Climate change and drought will impact San Diego County’s climate future, but regional water supply planning and adaptation measures will ensure a safe, reliable supply for the region.
Water supply strategy was one of the key points participants learned about during a Monday panel discussion, “San Diego County’s Climate Future,” hosted online by the San Diego County Water Authority, Citizens Water Academy, Leaders 20/20 and San Diego Green Drinks.
After two exceptionally dry California winters, the East Bay Municipal Utility District is on the brink of declaring a stage 1 drought and asking customers to establish a district-wide voluntary water use reduction of 10 percent.
The utility district’s board of directors is meeting Tuesday night and district staff members will present the 2021 Water Supply Availability and Deficiency Report and make the recommendation.
The long-term drought and effects of climate change means more trouble for the millions of people that depend on the Colorado River.
In a statement released in early April, the Arizona Department of Water Resources, and the Central Arizona Project state that they expect the first-ever shortage declaration for the river in 2022, meaning substantial cuts to Arizona’s share of the water supply.
Scientists have few categories at their disposal to describe droughts, which are more complex than mere shortages of precipitation or surface water. For example, some local shortages can be invisible, as when water is transferred into a dry area from a distant source. Other shortages are chronic, with communities continuously requiring more water than is available, even in wet years. Some water shortages occur when water quality becomes so degraded that even though there may be plenty of water available, little of it is usable. With such variation in conditions, scientists need better language to conceptualize droughts.
Climate change and drought will impact San Diego County’s climate future, but regional water supply planning and adaptation measures will ensure a safe, reliable supply for the region.
Water supply strategy was one of the key points participants learned about during a Monday panel discussion, “San Diego County’s Climate Future,” hosted online by the San Diego County Water Authority, Citizens Water Academy, Leaders 20/20 and San Diego Green Drinks.
Panel moderator Kelley Gage, Water Authority Director of Water Resources, kicked off the climate conversation by describing the investments and steps taken by the Water Authority and its 24 member agencies to secure the region’s water future.
“Since our founding more than 75 years ago, our mission in partnership with our 24 member agencies is to ensure a clean and reliable supply of water for the region,” said Gage. “As part of that mission we’re involved in partnerships like the one that we have today and the research to ensure that we have planned for the impact of climate change in our water supplies.”
Gage said the Water Authority has developed a climate action plan.
“As part of our strategic planning we have developed a climate action plan which is an interdisciplinary effort to promote and coordinate implementation of climate change strategies and related activities across the Water Authority,” said Gage. “We have reached our goals for 2020 and we are on track for our 2030 goals.”
The Water Authority partnered with the Scripps Institution of Oceanography, Center for Wester Weather and Water Extremes, at UC San Diego in 2020 to better predict atmospheric rivers and improve water management before, during, and after those seasonal storms. The Center and its partners share best practices in forecast-informed reservoir operations, increased research around atmospheric rivers and droughts, and develop strategies for mitigating flood risk and increasing water supply reliability.
Marty Ralph, Researcher in Climate, Atmospheric Science & Physical Oceanography at Scripps Institution of Oceanography, and Director of the Center for Western Weather and Water Extremes, opened the panel with information on advanced research around atmospheric rivers.
Atmospheric rivers are long narrow bands of airborne water vapor, providing up to half the annual precipitation and mountain snow that is key to California’s water supply. New research allows reservoir operators to use atmospheric river forecasts to better predict storm events and prevent unnecessary stored water releases.
“This stored water has helped to cope with the third driest year on record for the region,” said Ralph.
Another Scripps Institution of Oceanography researcher, Alexander “Sasha” Gershunov, said that California receives most the country’s extreme precipitation events due to atmospheric rivers. Low and medium intensity precipitation events are predicted to decrease, while high intensity precipitation events are predicted to increase, especially in California.
“With warming, atmospheric rivers get stronger, wetter, longer, and more impactful, and they also produce more of our annual precipitation total,” said Gershunov. “There are many implications of these changes from water resources management, to wildfires, to debris flows.”
Darbi Berry, Program Manager at the San Diego Regional Climate Collaborative, described projects moving forward in the region to address equity issues related to water availability and pollution. Advancing the Nexus of Water and Equity looks at how different communities are impacted by a changing climate.
Increased variability in rainfall events and the potential for flooding in the San Diego region is a contributing factor to ongoing water quality issues in disadvantaged neighborhoods. One project carried out to address these equity issues is the National City, Paradise Creek project which re-graded a creek that was continuously overflowing and causing flood damage during atmospheric river events.
Sonoma County is facing a historic drought after two dry winters and, on Tuesday, county supervisors are expected to proclaim a drought emergency.
“We’re looking, today, at the lowest level our reservoirs have ever been since they were built,” said Brad Sherwood, the spokesman at Sonoma Water.
By the time this column is published, Northern California may be receiving some much-needed rain, and possibly some snow. However, late-season precipitation does not change the reality that California is in one of its periodic droughts after two dry years.
Major Northern California reservoirs are only about half-full due to scanty runoff from mountain snowpacks, farmers are getting tiny percentages of their normal water allotments, and local water agencies are beginning to impose restrictions on household use.
Longtime Bay Area residents are all too familiar with ground-parching droughts, those years when our hills are late turning green and early turning brown. Now it looks like we’ve entered another dry patch barely four years after emerging from the last one — an ominous sign that our meteorological cycles of boom and bust are picking up speed.
The water level of Lake Mead, the country’s largest reservoir, has dropped more than 130 feet since the beginning of 2000, when the lake’s surface lapped at the spillway gates on Hoover Dam.
Twenty-one years later, with the Colorado River consistently yielding less water as the climate has grown warmer and drier, the reservoir near Las Vegas sits at just 39% of capacity. And it’s approaching the threshold of a shortage for the first time since it was filled in the 1930s.
Limited access to clean water remains a struggle for millions of Americans. And lack of water access is expected to become an even greater problem in the coming years across the U.S. and around the world.
