RES 2026043 - Laserfiche WebLink

Section 6 2025 Urban Water Management Plan Water Supply Characterization City of Pleasanton Public Draft | May 2026 6-29 EKI Environment & Water, Inc. In December 2016, the Zone 7 Board authorized participation in Phase 1 of the project. In January 2022, the Zone 7 Board authorized participation through the completion of Phase 2 at the end of December 2024. Phase 2 focused on completing the environmental documentation, securing key permits, advancing design to a 30% level, and preparing for long-term financing. Additionally, in January 2026, the federal government approved the Record of Decision for the project. Sites Reservoir is expected to break ground in late 2026 and is planned to be fully operational in 2034. For this 2025 UWMP, 4,000 AFY of future supply from Sites Reservoir will be available to Zone 7 by 2034. 6.8.2 Infrastructure Projects 6.8.2.1 Chain of Lakes Conveyance System Zone 7 is planning the Chain of Lakes Conveyance System (COLCS), a project that interconnects retired gravel quarries with existing water supplies for local surface water storage. This project will have multiple benefits, including: • provide Zone 7 with an emergency supply during a prolonged SWP outage, • enhance drought supplies, • improve recharge of the local groundwater basin, • make water available for transfers, • allow Zone 7 to divert surplus water, and • perfect local water rights. The current phase of the project involves two of the retired quarry lakes, Lake I and Cope Lake, which Zone 7 already owns. The project would build a two-way pipeline to allow them to be used as a reservoir. During wet periods, the project will enable the storage of local and SWP water that would otherwise be lost or require non-local storage. This water would then be pumped back to Zone 7’s DVWTP during dry periods, thereby enhancing water supply reliability. The project involves constructing a 42-inch diameter, 6.5-mile bidirectional pipeline between DVWTP and Lake I, in addition to inlet and outlet facilities at Lake I, a pump station, and PFAS treatment facilities at DVWTP. Lake I and Cope Lake have a combined storage capacity of approximately 36,400 AF. Over the coming years, additional quarries are slated to be transferred to Zone 7 and integrated into this project, adding storage capacity or other multi-benefit opportunities. As shown in Figure 6-6, the COLs includes ten lakes named Lakes A through I and Cope Lake, which cover approximately 1,500 acres. In 2023, Zone 7 completed a pipeline alignment study to evaluate the cost and benefits associated with potential pipeline alignments. The West Alignment was chosen as the preferred alternative due to its shortened route compared to other alternatives, use of an existing access road/recreational trail, and avoidance of construction through the quarries. In 2024, a feasibility study was done, and from 2025- 2026, three facilitated brainstorming workshops were conducted to define and develop the project. If approved by the Zone 7 Board, planning efforts over the next few years include preliminary engineering and design, permitting, and obtaining right-of-way easements.