Department of Water Resources

Climate Impact & Sustainability Data (2010, 2021-10 to 2022-09)

The Delta is in ecological crisis, resulting in high levels of conflict that affect the sustainability of existing water policy in California. Several species of fish have been listed as protected species under the California Endangered Species Act (CESA) and under the federal Endangered Species Act (ESA).
Recent Delta flows are insufficient to support native Delta fishes for today’s habitats.
The effects of non-flow changes in the Delta ecosystem, such as nutrient composition, channelization, habitat, invasive species, and water quality, need to be addressed and integrated with flow measures.

Development of flow criteria for the Delta ecosystem to protect public trust resources.
Increased flows to protect public trust resources.
Studies and demonstration projects for, and implementation of, floodplain restoration, improved connectivity and passage, and other habitat improvements should proceed to provide additional protection of public trust uses and potentially allow for the reduction of flows otherwise needed to protect public trust resources in the Delta.
The Central Valley and San Francisco Regional Water Quality Control Boards should continue developing Total Maximum Daily Loads (TMDLs) for all listed pollutants and adopting programs to implement control actions.

Narrowing of hydrologic datasets to the most recent 30-year period (1991-2020) from a 50-year (1966-2015) period in order to better reflect the effect of climate change on snow, precipitation, and runoff.
Development of new statistical models (Eqn 2022) based on updated, 30-year hydrology using machine learning techniques.
Improved automation of daily and monthly data collection and calculations.
Establishment of a new methodology to evaluate and improve 90 percent and 10 percent exceedance forecasts.
Updating of Water Supply Index methodologies to better account for future precipitation distribution across exceedances, volume prediction, and historical flow regimes.
Expanded use of machine learning to better classify data based on new climate change models.
Training for staff on iSnobal to support Aerial Snow Observatory work.
Development of iSnobal models for the Tuolumne, Merced, San Joaquin, Kings, and Kaweah watersheds.
Launching of a pilot program in partnership with Airborne Snow Observatories, Inc. and the National Center for Atmospheric Research to develop coupled atmosphere watershed models in the San Joaquin and Feather River watersheds.

Medium-term Goals:

Transition to modeling tools that are physically based and climate-informed by water year 2025

Short-term Goals:

Implement a forecast verification process by November 2023
Publish on its website a timeline affirming when it will implement its updated model and procedures across all of the watersheds by November 2023

DWR significantly overestimated the 2021 water supply.
DWR has not fully updated its forecasting model and related procedures to better account for the effects of climate change.
DWR lacks a formal process for evaluating its forecasting model.
DWR does not have a comprehensive, long-term plan for identifying, mitigating, or responding to the effects of more severe future droughts on the State Water Project.
DWR has not consistently documented the reasons for its planned and actual water releases.
DWR has not accounted for the possibility of more extreme future conditions when it develops its monthly water allocation analysis and water storage target for the Lake Oroville reservoir.
DWR lacks a formal process for periodically evaluating certain State Water Project operations to identify opportunities for improvement.

DWR developed a plan to make its forecasting more resilient to the effects of climate change and entered into various contracts for technical assistance to improve its forecasts.
DWR is continuing to implement its plan to adopt an updated water supply forecasting model and updated procedures.
DWR is developing a long-term plan for proactively mitigating and responding to the impacts of drought on the project.
DWR is developing a policy and set of procedures for documenting its monthly and annual plans for operating the State Water Project.
DWR will evaluate the data and information that it relies upon in its monthly and annual planning for its Lake Oroville reservoir operations.
DWR will develop and implement a formal, written process for reviewing its planning and operations at least once annually.

Climate Registry
Climate Leadership Conference
U.S. Environmental Protection Agency
Center for Climate and Energy Solutions
14 awards for climate action including membership in the Climate Leadership Awards Hall of Fame (2022)