Building Drought Resilience in California’s Cities and Suburbs

Public Policy Institute of California (PPIC) | June 1st, 2017

Droughts are a recurring feature of California’s climate. Major droughts provide an opportunity to review management responses and derive policy lessons that can better

Droughts are a recurring feature of California’s climate. Major droughts provide an opportunity to review management responses and derive policy lessons that can better prepare society for the next one. Here we take stock of how California’s cities and suburbs have responded to recent droughts, review the state’s evolving role in urban drought management, and recommend actions to increase urban areas’ drought resilience. California’s urban water supply system is complex and highly decentralized, with 400-plus utilities serving more than 90 percent of the state’s residents. Following the hard lessons learned from the 1976–77 and 1987–92 droughts, these utilities made substantial investments in drought resilience. This included diversifying supplies with new surface and underground storage, interconnections with neighboring suppliers, recycled wastewater, and water transfer agreements, as well as freeing up supplies by reducing indoor water use. Consequently, urban water suppliers generally believed they were prepared as the state entered a five-year drought in 2012.

Bulletin 132-77 The California State Water Project -- 1976 Activities and Future Management Plans

California Department of Water Resources (DWR) | November 30th, 1977

The 1975-76 and 1976-77 water years (a water year begins October 1 and extends through September 30) were the first years of critical water shortage since operation of th

The 1975-76 and 1976-77 water years (a water year begins October 1 and extends through September 30) were the first years of critical water shortage since operation of the State Water Project began in 1962. The shortage of new water supplies, which are far below the quantities normally expected during the winter and early spring seasons, has had far-reaching effects. The management of available State Water Project supplies on a day-to-day basis is critical during these times, for we must make most efficient use of available water supplies including the maintenance of water quality in the Delta as required by law. Although we don't know what next year may bring, we must prepare for another season of minimum precipitation. A public awareness program has been a part of the Department's responsibilities during the current drought, and we have done everything possible to inform the public of the critical situation at hand. The drought program has kept our water contractors and the people of California current with evaluations of what can be expected from the State Water Project during 1976 and within the foreseeable future.

Bulletin 132-78 The California State Water Project -- 1977 Activities and Future Management Plans

California Department of Water Resources (DWR) | October 31st, 1978

1977 was a bittersweet year for the State Water Project. The worst drought in our State's history limited our ability to serve our 31 water service contractors; yet at th

1977 was a bittersweet year for the State Water Project. The worst drought in our State's history limited our ability to serve our 31 water service contractors; yet at the same time the largest water exchange in the history of the State took place between urban users in the San Francisco Bay area, agricultural users in the San Joaquin Valley, and The Metropolitan Water District of Southern California with San Bernardino Valley Municipal Water District, Coachella Valley County Water District, and Desert Water Agency. This greatly helped to significantly reduce the magnitude of the shortage.

Bulletin No. 39-57, Water Supply Conditions in Southern California during 1956-1957, Volume II, Precipitation and Water Level Data Central Coastal and Los Angeles Regions

California Department of Water Resources (DWR) | June 16th, 1958

Bulletin No. 39-57 Volume I Bulletin No. 39-57 Volume III Bulletin No. 39-57 Volume IV

Bulletin No. 39-57 Volume I Bulletin No. 39-57 Volume III Bulletin No. 39-57 Volume IV

Bulletin No. 39-57, Water Supply Conditions in Southern California during 1956-1957, Volume III, Precipitation and Water Level Data Lahontan, Colorado River Basin, Santa Ana, and San Diego Regions

California Department of Water Resources (DWR) | June 16th, 1958

Bulletin No. 39-57 Volume I Bulletin No. 39-57 Volume II Bulletin No. 39-57 Volume IV

Bulletin No. 39-57 Volume I Bulletin No. 39-57 Volume II Bulletin No. 39-57 Volume IV

Bulletin No. 39-57, Water Supply Conditions in Southern California during 1956-1957, Volume IV Cross-Indexes

California Department of Water Resources (DWR) | June 16th, 1958

Bulletin 39-57, Volume I Bulletin 39-57 Volume II Bulletin 39-57 Volume III

Bulletin 39-57, Volume I Bulletin 39-57 Volume II Bulletin 39-57 Volume III

Bulletin No. 39-58, Water Supply Conditions in Southern California during 1957-1958, Volume I

California Department of Water Resources (DWR) | August 1st, 1960

Bulletin No. 39-59, Water Supply Conditions in Southern California during 1958-1959, Volume III, Water Level Data Lahontan, Colorado River Basin, Santa Ana, and San Diego Regions

California Department of Water Resources (DWR) | May 1st, 1961

California forest die-off linked to multi-year deep soil drying in 2012–2015 drought

Nature Portfolio (Springer Nature) | July 1st, 2019

Widespread episodes of recent forest die-off have been tied to the occurrence of anomalously warm droughts, although the underlying mechanisms remain inadequately

Widespread episodes of recent forest die-off have been tied to the occurrence of anomalously warm droughts, although the underlying mechanisms remain inadequately understood. California’s 2012–2015 drought, with exceptionally low precipitation and warmth, and widespread conifer death, provides an opportunity to explore the chain of events leading to forest die-off. Here, we present the spatial and temporal patterns of die-off and moisture deficit during California’s drought, based on field and remote sensing observations. We found that die-off was closely tied to multi-year deep-rooting-zone drying, and that this relationship provides a framework with which to diagnose and predict mortality. Marked tree death in an intensively studied Sierra Nevada forest followed a four-year moisture overdraft, with cumulative 2012–2015 evapotranspiration exceeding precipitation by ~1,500 mm, and subsurface moisture exhaustion to 5–15-m depth. Observations across the entire Sierra Nevada further linked tree death to deep drying, with die-off and moisture overdraft covarying across latitude and elevation. Unusually dense vegetation and warm temperatures accelerated southern Sierran evapotranspiration in 2012–2015, intensifying overdraft and compounding die-off by an estimated 55%. Climate change is expected to further amplify evapotranspiration and moisture overdraft during drought, potentially increasing Sierran tree death during drought by ~15–20% °C−1.

California Water Action Plan (2016 Update)

State of California | January 1st, 2016

California is currently experiencing one of the worst droughts in memory. The 2016 water year is off to a good start, but with four consecutive dry years and the record l

California is currently experiencing one of the worst droughts in memory. The 2016 water year is off to a good start, but with four consecutive dry years and the record low snowpack of 2015, drought conditions may continue for a fifth straight year. Flooding in the midst of drought is likely, given strong El Niño conditions in the Pacific Ocean. Nothing focuses Californians’ attention on our water resources like the extremes of flood and drought. There is broad agreement that the state’s water management system is currently unable to satisfactorily meet both ecological and human needs, too exposed to wet and dry climate cycles and natural disasters, and inadequate to handle the additional pressures of future population growth and climate change. Solutions are complex and expensive, and they require the cooperation and sustained commitment of all Californians working together. To be sustainable, solutions must strike a balance between the need to provide for public health and safety (e.g., safe drinking water, clean rivers and beaches, flood protection), protect the environment, and support a stable California economy. This action plan lays out our challenges, our goals and decisive actions needed now to put California’s water resources on a safer, more sustainable path. While this plan commits the state to moving forward, it also serves to recognize that state government cannot do this alone. Collaboration between federal, state, local and tribal governments, in coordination with our partners in a wide range of industry, government and nongovernmental organizations is not only important—it is essential. The input and contributions received from all of these partners throughout the drafting of this action plan have resulted in a comprehensive and inclusive plan.