Colorado River by the Numbers

1,450 miles long, from its headwaters in the Never Summer Wilderness Mountains, Colo., to the Gulf of California in Mexico.

* 20 million people in Wyoming, Colorado, Utah, New Mexico, Arizona, California, Nevada and Mexico depend on the Colorado for water and power. Among major cities receiving its water are Los Angeles, San Diego, Phoenix, Denver, Las Vegas, Salt Lake City and Albuquerque.

* Primary source is snowmelt, as well as an average of 4 inches or less of rainfall a year in some places.

* The river irrigates 3.5 million acres of farmland, which produce $1.5 billion in gross crop value. Primary crops include alfalfa, wheat, grasses and pasture.

* Nearly 30 million people visit the Colorado each year, visiting 57 man-made reservoirs with 560,649 acres of surface area available for recreation. Between the reservoirs and the river, there are 4,667 miles of shoreline on the Colorado. Recreation brings in at least $1.25 billion a year.

* 49 dams in the Colorado River system, including Hoover, Flaming Gorge and Glen Canyon dams.

* Eleven federal hydropower plants produce 11.8 billion kilowatt hours of energy worth about $157 million a year.

* The Colorado River Compact, approved in 1922, guarantees 7.5 million acre-feet of water to the Upper Basin states of Colorado, New Mexico, Utah and Wyoming; and 7.5 million acre-feet to the Lower Basin states of Arizona, California and Nevada.

* More than 30 American Indian tribes live along the Colorado. They include the Navajo, the Havasupai, the Colorado River, the Cocopa and the Zuni.

* Dozens of exotic, or introduced, fish live in the Colorado, including salmon, trout, catfish, killifish, shad and bass. There are also dozens of native fish, many of which are endangered, including the humpback chub, bonytail chub, Colorado squawfish and razorback sucker. More than 100 species are considered by state or federal authorities to be at risk.

* Lake Mead, the nation’s largest man-made reservoir, can store 28.5 million acre-feet (9.2 trillion gallons) of water, enough to cover the state of Pennsylvania a foot deep. It has 550 miles of shoreline.

* Lake Powell has 1,900 miles of shoreline.