Current Conditions

Click on the images below to see the full-size version.

US Seasonal Drought Outlook
Source: NWS

San Joaquin Precipitation 
Source: DWR

Tulare Basin Precipitation
Source: DWR

California Fire Map
Source: CAL FIRE


Update on the California Drought: March 7 – April 3, 2017

From the Pacific Institute’s California Drought Response Team

Top Story

Bills Aim to Provide Long-Term Drought Solutions

Since record-keeping began in 1895, California has experienced the second wettest December through February this winter with 184% of average precipitation. The latest manual snow survey by the Department of Water Resources (DWR) at Phillips station in the Sierra Nevada found a snow-water equivalent (SWE) of 46.1 inches, 183% of the long-term average. (SWE is the depth of water that theoretically would result if the entire snowpack melted instantaneously.) On average, the snowpack supplies about 30% of water needs in California.

As California moves away from a state of drought emergency, it is time to pivot toward long-term solutions to help safeguard the state against future droughts. Several bills have been proposed to this end, including:

  • AB 1667: Introduced by Assemblymember Laura Friedman, this bill would require the installation of dedicated landscape water meters on commercial, institutional, industrial, and multifamily service connections. The bill would help water managers measure outdoor water use and better plan for conservation and efficiency measures.
  • SB 740: Introduced by Sen. Scott Wiener, this bill would require the State Water Resources Control Board, in consultation with other state agencies, to adopt regulations for developing oversight and management programs for the onsite treatment of water for non-potable use, providing an alternative supply of water.
  • SB 252: Introduced by Sen. Bill Dodd, this bill highlights the need for more transparency in new well construction in order to manage groundwater more sustainably. The bill would require a city or county overlying a critically overdrafted basin to make certain information about new wells publicly available and easily accessible before issuing any new well permit. Additionally, the Department of Water Resources would be required to provide utilities overlying a critically overdrafted basin ongoing technical assistance to implement provisions that comply with the bill. If the new plan is approved, a well completion report which includes information on well capacity (such as the estimated pumping rate) would have to be made available to the public.


In Other News

  • The US Bureau of Reclamation (USBR) has announced the 2017 water supply allocation for the remaining Central Valley Project (CVP) contractors. All north-of-Delta and in-Delta contractors will receive full allocation. South-of-Delta water contractors serving cities will be allocated 90% of the contract supply while those serving farms and other agricultural areas will be allocated 65% of the contract supply. The low allocation for agricultural water contractors is a result of carryover storage requirements. USBR is likely to increase this initial allocation after more information on snowmelt becomes available. Data on historical water allocations can be found here.
  • Despite the rain, Californians have been continuing to conserve water. Statewide water savings for January 2017 was 20.5% compared to the December 2013 production baseline, and 17.2% more than January 2016 savings, when state-mandated conservation targets were in place. Savings from June 2015 through January 2017 totaled over 2.50 million acre-feet.
  • NOAA’s Climate Prediction Center has projected that sea surface temperatures in the equatorial Pacific Ocean (i.e., the part of the ocean near the equator) will remain close to the long-term average through at least spring 2017. However, there is an increasing possibility of El Niño developing in the fall. El Niño is associated with dry weather patterns in Hawaii, the Pacific Northwest, the Rocky Mountains, and the Ohio Valley.
  • A recent study published in Geophysical Research Letters analyzed the contribution of human water management to the intensification or mitigation of drought in California from 1979 to 2014. Findings showed that in 2014, water management helped to alleviate water shortages by about 50% in Southern California through reservoir reoperation, while human water consumption (primarily through irrigation) increased the duration of drought by 50% and the water deficit in the Central Valley by 50% to 100%.
  • A new study from Princeton University found that some droughts can travel hundreds of miles from where they originated and that droughts tend to become larger and more intense before conditions improve. The insight that droughts are a dynamic force similar to hurricanes can help predict their development and forecast their paths.
  • A study by Chapman University researchers to evaluate water conservation messaging found that regardless of the strategy, these messages have led to a negative change in attitude. Initial attitudes were generally highly favorable regarding conservation, but this favorability decreased after message exposure. However, the study did not test for the specific reason for the negative effect.
  • The Sierra Nevada Conservancy recently published a new report update detailing the dire state of California forests. The combined effects of bark beetles and drought on overgrown forests in the state resulted in about 83 million trees dying between 2014 and 2016. Overgrown forests facilitated the spread of bark beetles. Trees became more vulnerable as the drought reduced their ability to secrete resin to ward away these insects. Additionally, the drought, warmer temperatures, and overgrown forests fueled large, catastrophic wildfires.


California Drought Status

Drought Monitor

Drought conditions in this period remained relatively the same as last month. The “extreme” and “exceptional” drought designations have been removed from the state’s drought monitor. As of March 28, 2017, about 8% of the state is experiencing moderate to severe drought conditions, a one percentage point decrease from last month. About 77% of the state is identified as drought-free.


Since the beginning of the water year on October 1, 2016, cumulative precipitation in California’s three key hydrologic regions has been far above the long-term average. As of April 3, 2017, the Northern Sierra region had received 83 inches of precipitation and is on track to receive more precipitation than in the 1982-1983 water year, the wettest on record. The San Joaquin and Tulare Basin regions remain very wet, although they are unlikely to surpass the wettest years’ records. As of April 3, these regions had received about 65 and 43 inches of cumulative precipitation, respectively, almost doubling the long-term average for this date.

California’s snowpack conditions are excellent. In early April, the electronic reading showed that total snowpack was about 160% of April 1 average (when snowpack is expected to be at its peak). The manual snow survey conducted on March 30 at Phillips station in the Sierra Nevada found a snow-water equivalent (SWE) of 46.1 inches, 183% of the long-term average for this date.

Reservoir Conditions

The water levels in California’s major reservoirs (representing 27.3 million acre-feet of storage) have remained the same as last month, representing 76% of the statewide capacity. Current storage levels are 109% of the historical average for this time of year, about 16 percentage points lower than last month. As of April 3, conditions at selected reservoirs were as follows:

  • The water level at Lake Shasta was at 110% of the historical average for this time of year. Lake Oroville and Folsom Lake were at 100% and 93% of the historical average, respectively.
  • The water level at the New Melones Reservoir, another major reservoir with a 2.4 million acre-feet capacity, was at 121% of the historical average for this time of year.
  • The water level at the San Luis Reservoir was at 109% of the historical average for this time of year.
  • Lake Cachuma, which supplies water to the city of Santa Barbara and other urban areas in Southern California, remains well below average. Over March, the water level increased slightly from 45% to 48% of capacity. As of April 3, the water level was at 57% of the historical average for this time of year.


We will resume updates when the 2017 wildfire season begins (typically in May).


Statewide hydroelectric power generation improved considerably in January 2017. Production was about 3,800,000 MWh, an increase of 250% over last year’s January production of slightly over one million MWh, and an increase of 16% over 2011’s wet January. With record-high precipitation, hydropower production is expected to increase given snowmelt and will likely peak between May and July 2017.

Groundwater Conditions

Groundwater conditions have likely improved as a result of recent storms, but comprehensive data are updated infrequently. Some recent data are available for adjudicated basins for the 2015-2016 water year.

The most comprehensive data on groundwater conditions are based on measurements taken in spring 2016. Maps of spring and fall groundwater level changes can be found here. Parts of the Tulare Lake, the South Coast, and the Colorado River hydrologic regions experienced groundwater declines of more than 100 feet between fall 2011 and fall 2015.

Additional Resources

  • The California Data Exchange Center provides California water and weather-related resources including snow surveys and rainfall maps. It is managed by the California Department of Water Resources (DWR).
  • A “one-stop shop” for water data and maps is being offered by the National Oceanic and Atmospheric Association (NOAA).
  • The Tree Mortality Viewer shows areas of high hazard zones and related information. The tool was created by the Tree Mortality Task Force, comprised of state and federal agencies, local governments, utilities, and other stakeholders.
  • The California Harmful Algal Blooms (HABs) Portal provides timely information on reported sightings of the potentially toxic blue-green algal blooms and affected water bodies (Last updated 9/20/2016).
  • The Groundwater Information Center (GIC) interactive map is available for public use. Developed by the California Department of Water Resources, it provides visualization for groundwater depth, changes in groundwater level, as well as land subsidence.
  • River conditions by the California Nevada River Forecast Center (CNRFC).
  • Interactive map of residential and system-wide water use in California by the Pacific Institute.
  • California climate anomaly maps and tables by the Western Regional Climate Center (WRCC).