Snowpack levels now lagging

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Snowpack levels now lagging
BONE-DRY APRIL IN SIERRA TIGHTENS SUMMER WATER SUPPLY IN VALLEY

By Paul Rogers
Mercury News
Article Launched: 05/02/2008 01:30:42 AM PDT

Just two months ago, it appeared that Northern California was in store for a nice wet year - or at least a year of normal rain and snow levels - following a dry 2007.

But March and April were the driest months in the Sierra Nevada since records were first kept in 1922, state water officials announced Thursday.

As a result, the Sierra Nevada snowpack averaged 67 percent of normal for May 1 in the state's final snowpack measurement of the year, down from 95 percent April 1.

And while Silicon Valley won't face mandatory water rationing, the bottom line is that Bay Area water supplies will be tighter this summer than anyone had expected.

"In March, things were looking pretty good," said Frank Gehrke, chief of the snow survey program for the state Department of Water Resources in Sacramento. "But it stopped snowing in March and April. Bang! It literally just shut off."

Hydrologists for the department said conditions aren't bleak enough to describe this summer as a drought. But they worried that if snowfall is low next year, the state will face major water problems.

After snow builds up every winter and spring on the Sierra mountains, it melts during the summer, flowing into rivers and San Francisco Bay's delta.

But this April and May, only 2.3 inches of rain fell in the Northern Sierra between Lake Tahoe and Mount Lassen - the lowest since 1922.



Without rain, there was almost no new snow to follow the heavy amounts from January and February. Worse, said Gehrke, no storms meant lots of sunlight. And that meant more melting.

So overall runoff is expected this year to only be about 55 percent of normal.

In Silicon Valley, that means concern and caution, but not full-blown crisis.

Residents will be asked to continue last year's 10 percent voluntary reductions this summer, said Susan Siravo, spokeswoman for the Santa Clara Valley Water District.

"We still have good groundwater reserves and our reservoir levels are pretty good," Siravo said. "March and April have been very dry. But we got a high level of runoff in January and February."

The district's 10 reservoirs were 68 percent full Thursday.

So far this year, San Jose has received 11.25 inches of rain - 77 percent of normal for this time of year.

It would have been more, but April was bone-dry. Only one-tenth of an inch of rain fell in San Jose in all of April - compared with 2.6 inches for the average April.

The trick this summer is to focus on lawn and gardens, which use half the water in an average house, Siravo said.

"Fix leaks and broken sprinkler heads," she said. "Water at night or early in the morning. Most people can have a healthy lawn watering three days a week. You can easily cut back 10 percent."

Some Silicon Valley residents already have started.

With the dry spring, sales of drought-tolerant plants are double this year what they normally would be, said Ron Kanemoto, manager of Yamagami's Nursery in Cupertino.

"Water is on people's minds, definitely," he said. "Last weekend, I got chastised by a customer for not having drip irrigation equipment. We had discontinued it about five years ago because we weren't selling it. Now you can tell the interest is coming back."

Unlike other Bay Area locales, Santa Clara County has the geology that allows huge volumes of groundwater to be stored in underground aquifers. Those supplies make up about half of the water for the district's 1.8 million customers, with the other half coming from the delta.

Other Bay Area water districts are much more strapped.

The East Bay Municipal Utility District staff will recommend May 13 that the agency's board impose mandatory summer water rationing of at least 15 percent, said spokesman Charles Hardy. That will be the first time the district's 1.3 million residents from Hayward to Walnut Creek have faced mandatory rationing since 1991.

The reason? East Bay MUD has no groundwater storage and its watershed is at a relatively low Sierra elevation.

Meanwhile, the 2.4 million people from Milpitas and Hayward to San Francisco who get their water from the Hetch Hetchy Reservoir in Yosemite National Park will be asked this summer for only voluntary cutbacks.

That's because last year, they were asked to voluntarily cut use 10 percent and they responded with a 13 percent reduction, said Tony Winnicker, a spokesman for the San Francisco Public Utilities Commission. Also, that system's reservoirs are 70 percent full.

Compounding the nervousness this year, last year's Sierra snowpack - 28 percent of normal on May 1 - was the lowest in nearly 20 years. That meant less runoff to fill the state's large reservoirs, making this year even more critical.

Across the state, farmers and large Southern California water districts used the snowpack news to urge state lawmakers to approve more money to build new dams and canals.

Because a judge ordered pumping from the delta cut last year by up to 30 percent to protect an endangered fish, farmers are facing wrenching cutbacks, said Laura King Moon, a spokeswoman for the State Water Contractors, a group of 27 agencies that import delta water.

"Not only are we facing severe restrictions under the Endangered Species Act on how much water we can deliver, less than average runoff means that water supplies are down as well," she said.

Contact Paul Rogers at progers@mercurynews.com or (408) 920-5045.