By Jay Lund, Josue Medellin, John Durand, and Kathleen Stone

Lake Cachuma in Southern California, February 2017

Droughts and floods have always tested water management, driven water systems improvements, and helped water organizations and users maintain focus and discipline.  California’s 2012-2016 drought and the very wet 2017 water year were such tests.  Historically, major droughts accelerate innovation and are career tests for agency and political leaders.  We recently summarized major lessons from California’s 2012-2016 drought (Lund et al. 2018). (Wet year failures from 2017 brought additional lessons.)

California accommodated the most recent droughts and floods fairly well – with some important exceptions.  It is worthwhile to show how such a large drought could have such small impacts on most Californians, and to draw lessons for how all sectors might reduce drought impacts in the next inevitable drought.  Contrasts for four sectors are particularly poignant.  Future droughts and floods are expected to be greater and perhaps more frequent, so recent relative success should not encourage complacency.

Managed well and poorly

California’s large urban systems fared well in the drought.  This contrasted with previous major droughts in 1976-77 and 1988-92, when major water systems were forced into mandatory water conservation.  Santa Cruz and Santa Barbara (with relatively isolated water supply systems) were the only major cities which imposed mandatory use reductions due to local water supply shortages, for one year each of the 5-year drought.  Despite sizable population growth since previous droughts, major urban areas were well prepared for this drought due to increasing water conservation (substantially driven by more conserving plumbing standards) and major improvements in infrastructure and regional cooperation (expanded groundwater and surface storage, wastewater reuse in southern California, drought plans, and water trades and markets) since previous major droughts.  In 2015, mandatory statewide reduction in urban water use by 25%, to prepare for a longer drought, led to negligible regional economic impacts because it was accommodated mostly by reducing urban landscape irrigation (normally about 50% of statewide annual urban water use).

Most agricultural areas largely continued to prosper during the drought, thanks largely

Fallowed field in southern Central Valley, 2015

to groundwater access, good national and global commodity prices, and flexible operations and water trades.  However, agricultural production and management was challenged widely and some farming areas found themselves unprepared and suffered considerable losses.  Again, preparation was key to minimizing losses.  The prominent importance of groundwater led to state regulation of groundwater in 2014 to help ensure adequate sustainable groundwater supplies for more profitable perennial crops, which are more expensive to fallow in dry years.

Rural drinking water supplies faced sometimes severe challenges, largely due to additional agricultural pumping from deeper, larger-capacity wells.  These small systems, which are more vulnerable under many conditions, remain one of California’s most challenging, but more solvable water problems.  A modest amount of regular funding, well organized and applied, along with better sustained groundwater levels, would address the worst of this problem for future droughts.

Ecosystems saw the greatest drought impacts, which are still being felt in terms of recent wildfires.  Perhaps the biggest effects of the drought are for forests and wildfires statewide.  Several recent large wildfires, made worse by the drought and climate warming, have been locally devastating and had a statewide economic impact many times that of the major 5-year drought.  Aquatic ecosystems in much of the state, already weakened by longstanding multiple stressors and unrecovered from previous droughts, were also harmed.  Environmental flows were sometimes reduced in favor of economic activities.  Waterfowl were less harmed in the drought due to effective cooperation among private, NGO, state, and federal refuge managers to adaptively manage and supply wetlands for migratory birds, an example of effective drought management for an ecosystem.  Again, for all these sectors, reductions of future drought impacts will require organization and investment in preparation well beyond that done before the drought.

Lessons from California’s 2012-2016 drought

1. Drought tests improve management in well-run water systems. Each drought in California’s history has led to improvements in water management, often responding to long-term problems and opportunities. The recent drought highlighted the dependence of California’s agriculture on groundwater in dry periods, and brought substantial legislation for more effective local groundwater management. Incremental improvements in water accounting, urban water conservation, and other areas were accelerated by the drought. Diligent reflection and discussion from the recent drought should lead to further improvements, particularly for the less prepared, less organized areas of managing ecosystems, rural water supplies, and environmental and water right regulations. The reports for the Oroville spillway failures in 2017 and the 1976-77 drought are superb examples.
2. California’s diverse economic structure and deep global connections greatly reduce drought’s economic impacts. California and other modern global economies depend less on abundant water supplies than in the past. High values for California’s major export crops greatly reduced the impacts of fallowing to about 6% of the least-profitable irrigated land during the drought. Despite important local problems, the drought had little effect on California’s statewide economy. Urban areas, supporting most people and economic activity, had already developed diversified water supply and conservation portfolios successfully from previous droughts, with some additional improvements.
3. Globally, California is more robust to drought and climate change from its organized water systems, irrigated agriculture with diversified supplies, substantial groundwater, and adaptability with water networks and markets. California’s extensive diverse water infrastructure allowed more than 70% of water supplies lost to drought to be replaced by pumped groundwater for agriculture and shifting of surface water supplies, requiring greater groundwater recharge in the long term. California’s irrigation infrastructure and network of reservoirs and canals mute drought effects, and are particularly effective for protecting the most valuable crops and economic activities. With long-term reductions in the least-profitable irrigated area, this system can be sustainable.
4. Ecosystems were the sector most affected by the drought, given the weak condition of many native species after decades of losses of habitat and water and the growing abundance of invasive species. Forests are particularly vulnerable and difficult to protect from droughts. With each drought, humans become better at weathering drought, but effective institutions and funding are lacking to improve ecosystem management and preparation for drought. Dedicated environmental water rights and restoration and migration programs can help support ecosystems. Such actions are needed to break the cycle accumulating drought impacts to ecosystems.
5. Small rural water systems are especially vulnerable to drought. Small systems often struggle in normal years, lack economies of scale, typically have only a single vulnerable water source, and commonly lack sufficient organization and finance. Accumulating overdraft, accelerated during drought, brings a growing number of dry domestic and community wells in rural areas.
6. Every drought is different, and motivates further improvements. Each drought is hydrologically unique and occurs under different historical, economic, ecosystem, and climate conditions. But all droughts provide opportunities and incentives to improve water management for changing conditions and priorities. In well-managed systems, each drought is greeted with improved preparations from previous droughts.

Major water agencies should reflect on and document lessons from the last drought to help prepare for the future droughts.  Such documents are important for policy discussions and as background for water managers and policy-makers entering a new drought.  Periodic regional drought “dry run” exercises also would help prepare agencies for droughts, and particularly help agencies to work well together during drought (and at other times) – much like annual flood and earthquake exercises.

Every generation needs at least one threatening drought to motivate water system improvements and collaborations among the many agencies and interests involved in water management and use.  Droughts are unavoidable, but their effects are much less if we organize, prepare, and respond appropriately.

Further reading

Department of Water Resources (DWR) (1978), The 1976-1977 California Drought – A Review, California Department of Water Resources, Sacramento, CA, 239 pp.

Hanak, E., J. Mount, C. Chappelle, J. Lund, J. Medellín-Azuara, P. Moyle, and N. Seavy,  What If California’s Drought Continues?, 20 pp., PPIC Water Policy Center, San Francisco, CA, August 2015.

Independent Forensic Team, Independent Forensic Team Report – Oroville Dam Spillway Incident, 5 January 2018.

Lund, J.R., J. Medellin-Azuara, J. Durand, and K. Stone, “Lessons from California’s 2012-2016 Drought,” Journal of Water Resources Planning and Management, October 2018. (open access)

Medellín-Azuara, J., D. MacEwan, R.E. Howitt, G. Koruakos, E.C. Dogrul, C.F. Brush, T.N. Kadir, T. Harter, F. Melton, J.R. Lund,” Hydro-economic analysis of groundwater pumping for California’s Central Valley irrigated agriculture,” Hydrogeology Journal, Vol. 23, Issue 6, pp 1205-1216, 2015.

Jay Lund is the Director of the UC Davis Center for Watershed Sciences. Josue Medellin is an acting Associate Professor of Engineering at UC Merced.  John Durand is a professional researcher and Kathleen Stone is a graduate student at the UC Davis Center for Watershed Sciences.