Tulare Lake

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.

When is Groundwater Recharge a Beneficial Use of Surface Water?

University of California, Berkeley (UC Berkeley) | August 1st, 2018

Any diversion and use of surface water in California requires a water right. Today, to receive a new water right permit, an entity that wants to appropriate surface water

Any diversion and use of surface water in California requires a water right. Today, to receive a new water right permit, an entity that wants to appropriate surface water must file an application with the Board. The Board may only approve an application if it determines that the proposed use of the water is for a reasonable and beneficial purpose. Currently, there is uncertainty about whether—and, if so, under what circumstances—the Board will consider groundwater recharge to be a beneficial use of water. California law makes clear that the act of recharging groundwater, alone, is not a beneficial use of water. Instead, the specific purpose of the recharge is key.

White Wolf Subbasin Technical Report

Wheeler Ridge-Maricopa Water Storage District | March 16th, 2016

The purpose of the White Wolf Subbasin Technical Study (Study) is to support the basin boundary modification request (Request) being jointly submitted to DWR by Wheeler-R

The purpose of the White Wolf Subbasin Technical Study (Study) is to support the basin boundary modification request (Request) being jointly submitted to DWR by Wheeler-Ridge Maricopa Water Storage District (WRMWSD), Arvin-Edison Water Storage District (AEWSD), and Tejon-Castac Water District (TCWD) (collectively referred to as the Districts), in accordance with the Basin Boundary Emergency Regulations. Request is a scientific request that involves the subdivision of the Kern County Subbasin of the San Joaquin Valley Groundwater Basin (DWR Basin 5-22.14) into two separate subbasins: the Kern County Subbasin and the White Wolf Subbasin (Subbasin). As shown on Figure 1, the proposed revision divides the subbasins along the White Wolf Fault (WWF), relying upon scientific evidence that demonstrates that the WWF provides a significant impediment to groundwater flow.

Who makes decisions about California's water?

Restore the Delta | January 9th, 2023

This project collected and created data on California's water managers at the state, local and individual level to determine their race and gender. At the State level, we

This project collected and created data on California's water managers at the state, local and individual level to determine their race and gender. At the State level, we used the State Workforce Analysis to examine the race and gender of water-related state executives. At the local level, we coded about 1500 directors of water agencies for race and gender and then compared each board to the race and gender of the agency service areas. At the individual level, we coded nearly 14,000 individual rights holders for race. The results were not surprising. At every level, the people who make decisions about California's water are more white and more male than the population of California. At the local agency level, boards of directors are 86% White and 79% male. At the individual level, 91% of small named water rights holders have last names that code as White.

Why People Adopt Climate Change Adaptation and Disaster Risk Reduction Behaviors: Integrated Model of Risk Communication and Results from Hurricanes, Floods, and Wildfires

American Meteorological Society (AMS) | November 1st, 2022

With climate change, weather and climate disaster risks are increasing. At-risk individuals can take climate adaptation and disaster risk reduction behaviors to mitigate

With climate change, weather and climate disaster risks are increasing. At-risk individuals can take climate adaptation and disaster risk reduction behaviors to mitigate and prepare for disaster risks, reduce costs from damage, and save their lives. However, previous fragmented studies have not provided an integrated model to directly compare the factors and identify factors that are most influential in at-risk community members’ behaviors. I present the Integrated Model of Risk Communication by consolidating major theories. This study uses structural equation modeling of quantitative surveys to simultaneously test the impacts of 15 factors on 15 adaptation behaviors for the two most common federally declared disasters (wildfires and hurricanes with floods) in three disaster-prone U.S. states (California, Florida, and Texas) (N = 3,468). Specifically, this study examines 15 behaviors including preparedness, nonstructural mitigation, structural mitigation, insurance purchase, and adaptation policy support. Social norms perceptions, self-efficacy, response efficacy, and resource constraints strongly affect behaviors. Response efficacy strongly affects policy support. Risk perception, knowledge, and climate change perception—commonly argued to be key drivers—are insignificant or weak. The models explain 55%–86% of the variance in adaptation behaviors. Results suggest that the focus of adaptation efforts may need to shift from risk perception and climate change perception to efficacy and social norms.

Widespread aquifer depressurization after a century of intensive groundwater use in USA

American Association for the Advancement of Science (AAAS) | September 15th, 2023