Colorado Water: The Big Picture 

A little perspective on fresh water

• Of the Earth’s total water supply, 97 percent is salt water; the rest is fresh water.
• Only .05 percent of the Earth’s fresh water supply is found in streams and lakes.

Who claims stream flow in the lower 48 states?

• Draw an imaginary line from north and south through the Kansas-Missouri border. 73 percent of nation’s stream flow is claimed by states east of that line.
• The Pacific Northwest claims 13 percent of stream flow.
• Fourteen percent of stream flow is shared by 14 Western states, which make up over half of the country’s land area.

Colorado has been called the Mother of Rivers for good reason. The headwaters of four rivers are born here, in the high mountains of the Continental Divide.

1. Colorado River
2. Platte River
3. Arkansas River
4. Rio Grande

These rivers also determine the state’s four watersheds. Everyone in Colorado lives in a watershed.

Water and climate:

• Statewide, Colorado receives about 16.5 inches of precipitation each year, though it varies greatly depending on location.
• Some parts of the state only receive 5 inches of precipitation annually while others can get up to 50 inches.
• In Colorado’s high altitude, semi-arid climate, 85 percent of the state’s precipitation is lost due to evaporation and transpiration.
• Eighty percent of Colorado’s annual water supply comes from snowpack runoff.

About 100 million acre feet of water falls on the state every year.

Consumptive use of water in Colorado:

• Agriculture uses 85 percent.
• Industry uses 6 percent.
• Municipal and domestic use 9 percent.

Location, location, location

• Eighty percent of Colorado’s moisture falls on the West Slope where only one in 10 Coloradans live, so many diversion projects and storage reservoirs have been constructed through the years.

Trends in Colorado water management

• The U.S. Bureau of Reclamation has shifted its priorities from building large water storage projects to promoting more efficient use of existing water supplies, water management, dam safety and water quality protection.
• The Colorado Water Conservation Board also stresses rehabilitation and management of existing water supply rather than construction projects.

For more information on the subject, see the booklet "Colorado Water," published by the League of Women Voters of Colorado.