The Colorado River is a major river of the western United States and northwest Mexico in North America. Its source is La Poudre Pass Lake. Located in the Rocky Mountains of north-central Colorado, it flows southwest through the Colorado Plateau country of western Colorado, southeastern Utah, and northwestern Arizona, where it flows through the Grand Canyon. It turns south near Las Vegas, Nevada, forming the Arizona–Nevada border in Lake Mead and the Arizona–California border a few miles below Davis Dam between Laughlin, Nevada and Needles, California, before entering Mexico in the Colorado Desert. Most of its waters are diverted into the Imperial Valley of Southern California. In Mexico, its course forms the boundary between Sonora and Baja California before entering the Gulf of California. This article describes most of the major features along the river. The gulf of california is over here
Colorado The Colorado River rises on the Continental Divide at La Poudre Pass, in Rocky Mountain National Park, about north of Lake Granby, as a tiny stream draining a wet meadow. At the river's headwater, the Continental Divide forms the boundary between the Gulf of Mexico and Pacific Ocean watersheds of North America, between Colorado's Grand and Larimer counties, and the northern boundary of Rocky Mountain National Park.
The river's first diversion is here at its headwater. The Grand Ditch redirects water from the Never Summer Mountains, which would have flowed into the Colorado River, to instead flow across the divide through La Poudre Pass to irrigate farmland to the east.
About a mile (1.5 km) downstream from its source, the Colorado River has carved its first canyon, the narrow, deep Little Yellowstone Canyon. It then flows through the broad Kawuneeche Valley, where it is joined by U.S. Highway 34, which will roughly parallel it to the town of Granby. It finally exits Rocky Mountain National Park, flowing into Shadow Mountain Lake and then into Lake Granby, which are portions of the Colorado-Big Thompson Project, a large trans-basin water storage and delivery project that diverts water from the Colorado River under the Front Range mountains to provide an agricultural and municipal water supply for the northern Front Range and plains of Colorado. The traditional breakdown of water usage for the river in the state is approximately 80 percent for agriculture and 10 percent for municipal and industrial consumption.Spivak, Daniel S. “The Colorado River Drought Contingency Plan: An Opportunity for Exploring Demand Management Through Integrated and Collaborative Water Planning.” Natural Resources Journal, vol. 61, no. 2, 2021, pp. 173–204. JSTOR website Retrieved 5 June 2023.
Starting in Granby, the river is roughly paralleled by U.S. Highway 40 to the town of Kremmling, and by the tracks of the Union Pacific Railroad until about the Utah border, carrying the Amtrak California Zephyr passenger train. The canyons and valleys of the Upper Colorado River are among the scenic attractions for passengers on this rail route.
Just downstream from Granby, the Colorado is joined by the Fraser River and flows through Windy Gap Reservoir, where more water is diverted to the Front Range via the Windy Gap Project. At Hot Sulphur Springs the river flows through Byers Canyon and then is joined by the Williams Fork from the left and Muddy Creek from the right shortly thereafter. Just below Kremmling it is joined by the Blue River from the left before flowing through Gore Canyon, famous for its challenging rapids for the sport of whitewater rafting, and where it drops significantly until State Highway 131 crosses at the village of State Bridge, where the Piney River joins from the left. The Eagle River joins from the left in the town of Dotsero, from where Interstate 70 will parallel the Colorado almost until it enters Utah.
Below Dotsero the Colorado flows through Glenwood Canyon, emerging at the city of Glenwood Springs where the swift flowing Roaring Fork River, its second largest tributary in Colorado joins from the left. West of Glenwood Springs, the Colorado runs through a wider valley along the northern foothills of the Grand Mesa, passing the towns of New Castle, Silt, Rifle and De Beque. It then flows through De Beque Canyon, where it is joined by Plateau Creek.
The Colorado then enters the Grand Valley, where its waters are used to irrigate over of agricultural land. Here it passes Grand Junction, the largest town on the upper Colorado, where it is joined by the Gunnison River, its largest tributary within Colorado and second largest overall. The Gunnison drains from the northern San Juan Mountains, Elk Mountains and Sawatch Range – which includes Colorado's highest peak, Mount Elbert – and carves the Black Canyon of the Gunnison before joining the Colorado. In the Grand Valley the Colorado becomes a meandering river in contrast to the steep mountain canyons above Grand Junction. It ranges from wide and from in depth with occasional deeper areas.
From there the Colorado turns northwest, past Fruita and entering Ruby Canyon as it approaches the Colorado Plateau. It turns southwest once again just before entering Utah.
Utah
In Utah the Colorado enters the high desert canyon country of the Colorado Plateau, flowing swiftly southwest through Westwater Canyon. Near Dewey it picks up the Dolores River, which together with its tributary the San Miguel drains the western slope of the San Juan Mountains. It then passes the Fisher Towers and forms part of the southern border of Arches National Park before entering the Moab Valley at Moab. Just below Moab it carves through a deep mountain pass known as "The Portal".
The Colorado then passes by Dead Horse Point State Park before entering the backcountry of Canyonlands National Park where it is joined from the north by the Green River, its biggest tributary. The Green, flowing from the Wind River Range of western Wyoming, drains in southwest Wyoming, northeast Utah and northwest Colorado. It is much longer than the Colorado above their confluence and carries a larger load of silt, though the Colorado has a slightly greater flow. Before an act of Congress changed the name in 1921 this confluence marked the official beginning of the Colorado River proper. The approximately of the Colorado above the confluence of the Green, including the entire section within Colorado, was known as the Grand River.
Below the Green River the Colorado flows through Cataract Canyon, which contains some of its most difficult rapids. At Hite the Hite Crossing Bridge – the only bridge over the Colorado for nearly – carries Utah State Route 95 over the river. Below here the Colorado is joined by the Dirty Devil River and begins to widen into Lake Powell, the giant reservoir formed by Glen Canyon Dam downstream. Lake Powell, a popular houseboating destination, is surrounded by the Glen Canyon National Recreation Area and receives over 2 million visitors each year despite its remote location. Before the dam was completed in 1966 the Colorado flowed through Glen Canyon, a sandstone gorge known for its colorful and intricately sculpted rock formations.
The Escalante River, a desert stream which runs through the sinuous slot canyons of Grand Staircase–Escalante National Monument, joins about two-thirds of the way down Lake Powell. The San Juan River, which carries runoff from the southern slopes of the San Juan Mountains and the Four Corners region in Colorado and New Mexico, joins several miles further downstream; it forms an arm of the lake nearly long. Although the San Juan contributes only about one-tenth of the Colorado River flow, it is extremely muddy, contributing as much as 40 percent of the total sediment load. The area around the confluence is dominated geographically by Navajo Mountain which rises over a mile (1.6 km) above the surrounding landscape, which is part of the Navajo Nation. Rainbow Bridge, one of the highest natural bridges in the world, is located at the tip of an arm of Lake Powell at the foot of Navajo Mountain.
Arizona Glen Canyon Dam, which creates Lake Powell, is situated in the town of Page in northern Arizona only about by river from the Utah border. The dam impounds the Colorado primarily for hydroelectricity generation. In front of the dam the Glen Canyon Bridge carries U.S. Route 89 over the Colorado River. Below here the Colorado flows through the last of Glen Canyon, passing the scenic Horseshoe Bend, before emerging briefly from its canyons at Lee's Ferry, where it is joined by the warm, shallow, muddy Paria River. Historically a ford used by Native Americans, explorers and settlers, Lee's Ferry serves as the dividing point between the Upper and Lower Colorado River Basins, which were each allocated one-half of the Colorado River flow in the Colorado River Compact of 1922.
Below Lee's Ferry the Colorado begins to trend more south than southwest, through the vertical-walled Marble Canyon which is crossed by the twin Navajo Bridges as it enters Grand Canyon National Park. At the southern end of Marble Canyon, the river is joined by another tributary, the capricious Little Colorado River, which drains the Painted Desert region of northeast Arizona and western New Mexico. Although normally a calm and clear spring-fed stream, it can rise dramatically following monsoon storms over the Colorado Plateau.
Then the river then turns abruptly west directly across the folds and fault line of the plateau, through the Upper and Lower Granite Gorges of Grand Canyon, which is long and from between the upper cliffs. The walls, high, drop in successive escarpments of , banded in splendid colors toward the narrow gorge of the present river. The river itself is a nearly uninterrupted series of violent rapids separated by calm, short pools. Deep inside the canyon it is joined from the north by Kanab Creek, which flows from southern Utah, and then from the south by Havasu Creek, known for the waterfalls it forms on the Havasupai Reservation. Further downstream it passes the Uinkaret volcanic field, where basalt eruptions millions of years ago formed huge lava dams across the Colorado. Although the dams have mostly been erased by erosion, a small portion remains as Lava Falls, generally considered the most difficult and dangerous rapids for boaters on the Colorado River.
The Colorado then swings sharply south and turns northwest north of Peach Springs, emerging from the Grand Canyon at the Grand Wash Cliffs, where it widens into the upper reaches of Lake Mead. The area also marks the general boundary between the Colorado Plateau and the Mojave Desert. Shortly west of that point it begins to form the border of Nevada to the north/west and Arizona to the south/east.
Nevada/Arizona
Lake Mead, formed by the Hoover Dam about southeast of Las Vegas, Nevada, is the largest reservoir in the United States with a full capacity of and a water surface of nearly . However, the lake has not been full for many years due to a combination of drought and increased water usage by Colorado River Basin states. Situated in the Lake Mead National Recreation Area, Lake Mead is a popular recreation site – visited by almost 8 million people a year – and a critical source of water for the Las Vegas metropolitan area, Central Arizona and Southern California.