Report 2022-106 Recommendations

To ensure that its B120 water supply forecasts are as accurate as possible, DWR should implement a forecast verification process by November 2023 that includes the following:

1. An annual evaluation of the accuracy of each of its monthly forecasts using multiple means in accordance with best practices, including an assessment of whether actual runoff fell within its probability range and an assessment of the accuracy of its median forecast.

2. Identification of the likely causes of greater-than-expected forecast errors.

3. An annual assessment of opportunities for improvement and enhancement, including identifying and evaluating available and emerging forecasting technologies.

4. The development and implementation of plans to improve its forecasts based on the findings from its annual evaluation.

5. Annual reporting on its water supply forecasting web page about the above actions so that the public is aware of the steps it is taking to improve and enhance the accuracy and predictive capability of its forecasts.

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.

To better prepare to effectively manage State Water Project operations during future, possibly more extreme drought periods, DWR should, by May 2024, develop a long-term plan for proactively mitigating and responding to the impacts of drought on the project. In accordance with drought preparation best practices, DWR should include the following components in the plan:

1. An assessment of the potential impacts of drought on the State Water Project that accounts for the possibility that climate change may result in more severe droughts.

2. An assessment of DWR's current capability to address those potential impacts, as well as the identification of any steps that DWR must take to gain needed capabilities.

3. Specific strategies for operating the State Water Project to mitigate and respond to the identified impacts of drought while still achieving the project's objectives.

4. A description of the circumstances that would trigger DWR to begin implementing its drought response strategies.

5. Provisions requiring DWR to update the drought plan at least once every five years and also after each drought to incorporate lessons learned.

To ensure that it can demonstrate effective oversight of State Water Project operations and efficient use of the project's water supply, DWR should, by May 2024, develop and implement a policy and set of procedures for documenting the following:

1. Its monthly and annual plans for operating the State Water Project, including the amount of water that it intends to release, store, and export.

2. The rationale behind its plans and an explanation of how the plans will help it to achieve the project's objectives.

3. A description of any changes that it makes during its operations that deviate from its plans.

4. The rationale for any changes that it makes, including the conditions that led to the change, the specific reason for the change, and any viable alternatives that it considered.

5. The degree to which it succeeds in achieving each of the project's various objectives on a monthly and annual basis.

To ensure that its operation of the State Water Project reflects the possibility of more extreme climate conditions, DWR should, by May 2024, evaluate the data and information that it relies upon in its monthly and annual planning for its Lake Oroville reservoir operations, including the volumes of water that it will need to store to achieve its objectives. It should update the data and information as needed.

To ensure that it continually improves the effectiveness of its management of the State Water Project, DWR should develop and implement a formal, written process for reviewing its planning and operations at least once annually. This process should include the following:

1. An assessment of DWR's success at achieving each of the project's various objectives.

2. An evaluation of DWR's actions to achieve its objectives, including the decisions that it made in its planning and in its day-to-day management of the project. DWR should identify actions that assisted it in achieving its objectives and that would benefit its operations in the future, as well as actions that were less effective.

3. Documentation of lessons learned from the evaluation of its actions and, if necessary, updates to its planning or procedural documents to incorporate changes.