As California’s drought continues through our dry summer, urban water users locally and throughout California have dramatically reduced water usage. Our local aquifer is looking good, but in the Central Valley, ground subsidence and fish are much worse.
August was dry and warm in Los Altos, California, as usual. There was no surprise for August rainfall — zero rainfall is normal, and only .01 inches fell. November is the next month averaging more than an inch of rain, so we can expect two more dry months. Forecasts of an El Niño and more rain are strengthening; we’ll see how that pans out.
With insignificant variation for August rainfall, the cumulative rainfall since January 2013 remains at 53% of normal.
As with previous months, the daytime high temperature is about normal, while the overnight low temperature remains much higher than normal.
Urban water usage drops dramatically
Statewide and locally, urban water users are conserving more than the state standard of 25%. This is wonderful, showing that the people understand the drought and are modifying their water usage behavior. From the state press release,
Despite continued hot conditions, Californians surpassed June’s conservation rate and reduced water use by 31.3 percent during July, exceeding Governor Edmund G. Brown Jr.’s 25 percent mandate for a second consecutive month since the new emergency conservation regulation took effect.
Locally, we’re doing even better. Our town is served by California Water, and Cal Water customers continue to conserve more water than the state standard of 32% for our area. We used more water per capita than most during the 2013 baseline period, so we’re now expected to conserve more than the state standard of 25%.
Other cities in our Santa Clara Valley are similarly conserving this summer. Our collective water conservation is improving the aquifer under the valley. Groundwater pumping for the past three months is much lower than the past five years, and the groundwater level at an index well in San Jose is rising through the summer. Looking at past years, the groundwater level usually falls during our dry summer.
Ground subsidence increases in the Central Valley
In our neighboring Central Valley, land subsidence is increasing. As water deliveries to farms have been cut, farmers continue to pump groundwater. From the California Department of Water Resources,
As Californians continue pumping groundwater in response to the historic drought, the Department of Water Resources today released a new NASA report showing land in the San Joaquin Valley is sinking faster than ever before, nearly two inches per month in some locations. …
Land near Corcoran in the Tulare basin sank 13 inches in just eight months—about 1.6 inches per month. One area in the Sacramento Valley was sinking approximately half-an-inch per month, faster than previous measurements. NASA also found areas near the California Aqueduct sank up to 12.5 inches, with eight inches of that occurring in just four months of 2014.
The increased subsidence rates have the potential to damage local, state, and federal infrastructure, including aqueducts, bridges, roads, and flood control structures. Long-term subsidence has already destroyed thousands of public and private groundwater well casings in the San Joaquin Valley. Over time, subsidence can permanently reduce the underground aquifer’s water storage capacity.
Fish nearing extinction in the Delta
Wildlife is taking a hit during the drought. A smelt in the delta feeding San Francisco Bay may be nearing extinction.
Another native fish of the Sacramento-San Joaquin Delta appears to be rivaling the cliffhanger status of the delta smelt.
Relative to its historical abundance, the lesser-known longfin smelt has experienced an even bigger decline than delta smelt — and may be in bigger trouble — according to trawl surveys of Delta fishes.
In the past two years, catches of adult longfins have been close to zero, and a recent larval survey found alarmingly few of the smelt. The dramatic downturn is likely a result of the drought, as with the tinier delta smelt.