California Drought Watch

A monthly look at the water shortage With the wet season half over, the amount of snow and rain to fall over California’s mountains has been far below normal. In the Sacramento River basin, the main source of water for Southern California, less precipitation has fallen than in 1977, the driest season on record. This is also the fifth unusually dry winter in the Eastern Sierra, a key city of Los Angeles source, based on snowfall at Lake Mary. Less water may also be available to Southern California this year from the Colorado River.

The Bottom Line

January is usually California’s wettest month--18% of the entire year’s precipitation should fall. But with the month mostly dry, many reservoirs have dropped lower than in 1977, at the start of the worst year on record. On Tuesday, the state Water Resources Control Board begins hearings that could lead to the stiffest water use rules this century in California.

Colorado River Southern California has been told to expect 25% less water from the river--about 300,000 acre-feet--than it got last year. The flow to California may increase later if rain and snow means Arizona needs to import less water.

Coastal rainfall yardstick: As of January 25 San Francisco: 31% of normal San Diego: 49% of normal Santa Barbara: 24% of normal Santa Ana: 29% of normal Ventura: 19% of normal Los Angeles: 19% of normal

What is a Drought? The Sacramento River Index, which measures the amount of annual runoff water in the Sacramento River system, is a primary indicator used by the state for determining that a drought exists. When the index shows that the runoff has dropped to the critical level--defined as below 10.2 million acre-feet (*)-- it is generally considered a drought year.

The Scale Sacramento River Index (In millions of acre-feet of water) Wet: 19.6 and above Above Normal: 15.7-19.6 Below Normal: 12.5-15.7 Dry: 10.2-12.5 Critical: 10.2 and below The Current Figures Here are the index levels for the last two years 1990: 9.2 1991 (forecast): 7.9 The History Index for two worst drought periods on record.(1977 was the driest year on record) 1976: 8.1 1977: 5.1 1929-34: 9.8 (average) * An acre-foot of water is the amount of water it would take to cover an acre with one foot of water or 326,000 gallons. Source: California Department of Water Resources, Santa Barbara Dept. of Water, Johnston Weather Watch

Viewpoint “There is a 1 in 10 chance of this being a normal year.”--Douglas Priest, manager of the state Drought Center