river enters Marble Canyon ,
6099-454: The Grand Canyon, reaching peak discharges as great as 17 million cubic feet per second (480,000 m /s). Small numbers of Paleo-Indians of the Clovis and Folsom cultures inhabited the Colorado Plateau as early as 10,000 BCE, with populations beginning to increase in the Desert Archaic period (6000 BCE–0 CE). While most early inhabitants were hunter-gatherers, evidence of agriculture, masonry dwellings and petroglyphs begins with
6206-412: The Grand Canyon. 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 10,000 cubic miles (42,000 km ) of material that walled off
6313-412: The Grand Canyon. At least 13 lava dams were formed, the largest of which was more than 2,300 feet (700 m) high, backing the river up for nearly 500 miles (800 km) to present-day Moab, Utah. The lack of associated sediment deposits along this stretch of the Colorado River, which would have accumulated in the impounded lakes over time, suggests that most of these dams did not survive for more than
6420-412: The Lower Basin from August through October, contributing much of the flow in tributaries below Lees Ferry and often causing flash flooding . Since the initial closure of Hoover Dam in 1934, lower Colorado River flows have been greatly moderated, with monthly means below the dam ranging from 16,400 cu ft/s (460 m /s) in May to 11,200 cu ft/s (320 m /s) in October. Upstream of
6527-460: The Moab Valley between a pair of 1,000-foot (300 m) sandstone cliffs. 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. Below the confluence with the Green River , its largest tributary, in Canyonlands National Park ,
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#17327985649986634-405: The Rio Grande Valley, while others persisted in smaller settlements on the Colorado Plateau. Puebloan descendants include the Hopi , Zuni , Laguna and Acoma peoples of modern Arizona and New Mexico. O'odham peoples, including the Akimel O'odham (Pima) and Maricopa who continue to live in southern Arizona, are believed to be descended from the Hohokam. The lower Colorado River valley
6741-488: The Rockies to less than 4 inches (100 mm) in dry desert valleys. The Upper Basin generally receives snow and rain during the winter and early spring, while precipitation in the Lower Basin falls mainly during intense but infrequent summer thunderstorms brought on by the North American Monsoon . Precipitation is influenced by the El Niño-Southern Oscillation (ENSO) with El Niño being associated with wetter conditions and La Niña with drier conditions. The effect of ENSO
6848-411: The Rockies. Water diversions have effectively removed some tributaries entirely, including the Gila River, once the Colorado's largest tributary below Lees Ferry. Most Colorado River water is diverted in the United States, with only about 2.8 million acre-feet (3.5 km ) per year reaching Mexico since 1950. At Morelos Dam, the remaining flow is diverted to irrigate the Mexicali Valley, leaving
6955-475: The Spanish called the Colorado were in fact connected. William H. Ashley made an unsuccessful attempt to navigate from the Green River to the Colorado's mouth in 1825. In 1826, Jedediah Smith arrived at the lower Colorado River, referring to it as the Seedskeedee, and proceeded upstream, exploring as far as Black Canyon. During the 1830s, various fur trappers from Wyoming made it as far downstream as Cataract Canyon and Glen Canyon, but none were able to navigate
7062-425: 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 . After entering Mexico, the Colorado approaches the mostly dry Colorado River Delta at
7169-420: The U.S. Army established Fort Yuma , creating the first permanent U.S. settlement along the river. This served as a military garrison and supply point for settlers headed to California along the Southern Emigrant Trail . Due to the arduous task of ferrying supplies overland, the schooner Invincible attempted to bring supplies up the river but was thwarted by the delta’s strong tides. Steamboats were brought to
7276-450: The Virgin River, enabled shipping of their produce by wagon to gold mining districts further south. Although the Mormons abandoned St. Thomas in 1871, a salt-mining industry persisted here, and steamboats operated up to nearby Rioville into the 1880s. In 1879 a group of Mormon settlers made their way to southeastern Utah, blasting the precarious Hole in the Rock Trail to cross the Colorado River at Glen Canyon, subsequently establishing
7383-447: The beginning of the Grand Canyon , passing under the Navajo Bridges on a now southward course. 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 (1.6 km) into the Colorado Plateau, exposing some of the oldest visible rocks on Earth, dating as long ago as 2 billion years. The 277 miles (446 km) of
7490-416: The central portion. The Colorado Plateau is home to most of the major canyon systems formed by the Colorado River and its tributaries, particularly those of the Green and San Juan rivers. 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
7597-432: The channel, we know not; what walls rise over the river, we know not; Ah, well! we may conjecture many things. The men talk as cheerfully as ever; jests are bandied about freely this morning; but to me the cheer is somber and the jests are ghastly. In 1858, gold was discovered on the Gila River east of Yuma, then along the Colorado River at El Dorado Canyon, Nevada and La Paz, Arizona . As prospectors and settlers entered
7704-644: The community of Bluff . Due to the dry climate, these settlements depended heavily on irrigation. In central Arizona, settlers uncovered and re-established canals previously used by the Hohokam. Following tensions between Mormon settlers and the U.S. government in the Utah War , a local militia including John D. Lee perpetrated the 1857 Mountain Meadows Massacre , in which 120 non-Mormon settlers were killed. Fearing retribution, Lee moved in 1870 to
7811-454: The course of a week, or even a day." The LCRV is one of the most densely populated areas along the river, and there are numerous towns including Bullhead City, Arizona , Needles, California , and Lake Havasu City, Arizona . 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 . The last major U.S. diversion
7918-540: 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. Below the dam the river passes under the Mike O'Callaghan–Pat Tillman Memorial Bridge —which at nearly 900 feet (270 m) above the water is the highest concrete arch bridge in the Western Hemisphere —and then turns due south towards Mexico, defining
8025-595: 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 . The western boundary of the Colorado River Basin is formed by various ranges and plateaus that border the Great Basin , including the Uinta Mountains and Wasatch Range . Major Great Basin watersheds bordering the Colorado River Basin are
8132-482: The fact that the Green River is the larger drainage basin.” On July 25, 1921, President Warren G. Harding signed House Joint Resolution 32 - “To change the name of the Grand River in Colorado and Utah to the Colorado River.” Intermountain West The Intermountain West has a basin and range and plateau topography. Some of the region's rivers reach the Pacific Ocean , such as
8239-520: The ferry obsolete. The Denver and Salt Lake Railway (D&SL), incorporated in 1902, sought to provide a more direct connection between Denver and Salt Lake City than either the transcontinental railroad through Wyoming or the D&;RGW’s route via Black Canyon and Durango. The D&SL completed a rail line into the upper headwaters of the Colorado River and blasted the Moffat Tunnel under
8346-529: The first European to see the river, when in 1536 he sailed to the head of the Gulf of California. In 1540 García López de Cárdenas became the first European to see the Grand Canyon, during Coronado 's expedition to find the Seven Cities of Gold ("Cibola"). Cárdenas was apparently unimpressed with the canyon, greatly underestimating its size, and left in disappointment with no gold to be found. In
8453-408: The first known inhabitants of this part of the Rocky Mountains, and made use of an extensive network of trails crisscrossing the mountains to move between summer and winter camps. The Ute were divided into numerous bands with separate territories but shared a common language and customs. The Uncompahgre or Tabeguache lived around the confluence of the upper Colorado and Gunnison Rivers, an area including
8560-452: The first part of non-natives to travel the length of the Grand Canyon, and the first to successfully travel by boat from the upper Green River to the lower Colorado. Powell led a second expedition in 1871, with financial backing from the U.S. government, and continued to conduct geographical and botanical surveys across the region until the 1890s. Another Grand Canyon river expedition was led in 1889-1890 by Robert Brewster Stanton to survey
8667-582: The founding of Breckenridge, Colorado . Up until the 1860s, southwestern Colorado had remained relatively untouched by U.S. westward expansion, as the Americans had recognized Ute sovereignty by treaty. Following the 1861 carving out of Colorado Territory and further mineral strikes including Ouray and Telluride , Ute leaders were coerced into signing the 1873 Brunot Agreement , in which they lost rights to most of their land. A flood of mineral prospecting and settlement ensued in western Colorado. By 1881,
8774-485: The full length of the river. In 1843 John C. Frémont explored the Great Basin and conclusively determined no Buenaventura River flowed west to California; thus, the direction of river flow must be southwest. By the early 19th century, the stretch of the Colorado above the confluence of the Green River at Cataract Canyon , Utah, became known to fur trappers as the "Grand River", though the exact origin of this name
8881-536: The intermittent Gila River —which carries runoff from western New Mexico and most of Arizona–before defining 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. Below San Luis Río Colorado , the Colorado passes entirely into Mexico, defining
8988-753: The land area of the Colorado River Basin, but contributes 92 percent of the runoff. The entire eastern boundary of the Colorado River Basin runs along the North American Continental Divide and is defined largely by the Rocky Mountains and the Rio Grande Basin . The Wind River Range in Wyoming marks the northern extent of the basin, and is separated from the Colorado Rockies by the endorheic Great Divide Basin in southwestern Wyoming. Streams that are nearby
9095-513: The lower Colorado River. However, Spanish attempts to control the crossing led to the 1781 Yuma revolt, in which over 100 soldiers and colonists were killed, and the settlements were abandoned. The Quechan blocked foreigners’ use of the crossing until the arrival of American mountain men and fur trappers in the 1820s. The name Rio Colorado first appears in 1701, on the map "Paso por Tierra a la California" published by missionary Eusebio Kino , who also determined during that time that Baja California
9202-565: The majority of Colorado River runoff. Tributaries between there and Imperial Dam near the US–Mexico border contribute a further 1.1 million acre-feet (1.4 km ), and the Gila– Salt River system historically accounted for another 1.7 million acre-feet (2.1 km ). While much of this water was lost to evaporation in the deserts of the Lower Basin, anywhere from 10 to 20 million acre-feet (12 to 25 km ) per year reached
9309-495: The massive Hoover and Glen Canyon Dams, inflows to Lake Powell still experience distinct spring highs and winter lows, though overall volumes have been reduced due to Upper Basin water diversions. Flow regimes in a few Upper Basin tributaries, such as the Yampa River , remain almost completely unaltered. By the 1950s, the Colorado delta was regularly drying up in fall and winter, though spring high flows often still made it to
9416-688: The north and south, and enabled the expansion of trade to the Pima and Maricopa in the east and coastal California tribes in the west. The Navajo (Diné) began migrating into the Colorado River Basin around 1000-1500 CE, and eventually exercised influence over much of the Colorado Plateau. Originally hunter-gatherers, they acquired knowledge of farming from the Puebloans and adopted a more sedentary lifestyle over time, making extensive use of irrigation in their settlements. The Navajo gradually displaced Hopi settlements as they expanded into northern Arizona after
9523-524: 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 260 feet (79 m) below sea level. Since then the river has changed course into the Salton Sink at least three times, transforming it into Lake Cahuilla , which at maximum size flooded up
9630-423: The ocean. After the initial closure of Glen Canyon Dam in 1963, these seasonal flows were almost completely eliminated, with the exception of a few very wet years, such as 1983–1987. In 1984, 16.5 million acre-feet (20.4 km ) of excess runoff reached the ocean. Flows have further declined due to evaporation from reservoirs and, particularly after 2000, reduced snowpack with warming winter temperatures in
9737-462: The railroad had reached Grand Junction, and a spur up the Colorado to Glenwood Springs was completed in 1887. In Arizona and Utah Territories , many early settlers were Mormons fleeing religious persecution in the Midwest. Mormons founded agricultural colonies at Fort Santa Clara in 1855 and St. Thomas , now flooded under Lake Mead, in 1865. Stone's Ferry , crossing the Colorado at the mouth of
9844-572: The region, they became involved in skirmishes with the Mohave, spurring U.S. Army expeditions that culminated in the 1859 Battle of the Colorado River which concluded the Mohave War . In the 1870s the Mohave were moved to the Fort Mohave and Colorado River reservations. Chemehuevi and later some Hopi and Navajo peoples were also moved to the Colorado River reservation, where they today form
9951-466: The remote Pahreah Crossing in Arizona, where he took over a ferry first established in 1864 by Jacob Hamblin . This, the only river crossing for hundreds of miles not hemmed in by vertical canyon walls, became known as Lee's Ferry . While Lee was tried and subsequently executed in 1877, the ferry remained a major transportation link until the Navajo Bridge was completed nearby in 1928, rendering
10058-454: The river that flow through the Grand Canyon are largely encompassed by Grand Canyon National Park and are known for their difficult whitewater, separated by pools that reach up to 110 feet (34 m) in depth. At the lower end of Grand Canyon, the Colorado widens into Lake Mead , the largest reservoir in the continental United States, formed by Hoover Dam on the border of Arizona and Nevada . Situated southeast of metropolitan Las Vegas ,
10165-612: 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
10272-528: The river's suitability as a navigation route, Ives remarked: "Ours has been the first, and will doubtless be the last, party of whites to visit this profitless locality. It seems intended by nature that the Colorado River, along the greater portion of its lonely and majestic way, shall be forever unvisited and undisturbed." The last part of the Colorado River to be surveyed was the Grand Canyon itself. In 1869, John Wesley Powell with nine men set out on an expedition from Green River Station, Wyoming . They were
10379-573: The river, starting in 1852 with the sidewheeler Uncle Sam , whose first voyage from the Gulf to Yuma took fifteen days. Exploration by steamboat soon advanced upriver. In 1857, George A. Johnson in the General Jesup was able to reach Pyramid Canyon , over 300 miles (480 km) north of Fort Yuma. He was followed by Lt. Joseph Christmas Ives who used a specially built shallow-draft steamboat, Explorer , to reach Black Canyon , where Hoover Dam stands today. Having set out to determine
10486-464: The same year Melchior Díaz explored the Colorado River's delta and named it Rio del Tizon ("fire brand river"), after seeing a practice used by the local people for warming themselves. By the late 1500s or early 1600s, the Utes had acquired horses from the Spanish, and their use for hunting, trade and warfare soon became widespread among Utes and Navajo in the Colorado River basin. This conferred them
10593-519: The seventh largest drainage basin in North America. About 238,600 square miles (618,000 km ), or 97 percent of the basin, is in the United States. The basin extends into western Colorado and New Mexico, southwestern Wyoming , eastern and southern Utah, southeastern Nevada and California, and most of Arizona. The areas drained within Baja California and Sonora in Mexico are very small and do not contribute significant runoff. Aside from
10700-506: The tidal bore—locally called El Burro —formed in the estuary about Montague Island in Baja California and propagated upstream. The Colorado is joined by over 25 significant tributaries, of which the Green River is the largest by both length and discharge. The Green River takes drainage from the Wind River Range of west-central Wyoming, from Utah's Uinta Mountains , and from the Rockies of northwestern Colorado. The Gila River
10807-565: The tip of the Gulf of California between Baja California and Sonora . Known for its dramatic canyons, whitewater rapids, and eleven U.S. National Parks , the Colorado River and its tributaries are a vital source of water for 40 million people. An extensive system of dams , reservoirs, and aqueducts divert almost its entire flow for agricultural irrigation and urban water supply. Its large flow and steep gradient are used to generate hydroelectricity , meeting peaking power demands in much of
10914-532: The upper Colorado River basin. Large-scale river management began in the early 1900s, 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 1910 and 1970; the largest, Hoover Dam , was completed in 1935. Numerous water projects have also involved state and local governments. With all of their waters fully allocated, both
11021-478: The valley to present-day Indio, California . 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 1.8 million and 10,000 years ago, massive flows of basalt from the Uinkaret volcanic field in northern Arizona dammed the Colorado River within
11128-509: The waves better, and we shall have little to carry when we make a portage. We are three-quarters of a mile in the depths of the earth, and the great river shrinks into insignificance, as it dashes its angry waves against the walls and cliffs, that rise to the world above; they are but puny ripples, and we but pigmies, running up and down the sands, or lost among the boulders. We have an unknown distance yet to run; an unknown river yet to explore. What falls there are, we know not; what rocks beset
11235-639: The western third of Montana , Arizona north of the Mogollon Rim , Colorado from the Front Range westward, New Mexico from the central mountain chain westward, California east of the Sierra Nevada and Cascade ranges, and Far West Texas from the Pecos River westward. The intermountain states are so named from having all or portions between the Rockies, Sierras, and Cascades. The intermountain states are included among states classified as
11342-539: Was a peninsula, not an island as previously believed. In the 1700s and early 1800s many Spanish and American explorers believed in the existence of a Buenaventura River that ran from the Rocky Mountains to the Pacific coast. In 1776, Silvestre Vélez de Escalante attached this name to the upper Green River, and a number of later maps showed this connecting to Lake Timpanogos (now Utah Lake ) and flowing west to California. The Dominguez–Escalante expedition first reached
11449-837: Was inhabited for thousands of years by numerous tribes of the Patayan cultures, many of which belong to the Yuman-Cochimi language group . These include the Walapai , Havasupai and Yavapai in the Grand Canyon region; the Mohave , Halchidhoma , Quechan , and Halyikwamai along the Colorado River between Black Canyon and the Mexican border, and the Cocopah around the Colorado River Delta. The Chemehuevi (a branch of
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