Report 2022-106 Recommendation 2 Responses

Report 2022-106: Department of Water Resources: Its Forecasts Do Not Adequately Account for Climate Change and Its Reasons for Some Reservoir Releases Are Unclear (Release Date: May 2023)

Recommendation #2 To: Water Resources, Department of

To ensure that its water supply forecasts better account for the observed effects of climate change as soon as possible, DWR should continue to implement its plan to adopt an updated water supply forecasting model and updated procedures. By November 2023 DWR should also do the following:

1. Publish on its website a timeline affirming when it will implement its updated model and procedures across all of the watersheds for which it produces a water supply forecast.

2. Establish and publish the specific criteria that it will employ to determine when its updated model has demonstrated sufficient predictive capability to be ready for use in each of the watersheds.

3. Provide annual updates on its website regarding the status of its implementation of the updated model and procedures.

60-Day Agency Response

In March 2023, DWR adopted the Roadmap for a Climate Resilient Forecasting Framework (Roadmap) that includes annual forecast modeling assessments, latest developments, and achievements. The Roadmap is publicly available on DWR website (Link: https://water.ca.gov/roadmap) and is a working document and will continually be updated.

DWR publishes a Hydroclimate Report and presentations on annual forecasting assessment that includes observed effects of climate change on the Department's California Data Exchange Center's website. The next Hydroclimate Report will be available in April 2024 for the previous water year.

California State Auditor's Assessment of 60-Day Status: Pending

DWR posted the Roadmap on its website, however, as we discuss in the text of the report, the Roadmap does not yet include accountability mechanisms to ensure that it implements its new model promptly. Further, although the plan includes the objective of developing forecast model performance tools, it does not contain specific criteria for determining whether the new model is sufficiently accurate for use or a timeline for implementation. We look forward to following DWR's progress in implementing its planned updates to its forecasting methodology in future updates.

All Recommendations in 2022-106

Agency responses received are posted verbatim.