California Water: Snowpack Low in Sierra Nevada & Rocky Mountains

Snow from the Sierra Nevada Mountains provides California homes and farms with a third of their water usage, and this year there's not much of it yet. State officials today took manual and electronic readings of snowpack statewide finding that it was among the driest for the date on record.

"Fortunately, we have most of winter ahead of us, and our reservoir storage is good," said Mark Cowin, Director of the Department of Water Resources, which manages California's State Water Project.

The findings show that snowpack is 81 percent lower than normal for today's date, but thanks to last year's near-record snowpack and heavy rains, key reservoirs are fuller than normal.

The State Water Project serves 29 public agencies, amounting to two-thirds of the state's population up and down the state.

At this time, 60 percent of the requested water from agencies is expected to be allocated. That number is based reservoir carryover from the last winter when 80 percent of the requested water was fulfilled.

"The last 100 percent allocation -- difficult to achieve even in wet years because of Delta pumping restrictions to protect threatened and endangered fish -- was in 2006," the agency noted in a press release. Since then, allocations have been 60 percent in 2007, 35 percent in 2008, 40 percent in 2009 and 50 percent in 2010.

The numbers are also low in the Rocky Mountains, which sends Southern California about a third of its water by way of the Colorado River. "Statewide, snowpack is 73 percent of average. That ranks as the fourth-driest measurement in the past 30 years," according to the Denver Post. "No year in the past three decades that has started this far below average has recovered to average snowpack by the start of spring."

The river's largest reservoir, Lake Mead, saw its "first annual gain since 2005 and the largest since 1957," writes water journalist Emily Green at her blog Chance of Rain. That's thanks, again, to the big snow and rain season last year. But as Green notes, the low snowpack and below normal local rainfall is bad news.

California officials will do another manual reading next month.

Photo by Flickr user w_miller, used under a Creative Commons License.