Water Rights and Climate Change
Facing the threat of greater scarcity of water supplies, increased water demand, and limited water supply reliability, California has increased focus on actions to build resilience and meet California’s water needs through the 21st century. The Water Boards have taken a variety of actions to respond to climate change.
As the patterns of runoff are projected to change and past conditions are no longer a reliable guide to future conditions, it is a good practice to consider impacts of climate change in water availability analyses.
- Staff report on climate change and water rights (February 2021) outlines recommendations to make water availability analysis for permitting new water rights more robust, and actions to support an effective water rights response to climate change.
- Stakeholders were invited to provide input and propose other options not listed in the report. A 55-day public comment period closed on March 31, 2021. If you would like a copy of the comments received on the staff report, please contact Jelena Hartman.
- Staff hosted a public webinar on March 18, 2021 to present an overview of the report. Webinar recording is available online.
Climate Change Considerations for Appropriative Water Rights Applications. Fact Sheet for applicants on how climate change is expected to affect water availability, and resources that may aid with selecting season, rate, and volume of diversion to improve the long-term feasibility of their water right.
Data and Tools
California has invested in considerable amount of research to understand how a changing climate will affect the State, and develop data, tools, and guidance relevant for water resources planning and management in California. Below are select links to climate change science and tools:
- SGMA Climate Change Resources. California Department of Water Resources provides climate change data, tools, and guidance to support implementation of Sustainable Groundwater Management Act (SGMA). The data include historical detrended precipitation, and reference evapotranspiration along with change factors for projected climate conditions centered around 2030 and 2070. The hydrological data provide projected unimpaired stream inflows for major streams in the Central Valley, and streamflow change factors for areas outside of the Central Valley and smaller ungaged watersheds within the Central Valley.
- Cal-Adapt. Web portal designed to provide access to the wealth of data and information that has been, and continues to be, produced by State of California's scientific and research community. The data include daily temperature and precipitation for the historical period (1950-2005), and for future scenarios (2006-2100), along with relative humidity, wind speed, and surface solar radiation for a subset of models. Historical and future daily hydrological data estimated using Variable Infiltration Capacity model include snow cover, soil moisture, runoff, water loss from plants, surface moisture and heat fluxes.
- California’s Fourth Climate Change Assessment. Designed to assess the impacts and risks from climate change, the Fourth Assessment provides scientific foundation for understanding climate-related vulnerability at the local scale and informing resilience actions.
Applicants may want to review if a water management planning conducted for their area addressed climate change impacts, or if other permitting projects in their stream system have developed information that may be adapted to their project. Examples of regional planning efforts that consider climate change include:
- Groundwater Sustainability Plans (GSP) were required to evaluate future scenarios of hydrologic uncertainty associated with projections of climate change.
- Integrated Regional Water Management (IRWM) Plans were required to include climate change consideration in analyses.
- Flood-Managed Aquifer Recharge (Flood-MAR) is exploring a wide range of climatic perturbations in watershed-scale pilot studies (Tuolumne River Watershed, and Merced River Basin).
For climate change inquiries, please contact Jelena Hartman at (916) 327-8621 or firstname.lastname@example.org.
Application resources describe the Water Rights Permitting Process. For inquiries regarding filing an application to appropriate water, please contact Permitting Staff responsible for your county or area of interest.