Tulare Lake

Water Use in California

Public Policy Institute of California (PPIC) | April 19th, 2023

Water Year 2017: What a Difference a Year Makes

California Department of Water Resources (DWR) | October 3rd, 2022

The very wet conditions of 2017 gave many parts of the state access to excess surface waters for both planned and impromptu groundwater recharge, and fall 2017 groundwate

The very wet conditions of 2017 gave many parts of the state access to excess surface waters for both planned and impromptu groundwater recharge, and fall 2017 groundwater level data (not available until the end of the calendar year) should show the effects of the substantial recharge water available

Water Year 2021 Compound Precipitation and Temperature Extremes in California and Nevada

American Meteorological Society (AMS) | December 23rd, 2022

The most intense 22-yr drought in the western United States since 800 CE (Williams et al. 2022) was extended by compound dry and hot extremes in Water Year 2021 (October

The most intense 22-yr drought in the western United States since 800 CE (Williams et al. 2022) was extended by compound dry and hot extremes in Water Year 2021 (October 2020–September 2021). Compared to an instrumental record that dates to 1895, low precipitation (Fig. 1a) and high temperatures (Fig. 1b) were widespread across the western United States. The intense and prevalent drought has caused water delivery shortages (U.S. Bureau of Reclamation 2021), damaged ecosystems (Wlostowski et al. 2022), and contributed to extreme wildfires (e.g., Fu et al. 2021; Gutierrez et al. 2021; Abolafia-Rosenzweig et al. 2022). California and Nevada (CA–NV) were once again at the epicenter of drought and heat in Water Year 2021 (California Department of Water Resources 2021). This was the first time since 1895 that precipitation fell below –1.5 standardized departures and temperatures exceeded 1.5 standardized departures concurrently for the two-state average (Fig. 1c). Precipitation and temperatures were individually extreme as well, as the former was the second lowest since 1895 and the latter was the second highest. We examine whether the co-occurrence of anthropogenic climate change and La Niña, two principal climate drivers during Water Year 2021, altered the risk of unprecedented compound dry and hot extremes in CA–NV during Water Year 2021. Our assessment investigates the factors related to compound extremes that lead to heightened societal impacts compared to individual extreme events (e.g., AghaKouchak et al. 2020; Zscheischler et al. 2020; W. Zhang et al. 2021).

Water, environment, and socioeconomic justice in California: A multi-benefit cropland repurposing framework

Science of the Total Environment (Elsevier) | November 22nd, 2022

Water, environment, and socioeconomic justice in California: A multi-benefit framework

Science of the Total Environment (Elsevier) | November 5th, 2022

Low-income, rural frontline communities of California's Central Valley experience environmental and socioeconomic injustice, water insecurity, extremely poor air quality,

Low-income, rural frontline communities of California's Central Valley experience environmental and socioeconomic injustice, water insecurity, extremely poor air quality, and lack of fundamental infrastructure (sewage, green areas, health services), which makes them less resilient. Many communities depend financially on agriculture, while water scarcity and associated policy may trigger farmland retirement, further hindering socioeconomic opportunities. Here we propose a multi-benefit framework to repurpose cropland in buffers inside and around (400-m and 1600-m buffers) 154 rural disadvantaged communities of the Central Valley to promote socioeconomic opportunities, environmental benefits, and business diversification. We estimate the potential for (1) reductions in water and pesticide use, nitrogen leaching, and nitrogen gas emissions, (2) managed aquifer recharge, and (3) economic and employment impacts associated with clean industries and solar energy. Retiring cropland within 1600-m buffers can result in reductions in annual water use of 2.18 km3/year, nitrate leaching into local aquifers of 105,500 t/year, greenhouse gas emissions of 2,232,000 t CO2-equivalent/year, and 5388 t pesticides/year, with accompanying losses in agricultural revenue of US$4213 million/year and employment of 25,682 positions. Buffer repurposing investments of US$27 million/year per community for ten years show potential to generate US$101 million/year per community (total US$15,578 million/year) for 30 years and 407 new jobs/year (total 62,697 jobs/year) paying 67 % more than prior farmworker jobs. In the San Joaquin Valley (southern Central Valley), where groundwater overdraft averages 2.3 km3/year, potential water use reduction is 1.8 km3/year. We have identified 99 communities with surficial soils adequate for aquifer recharge and canals/rivers within 1600 m. This demonstrates the potential of managed aquifer recharge in buffered zones to substantially reduce overdraft. The buffers framework shows that well-planned land repurposing near disadvantaged communities can create multiple benefits for agriculture and industry stakeholders, while improving quality of life in disadvantaged communities and producing positive externalities for society.

West-Wide Climate Risk Assessments: Irrigation Demand and Reservoir Evaporation Projections

U.S. Bureau of Reclamation (USBR) | February 5th, 2015

Section 9503 of the SECURE Water Act, Subtitle F of Title IX of P.L. 111-11 (2009) (SECURE Water Act), authorizes the Bureau of Reclamation (Reclamation) to evaluate the

Section 9503 of the SECURE Water Act, Subtitle F of Title IX of P.L. 111-11 (2009) (SECURE Water Act), authorizes the Bureau of Reclamation (Reclamation) to evaluate the risks and impacts of climate change in each of the eight major Reclamation river basins identified in the Act, and to work with stakeholders to identify climate adaptation strategies. Reclamation implements Section 9503 of the SWA through the Department of Interior’s WaterSMART Program1, which is working to achieve a sustainable water strategy to meet the Nation’s water needs now and for the future. Through Basin Studies, part of WaterSMART, Reclamation works with State and local partners to evaluate the ability to meet future water demands within a river basin and to identify adaptation and mitigation strategies of the potential impacts of climate change. Through another activity, West-Wide Climate Risk Assessments (WWCRA), Reclamation is working to provide projections of future changes in water supplies, water demands, and river system operations that could result from changes in climate. As part of WWCRA, Reclamation has conducted an analysis of the potential changes in crop irrigation demand in eight major river basins in the West and projections of evaporation for 12 reservoirs within those river basins when considering observed and projected impacts of climate change. This report contains the results of that analysis. The findings presented in this report are intended to be used for future basin-specific WWCRA impact assessments and Basin Studies conducted under WaterSMART if the teams conducting those studies elect to do so. This technical assessment report provides: (1) an analysis of changes in irrigation demand, and (2) an analysis of changes in evaporation for selected reservoirs across the major Reclamation river basins with respect to presently observed and projected future impacts of global climate change. The analysis involved developing irrigation demand and reservoir evaporation projections associated with World Climate Research Programme Coupled Model Intercomparison Project3 (WCRP CMIP3) climate projections that have been bias-corrected and spatially downscaled (BCSD) and served at the following Web site: http://gdo-dcp.ucllnl.org/downscaled_cmip_projections/dcpInterface.html. For the purposes of this study, CMIP3 climate projections were used because they represented the best available collection of climate projections at the onset of this effort (summer 2011 which was begun prior to the release of CMIP5). Although the CMIP3 and CMIP5 projections are considered equally likely potential climate futures at this time, there is significant variability in the two sets of projections. This is especially true with regard to precipitation projections, and it is significant to note the potential impact of this variability on future irrigation demand and net evaporation estimates. Changes to irrigation demand (model, described below) were analyzed for five climate change scenarios (warm-dry, warm-wet, hot-dry, hot-wet, and central tendency – ensemble median) that were informed by 112 BCSD-CMIP3 projections at three future periods: 2020s (years 2010-2039), 2050s (years 2040–2069), and 2080s (2070-2099) with 1950–1999 as the baseline period. The reservoir evaporation modeling (described below) was performed as transient simulations using the individual 112 BCSD-CMIP3 projections. Both the irrigation demands modeling and the reservoir evaporation modeling used observed data from weather stations representative of irrigated land areas and reservoir sites in a secondary bias correction step to account for local scale climate conditions in the climate change scenarios. Although it would be ideal to calculate future irrigation demands for all 112 projections using the transient method as was done for the future reservoir evaporation estimates, such calculations were not feasible given the multiple crops and numerous locations modeled.

Westside Subbasin Groundwater Sustainability Plan

Westlands Water District | January 23rd, 2020

Westside Subbasin Groundwater Sustainability Plan (Clarified and Amended GSP)

Westlands Water District | July 18th, 2022

Due to size, this file has been divided into 11 parts. Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8, Part 9, Part 10, Part 11

Due to size, this file has been divided into 11 parts. Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8, Part 9, Part 10, Part 11

What Can We Learn From How the State Responded to the Last Major Drought?

Legislative Analyst's Office (LAO) | May 13th, 2021

For the second consecutive year, the state is experiencing extremely low rates of precipitation. As we prepare for what could be an extended period of dry conditions, it

For the second consecutive year, the state is experiencing extremely low rates of precipitation. As we prepare for what could be an extended period of dry conditions, it is helpful to review how the state responded to the last major drought. Such information can inform—and thereby potentially improve—the state’s current and ongoing response to developing conditions. In this report, we summarize the major activities, spending, and policy actions undertaken by the state to respond to the severe drought that occurred from 2012 through 2016. We also describe current conditions, and highlight some key lessons the Legislature can learn from previous efforts to help guide its response to the emerging drought.

What If California’s Drought Continues?

Public Policy Institute of California (PPIC) | August 20th, 2015

California is in the fourth year of a severe, hot drought—the kind that is increasingly likely as the climate warms. Although no sector has been untouched, impacts so

California is in the fourth year of a severe, hot drought—the kind that is increasingly likely as the climate warms. Although no sector has been untouched, impacts so far have varied greatly, reflecting different levels of drought preparedness. Urban areas are in the best shape, thanks to sustained investments in diversified water portfolios and conservation. Farmers are more vulnerable, but they are also adapting. The greatest vulnerabilities are in some low-income rural communities where wells are running dry and in California’s wetlands, rivers, and forests, where the state’s iconic biodiversity is under extreme threat. Two to three more years of drought will increase challenges in all areas and require continued—and likely increasingly difficult—adaptations. Emergency programs will need to be significantly expanded to get drinking water to rural residents and to prevent major losses of waterbirds and extinctions of numerous native fish species, including most salmon runs. California also needs to start a longer-term effort to build drought resilience in the most vulnerable areas.