Colorado River on USA Map: A Geographic Overview
Colorado River is one of the most important rivers in the United States. Flowing for approximately 1,450 miles, it provides water to seven states in the western U.S. that are part of the Colorado River Basin. These states include Colorado, New Mexico, Utah, and Wyoming in the Upper Basin, and Arizona, California, and Nevada in the Lower Basin.
Additionally, it supplies water to Mexico. This river is crucial for agriculture, municipalities, hydropower generation, outdoor recreation, and the drinking water supply of several major cities, including Denver, Phoenix, and Los Angeles.
Table of Contents
Geographic Overview
Colorado River originates along the Continental Divide in Rocky Mountain National Park, Colorado. It then travels southwest, carving through the rugged landscapes of the Colorado Plateau and the Grand Canyon before finally reaching its mouth at the Gulf of California in Mexico.
Moreover, the river’s basin covers approximately 250,000 square miles, making it a significant geographical feature of the southwestern United States.
History and Exploration
The Colorado River has a rich history of exploration and settlement. The Spanish soldier Francisco de Ulloa was likely the first European to see the river. In 1776, the Spanish missionary Father Garcés named it “Rio Colorado,” meaning “Red River.” Congress officially applied the name “Colorado” to the entire river in 1921. Long before European explorers arrived, the prehistoric Hohokam civilization inhabited the region, followed by the Hopi and Pueblo tribes.
Course of the River
From its headwaters in the Rocky Mountains, the Colorado River flows southwest across the high Colorado Plateau into southeastern Utah and northwestern Arizona. It carves through deep canyons, including the famous Grand Canyon, before bending south to form state boundaries between Nevada and Arizona, and Arizona and California. Eventually, it reaches the Gulf of California, forming the border between the Mexican states of Sonora and Baja California.
Major Cities Along the River
The largest city in the Colorado River Basin is Phoenix, Arizona. Other important cities include:
- Duchesne and Moab, Utah
- Grand Junction, Colorado
- Boulder City and Las Vegas, Nevada
- Tucson and Yuma, Arizona
- Needles, California
Major Tributaries
Several tributaries contribute to the Colorado River’s flow. The major ones include:
- Gunnison River
- White River
- Yampa River
- San Juan River
- Dolores River
- Green River
- Little Colorado River
- Gila River
- Virgin River
Hydrological Features
- Length: Approximately 1,450 miles
- Width: Ranges from 50 feet at the headwaters to 200 feet at Grand Junction, Colorado
- Depth: About 30 feet in the lower Grand Canyon and less than 10 feet in the upper reaches
- Flow Rate: Near Lees Ferry, Arizona, the flow is about 8 million gallons per minute, reducing to 2 million gallons per minute at the mouth
- Highest Flow: Recorded in 1916 at Yuma, Arizona
- Lowest Flow: Occurred at Lees Ferry in 1924
Dams, Reservoirs, and Canals
To manage its water resources, the Colorado River has several dams and reservoirs, including:
- Flaming Gorge Dam (Utah)
- Navajo Dam (New Mexico)
- Glen Canyon Dam and Lake Powell (Arizona and Utah)
- Blue Mesa Dam (Colorado)
- Hoover Dam and Lake Mead (Nevada)
- Davis Dam and Lake Mohave (Nevada)
- Parker Dam and Havasu Lake (Arizona)
- Imperial Dam (Arizona)
Geology of the Basin
The Colorado River Basin spans three physiographic regions:
- Southern Rocky Mountain Province
- Basin and Range Province
- Colorado Plateau Province
The Colorado Plateau is composed of sedimentary rock layers, which have been uplifted and eroded over time to create dramatic landscapes, including mesas, buttes, natural bridges, and deep canyons. The southwestern portion of the basin, known as the Colorado Desert, is extremely arid and hot, with some areas lying below sea level.
Importance of the Colorado River
Colorado River serves as a lifeline for millions of people. About 70% of its water is used for agriculture, while between 35 and 40 million people rely on it for municipal water needs. The river also plays a key role in generating hydropower, supporting fish and wildlife habitats, and providing recreational opportunities such as rafting and fishing.
Additionally, under a 1944 treaty, the United States has an obligation to deliver a portion of the river’s water to Mexico.
