Jan 21 2009

Let It Pour

Posted by: Jonathan Marshall

The view from my window is not pretty today: cloudy, gray and damp. It would actually be a lot prettier, to my eye, if it were pouring rain.

That's because the state desperately needs more precipitation to break two years of drought, going on three. Unless we see a dramatic change in the weather, we'll likely suffer another rash of early season fires that scorch forests, grasslands and homes.

Residential and agricultural water users will feel the pinch of tighter rationing. Already, 21 water agencies across the state have imposed water rationing, and more will surely follow.

We'll also have less water for hydro generation, forcing PG&E and other utilities to rely more on fossil fuels for power. That will mean more greenhouse gas emissions and (other things being equal) higher rates. (Last year the utility's hydropower output was only about three-quarters of normal.)

One drought year is manageable. But water runoff has been low in California the previous two years--only 53 percent of average in 2006-7 and 60 percent of average in 2007-8. At the end of December, Oroville Reservoir was at the lowest level in history, and other major reservoirs are desperately low as well.

With the dry start to 2008-9, simply working our way back to an average runoff year would take another 10 feet to 20 feet of snow in the Sierra Nevada, according to the state Department of Water Resources.

The good news, says Gary Freeman, PG&E's principal hydrologist, is that weather fronts should bring some precipitation to northern and central California almost every day from now to the end of January.

The bad news is that "the amount of wetness will probably be small," Freeman says. "These storm fronts won't amount to much."

With half of our precipitation season yet to run, there's still a chance of turning the current dry spell into a normal or even wet year. But the probability of that happening is receding every day.

"Even if precipitation is normal going forward, we'll only end up at 80 percent of normal for the year," Freeman says. "That's pretty dry."

 

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