Created as part of a collection of Arizona river overview documents titled "River of the Month Series, Celebrating Arizona’s Rivers". These reports were prepared and supported by Environmental Defense Fund, Sonoran Institute, Sierra Club, Grand Canyon Trust, Western Resource Advocates, and University of Arizona Water Resources Center.
Often called the ―lifeblood of the West,‖ the Colorado River drains areas of seven U.S. and two Mexican states, and has shaped nearly every aspect of Arizona’s history. As early as 700 A.D., the Colorado River supported the indigenous people who first called Arizona home. Today, visitors to the Grand Canyon explore stunning tributary canyons and world-class rapids while admiring two billion years of geologic history revealed by the river’s forces. Further south, the canals of the Central Arizona Project carry Colorado River water 300 miles across the desert to Phoenix, Tucson, and important agricultural lands.
The Colorado has enabled the development that has shaped the Arizona we enjoy today. Although much of its water is diverted for urban and agricultural use, the river also nourishes vital habitat for diverse plant and animal species and is a place for recreation and refuge for many Arizona residents. Since Arizona lies almost entirely within the Lower Colorado River Basin, nearly all of the state’s waterways – from the largest rivers to the smallest perennial streams – eventually flow to the Colorado.