2021 Drought in California – in one page

by Jay Lund

Droughts and this drought in California

  • California has more hydrologic variability than any state in the US, meaning that we have more drought and flood years per average year than any other state.  This is a problem, but has also meant that we have designed for droughts, which are always testing us.
  • 2021 is the 3rd driest year in more than 100 years of precipitation record.  2020 was the 9th driest year in the precipitation record. 
  • Much warmer temperatures are further reducing streamflows and aquifer recharge, and has lengthened and deepened the wildfire season.
  • Large reductions are occurring in surface water available for agriculture, especially in the San Joaquin Valley, but also in the Sacramento Valley and smaller river valleys statewide.
  • Much increased groundwater pumping greatly reduces agricultural impacts, but affects rural wells.
  • Major forest and aquatic ecosystem impacts are occurring, especially for wildfires and salmon runs, particularly for winter-run salmon downstream of Shasta Dam.
  • A growing number of small communities and towns are being affected, in addition to more common problems for rural household and community wells. Santa Clara Valley (San Jose area) is the most-affected major urban area, seeking 30% water use reductions.


  • If next year is also dry, agricultural and environmental impacts will increase and urban impacts will expand.
  • Warmer temperatures from climate change are worsening droughts, reducing the amount of precipitation that arrives at reservoirs and aquifers, lengthening wildfire seasons, and worsening conditions for cold-water fish species, such as salmon.  We need to further adapt water, land, and environmental management for these changes.
  • Another dry year is likely. Very dry watersheds, very low reservoir levels, falling aquifers, and higher temperatures mean more precipitation is needed to make next year not dry.
  • Under SGMA, farmers will need to repay additional groundwater pumped during the drought, meaning some reductions in lower-valued crops in wetter years so aquifers can recover to sustain permanent crops in future droughts. Few basins can sustain aquifers with managed aquifer recharge alone; many will need deep reductions in aquifer pumping in wetter years.
  • Sizable long-term reductions in irrigated area seem unavoidable in parts of the San Joaquin Valley. Urban water conservation statewide is helpful, and still more conservation will help a bit.
  • A more formal state water accounting system is needed to support tighter surface water right administration, SGMA planning and implementation, and environmental uses. Water right curtailments are likely to become routine in more basins.

Further Reading

Arax, Mark (2021), “The Well Fixer’s Warning,The Atlantic, August 17.

Lund, J.R., J. Medellin-Azuara, J. Durand, and K. Stone, “Lessons from California’s 2012-2016 Drought,” J. of Water Resources Planning and Management, Vol 144, No. 10, October 2018.

Pinter, N., J. Lund, and P. Moyle. “The California Water Model: Resilience through Failure,” Hydrological Processes, Vol. 22, Iss. 12, pp. 1775-1779, 2019.


Jay Lund is Co-Director of the Center for Watershed Sciences and Professor of Civil and Environmental Engineering at the University of California – Davis.

About jaylund

Professor of Civil and Environmental Engineering Director, Center for Watershed Sciences University of California - Davis
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8 Responses to 2021 Drought in California – in one page

  1. lwintern says:

    Great summary. Thank you Jay Lund!

  2. Camalam says:

    “Water right curtailments are likely to become routine in more basins” from your last bullet point. Could you please expand a little on this? By what means, which rights, where.

    Thank you.

  3. Tawnya Martin says:

    Is it possible to build a water pipeline like the one from Alaska for oil from east coast to west coast capture all the rain and divert to california nevada etc?

  4. Can you break down how corporations like Nestle are able to pump out water in California with impunity?

  5. Edward Kehoe Merrick says:

    Why is no one discussing cutting canyons in the Coast Range and the Sierra Nevada to allow storms to pass through?

  6. James Michael Wharton says:

    Let’s build pipelines to pump water from the flooded east to the drought stricken west. Take the excess water from flooded plains along the Mississippi and Missouri rivers north of the Ohio river, where water quality is better, and pipe it to the reservoirs and headwaters of the west. This water would alleviate floods in the midwest and south, alleviate the extreme drought, loss of hydroelectric power in the west, and promote agriculture, production of livestock, and natural plant and wildlife. If oil and natural gas pipelines can be permitted and built clear across the U.S., certainly water pipelines can too!! Water pipelines are far more environmentally friendly than oil and gas and far less likely to be opposed. Building and powering such water pipelines would create thousands upon thousands of jobs and save the businesses and livelihoods of millions of citizens.
    The cost of doing nothing is immense. According to government and insurance statistics, the damages in the United States for flooding is at least $4.3 billion per year and for drought some $9.5 billion per year. Surely, in reality, these amounts are very conservative, as they do not take into account the costs due to unemployment support, reductions in agriculture and ranching, the costs of levies, deep well drilling, and what is more, the costs in human life and homelessness due to floods and drought.
    This would certainly be the most important infrastructure project ever! It can be done. Compare it to the Interstate Highway System and the Transcontinental Railroad. Use part of Congress’ hard infrastructure budget to build it. The increased revenue from the increase in economic activity might well pay for the project. Western agriculture and ranching would flourish, supplying food to the rest of the nation, create thousands upon thousands of jobs, and lessen the floods in the east. Everyone benefits!

    Bigthink.com, “Interstate Water System”, Henry Miller, et.al., 26 May 2021.
    Zamboanga.com, “Water Pipeline, USA, East to West”, for concept only, estimates incorrect.
    National Park Service, “Storage capacity of Lake Mead”.
    The Guardian, “Climate Crisis in the West”, Maanvi Singh.
    NOAAClimate.gov, “2010-2019: A landmark decade of U.S. billion dollar weather and climate
    Insurancejournal.com, “Insurance industry will withstand Ida’s losses….”, 2 Sep 2021.
    Weather.gov, “Flood History”.
    Climatesignals.org, “Mississippi River Basin Spring Flooding 2019”.

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