California

Background:

• Average annual rainfall - 200-500mm
• 65% of precipitation is lost to evaporation and transpiration
• 50% of California's rain falls between November and March

Reasons for Insecurity:

• Spatial imbalance - 3/4 of demand comes from the south - most rain falls in the north
• State Water Project - 20 dams and resevoirs irrigating o.3mn hectares of farmland, providing drinking water for 20mn people 
• Central Valley Project - 22 dams and resevoirs irrigating 0.2mn hectares of farmland, providing drinkng water for 2mn people
• Colarado River - 11 dams and resevoirs, irrigating 1.4mn hectares of farmland, providing drinking water for 25mn people
• Rainfall has been declining since the 1980s
• Uses 90bn gallons a year to water 900 golf courses
• 5.3mn acre-feet of water to irrigate pasture for beef…