The survey, conducted Tuesday, indicates snow water content is 76 percent of normal for the date, statewide. This time last year, snow water content was 60 percent of normal statewide.
While this year’s water content is higher than last, winter storms arrived late. It is too early to tell whether improved figures will translate into a better water year than the state experienced last year, when winter storms ended early leading to California’s driest spring on record.
Electronic sensor readings show northern Sierra snow water equivalents at 54 percent of normal for this date, central Sierra at 76 percent, and southern Sierra at 99 percent. The sensor readings are posted at http://cdec.water.ca.gov/cgi-progs/snow/DLYSWEQ.
In Lake County, where water supply is largely dependent on rainfall and snowpack from the Mendocino National Forest, Clear Lake's level on Wednesday was 1.16 Rumsey – the measure specifically used for Clear Lake. That's 0.11 Rumsey below Dec. 31, 2007.
The Mendocino National Forest conducts snow surveys beginning in late February. This past year, the first forest snow survey noted levels 156 percent of average, while measurements at the same time in 2007 had showed 92 percent of normal. However, dry conditions in both years led to lower readings later in the spring.
Lake County's creeks also appear to be running low. US Geological Survey stream gage measurements noted the following readings on Wednesday:
Kelsey Creek was discharging at 14 cubic feet per second, well below the median of 32. The creek's minimum recorded reading is 3.9, recorded, in 1991, while its maximum is 3,500 cubic feet per second, recorded in 1997.
Cache Creek at Hough Springs near Clearlake Oaks was discharging at 18 cubic feet per second, with a median reading of 47. Its minimum is 1.7 (recorded in 1977) and maximum is 7,300 (recorded in 1997).
Cache Creek near Lower Lake, discharging at 4.7 cubic feet per second, with a median reading of 2.9. Its lowest reading, in 1991, was 0.19; its highest, in 1997, was 4,530.
Putah Creek near Guenoc, discharging at 41 cubic feet per second, with a median reading of 126. Minimum reading was 2.4, recorded in 1937, while its maximum, in 2006, was 4,650.
California's water picture remains uncertain, despite the fact that Tuesday's measurements indicate an improvement over last years initial snow survey figures.
DWR Director Lester Snow noted that “the strain on California’s water supply persists.”
“Recent regulatory actions that further limit pumping through the Delta and deficits from the previous two dry years will require a very wet year to relieve the drought,” said Snow. “We must take immediate steps to protect the Delta ecosystem, conserve more water and develop additional groundwater and surface storage facilities to meet our future needs.”
Storage in California’s major reservoirs is low. Lake Oroville, the principal storage reservoir for the State Water Project (SWP), is at 28 percent of capacity, and 44 percent of average storage for this time of year.
Continuing dry conditions and court-ordered restrictions on Delta water exports are limiting water deliveries to farms and urban areas. DWR’s early estimate is that it will only be able to deliver 15 percent of requested State Water Project water this year to the Bay Area, San Joaquin Valley, Central Coast and Southern California. Increased precipitation this winter could increase this figure.
In December 2008, the U.S. Fish and Wildlife Service released a Delta smelt Biological Opinion which could reduce Delta exports by 20-50 percent. In December 2007, Judge Oliver Wanger restricted pumping to protect the Delta smelt, resulting in a 25 percent reduction in water deliveries. In a November 2008 decision, the California Fish and Game Commission implemented take restrictions for the longfin smelt which also could reduce water delivery pumping.
A Biological Opinion from the National Marine Fisheries Service to protect salmon and steelhead is expected in March. These regulatory actions have and will continue to significantly decrease deliveries to homes, farms, cities and industry by both the State Water Project and the federal Central Valley Project.
Snow water content is important in determining the coming year's water supply. The measurements help hydrologists prepare water supply forecasts as well as provide others, such as hydroelectric power companies and the recreation industry, with needed data.
Monitoring is coordinated by the Department of Water Resources as part of the multi-agency California Cooperative Snow Surveys Program. Surveyors from more than 50 agencies and utilities visit hundreds of snow measurement courses in California’s mountains to gauge the amount of water in the snowpack.
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