California’s DWR will conduct the season’s next-to-last snow survey this Thursday, March 28.
It is expected that the manual measurements will confirm electronic readings showing that snowpack water content is well below normal for the date.
Remote sensors today indicate that statewide, snowpack water content is 54 percent of average for the date. That is also 54 percent of the average April 1 reading when the snowpack normally is at its peak before the spring melt. The snowpack normally provides about a third of California’s water as it melts into streams, reservoirs and aquifers in spring and early summer.
November and December storms built a heavy snowpack early this season, but conditions since have been unusually dry.
How much record dry conditions in much of the state have depleted the snowpack will be assessed by surveyors from DWR and cooperating agencies as they take measurements up and down the mountain ranges.
One focus of attention Thursday will be on the manual survey scheduled for 11 a.m. off Highway 50 near Echo Summit. Reporters and photographers driving to this site – Phillips Station at Highway 50 and Sierra at Tahoe Road approximately 90 miles east of Sacramento – should park along Highway 50 and are advised to bring snowshoes or cross-country skis. Results should be available by 1 p.m.
Despite the dwindling snowpack, most key storage reservoirs are above or near historic levels for the date. An exception is San Luis Reservoir, a critical off stream reservoir south of the Sacramento-San Joaquin Delta that is only at 63 percent of its historic level for the date San Luis, which has a capacity of 2,027,840 acre-feet, normally is filled by pumping from the Delta, which has been restricted to protect Delta smelt and salmon.
(An acre-foot is 325,851 gallons, enough to cover one acre to a depth of one foot.)
DWR currently estimates that it will be able to deliver 35 percent of the slightly more than 4 million acre-feet of water requested by the 29 public agencies that distribute State Water Project water to more than 25 million Californians and nearly a million acres of irrigated farmland. The delivery estimate was reduced from 40 percent on Friday due to dry weather and pumping restrictions to protect Delta smelt and salmon.
The final SWP allocation for calendar year 2012 was 65 percent of requested deliveries. The initial delivery estimate for calendar year 2011 was only 25 percent of requested SWP water. However, as winter took hold, a near record snowpack and heavy rains resulted in deliveries of 80 percent of requests in 2011. The final allocation was 50 percent in 2010, 40 percent in 2009, 35 percent in 2008, and 60 percent in 2007. The last 100 percent allocation -- difficult to achieve even in wet years because of pumping restrictions to protect Delta fish -- was in 2006.
Electronic snowpack readings may be found at: http://cdec.water.ca.gov/cgi-progs/snow/DLYSWEQ.
Electronic reservoir level readings are available at: http://cdec.water.ca.gov/cgi-progs/products/rescond.pdf.