To: Board of Directors, Sonoma County Water Agency
Department or Agency Name(s): Sonoma County Water Agency
Staff Name and Phone Number: Kevin Booker 707-521-1865
Vote Requirement: Majority
Supervisorial District(s): Second
Title:
Title
Penngrove Sewer Capacity Evaluation
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Recommended Action:
Recommended action
Authorize Sonoma County Water Agency’s General Manager to execute the Amended and Restated Agreement for Penngrove Sewer Capacity Evaluation with Woodard & Curran, Inc. in substantially the form as the draft presented to this Board. The amended agreement increases the amount by $79,000; expands the scope of work to include analysis of additional flow data, updating the sewer model, and updating the sewer capacity report; and extends the agreement term by one-year for a new not-to-exceed agreement total of $179,000 and end date of December 20, 2025.
(Second District)
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Executive Summary:
In accordance with the California Statewide General Waste Discharge Requirements for Sanitary Sewer Systems, Water Quality Order No. 2022-0103 (WDR), Sonoma Water has developed a Sewer System Management Plan for the Penngrove Sanitation Zone. The Sewer System Management Plan describes how each collection system will be operated, maintained, and evaluated. One of the requirements of the Sewer System Management Plan is a System Evaluation and Capacity Assurance Plan. This amendment allows the collection of additional flow data to update the computer model to determine if the current design of the sewer collection system has the capacity to accommodate existing conditions and future growth.
Discussion:
HISTORY OF ITEM/BACKGROUND
Sonoma Water owns and operates the Penngrove Sanitation Zone (Zone). The Zone’s service area comprises 475 acres and serves a population of 1,264 (549 single-family dwelling unit equivalents). Construction of the collection system began in 1960, and the majority (80%) was constructed between 1960 and 1979. It includes 13.6 miles of sewers (9.4 miles of gravity sewer mains, 3.1 miles of force mains, and 1.1 miles of service laterals and 1 pump station). The collected sewage from the Zone is sent to the City of Petaluma's sewer system for conveyance to the Petaluma Wastewater Treatment Plant.
In accordance with the Waste Discharge Requirements (WDR), Sonoma Water has developed a Sewer System Management Plan for the Zone collection system. The Sewer System Management Plan describes how each collection system will be operated, maintained, and evaluated.
A requirement of the Sewer System Management Plan is a System Evaluation and Capacity Assurance Plan (SECAP). Currently, the capacity studies for the Zone need to be updated. In addition, sewer collection system modeling and capacity assessment are necessary to update the SECAP. Sonoma Water will evaluate the available and required capacity of the collection system, including identification of alternatives for system improvements.
Sonoma Water and Woodard and Curran, Inc. (Consultant) entered into an agreement for a sewer capacity evaluation, dated February 17, 2022, in the amount of $100,000. Under the original agreement, data of the collection system was collected, a computer model to simulate flows was built, and an analysis of the system was done. Upon review, staff felt additional data and analysis was needed in order to accurately model the sewer flows. Upon approval, Consultant will use additional flows data captured in January, February, and March of 2024, to conduct different flow scenarios of the collection system to determine capacity issues, if any, that need to be addressed for future growth. Upon completion, the computer model capacity report will be updated and included in the Zone’s Sewer System Management Plan and will meet the new WDR.
SELECTION PROCESS
Consultant was selected from a list of qualified consultants developed from a competitive selection process. Attached is a memo that explains the competitive selection process.
County of Sonoma Strategic Plan Alignment
N/A
Sonoma Water Strategic Plan Alignment
Goal: Planning and Infrastructure
Strategy: Conduct planning that integrates and balances operational, maintenance, and infrastructure priorities.
Action: Continue to engage in planning efforts to support reliable wastewater and flood management services.
Racial Equity:
Was this item identified as an opportunity to apply the Racial Equity Toolkit?
No
Prior Board Actions:
01/25/2022: Authorize Sonoma County Water Agency’s General Manager to execute an agreement with Woodard & Curran, Inc., for Penngrove sewer capacity evaluation and related services through December 20, 2024, in the not-to-exceed amount of $100,000.
Fiscal Summary
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Expenditures |
FY23-24 Adopted |
FY24-25 Projected |
FY25-26 Projected |
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Budgeted Expenses |
$79,000 |
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Additional Appropriation Requested |
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Total Expenditures |
$79,000 |
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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 |
$79,000 |
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Use of Fund Balance |
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General Fund Contingencies |
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Total Sources |
$79,000 |
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Narrative Explanation of Fiscal Impacts:
The budgeted amount of $79,000 is available from FY 2023/2024 appropriations for the Penngrove Sanitation Zone 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 1: Amended Agreement with Woodard & Curran, Inc.
Attachment 2: Consultant Selection Memo
Related Items “On File” with the Clerk of the Board:
None