BOARD AGENDA MEMORANDUM
Government Code § 84308 Applies: Yes ☐ No ☒
(If “YES” Complete Attachment A - Gov. Code § 84308)
SUBJECT: Title
Receive an Update on the Anderson Dam Seismic Retrofit Project and Coyote Creek Flood Protection Project.
End
RECOMMENDATION: Recommendation
Receive an update on the Anderson Dam Seismic Retrofit Project and Coyote Creek Flood Protection Project.
Body
SUMMARY:
BACKGROUND
The Anderson Dam Seismic Retrofit Project (ADSRP) will correct dam seismic deficiencies and meet all current Federal Energy Regulatory Commission (FERC) and California Department of Water Resources, Division of Safety of Dams (DSOD) dam safety design standards. The full reservoir capacity will be restored upon completion of the project.
Throughout 2019 to early 2020, project staff and consultants had been progressing with preparation of the 90% design plans and specifications and supporting environmental and permitting documents. On February 20, 2020, Valley Water received a letter order from FERC to immediately implement interim risk reduction measures at Anderson Dam to protect the public from dam failure due to seismic activity.
Valley Water is undertaking the Anderson Dam Federal Energy Regulatory Commission Order Compliance Project (FOCP) to comply with the February 20, 2020, directive from FERC. The construction improvements necessary to complete the FOCP have been grouped into five sub-projects to be completed before the ADSRP construction. Updates for two of these projects, the Anderson Dam Tunnel Project and the Coyote Creek Flood Management Measures Project are provided below. In addition, there are several other non-construction measures which are being implemented as part of the FOCP including maintaining the reservoir at the lowest level possible, known as “deadpool.”
The Valley Water Board of Directors certified the final Environmental Impact Report (EIR) for ADSRP on February 25, 2025. State and federal permits for various construction authorizations are currently in progress. The ADSRP team has prepared the 100% level design plans which will be used to advertise for construction bids. ADSRP construction bidding is anticipated to start in 2025 using a best-value model. The contractor will be selected in mid-2026 and the construction activities will take place from 2027 to 2033.
DISCUSSION
Anderson Dam Tunnel Project
The Anderson Dam Tunnel Project (ADTP) is currently being constructed and includes building a diversion system to augment the existing outlet, consisting of a new diversion tunnel, an outlet structure, a micro-tunnel lake tap, and modifications to Coyote Creek just downstream of the base of the dam. Once completed, the ADTP will serve as the Stage 1 Diversion System to divert inflows from the reservoir to Coyote Creek during the beginning of the Anderson Dam Seismic Retrofit Project (ADSRP). All of the ADTP elements, except for the micro-tunnel lake tap portion, will be incorporated into the final configuration of the ADSRP.
On April 27, 2021, Valley Water’s Board of Directors awarded the construction contract for the ADTP to the top-ranked best-value proposer, Flatiron West, Inc. (Contractor), in the sum of $161,140,321 and approved a contingency amount of $40,000,000 (25% of the contract price).
On January 28, 2025, the Board of Directors approved an increase of $40,000,000 to the construction contract contingency sum, bringing the total construction contract contingency to $80,000,000.
Several major elements of the ADTP construction have been completed to date including:
• Tunnel Excavation and Initial Lining
Tunnel excavation and initial lining of the tunnel were completed in April 2024. The Contractor used conventional mining methods, including drilling and blasting the rock to complete the excavation. The initial lining installed to support the excavation consists of an 8-inch thick layer of fiber-reinforced shotcrete (spray-applied concrete) and steel support arches spaced every 3 to 5 feet.
• Microtunnel and Laketap
Conclusion of tunneling and tapping into the reservoir was completed in August 2024. A micro-tunnel boring machine (MTBM) drilled through the last 350 feet of tunnel into the reservoir about 30 feet under the water surface. Sections of 8-foot diameter steel pipe were driven into the ground behind the MTBM in this portion of the tunnel.
• Diversion Outlet Structure (DOS) Construction
Construction of the DOS outside the downstream tunnel portal was completed in June 2024. The DOS will be used to house the two large fixed-con valves that control flows through the tunnel and dissipate the energy of the releases by reducing the velocity of the water. The foundation, walls, and roof of the structure are made of thick, reinforced concrete sections that were placed in multiple stages.
• North Channel Extension
Work to reopen the North Channel was completed in November 2024. The work included excavation, grading, and rock placement for over 1,600 linear feet starting outside the DOS to reconnect this historic creek channel back to Coyote Creek. A concrete labyrinth weir was also installed in the channel to dissipate the energy and control high flows to be released from Anderson Reservoir.
The remaining major construction elements to be completed by the end of 2026 include:
• South Channel Weir Construction
Improvement of the South Channel by constructing a new concrete weir, with a notch for low-flow passage. This weir will work in conjunction with the North Channel Weir to control flow releases from Anderson Reservoir in this reach of Coyote Creek.
• Final Tunnel Lining Installation
Construction of the final tunnel lining. There are three distinct structural systems that will be used for the final tunnel lining:
o Continuous Reinforced Concrete - a 24-inch thick, horseshoe-shaped arch, walls, and floor
o Articulating Joint Concrete Sections - a similar 24-inch -thick reinforced concrete structure with heavier reinforcement and gaps between sections every five or ten feet designed to independently displace if ground movements occur.
o Steel Pipe with Concrete Backfill - about 450 linear feet of 13-foot diameter steel pipe will be installed at the downstream end of the tunnel that exits the portal. The annular space will be backfilled with concrete.
• Diversion Outlet Structure (DOS) Large Diameter Pipe and Valve Installation
Installation of the large diameter steel pipes and valves in the DOS. As the 13-foot diameter steel pipe exits the tunnel, it bifurcates into two 11-foot diameter steel pipes. Each of the 11-foot diameter pipes have a butterfly valve and fixed cone valve to control flow releases and dissipate energy into the DOS.
Coyote Creek Flood Protection Project
Before the FERC order in 2020, Valley Water was working on planning and designing a project to provide flood protection against a 20-year flood event along Coyote Creek; this project was referred to as the original Coyote Creek Flood Protection Project (CCFPP). To comply with the February 20, 2020 FERC order that Valley Water must include measures to protect residents and properties downstream of the dam during implementation of FOCP, Valley Water accelerated a portion of the original CCFPP elements and included them as part of FOCP; these prioritized elements are now referred to as the Coyote Creek Flood Management Measures Project (CCFMMP), which is described in more detail below. The CCFMMP and CCFPP, collectively referred to as “Project”, represent phase one and phase two, respectively, of a 9-mile flood protection project along Coyote Creek between Montague Expressway and Tully Road in the City of San José.
Phase one, CCFMMP, is an expedited portion of the Project in response to the FOCP, which is a set of interim risk reduction measures required prior to construction and operation of the ADTP. The immediate objective of phase one, CCFMMP, is to reduce the risk of flooding in San Jose as a result of water releases from Valley Water’s Anderson Dam that may occur after construction of ADTP. The scope of phase one, CCFMMP, includes construction of seven (7) floodwalls in a total of three (3) reaches along Coyote Creek.
Construction of phase one, CCFMMP, began in Summer 2023 and has recently completed construction. Phase two, CCFPP, will construct all the remaining Coyote Creek flood protection elements, including steel sheet pile floodwalls, concrete T-walls, flood gates and flood doors, and passive barriers, within the Project geographic area that are necessary to convey flows similar to those that occurred during the February 2017 flood event and any additional flows from the new Anderson Dam stage 2 diversion tunnel, which will be part of the ADSRP. The Valley Water Board of Directors certified the final EIR for CCFPP on March 11, 2025. Regulatory permits for various construction authorizations are currently in progress. Phase two, CCFPP, is in the final stages of design and is anticipated to begin construction in Summer 2026.
Encampment Cleanup for Coyote Creek Flood Management Measures Project
To facilitate the construction of CCFMMP, on April 21, 2023, Valley Water and the City executed an agreement to relocate encampments of unsheltered people who had been located in the project footprint and staging areas. Per the agreement, Valley Water provided funding to the City for specific targeted services with the goal of safely relocating the encampments in the construction zone. Rather than displacing the unsheltered individuals without providing support, Valley Water and the City sought to ensure that these individuals would receive outreach and targeted services in furtherance of connecting them with emergency or temporary housing. Of 192 individuals living in the CCFMMP project areas who were identified by name, 178 received City outreach services and 120 exited to shelter or interim housing pursuant to this agreement.
The City has introduced No Encampment Zones (NEZ’s) along the Coyote Creek and other waterways to protect the environment and comply with stormwater permit requirements. These zones prevent new encampments from forming along the waterway and protect people, neighborhoods, and our environment. They include permanent signage, outreach, monitoring and action through a team of City employees that include BeautifySJ staff for monitoring and general outreach, Housing Department staff for housing specific outreach, and a newly formed SJPD Neighborhood Quality of Life team of officers for enforcement. At the time this memo was submitted, 14.7 miles of waterways along Coyote Creek have been cleared. Of this, 9.21 miles of Coyote Creek waterway have been established as No Encampment Zones. Permanent signage, monitoring, action and enforcement along the CCFMMP area exists along the Coyote Creek waterway, adjacent parks and open space from Yerba Buena Road downstream to Capitol Expressway, from Tully Road downstream to Keyes Street/ Story Road, from I-280 downstream to Roosevelt Park, and from Watson Park downstream to Berryessa Road. 19 escalated actions that included warnings and follow up abatements have occurred along these NEZ areas since they were established. Permanent signage is being produced and will be installed in the next phase of NEZ established areas from Capitol Expressway downstream to Tully Road and from Berryessa Road downstream to Old Oakland Road by October 2025. The section of Coyote Creek between Keyes Street / Story Road and I-280 will be introduced as a NEZ by Summer 2026.
While Valley Water has limited ownership on Coyote Creek as compared to the City, it has also established areas where camping is prohibited per its Water Resources Protection Zones Ordinance. These areas, known as Water Resources Protections Zones (WRPZs), encompass Valley Water-owned sections of Coyote Creek near Tully Road, as well as Valley Water property from the area of Ridder Park Drive downstream to San Francisco Bay. Valley Water has installed permanent signage to designate these WRPZs and to provide notice of the camping prohibition. Valley Water Operations & Maintenance Division field staff conduct regular inspections of the WRPZs to ensure compliance with ordinance restrictions and to educate individuals who may attempt to set up encampments in these areas.
ENVIRONMENTAL JUSTICE IMPACT:
There are no environmental justice impacts associated with this item.
FINANCIAL IMPACT:
There is no financial impact associated with this item.
CEQA:
The recommended action does not constitute a project under CEQA because it does not have potential for resulting in direct or reasonably foreseeable indirect physical change in the environment.
ATTACHMENTS:
Attachment 1: PowerPoint
UNCLASSIFIED MANAGER: Manager
Ryan McCarter, 408-630-2983