California’s drought is said. But there’s a surprising bright spot that may make this year better than last

 California's drought is said.  But there's a surprising bright spot that may make this year better than last

The outlook for California’s drought is grim.

The first five months of the year have been the driest on record. Snowpack in the mountains, at its usual April 1 peak, was the smallest it’s been in seven years. Reservoirs are hovering near historic lows for the season, including Lake Shasta, the state’s largest.

But there’s one, albeit small, bright spot: spring runoff. The water that pours from the mountains to rivers and streams, one of the most important barometers of state water supplies, is up substantially from over a year ago — though still far below normal.

As water managers painfully remember, a low point of the three-year drought was last spring when statewide runoff fell far short of expectations. Much of the melting snow and late-season rain, instead of flowing downhill to cities and farms, was sucked up by extraordinarily dry soils, thirsty plants and warm air. Consequently, reservoirs in Northern California captured 685,000 acre feet less water than what state planners had forecast, a difference that could supply more than 1 million households for a year.

Last year’s unexpected deficit led to a panicky ramp-up of water restrictions and questions about adequacy of the state’s supply forecasting, and no one wants to see the situation repeated.

Children play near a boat launch near where the shoreline of Lake Oroville is exposed. The runoff from the Feather River watershed is coming in better than last year but is still below average.

Carlos Avila Gonzalez/The Chronicle

“We feel better about the amount of runoff this year,” said David Rizzardo, a supervising engineer at the California Department of Water Resources. “It’s not going to end the drought, it’s nothing to write home about, but it’s a better picture than a year ago.”

The water captured from the Sierra and southern Cascades provides nearly two-thirds of California’s water. Because of this, runoff forecasts, particularly in dry years, are closely watched.

Over the past decade, in keeping with severe bouts of drought, runoff levels have tended lower than they have in more than a century of record-keeping, according to data from the US Geological Survey. Last year was the second lowest amount of runoff, following only 1977, when California was gripped by another extremely parched period that saw drastic water restrictions. Climate scientists say the trend is the clear impact of rising temperatures and more frequent dry spells.

This year, water experts say less water is being lost to soil infiltration, plant transpiration and evaporation largely because of the timing of storms over the wet season — this despite there being fewer storms than average during the water year of Oct. 1 to Sept. 31. October brought a period of heavy rain, lots of snow fell in December and some cool, damp weather arrived in April, all of which helped keep the moisture deficit in the environment from escalating like it did last year.

“The soils stayed wet throughout the winter so the melt that did happen later on was more efficient,” said Brett Whitin, service coordination hydrologist at the federal government’s California Nevada River Forecast Center in Sacramento.

House boats float on Lake Oroville.

House boats float on Lake Oroville.

Carlos Avila Gonzalez/The Chronicle

Soil plots in the Sierra Nevada monitored by the US Department of Agriculture and tracked by the forecast center in Sacramento show saturation levels at the start of summer were generally much higher than they were a year ago. This also bodes well for fire season, lowering the danger, at least initially.

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