File #: 23-1117    Version: 1 Name:
Type: Assistant CEO Item Status: Agenda Ready
File created: 10/12/2023 In control: Board of Directors
On agenda: 2/13/2024 Final action:
Title: Receive an Update on the Pacheco Reservoir Expansion Project, Project No. 91954002 (Merced County) (District 1).
Attachments: 1. Attachment 1: PowerPoint, 2. *Handout 8.1-A: Norton, 3. *Handout 8.1-B: Muirhead, 4. *Handout 8.1-C: Ballenger, 5. *Handout 8.1-D: Freedom, 6. *Handout 8.1-E: Rogers, 7. *Handout 8.1-F: Sierra Club, 8. *Handout 8.1-G: Bailey



Government Code § 84308 Applies:  Yes    No 
(If “YES” Complete Attachment A - Gov. Code § 84308)




Receive an Update on the Pacheco Reservoir Expansion Project, Project No. 91954002 (Merced County) (District 1).






Receive an informational update on the Operations and Benefits of the Pacheco Reservoir Expansion Project, Project No. 91954002.





On October 13, 2023, staff presented potential topics to the Water Storage Exploratory Committee (WSEC) for review and feedback to be presented in future quarterly updates regarding the Pacheco Reservoir Expansion Project (Project).

After discussion WSEC recommended bringing the potential topics to the full Board, which occurred on November 14, 2023.

Staff has previously presented a high-level overview of the proposed operations and benefits of the Project. In response to the updated list of future topics, staff has prepared a presentation providing a more detailed explanation of how Valley Water plans to operate the completed Project to include required infrastructure, redundancy plans and operational challenges. Staff has also provided additional detail on the Project’s benefits and how these benefits have been calculated and accounted for during the design phase. Staff brought this updated presentation to WSEC on December 8, 2023, for review and feedback.

The primary objective and benefit of the Project is to improve resiliency and provide Santa Clara Valley Water District (Valley Water) with emergency water supply. By having an approximately 100,000 acre-feet of additional storage, Valley Water would be able to maintain supply delivery during a Delta export outage, imported water conveyance outage, extended drought or another emergency.

Secondary benefits of the Project include reducing the San Luis Reservoir low point water quality issues. This is achieved by moving Valley Water’s CVP imported water out of San Luis into the expanded Pacheco Reservoir in the spring months prior to summer algae blooms when the water levels in San Luis Reservoir are well above the intake used by Valley Water.  This water stored in Pacheco Reservoir can then be used as a source during low point months in the summer and fall to help minimize spikes in taste and odor.

Additional secondary benefits include the environmental benefits of improving the Bay-Delta Ecosystem and restoring habitat in Pacheco Creek for federally threatened South-Central California Coast Steelhead (SCCCS). As part of the Water Storage Investment Program (WSIP), each project receiving funds is required to provide benefits for improving the Bay-Delta Ecosystem. The Project will meet this requirement by providing up to 2,000 acre-feet of water for wetlands in below-normal water years. Combined with other projects, this will increase food supply for migrating Pacific Flyway waterfowl in the fall and winter.

By providing improved flow and temperature conditions in Pacheco Creek in the summer months, the Project will provide substantial improvements to habitat conditions. The proposed flow release schedule was developed with close coordination with National Marine Fisheries Service (NMFS) and California Department of Fish & Wildlife (CDFW).  Based on the extensive analytics, the increased habitat provided by the Project is projected to increase the SCCCS cohort score by 147%.

Lastly, the Project will provide incidental flood protection benefits to downstream communities. While the expanded reservoir is not intended to be operated for flood control purposes, it will provide incidental flood protection by providing additional storage capacity in comparison to the existing reservoir. Additionally, there will be attenuation of flows and reduction of flood peaks due to the flows being routed through a larger reservoir and modified spillway configuration from the current conditions.




There are no Environmental Justice impacts associated with this item. However, the draft EIS/recirculated draft EIR will include an analysis of the Project’s social and economic impacts including environmental justice, as required by the National Environmental Policy Act.  The environmental justice impacts of the Project will be considered in future board actions. Some of the anticipated Environmental Justice Impacts include potential reduction of flood damages to several disadvantaged communities.




There is no financial impact associated with the recommendation in this item. The Project is currently included in the Board Adopted Capital Improvement Program Fiscal Year 2024-28 Five-Year Plan. Any future decisions on the course of the Project may have financial impacts.




The recommended actions in this item do not constitute a project under CEQA because they do not have a potential for resulting in direct or reasonably foreseeable indirect physical change in the environment.




Attachment 1: PowerPoint

*Handout 8.1-A: Norton

*Handout 8.1-B: Muirhead

*Handout 8.1-C: Ballenger

*Handout 8.1-D: Freedom

*Handout 8.1-E: Rogers

*Handout 8.1-F: Sierra Club

*Handout 8.1-G: Bailey





Ryan McCarter, 408-630-2983

Notice to Public:

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