Summer may see droughtlike conditions despite 'average' Sierra snowpack

California has been blessed this winter with an almost perfectly "average" snowpack in the Sierra Nevada, a far sight better than last year's dry conditions.

But in times of trouble, average often isn't good enough.

Many areas of the state will still experience droughtlike conditions this summer, despite the average snowpack. That's because a court order has curtailed water exports from the Sacramento-San Joaquin Delta since December to protect the fragile Delta smelt, a threatened species that may be near extinction.

"Average is sort of a modest target," said Frank Gehrke, chief of snow surveys for the state Department of Water Resources, after using a measuring tube to sample the snowpack Wednesday along Highway 50 near Echo Summit. "That used to be a 'C' when I was going to school. That wasn't something you aspired to."

DWR now projects it will be able to deliver only 35 percent of requested water to its urban and agricultural customers south of the Delta. The U.S. Bureau of Reclamation projects 75 percent deliveries to urban customers and 45 percent for agriculture. These numbers often increase later in the year as more data become available.

Another dry year would have meant even less water for these customers, which include an estimated 25 million Californians who get a portion of their supplies from the Delta.

The Delta naturally collects runoff from about 60 percent of the state and funnels it out to sea. State and federal pumping systems in the south Delta divert a portion of this water to the south Bay Area, Los Angeles and San Diego, and to farms in the San Joaquin Valley.

The pumping cutbacks are costing these customers about 6,000 acre-feet a day. Over a week, that amounts to a year's worth of water for 80,000 average homes. There's no other way to move that water south of the Delta without the pumping systems.

"That water's not going to be available to us," said Laura King-Moon, assistant general manager of the State Water Contractors, which represents agencies that buy Delta water from the state. "We have an artificial drought this year because of the regulatory restrictions on pumping."

With the pumps throttled back, many of those water users are being asked to adopt voluntary conservation measures. Some local water agencies have also imposed mandatory conservation targets and increased their water rates.

The pumping cutbacks will remain in place until September, a deadline set by a federal judge for completion of new permanent pumping rules. But because those new rules may require reduced pumping in the long term to protect the smelt, the reductions could continue.

California's Sierra Nevada snowpack is a vital water bank to help the state survive its dry summers. Gradual snowmelt and reservoir storage stretch this supply through the dry months.

Snowpack measurements, including those conducted in the field on Wednesday, show the water content of the snowpack statewide at 97 percent of average. That's much better than the 47 percent at this time last year.

But it doesn't necessarily overcome last year's drought.

Elissa Lynn, DWR senior meteorologist, said the total runoff projection for the water year, which runs through October, is estimated at only 72 percent of average. That is better than last year's 50 percent, and it's enough to avoid another drought year. But it's not enough to return state reservoirs to normal storage levels.

"Right now, we're sort of at a break-even point," she said. "At least right now, we're not making things worse."

The runoff projection is lower because soils that dried up in last year's drought will absorb lots of moisture. This winter's storms also brought more mountain snow than valley rain, which reduces runoff projections. Sacramento rainfall, for instance, is just 84 percent of average so far.

California normally sees significant rain and snow only between December and March. March has been dry in much of the state, which drags the numbers down.

Sacramento has never experienced a totally dry March. A weak storm on Friday may bring the city as much as one-tenth of an inch of rain, Lynn said, possibly saving the city from this dubious weather record.

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