Today isn’t the start of the new year for water managers, since it’s in the middle of the storm season, but it’s an occasion nonetheless to sound an alarm about drought.
Calendar year 2013 was the driest in Modesto in National Weather Service records dating to 1906. The Modesto Irrigation District recorded just one year that was worse – 1898.
The Weather Service tallied 4.45 inches of rain in its Modesto Airport gauge since last Jan. 1, beating the previous record low of 5.7 inches in 1929. The station’s average for a year is 12.14 inches.
MID reported 5.21 inches in its downtown gauge in calendar year 2013, second only to the 4.28 inches in 1898.
The district and the weather service officially measure rain from July 1 through June 30, which allows them to account for the series of storms that usually come between October and May. The California Department of Water Resources collects its data from Oct. 1 through Sept. 30.
“We put out the statistics for the calendar year because (lay) people are used to that,” said Michelle Mead, a meteorologist for the Weather Service in Sacramento.
Whatever the method, it’s clear that California has entered a third straight storm season with below-average rain and snow.
“We didn’t see any indication that this dry pattern would develop in the far West,” Nicholas Bond, a meteorologist at the federal Pacific Marine Environmental Laboratory in Seattle, told The Fresno Bee. “But it may be too early to panic. There’s a lot of the winter left, and California’s wet season is typically the strongest in January.”
As of Monday, the state agency reported that the snowpack in the central Sierra Nevada was 23 percent of average. It is the main water source for Stanislaus, Merced and San Joaquin counties and much of the Bay Area.
Farms and cities could face restrictions on river water if conditions do not improve. They also could increase their use of groundwater supplies that already are stressed in many places.
The central Sierra snowpack ended last winter at 52 percent of average and the winter before that at 50 percent. Those two years followed a 160 percent-of-average year that boosted reservoirs, buffering the effects of the drought.
That storage has shrunk. Don Pedro Reservoir on the Tuolumne, owned by MID and the Turlock Irrigation District, stands at 78 percent of its average level for this time of year. It and other reservoirs routinely drop in winter as part of the statewide flood-control system, but the current levels are worrisome.
The district boards will see how the rest of winter goes before deciding how to allot water for the 2014 irrigation season.
On the Stanislaus River, the Oakdale and South San Joaquin irrigation districts sold water to drought-stressed parts of the San Joaquin Valley in 2013. They, too, are monitoring conditions.
The Merced Irrigation District capped Merced River deliveries last year but made some higher-priced water available to farmers requesting it.
Parts of the west and south Valley face severe cutbacks from the federal Central Valley Project, which pumps water from the Sacramento-San Joaquin Delta. Drought and fish protections combined to reduce the 2013 allotments to as little as 20 percent of the contracted amount.
Some growers might get zero federal water in 2014, forcing them to rely on wells, purchase supplies from better-off areas, or forgo annual crops so they could get more irrigation to trees and vines.
History suggests that a slow start can be overcome. In the latter part of 1999, the Modesto district recorded 0.81 inches of rain. The first few months of 2000 brought 15.76 inches.
It can work the other way. The district recorded 6.53 inches in the latter months of 2012, well above average, but the next few months added just 3.47 inches and left the total below average.
Bond said some scientists believe the West’s dry spell is a preview of future droughts, which are expected to occur more often as the climate warms.
“No doubt it’s a wake-up call, and a lesson in how we will have to adapt,” he said. “But I think I’d rather just get the rainfall this year.”