After our glorious storms of December, the storm door slammed shut in January, and Los Altos received a pittance (.01 inches) of rain in January. The combination of warm January weather and no rainfall increases the climate stress on our plants and wildlife.
The US Weather Service expects the drought in California to persist or intensify in February, normally our wettest month. Snowpack and reservoirs in the Sierra Nevada mountains are well below normal. We continue to overdraft the aquifer under our valley to meet user demand. How is Los Altos responding to the drought? The City of Los Altos has water use data for Los Altos, but the City hasn’t made the data public. It looks like we’re using less water, but not as much as the State and County have called for.
Los Altos Weather
January is normally one of our wettest months, but we received almost no rain — only .01 inches.
The cumulative rainfall shows the growing gap between the blue normal rainfall and the red actual rainfall.
Our January was three degrees (F) warmer than normal.
The combination of warm weather and no rainfall increases the climate stress on our plants and wildlife.
Drought Persists or Intensifies
From the US Weather Service, “The very dry January, however, continued across much of California, negating the Water Year-to-Date surpluses most of the state had gained during a wet December.”
The December rainfall came from warm, tropical storms so our mountains had mostly rain instead of snow. From a San Francisco Chronicle article, “The troublingly clear skies and disturbingly gleaming sun over the past month have combined to reduce the California snowpack to 25 percent of normal for this time of year, on par with some of the worst years on record. But it was even worse last year at this time when the snowpack statewide was 14 percent of normal.”
The San Francisco Bay Area draws water from aquifers and the Sierra Nevada mountains, where snow levels and reservoirs are well below normal.
Snow makes up 60 percent of the water that is captured in California’s reservoirs when it melts in the spring. The snowmelt makes up 30 percent of the state’s overall water supply during a normal year, 80 percent of which is held behind Shasta and Oroville dams. That water is used to irrigate 8 million acres of farmland and quench the thirst of most of the state’s 38 million people.
It’s still early in the year, but reservoir levels are well below the average. Shasta Lake, the state’s largest reservoir, has only 65 percent of what it normally holds at this time of year. The lake is 44 percent full. Lake Oroville, the second-largest reservoir and the most important source for the State Water Project, is carrying 62 percent of what it normally holds at this time of year. It stands at 41 percent of capacity.
The outlook for February is no better, when the US Weather service expects the drought to persist or intensify. February is normally our wettest month. After February, our normal rainfall falls as we near the dry summer of our Mediterranean climate.
Los Altos response to the drought
The City of Los Altos has water use data for our city, but they haven’t made the data public.
A County report shows usage data for California Water Service Company, the water retailer serving Los Altos and several neighboring communities. Cal Water customers used 13%-19% less water, which is good but less than the 20% called for by the State and County.
To meet customer demand for water, we continue to overdraft the aquifer below our valley. Shown above as % Savings by Source of Supply, Cal Water increased pumping of groundwater by 20% in 2014.
From the bottom graph below, the level of the groundwater in the aquifer below our valley has fallen from the high point three years ago, when the drought started. The groundwater level fell about 30 feet last year. The other two graphs show above-normal groundwater pumping and minimal managed recharge this year. Comparing the blue lines in the two graphs, we’re pumping more groundwater than we’re putting back through recharge.