Mammoth Mountain received record snowfall in May 2019. Photo: Mammoth Mountain, Inc. California Reservoirs

Water Year 2020 Begins With Robust Reservoir Storage

Last winter was a bountiful one in terms of water supply for California, but it’s still too early to tell whether 2020 will be as generous.

The 2018-19 winter was one for the record books, with above-average precipitation. Snow continued to fall in late-spring, with several inches or more in the Sierra Nevada and the Southern California mountains.

Ski seasons were extended into May and June, delighting skiers and resort operators.

The snowfall, and a boost from late-season storms, increased the northern Sierra snowpack in May 2019, which was “atypical,” according to Alexi Schnell, water resources specialist with the San Diego County Water Authority.

The statewide Sierra Nevada snowpack was 164% of normal, with the northern Sierra at 172% of normal on May 23, 2019.

Major California Reservoirs Above Historical Average on November 8, 2019

Most major California reservoirs are above their historical averages as of November 8, 2019. (Graphic: California DWR)

Water Year 2020 begins with robust reservoir storage

The 2019 water year (October 1 – September 30) pushed snowpack levels well-above average and swelled major reservoirs to above-average. There were more than 30 atmospheric rivers, with many making landfall in Northern California. The state’s snowpack on April 1 was 175% of average.

The California Department of Water Resources said that makes a great start to 2020.

“We start the new water year in a good place,” said Karla Nemeth, director of the DWR. “However, we all know too well that California’s weather and precipitation are highly variable. What we have today could be gone tomorrow.”

Above average rainfall in San Diego

While the biggest gains in precipitation over the past year were in Northern California, the San Diego region also benefited. Water Year 2019 ended with the region at 125% of average rainfall at Lindbergh Field. The rainfall helped increase supplies in regional reservoirs.

Schnell cautioned that the climatological cycle in California can bring several consecutive years of drought, like the 2015-17 period, which prompted mandatory water-use reductions statewide.

Above-average temperatures in California in 2019

NOAA reported on November 6 that California experienced above-average to much-above-average temperatures from January through October 2019. The average U.S. temperature during that same period was 55.5°F, (0.5 of a degree above 20th-century average) “ranking in the warmest third of the record,” according to NOAA.

NOAA reported that California has had above-to much-above-average temperatures from January to October 2019.

NOAA reported that California has had above-to much-above-average temperatures from January to October 2019. (Graphic: NOAA)

Scripps Institution of Oceanography’s Center for Western Weather and Water Extremes, or CW3E, just released an analysis that calculated the odds of water year 2020 reaching 100% of water year normal precipitation totals. The odds range from 20 to 40% of the Southwest reaching 100% of water year normal precipitation.

Odds of reaching normal precipitation for Water Year 2020. (Graphic: CW3E, Scripps, UC San Diego)

National Weather Service seasonal outlook for precipitation

The three-month seasonal precipitation outlook for November-December-January by the National Weather Service Climate Prediction Center shows below-normal to normal precipitation in Central to Northern California and equal chances of below, near- or above-normal in southern California and much of the Southwest.

The November-December-January precipitation outlook from the National Weather Service.

The November-December-January precipitation outlook from the National Weather Service. (Graphic: NWS/NOAA)

“There will always be fluctuations based on weather and other factors, but the San Diego region continues to embrace water-use efficiency,” said Schnell. “The Water Authority and its 24 member agencies continue to increase San Diego County’s water supply reliability through supply diversification to provide a safe, reliable water supply to the region.”

Report credits San Diego County Water Authority for providing regional water solutions which include storing water in Lake Mead. Photo: National Park Service

San Diego County Quality of Life Indicators Mostly Positive in 2018

A report released today showed improvement in 2018 for the majority of 15 indicators used to measure San Diego County’s quality of life. The Equinox Project Quality of Life Dashboard measures and benchmarks several environmental and economic trends throughout the region.

The analysis highlighted the San Diego County Water Authority for developing water solutions for San Diego and the Southwest using a “portfolio approach.” One of the initiatives under that approach includes efforts to store water in Lake Mead on the Colorado River, which would benefit both San Diego County residents and many other river users.

San Diego County's water supply has diversified significantly over the last couple of decades.. Source: San Diego County Water Authority

San Diego County’s water supply has diversified significantly over the last couple of decades. Source: San Diego County Water Authority

The nonpartisan Equinox Project report is a source of public policy research and analysis to guide policymakers, planners and other officials, said Emily Young, executive director of The Nonprofit Institute at the University of San Diego, where the project is based.

Water use increased in 2018

“There’s no one indicator when you’re talking our quality of life in the San Diego region,” Young said. “And in fact, the whole point is all of these things are connected. If you’re talking about air quality, you really can’t talk about that if you’re not also talking about our transportation systems and the pollution generated from them.

“Whether we’re looking at an issue like water, which is very precious to the San Diego region, or other issues around transportation or housing, all of these are things that we’re measuring our progress on,” said Young.

Per capita water use in San Diego County

*This data includes agricultural water use served by local water agencies.
In 2018, National City had the lowest municipal and industrial (M&I) water use at 78 gallons per capita daily. Yuima’s high per capita M&I potable water use occurs because a large amount of water used for horticultural irrigation is classified as M&I, and the district services a small population (less than 2,000 people). Data Source: San Diego County Water Authority

Measuring quality of life

Six of the 15 indicators received a “thumbs-up” in the report, including air quality, electricity use and renewable energy. Four indicators, including water use, received a “thumbs-down.”

“Daily residential water consumption in San Diego County increased by 8.3% from 84 gallons per capita in 2017 to 91 gallons in 2018,” according to the report. “Water use has increased since the statewide water restrictions were lifted in 2017, though below pre-drought levels.”

*Sweetwater Authority is comprised of the South Bay Irrigation District and National City. The dataset excludes the City of Del Mar, the City of Oceanside, Camp Pendleton Marine Corps Base and the Yuima Municipal Water District.
In Q4 of 2018, residents in the Sweetwater Authority area (National City and South Bay) had the lowest residential water use in San Diego County. Santa Fe Irrigation District used 363 gallons per capita/day, the most water per capita in San Diego County. Data Source: State Water Resources Control Board, Urban Water Supplier Report, 2019

Water use lower in 2019

Despite the slight increase in water use during 2018, residents continue to conserve compared to previous years.

“While extreme dry conditions contributed to increased residential water use in 2018, per capita water use was still lower than historical, pre-drought levels,” said Alexi Schnell, water resources specialist with the Water Authority. “Water use to date in 2019, a much wetter year, has been consistently lower than in 2018.

“There will always be fluctuations based on weather and other factors, but the San Diego region continues to embrace water-use efficiency, and per capita water use in the region is not forecasted to return to pre-drought levels for the foreseeable future,” Schnell added.

The report noted that “the San Diego region is making significant commitments to water efficiency and recycling” and has diversified local supply with the Claude “Bud” Lewis Desalination Plant in Carlsbad, the nation’s largest seawater desalination plant.