It’s the first day of summer, but warm temperatures and dry conditions already are familiar to most Californians, who wonder if the state is sliding into another drought. But water experts can’t predict the future.
By the end of this month, Southern California will have suffered through its driest 12-month period in over a century, according to the state Department of Water Resources, which tracks rainfall, runoff and water conditions, and makes predictions about future supplies. Northern California has been dry, too.
But while the bad news is that it’s hot and dry, the good news is that last year was a wet year, and that the state can now draw on its stored supplies.
“Because we have so much reservoir storage and groundwater supply, the impacts thus far have been minimal” said Jeanine Jones, interstate resources manager for DWR.
In the terminology of state water experts, “drought” refers to two consecutive years in which rainfall is below average. But the term doesn’t necessarily apply statewide, but to conditions in specific geographic areas. For example, Arcata may be wet, while Ojai may be dry and Norco drier still. “It really depends on your local condition,” Jones said.
The worst year for runoff–the melting snows from the Sierra Nevada that provides most of the state’s water–was in 1977, when it reached only 20 percent of normal. That year “has the distinction of being the single driest year of California’s measured hydrologic record,” the DWR noted.
The most recent, sustained drought period statewide was 1987-92, a five-year period during which the state experienced consistently below-average rainfall. Regionally, Southern California also experienced consecutive dry years in the late 1990s and early 2000s. Another significant drought occurred during 1928-34. The state experienced a half-dozen droughts of three years or more each during the 20th century, according to DWR.
During the 1987-92, drought, most large urban areas in California coped with water-shortage impacts through voluntary conservation and mandatory rationing at 20 percent to 30 percent levels. Reductions in residential outdoor water use, mostly for lawn watering and landscaping, contributed to much of the savings, the DWR noted. Those hard hit financially included California’s landscaping and nursery industries, which were estimated to have lost $460 million in gross revenues in 1991, the driest year of the six-year drought.
“Past droughts have shown that actual health and safety impacts–lack of water for human consumption, sanitation, and fire protection–have occurred in small water systems in rural areas,” the DWR said. “Systems most at risk are those that depend on groundwater from unreliable fractured rock sources or from small coastal terrace groundwater basins. The at-risk geographic areas are the foothills of the Sierra Nevada and Coast Range and the North and Central Coast regions.”
Drought’s largest economic impacts include those associated with wildfires and damage to timber resources, DWR noted.