Title
Overview of the Draft Interlake Tunnel and San Antonio Spillway Modification Assessment Engineer’s Report. (Staff Presenter: Amy Woodrow)
Report
In February 2017, the Monterey County Water Resources Agency (“Agency”) entered into grant agreement number 4600011748 (“Agreement”) with the Department of Water Resources of the State of California (“State” or “DWR”) to assist in financing the Interlake Tunnel and San Antonio Spillway Modification Project (“Project”).
One of the deliverables in the Agreement is a Draft Engineer’s Report for the Project including a Project Description and Assessment Methodology. The Agency worked with Bartle Wells Associates to prepare the Draft Interlake Tunnel and San Antonio Spillway Modification Assessment Engineer’s Report (“Draft Engineer’s Report”) (Attachment 1). The Draft Engineer’s Report utilizes data derived from the Salinas Valley Historical Benefits Analysis Update, prepared in 2024, which consisted of a hydrologic and flood control analysis prepared by West Yost and an economic benefits analysis prepared by One Water Econ (“HBA Update”) to compare benefits that would result from the Project. The HBA Update was provided to the Planning Committee in April 2025 and the reports are available on the Agency’s website under News/Announcements (Attachment 2).
The Draft Engineer’s Report utilizes the same geographic extent as the Agency’s Zone 2C and examines primarily the water supply and flood protection benefits that could accrue within that area from the Project. The Project also provides additional benefits, such as recreation and environmental benefits, that are discussed as General Benefits in the Draft Engineer’s Report.
The Draft Engineer’s Report presents three options for allocating Project benefits across the geographic space. These options, which range from broad to more specific, are discussed in detail and are presented with the intention of providing a catalyst for discussion about future cost allocation approaches.
Funding to complete a Draft Engineer’s Report for the Project was provided in full by grant agreement number 4600011748 with the Department of Water Resources of the State of California.
Prepared by: Amy Woodrow, Senior Water Resources Hydrologist, (831) 755-4860
Approved by: Ara Azhderian, General Manager, (831) 755-4860
Attachments:
1. Draft Interlake Tunnel and San Antonio Spillway Modification Assessment Engineer’s Report
2. HBA Update Overview