California’s Water Resources

1. California’s Water Resources Chapter 13A, Section 2

2. California’s Water Supply • The main sources of California’s freshwater supply are precipitation, surface water, and groundwater • California receives an average of about 58 cm of precipitation per year • Northern CA and mountains receive most of the precipitation • Some of CA’s precipitation flows back into the lakes, rivers, and streams that make up the state’s drainage basins; supplies half of the freshwater needs for the year • One of CA’s major sources of fresh water is the Colorado River • Some precipitation seeps into the ground to become groundwater; accounting for 30% of fresh water used • Most groundwater is used in the area from which the water is withdrawn • Desalination – removal of salt from ocean water to obtain fresh water

3. California’s Average Annual Precipitation

4. California’s Drainage Basins

5. Concept Check • What is desalination? • Desalination is the removal of salt from ocean water to obtain fresh water.

6. California’s Water Projects • To meet freshwater needs throughout the state, California has an intricate network of water storage and distribution systems, or water projects • Aqueduct – pipe, or channel, through which water flows from a higher elevation to a lower elevation • The Los Angeles Aqueduct carries water 359 km from the Owens River east of the Sierra Nevada, providing L.A. with water since 1913 • California’s State Water Project (SWP) is one of the nation’s largest water distribution systems, transporting water from northern CA to southern • The federal government has also constructed major water projects in CA

7. California’s Water Projects Yellow = Federal Green = Local Red = State

8. Water Needs • Most of California’s water supply is used to grow crops • The rest is used in homes, businesses, and industries, or has been set aside for recreation or wildlife use • About 80% of fresh water used each year goes toward irrigating crops • Think of all the ways you use water, this adds up to about 380 liters per person per day • The major use of water in industry is as a coolant—either to cool products or the equipment used to make products • CA preserves some streams and rivers as fisheries and as recreation zones, not diverting the water from these areas

10. Assignment • Read Chapter 13A, Section 2 (pg. CA 13-CA 19) • DO Section 13A.2 Assessment #1-7 (pg. CA 19)