Drought

Folsom Lake dropped to historically low water levels in January 2014.

Folsom Lake dropped to historically low water levels in January 2014. DWR/2014.

Note: Visit drought.ca.gov for water shortage assistance and information on drought-related financial assistance.

California is no stranger to drought; it is a recurring feature of our climate. We recently experienced the 5-year event of 2012-2016, and other notable historical droughts included 2007-09, 1987-92, 1976-77, and off-and-on dry conditions spanning more than a decade in the 1920s and 1930s.

Paleoclimate records going back more than 1,000 years show many more significant dry periods. The dry conditions of the 1920s-30s, however, were on a par with the largest 10-year droughts in the much longer paleoclimate record.

Droughts cause public health and safety impacts, as well as economic and environmental impacts. Public health and safety impacts are primarily associated with catastrophic wildfire risks and drinking water shortage risks for small water systems in rural areas and private residential wells. Examples of other impacts include costs to homeowners due to loss of residential landscaping, degradation of urban environments due to loss of landscaping, agricultural land fallowing and associated job loss, degradation of fishery habitat, and tree mortality with damage to forest ecosystems.

Unfortunately, the scientific skill to predict when droughts will occur – which involves being able to forecast precipitation weeks to months ahead – is currently lacking. Improving long-range weather modeling capabilities is an area of much-needed research.

Defining Drought

Defining drought is based on impacts to water users. California is a big state and impacts vary with location. Hydrologic conditions causing impacts for water users in one location may not represent drought for water users in a different part of California, or for users with a different water supply. Individual water agencies may use criteria such as rainfall/runoff, amount of water in storage, or expected supply from a water wholesaler to define their water supply conditions.  

Drought is a gradual phenomenon, occurring slowly over a period of time. Storage, whether in surface water reservoirs or in groundwater basins, buffers drought impacts and influences the timing of when drought impacts occur. A single dry year isn’t a drought for most Californians because of the state’s extensive system of water infrastructure and groundwater resources buffer impacts.

Drought impacts are felt first by people most dependent on annual rainfall – such as ranchers using dryland range or rural residents relying on wells in low-yield rock formations. Drought impacts increase with the length of a drought, as carry-over supplies in reservoirs are depleted and water levels in groundwater basins decline.

Provisions of California’s Emergency Services Act have been used to declare a statewide drought emergency for only two of our droughts, the 2012 to 2016 event and its immediate predecessor in 2007-09.

News and Updates

Fishermen head out from this dock near Dinosaur Point on the San Luis Reservoir near dawn in Merced County on Aug. 23, 2021.

DWR announced it is increasing the State Water Project allocation to 15 percent of requested supplies for 2022. Last month, due to low water levels, the Department announced that the initial allocation would cover only critical health and safety needs of the 29 water agencies that contract to receive State Water Project supplies.

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A cabin in the Sierra Nevada near Phillips Station where the first snow survey of the season took place December 30, 2021.

Most Californians have been experiencing a very wet holiday season. December storms have brought significant rain and record-breaking snow, sending water into our parched state reservoirs and adding to our Sierra Nevada snowpack, which is running well above average for this time in the season.

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