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.