Climate Warming and Water Management Adaptation for California

Climactic Change (Springer) | June 10th, 2010

The ability of California’s water supply system to adapt to long-term climatic and demographic changes is examined. Two climate warming and a historical climate

The ability of California’s water supply system to adapt to long-term climatic and demographic changes is examined. Two climate warming and a historical climate scenario are examined with population and land use estimates for the year 2100 using a statewide economic-engineering optimization model of water supply management. Methodologically, the results of this analysis indicate that for long-term climate change studies of complex systems, there is considerable value in including other major changes expected during a long-term time-frame (such as population changes), allowing the system to adapt to changes in conditions (a common feature of human societies), and representing the system in sufficient hydrologic and operational detail and breadth to allow significant adaptation. While the policy results of this study are preliminary, they point to a considerable engineering and economic ability of complex, diverse, and intertied systems to adapt to significant changes in climate and population. More specifically, California’s water supply system appears physically capable of adapting to significant changes in climate and population, albeit at a significant cost. Such adaptation would entail large changes in the operation of California’s large groundwater storage capacity, significant transfers of water among water users, and some adoption of new technologies.

Climate, Drought, and Sea Level Rise Scenarios for the Fourth California Climate Assessment

California Energy Commission (CEC) | August 27th, 2018

Daily temperature and precipitation over California at a resolution of 1/16° (about 6 km, or 3.7 miles) were generated to support climate change impact studies for the

Daily temperature and precipitation over California at a resolution of 1/16° (about 6 km, or 3.7 miles) were generated to support climate change impact studies for the energy system and other sectors featured in the California’s Fourth Climate Change Assessment. The data, derived from 32 coarse-resolution (~ 100 km) global climate models (GCMs), were bias corrected and downscaled using the Localized Constructed Analogues (LOCA) statistical method. The data cover 1950-2005 for the historical period and 2006-2100 for two future climate projections using medium and high greenhouse gas and aerosol emissions scenarios. Statewide, temperature is projected to increase 2-4 °C (medium emissions scenario) to 4-7 °C (high emissions scenario) by the end of this century. Precipitation shows fewer wet days, wetter winters, drier springs and autumns, and an increase in dry years as well as maximum precipitation in a single day. Ten GCMs that closely simulate California’s climate are identified for studies where all 32 GCMs cannot be used. Additional variables were downscaled for these 10, including wind speed, specific and relative humidity, and surface solar radiation. Four models that span the temperature and precipitation changes from the 10 are identified for studies that cannot accommodate the 10. Wind speed shows small decreases, while relative humidity changes are more complicated, with coastal increases but decreases inland. Surface solar radiation shows small Southern California increases in spring. The downscaled fields were applied to the Variable Infiltration Capacity (VIC) land surface model to develop snow cover, soil moisture, runoff, water loss from plants, surface heat fluxes, and other parameters. Moisture deficit is projected to increase over much of the state, particularly Northern California and the Sierra Nevada, while top level soil moisture is projected to decrease, particularly in Southern California. Most streamflows shift to earlier in the year, with the bigger shifts experienced in basins which currently have substantial contributions from snowmelt. Two versions of a 20-year dry spell were identified from one of the GCM simulations to investigate future drought: the original episode from 2051-2070, and one shifted earlier in the century with temperatures consistent with 2023-2042. For both, we provide downscaled temperatures and precipitation along with VIC hydrological output. Sea level rise (SLR) projections for California were generated using a probabilistic approach employing estimates of the components that contribute to global and regional SLR, including new science on the possibility of increased contribution from Antarctica. Hourly projections of sea level at selected coastal locations were generated out to 2100 that include tides, regional and local weather influences, and short period Pacific climate fluctuations along with the aforementioned sea level rise scenarios. The climate scenario and SLR data are available online from cal-adapt.org.

Coastal Plain of Orange County, Basin 8-001 Alternative to a Groundwater Sustainability Plan

Orange County Water District (OCWD) | January 1st, 2017

Colorado River Basin Water Supply and Demand Study

U.S. Bureau of Reclamation (USBR) | December 1st, 2012

The Colorado River Basin Water Supply and Demand Study (Study), initiated in January 2010, was conducted by the Bureau of Reclamation’s (Reclamation) Upper Colorado and

The Colorado River Basin Water Supply and Demand Study (Study), initiated in January 2010, was conducted by the Bureau of Reclamation’s (Reclamation) Upper Colorado and Lower Colorado regions, and agencies representing the seven Colorado River Basin States1 (Basin States) in collaboration with stakeholders throughout the Colorado River Basin (Basin). As defined in the Plan of Study, the purpose of the Study is to define current and future imbalances in water supply and demand in the Basin and the adjacent areas of the Basin States that receive Colorado River water over the next 50 years (through 2060), and to develop and analyze adaptation and mitigation strategies to resolve those imbalances. The Study does not result in a decision as to how future imbalances will or should be addressed. Rather, the Study provides a common technical foundation that frames the range of potential imbalances that may be faced in the future and the range of solutions that may be considered to resolve those imbalances.

Colorado River Hydrologic Region Groundwater Update

California Department of Water Resources (DWR) | April 1st, 2015

The primary goal of the Colorado River Hydrologic Region (Colorado River region) groundwater update is to expand information about region-specific groundwater conditions

The primary goal of the Colorado River Hydrologic Region (Colorado River region) groundwater update is to expand information about region-specific groundwater conditions for California Water Plan Update 2013, and to guide more informed groundwater management actions and policies. A second goal is to steadily improve the quality of groundwater information in future California Water Plan (CWP) updates to a level that will enable regional water management groups (RWMGs) to accurately evaluate their groundwater resources and implement management strategies that can meet local and regional water resource objectives within the context of broader statewide objectives. The final goal is to identify data gaps and groundwater management challenges meant to serve as a guidepost for prioritizing future data collection and funding opportunities relevant to the region. This regional groundwater update is not intended to provide a comprehensive and detailed examination of local groundwater conditions, or be a substitute for local studies and analysis. Where information is readily available, the update does report some aspects of the regional groundwater conditions in greater detail.

Comment Letter on the Draft Water Resilience Portfolio for the State of California

Pacific Institute | February 7th, 2020

This comment letter conveys summary comments and suggestions on the draft Water Resilience Portfolio released by California state agencies, drawing on the considerable ex

This comment letter conveys summary comments and suggestions on the draft Water Resilience Portfolio released by California state agencies, drawing on the considerable experience Pacific Institute has around themes of water efficiency, stormwater management, and the Salton Sea. The letter was authored by staff at Pacific Institute and directed to the Governor’s Water Portfolio Program at the California Natural Resources Agency.

Comment Letter on the Draft Water Resilience Portfolio for the State of California Regarding a Multi-Benefit Approach

Pacific Institute | February 7th, 2020

This comment letter focuses on how the California Water Resilience Portfolio can incorporate multiple benefits when prioritizing and funding water management strategies t

This comment letter focuses on how the California Water Resilience Portfolio can incorporate multiple benefits when prioritizing and funding water management strategies throughout the state. It was sent on behalf of a group of interested parties with significant experience in evaluating and considering the multiple benefits of water-related projects, and it was directed to the Governor’s Water Portfolio Program at the California Natural Resources Agency.

Comparing Futures for the Sacramento-San Joaquin Delta

Public Policy Institute of California (PPIC) | July 16th, 2008

For over 50 years, California has been pumping water through the Sacramento-San Joaquin Delta for extensive urban and agricultural uses around the state. Today, the Del

For over 50 years, California has been pumping water through the Sacramento-San Joaquin Delta for extensive urban and agricultural uses around the state. Today, the Delta is ailing and in urgent need of a new management strategy. This report concludes that building a peripheral canal to carry water around the Delta is the most promising way to balance two critical policy goals: reviving a threatened ecosystem and ensuring a reliable, high-quality water supply for California. More information can be found in the following supporting appendices: Appendix A. Policy and Regulatory Challenges for the Delta of the Future Appendix B. Levee Decisions and Sustainability for the Delta Appendix C. Delta Hydrodynamics and Water Salinity with Future Conditions Appendix D. The Future of the Delta Ecosystem and Its Fish Appendix E. Expert Survey on the Viability of Delta Fish Populations Appendix F. The Economic Costs and Adaptations for Alternative Delta Regulations Appendix G. Peripheral Canal Design and Implementation Options Appendix H. Delta Drinking Water Quality and Treatment Costs Appendix I. The Economic Effects on Agriculture of Water Export Salinity South of the Delta Appendix J. Decision Analysis of Delta Strategies Interactive Map: Voting Patterns on Proposition 9 (Peripheral Canal), June 1982 Interactive Map: A Multi-Purpose, Eco-Friendly Delta Interactive Feature: Delta Island Flooding (With Repairs) Interactive Feature: Delta Island Flooding (No Repairs)

Comparison of U.S. Geological Survey and Bureau of Reclamation Water-Use Reporting in the Colorado River Basin

U.S. Geological Survey (USGS) | September 2nd, 2019

The use of water in the United States is arguably one of the most important factors determining water availability at any specific place and time. Numerous local, State,

The use of water in the United States is arguably one of the most important factors determining water availability at any specific place and time. Numerous local, State, and Federal entities develop, compile, and report water-use data, which can lead to confusing or conflicting information. This report was authored jointly by the U.S. Geological Survey (USGS) and Bureau of Reclamation (Reclamation) to compare and contrast the two agencies’ water-use information programs in the Colorado River Basin. The report also describes the legal drivers for each program, clarifies confusing terminol- ogy, compares the methods used, and contrasts the information reported by each agency. This detailed comparison demon- strates that these two Federal agencies have different missions, different programmatic drivers, and different user communi- ties, all of which lead to different approaches to water-use data collection, analysis, and reporting. This report highlights those differences and explains why the USGS and Reclamation programs exist and how the data serve different user communities. Even though the two water-use programs are different by design and purpose, the program comparison presented in this report has identified opportunities for closer coordination and sharing of information between the USGS and Reclamation, as well as program components where agency collaboration can improve water-use estimate methodologies. This comparison effort emphasizes that it is incumbent upon each agency to clearly define the meaning of the terms used and the appropri- ate application of the reported information to avoid confusion or the accidental misuse of the information. An additional benefit of this comparison effort is the formation of a joint USGS/ Reclamation water-use team that will continue to investigate opportunities to expand and coordinate future water-use data compilation and reporting.

Conceptual model for salinity in the Central Valley and Sacramento-San Joaquin Delta

Central Valley Drinking Water Policy Workgroup | July 13th, 2007

This report examines the state of knowledge about the causes of salinity increase in the system and opportunities to improve the Delta as a source of municipal and agricu

This report examines the state of knowledge about the causes of salinity increase in the system and opportunities to improve the Delta as a source of municipal and agricultural water supply. It begins with background information about salinity, its measurement, and its impacts. Following that, we present observed salinity in the Bay-Delta system. The conceptual models section, the core of this report, then seeks to explain the forces and processes (drivers) that cause the salinity patterns we observe. The computational models section introduces some of the tools available to assist with salinity management and planning. The last chapter explores the implications of the conceptual model for monitoring and management of salinity.