Anza-Borrego Desert Research Center-Sicco Rood-March-2020-WNN water supplyMorning view of snow coating the upper parts of Anza-Borrego Desert on March 27. Photo: Sicco Rood / University of California, Irvine Steele/Burnand Anza-Borrego Desert Research Center

Water Supply Diversification Overcomes Dry Winter

No ‘March Miracle’ for snow and rain in California, but the San Diego County Water Authority has diversified water supply sources to weather the boom-and-bust cycle of California winters.

March brought abundant precipitation throughout California, but not enough to offset a dry February. Most large urban water agencies in the state maintain a reliable water supply in wet and dry years.

“California’s climate variability is why a water resilience portfolio is needed to provide a safe and plentiful water supply,” said Goldy Herbon, Water Authority senior water resources specialist. “Whether a wet or dry year, the Water Authority and its 24 member agencies have successfully diversified water sources to ensure a reliable supply to meet the needs of the region’s 3.3 million people.”

The supply sources include water from the Claude “Bud” Lewis Carlsbad Desalination Plant, where ten workers volunteered to live on-site to keep the water flowing during the coronavirus pandemic.

Lindbergh Field has received 9.76 inches of rain – or 108% of normal – from October 1, 2019 – April 2, 2020. Many areas in the San Diego region received snow in March, including the Anza-Borrego Desert State Park.

Even with a lackluster winter, the state’s six largest reservoirs hold between 82% and 125% of their historical averages for April 1, according to the California Department of Water Resources. Lake Shasta is 98% of its historical average and is at 79% of capacity.

Major California Reservoirs-April 1 2020-WNN-CA DWR graphic

The Department of Water Resources April 1 conducted the fourth manual snow survey of 2020 at Phillips Station near Lake Tahoe. The manual survey recorded 43.5 inches of snow depth and a snow water equivalent (SWE) of 16.5 inches, which is 66% of the April average for this location.

The SWE measures the amount of water contained in the snowpack, which provides a more accurate forecast of spring runoff. Measurements from the 130 electronic snow sensors, scattered throughout the state, indicate that the statewide snowpack’s water equivalent is 15.2 inches, or 53% of the April average.

Sierra Nevada Snowpack Comparison-NASA satellite image-WNN-April 2020

The natural-color satellite images above, acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on NASA’s Terra and Aqua satellites, show the area covered by snow in March 2020 compared to March 2017 (a record high year). Graphic: NASA/NASA JPL

“While today’s survey results show our snowpack is better off than it was just last month, they still underscore the need for widespread, wise use of our water supplies,” said DWR Director Karla Nemeth. “California’s climate continues to show extreme unpredictability, and February’s record dryness is a clear example of the extremes associated with climate change.”

On average, the snowpack supplies about 30% of California’s water needs as it melts in the spring and early summer, the state agency reported in news release.