Colorado River Map -- National Geographic

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Data Sources

River flow volumes: US Geological Survey (USGS).

Diversion flow volumes: US Bureau of Reclamation.

Dams, canals, pipelines, and aqueducts: USGS and
National Geographic. Latest available data shown.

This map was made possible with support from the Walton Family Foundation.

The Colorado River

The Colorado River supplies water for 30 million people. It is one of the most contested, recreated-upon, and carefully controlled rivers on Earth. Diverted under peaks, utilized by turbines that create hydropower, and stored by enormous reservoirs, the 1,450-mile-long Colorado faces growing challenges associated with increasing population, declining ecosystems, drought, and expected climate change. Click on a topic below to learn more.

High River Flow

The river experiences wet and dry periods that can last for years. Rocky Mountain spring snowmelt fuels up to 90 percent of river flows. So years with more precipitation, such as 1983-1987, result in more robust river flows. The light blue area represents the average annual volume of water in million acre-feet (1 acre-foot is equal to 325,851 gallons).
Low River Flow

Climate projections show that predicted higher temperatures are likely to result in shorter winters, earlier spring runoff, increased evaporation, and a future reduction of Colorado River stream flow and water supplies. The dark blue area represents the average annual volume of water in million acre-feet during the period from 2003-2007.
Diversions

Outgoing diversions include aqueducts, tunnels, pipelines, and canals that channel water for agricultural, municipal, and industrial use (only major diversions are shown). Agriculture consumes 78 percent of the Colorado River's water and 22 percent is consumed for municipal and industrial use.
Dams, Reservoirs, Canals, and Pipelines

More than a hundred dams have been built by the Bureau of Reclamation and the Army Corps of Engineers for flood control and to create hydroelectricity and store agricultural and municipal water. They harness the river's widely varying flows to generate a steady water supply. Despite the widespread benefits of reclamation efforts, over-allocation and drought have placed significant stress on reservoirs and water storage.
Stories and Photos

See stunning pictures and video of the mighty Colorado River as it runs from the Rocky Mountains, through the Grand Canyon. Read news related to why the Colorado no longer flows to the sea, and see National Geographic magazine features on the West's water woes.
Important Features

Learn about the Colorado River Basin's important features and policies, from Native American water rights to large-scale diversions and reservoirs that fuel big cities from Denver to Las Vegas.

Balancing Limited Supply With Increasing Demand

The Colorado River Basin is a critical component of North American water supply, providing H2O to 30 million people and thousands of acres of farmland. When Colorado River withdrawals were first allocated among the river basin’s seven states, in 1922, the river held 17.5 million acre-feet (5.7 trillion gallons) of water. However, new science has shown that 1922 was part of an especially wet period. The river now averages about 14.7 million acre-feet per year and is allocated among seven states and Mexico. Water managers are trying to address growing challenges associated with over-allocation, rapidly increasing urban populations, development of unused water rights, and expected climate change. The water levels of the river’s two largest reservoirs—Lake Mead and Lake Powell, stored by Hoover and Glen Canyon Dams—have dropped significantly in recent years, threatening supplies for major cities. In addition, the trapping of silt behind dams also limits the quality and extent of river habitats.

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Help Save the Colorado River

You can help restore freshwater ecosystems by pledging to cut your water footprint. For every pledge, Change the Course will restore 1,000 gallons back to the Colorado River.

NG's Freshwater Advocates

Sandra Postel

Sandra is a leading authority on international freshwater issues and is spearheading our global freshwater efforts.
Jonathan Waterman

He's paddled the Colorado River from its headwaters to the delta, in an effort to bring awareness to this mighty river at risk.
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For more than 15 years, Osvel Hinojosa Huerta has been resurrecting Mexico's Colorado River Delta wetlands.

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