Troubled at first when our fernspolypodium californicum (California polypody) died back in June, I now enjoy the polypody’s use of dormancy to survive the harsh, dry summer of California. In our Mediterranean climate, we have mild, wet winters and dry, hot summers. Very appropriately, the polypody fern is lush and green when we have rain, and it goes dormant in the summer, when we get little rain for six months.
To illustrate how the polypody fades as summer nears, here are photos of the same fern frond at one-week intervals this June. On June 1, the polypody frond is turning yellow with some burnt spots. The fronds in the background are in deeper shade, and they are green.
One week later, the frond is no longer green, and the frond tips are brown. Sunlight filtered by an oak tree shines on the frond and lights the spider webs on the frond tips.
Two weeks after the initial photo, the polypody frond, now brown and curled, lies on the oak leaf litter. Fronds in deeper shade are still green, and some are fading.
The polypody, a California native plant, is a visible harbinger of summer.
I’m learning to use depth of field to focus attention on the subject, the polypody frond. When the frond was upright, I photographed it in a single plane where the entire frond was about the same distance from the camera. Therefore, I could use a narrow depth of field. By the 15th, the frond had fallen toward where I shot the first photos. To use the same viewpoint as before, I needed a greater depth of field to still keep the frond in focus and blur out the background.
We visited the Sunset garden for the first time last week, just before it closed for good. The garden is part of the Sunset magazine, which advertises itself as “the premier resource for achieving the ultimate Western lifestyle”. It was a vibrant brand in the ’60s and ’70s, when the West was growing by leaps and bounds. But the magazine was sold to Time-Warner, which recently sold the garden and buildings to a developer. Located in Menlo Park, California, the 7-acre site is valuable, being less than two miles from the Stanford University and Facebook campuses. Continue reading Sunset Garden Fades in the West
Continuing my monthly weather posts, March was warmer and drier than normal in Los Altos, California, as California’s drought stretches into the fourth year. Landscaping needs more water than usual due to the warm, dry weather. Despite calls to reduce water consumption, it’s hard to stop watering drought-stressed trees and shrubs that took years to grow. With the warm winter, I was concerned that our fruit trees didn’t receive enough winter chilling, but this morning’s photo of our pluot tree shows that fruit has set.
Acknowledging that there’s not end in sight for the drought, California’s governor issued an executive order designed to reduce urban water usage by 25%. Although much needed, almost all the measures will take months to significantly reduce water usage. Meanwhile, the State and County asked for a 20% reduction in water use a year ago, but our county conserved 13% in 2014 and 4% so far in 2015. Even if we achieve the 25% savings this year, we’ll continue overdrafting the aquifer beneath our valley.
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.
This post continues a monthly series of posts about California’s drought, with weather data from my hometown of Los Altos, south of San Francisco.
We had a September rainstorm of .41 inches, more than the total rainfall (.25 inch) we normally get for the four months of June to September. Our dry season is almost over, but California’s drought is now forecast to continue through the end of 2014. Local groundwater levels fell significantly during the past year, so we’re pumping more groundwater than is being replenished. California passed a historic law saying that we’ll manage groundwater by 2040. Almost all the oil wells fracked in California draw their water from the California aqueduct, based on early reports.
Here’s the Los Altos rainfall for 2013 and 2014. Since May our monthly rainfall has been less than half an inch.
The lack of rain the past few months is dwarfed by the low rainfall for three years. The chart below shows our accumulated low rainfall for 2013 and 2014.
The trend of above-normal monthly low temperatures continues.
This spring and summer, the US Weather Service predicted an El Niño event, which indicates above-normal rainfall. However, as shown in the above featured image, they now predict below-normal rain for most of California through the end of the year, so our drought is expected to continue. OND is the Weather Service’s abbreviation for October-November-December, and CPC is the Climate Prediction Center. From their September drought update,
For the OND season, CPC’s precipitation outlook favors below-median precipitation over northern California and northwestern Nevada, above-median precipitation over far southern California, and EC anticipated elsewhere. The U.S. Seasonal Drought Outlook favors drought persistence/intensification across all but far southern sections of both California and Nevada, and much of western Utah.
With less rainfall, California has reduced deliveries of water to farmers and cities. To compensate for reduced deliveries from the State, our local water companies might be pumping more groundwater.
The California Department of Water Resources shows that groundwater levels in the south San Francisco Bay Area have fallen during the past year. All wells show decreased groundwater level, as shown by the yellow, orange, and red dots. As shown by the red dots, the groundwater level at about half the wells has fallen by more than ten feet. The falling groundwater level indicates that we’re pumping groundwater faster than it’s being replenished. This data is from Spring 2014. With reduced water deliveries this summer, overdrafts of groundwater will probably continue.
As the groundwater level drops, the risk of subsidence, our ground sinking, increases. The town of Alviso dropped thirteen feet due to subsidence in the early 1900s. Many communities ring the south bay and are therefore vulnerable to increased flooding if our ground sinks due to groundwater pumping. The thirteen feet of subsidence last century is several times more than any EPA estimate of sea level rise during this century.
“California will no longer be the only western state with a pump-as-you-please approach to groundwater” is the lead paragraph for this Wall Street Journal article. From National Geographic, in September “California Governor Jerry Brown signed a package of three bills designed to regulate the pumping of water from underground aquifers.” This is important for California because “aquifers provide 30 to 40 percent of the state’s water supply in normal years but close to 60 percent in drought years.” “The new laws give local agencies five to seven years to develop those groundwater plans, and until 2040 to implement them.” The new laws are a step in the right direction, but the new laws allow 25 years for plans to be drafted and implemented.
Water is sometimes used to extract oil — fracking uses high-pressure blend of water, sand and chemicals to crack rocks containing oil or natural gas. A federal study found that “fracking for oil in California happens at shallower depths than previously realized and could pose a risk to precious groundwater supplies”, especially in Kern County. Per well reports to date, 93% of fracked California wells used water from the California aqueduct; 6% used groundwater.
As expected, our home town of Los Altos, California, received no rain in August. In the middle of the dry summer of our Mediterranean climate, we have received only .01 inches of rain the past four months. The trend of warmer-than-normal overnight low temperatures continues. The California legislature passed two bills so that California would begin to regulate groundwater pumping, as state groundwater levels continue to drop.
First, here’s the graph of our rainfall through the end of August.
Little or no rain during June, July, and August is normal. No rain in May and little rain last winter are below normal. Little rain the past three years in the San Francisco Bay Area is indicative of California’s drought. Our local data is shown below.
The trend of above-normal overnight temperatures continues. For 17 of the past three months, our monthly low temperature has been above the historic average. This is like flipping a coin 20 times and getting 17 tails — very unlikely. The high temperatures are what you’d expect, where the measured temperature exceeds the average roughly half the time. (The August value for the historic low temperature is 55 degrees, but I couldn’t get Excel to show this.)
Three years into our drought, there’s little news for August. From the San Francisco Chronicle, “The worst drought in a generation has pushed California lawmakers to overhaul the state’s longstanding “pump-as-you-please” groundwater policy under a package of bills lawmakers sent Friday to Gov. Jerry Brown.”
The California Department of Water Resources has a wonderful interactive map showing ground water depletion. The map below shows ground water depletion during the past year. Red dots show locations where the level of groundwater has dropped by more than 10 feet. Red and orange (decreased ground water level) dominate the map, and there’s almost no green (increased ground water level).
From the Chronicle article,
Groundwater accounts for 60 percent of the state’s water use during drought years, yet it is not as regulated and closely managed as water from reservoirs, rivers and streams. The pumping has been so great in recent years that wells are running dry and the land is falling as water-drained soil is compressed. That in turn has led to billions of dollars in damage to roads, aqueducts, canals and pipelines, supporters say.