To: Sonoma County Water Agency
Department or Agency Name(s): Sonoma County Water Agency
Staff Name and Phone Number: Brad Sherwood 707-547-1900, Dale Roberts 707-547-1979
Vote Requirement: Majority
Supervisorial District(s): Fifth
Title:
Title
River Diversion Structure Modernization
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Recommended Action:
Recommended action
A) Adopt and approve the Project Manual and Drawings (“plans and specifications”) entitled “River Diversion Structure Modernization.”
B) Award the contract to Corcus Construction, Inc. for $6,602,150 for construction of the River Diversion Structure Modernization Project and authorize the Chair to execute the contract.
C) Authorize the General Manager of Sonoma County Water Agency to sign Section 00 65 23 (Agreement and Release of Any and All Claims), with County Counsel review, if any unresolved claims are listed by the contractor.
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Executive Summary:
This item requests approval of a contract with Corcus Construction, Inc. for $6,602,150 for construction of the River Diversion Structure Modernization Project (Project). Sonoma Water’s River Diversion Structure (RDS) was originally constructed in 1975 to divert water from the Russian River (River) into a series of infiltration ponds to recharge the alluvial aquifer feeding collectors 3, 4, and 5. The Project will replace items at the ends of their useful lives with components such as access platforms and mechanical, electrical, and instrumentation equipment.
Discussion:
River Diversion Structure Modernization Project (Project) consists of construction of Sonoma Water’s river diversion structure improvements located at 10290 Westside Road in Healdsburg, California. The Project includes, but is not limited to, removal and replacement of existing river diversion equipment and structures, such as access platforms, a medium-voltage switchgear, a step-down transformer, a motor control center, vertical turbine pumps, piping, facility lighting, heating, ventilation, and air conditioning, and a programmable logic controller; and construction of a flow metering system including vaults, meters, piping, electrical, and instrumentation.
The engineer’s estimate was $6,632,400. The Project was advertised for bids on June 22, 2026.
On September 8, 2026, seven bids were received per the attached Bid Summary. The lowest responsive and responsible bid is from Corcus Construction, Inc. and is $30,250 below the Engineer’s Estimate. Corcus Construction, Inc. is experienced in this type of construction and met the experience requirements.
A contractor must execute a release of claims (Section 00 65 23) before final payment but may except any unresolved claims from the release. The requested action authorizes the General Manager to approve the release unless the contractor lists unresolved claims. In that case, County Counsel must review Section 00 65 23 prior to General Manager approval.
Construction on the Project is scheduled to begin approximately December 14, 2026, with an estimated completion date of August 24, 2028.
CALIFORNIA ENVIRONMENTAL QUALITY ACT
The General Manager determined that the Project is categorically exempt from the California Environmental Quality Act (CEQA) pursuant to sections 15301(b), Existing Facilities, and 15302(c), Replacement or Reconstruction. A Notice of Exemption was filed on November 13, 2025.
County of Sonoma Strategic Plan:
N/A
Sonoma Water Strategic Plan Alignment:
This item directly supports Sonoma Water’s Strategic Plan and is aligned with the following goal, strategy, and action item.
Goal: 2. Planning and Infrastructure - Implement comprehensive, integrated, and innovative infrastructure planning to strengthen existing services, minimize life cycle costs, and prepare for the future.
Strategy: 2.3 Fund and implement the planned capital and maintenance projects on schedule to ensure reliable services.
Action Item: 2.3.2 Fund Capital Improvement Program budgets to meet infrastructure needs.
The River Diversion Structure Modernization Project will replace components over five decades old that are at the end of their useful lives to allow Sonoma Water to continue to reliably and cost effectively provide potable water service for future decades.
Racial Equity:
Was this item identified as an opportunity to apply the Racial Equity Toolkit?
No
Prior Board Actions:
11/04/2025: Authorize Sonoma County Water Agency’s General Manager to execute the Second Amended and Restated Agreement to include use of Wellfield Building and a regulatorily required flow meter and vault, and additional design engineering for completion of the Project design of the River Diversion Structure Modernization Project with Brelje & Race Engineering Consultants.
03/26/2024: Authorize Sonoma County Water Agency’s General Manager to execute the First Amended and Restated Agreement to include necessary geotechnical work at the site and additional design engineering for completion of the Project design of the River Diversion Structure Modernization Project with Brelje & Race Engineering Consultants.
08/02/2022: Authorize Sonoma County Water Agency’s General Manager to execute an agreement with Brelje & Race Engineering Consultants for engineering and design services of the River Diversion Structure Modernization Project which was originally constructed in 1975 for supplementary recharging of the alluvial aquifer, has reached the end of its useful life and requires replacement.
Fiscal Summary
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Expenditures |
FY26-27 Adopted |
FY27-28 Projected |
FY28-29 Projected |
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Budgeted Expenses |
$6,602,150 |
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Additional Appropriation Requested |
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Total Expenditures |
$6,602,150 |
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Funding Sources |
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General Fund/WA GF |
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State/Federal |
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Fees/Other |
$6,602,150 |
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Use of Fund Balance |
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General Fund Contingencies |
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Total Sources |
$6,602,150 |
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Narrative Explanation of Fiscal Impacts:
Budgeted amount of $6,602,150 is available from FY 2026/2027 for the Common Facilities fund. No additional appropriation is required.
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Staffing Impacts: |
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Position Title (Payroll Classification) |
Monthly Salary Range (A-I Step) |
Additions (Number) |
Deletions (Number) |
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Narrative Explanation of Staffing Impacts (If Required):
N/A
Attachments:
Attachment - Bid Abstract
Related Items “On File” with the Clerk of the Board:
Project Manual and Drawings