Although a few storms in March delivered some rain and snow across California, the Golden State experienced a mostly dry winter season. The result: most of Santa Clara County and nearly all of California are in a drought, according to the U.S. Drought Monitor.
Snowpack in the Sierra Nevada measured at 59% of average on April 1, according to the California Dept. of Water Resources. Locally, rain totals in our county this season are at about 50% of normal and storage levels at our reservoirs are at 26% of average. Also, the amount of imported water that Valley Water will receive this year was drastically reduced.
Despite these challenges, Santa Clara County’s water supply outlook appears adequate for the remainder of the year. We anticipate sufficient supplies to meet demands in 2021. Our current groundwater levels are good, and we are maximizing our withdrawals of water from the Semitropic Groundwater Storage Bank near Bakersfield. Valley Water is also actively working to purchase additional water supplies to help meet demands.
But as we look to the future, we can’t just sit back and hope for rain and snow next winter. We need to prepare today in case these drought conditions worsen.
That’s why it’s crucial Valley Water continues to invest in conservation programs and our aging infrastructure, including pipelines, water treatment plants and the retrofitting of Anderson Dam in Morgan Hill. We also need to make smart investments to secure water supplies for the future, such as expanding our county’s use of recycled and purified water.
The Valley Water Board of Directors continues to call for a 20% voluntary reduction in water use compared to 2013, which we implemented during the last historic drought. In the previous seven years, water use in Santa Clara County was down by about 21% compared to 2013. Water saved today is water that’s available in the future.
“We must all do our part and conserve water,” Valley Water Board Chair Tony Estremera said. “We believe that conservation is a way of life here in Santa Clara County.”
The Board of Directors is scheduled to receive an update from Valley Water staff on the water supply outlook at its board meeting on April 27, at which time the Board of Directors could consider changes to the existing policy of a 20% voluntary water conservation effort in Santa Clara County.
Valley Water offers a wide-ranging conservation program to help residents and businesses save water and money. You can learn more about our robust programs by visiting watersavings.org.
Why the snowpack is important
More than half of Santa Clara County’s water supply comes from hundreds of miles away – first as snow or rain in the Sierra Nevada range of northern and eastern California, then as water in rivers that flow into the Sacramento-San Joaquin River Delta.
Often called “imported water,” it is brought into the county through the complex infrastructure of the State Water Project, the federal Central Valley Project, and San Francisco’s Hetch Hetchy system.
The April 1 snowpack survey is a key indicator for planning statewide summer water supplies because it’s typically when the snowpack is at its deepest with the most water content. Snow in the Sierra Nevada melts and is captured in reservoirs across the state.
The below-average snowpack levels and rain this winter, combined with the dry soil conditions that reduced runoff into key reservoirs, resulted in a decrease in State Water Project and Central Valley Project supplies. At the beginning of 2021, Valley Water’s State Water Project allocation was 10%, but that was reduced to just 5% in March, providing only 5,000 acre-feet of water. Valley Water’s Central Valley Project supply has also been slightly reduced.
Semitropic Groundwater Storage Bank
In years when there’s a large Sierra snowpack, such as the 2016-17 and 17-18 water years, our local reservoirs are often at capacity. There are times when our share of available imported water from the Central Valley Project and State Water Project is more than we need and more than we can store in San Luis Reservoir in Merced County, locally in Anderson and Calero reservoirs or in our local groundwater aquifer.
When that occurs, we can send that surplus water down the California Aqueduct to a groundwater basin near Bakersfield in Kern County. Valley Water’s portion of that Semitropic Groundwater Storage Bank is 350,000 acre-feet. Currently, Valley Water’s storage in the Semitropic Bank is over 333,000 acre-feet, or 95% of capacity. Valley Water plans to withdraw about 30,000 acre-feet from this bank to supplement our county’s water supply this year.
This past fall, Valley Water lowered the water levels in Anderson Reservoir as part of our effort to strengthen the existing dam so it can safely withstand a large earthquake. The project will keep the public safe and, once finished, allow Valley Water to store water in Anderson Reservoir. While this vital work is done, we will have to rely more on imported water over the next ten years during construction at Anderson Dam.