BOARD AGENDA MEMORANDUM
Government Code § 84308 Applies: Yes ☐ No ☒
(If “YES” Complete Attachment A - Gov. Code § 84308)
SUBJECT: Title
Update on Anderson Dam Seismic Retrofit Project and Coyote Creek Flood Protection Project.
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RECOMMENDATION: Recommendation
That the Santa Clara Valley Water District (Valley Water) Board and the City of San Jose (City) Mayor and Council receive an update on the Anderson Dam Seismic Retrofit Project and Coyote Creek Flood Protection Project.
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SUMMARY:
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 which are all in construction now. 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 ADSRP team has prepared the 90% level design and the design plans are being reviewed by FERC and DSOD. Valley Water also released the draft Environmental Impact Report (EIR) for ADSRP for public review on September 1, 2023 and the comment period will be ending on November 8, 2023. Valley Water conducted a public meeting on October 4, 2023 in Morgan Hill to solicit comments on the draft EIR. ADSRP Construction bidding is anticipated to take place in 2025 with a six-year construction period from 2026 to 2032.
DISCUSSION
Anderson Dam Tunnel Project
The Anderson Dam Tunnel Project (ADTP) is one of five capital construction projects included in the FOCP. The 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.
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., in the sum of $161,140,321 and approved a contingency amount of $40,000,000 (25% of the contract price).
Since the construction contract was awarded, significant progress has been made. The contractor completed the soil nail wall to strengthen roughly 15,000 square feet of the hillside above the outlet for the new diversion tunnel in the summer of 2022. Excavation of the tunnel commenced in November of 2022 with approximately 1,000 feet of the 1,750 feet of tunnel excavated as of October 2023. The 90 feet-deep high-level outlet works drop shaft excavation and initial lining was completed in December 2022. The contractor continues construction of the reinforced concrete diversion outlet structure which will house two 132-inch diameter fixed cone valves to control and dissipate the energy of water releases to Coyote Creek. Dredging operations are ongoing in Anderson Reservoir to excavate the lake tap portal below the water surface. Grading work to reopen the North Channel below the dam is also taking place. The ADTP is anticipated to be completed in summer 2025, prior to the ADSRP construction.
Coyote Creek Flood Protection Project Before the FERC order in 2020, Valley Water was working on planning and design of 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 details below. The remainder of the original CCFPP elements not included in the FOCP are now in the design/CEQA review phase, and the project name of CCFPP is retained. The overall flood risk reduction objective of CCFMMP and CCFPP is protecting areas of Coyote Creek against a flood event equivalent to the February 2017 flood or approximately a 20-year flood event. This goal will be met by the completion of CCFMMP and CCFPP.
On May 16, 2023, Valley Water Board of Directors awarded the construction contract for the CCFMMP to Gordon N. Ball, Inc., in the sum of $43,927,438 and approved a contingency amount of $6,589,116 (15% of the contract price).
CCFMMP is being constructed and includes construction of seven floodwalls in a total of three reaches along Coyote Creek. CCFMMP is expected to be completed in October 2024, prior to completion of ADTP. The City and Valley Water entered into an agreement in April 2023 to address unhoused encampments and facilitate construction of CCFMMP and CCFPP. Valley Water and City staff worked together and achieved the common goal of safely relocating the unhoused along Coyote Creek with an initial focus on areas within the CCFMMP limits by June 2023. In addition, Valley Water and City staff worked closely on the City’s Coyote Creek Trail Project, which is also in construction at the same time as CCFMMP and have a common work area near Highway 101.
CCFPP is currently in design and CEQA review phase. Valley Water is preparing a Draft ElR for CCFPP, which is anticipated to be released for public review in summer of 2024, with construction estimated to begin in spring of 2025. Valley Water staff have been working closely with City of San Jose parks staff regarding the CCFPP elements that will be constructed at Watson Park, Williams Street Park, and Selma Olinder Park.
ENVIRONMENTAL JUSTICE IMPACT:
There are no Environmental Justice impacts associated with this item. However, environmental justice impacts associated with the ADSRP and CCFPP will be provided when these projects are presented to Valley Water Board for consideration prior to project approval. Valley Water has solicited community input for consideration through public meetings during development of ADSRP and CCFPP, which helped inform the project design.
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 the 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
Bhavani Yerrapotu, 408-630-2735