TO:Andrew P. Powers, City Manager
FROM:Nader Heydari, Public Works Director
DATE:September 23, 2025
SUBJECT: Unit W Wastewater Interceptor Improvements (CI 5445) RECOMMENDATION:
1. Approve Third Amendment to Professional Services Contract No. 13560-2024 with Padre Associates, Inc. (Ventura, CA), for additional Environmental and Monitoring Services for the Hill Canyon Treatment Plant (HCTP) Unit W Wastewater Interceptor Improvements Project (CI 5445) in the amount of $33,879.62, for a revised not-to-exceed amount of $124,182.62.
2. Authorize expense in the amount of $33,879.62 for additional construction environmental and monitoring services, from A/C #624-8220-682-8300 (Wastewater Capital Fund Improvements, CI 5445).
3. California Environmental Quality Act (CEQA): A Mitigated Negative Declaration (MND) was approved for this project by City Council on February 22, 2022.
LEVINE ACT ITEM: Yes
FINANCIAL IMPACT:
No Additional Funding Requested. $1,199,039 in available carryover budget is included in the FY 2025-26 Wastewater Capital Fund for CI 5445.
BACKGROUND:
The City’s HCTP provides tertiary-level wastewater treatment for the community of Thousand Oaks. As part of the overall wastewater collection and treatment system, large-diameter wastewater interceptor pipelines were installed to transport the wastewater from the community and deliver it to the HCTP. The Unit W Wastewater Interceptor is a gravity collection pipeline that originates near The Oaks Mall and transports a large volume of wastewater along the Arroyo Conejo Creek to the HCTP (Attachment #1).
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The Unit W pipeline was installed in the 1960s, and improvements have been made over the following decades. In the lower portion of the interceptor, the original 1960s Unit W pipeline consists of a 30-inch diameter pressurized pipeline with two major wastewater access structures (Structure W-1 and Structure W/F).
The structures enable staff to control and access the wastewater interceptors.
This project involves important rehabilitation of Unit W, some of the City’s largest and most essential wastewater interceptor pipelines. The improvements will help prolong the life of current assets and reduce overall risks and maintenance costs to these critical wastewater pipelines. This portion of wastewater interceptor pipelines is nearing the end of its service life, is located deep in the canyon, and is difficult to access.
The project’s scope of work includes exposing and reviewing the existing condition of the two main pipelines towards the south headworks at the HCTP, which includes approximately 5,000 feet of 20- to 42-inch diameter pipes (Attachment #1). This project also includes replacing non-functioning isolation valves, installation of several additional new structures to gain access to the existing pipelines, installation of a temporary wastewater bypass pipeline, and closed- circuit television (CCTV) work inside of the existing wastewater pipelines to evaluate their condition.
The condition assessment of the existing facilities included with this project is the first phase of a potential two-phase project. After completing this phase and obtaining the necessary internal pipeline CCTV information, staff will evaluate the need for the second phase, which involves replacing any identified defective lining.
The second phase is included under CI 5681 in the Adopted FY 2025-2027 Capital Improvement Program Budget.
On February 27, 2024 , City Council approved a Single-Source Designation and Professional Services Agreement with Padre Associates, Inc. (Padre), in the not- to-exceed amount of $83,468, to prepare the required project regulatory permit applications, as well as perform the environmental analysis for the project impacts, and the CEQA compliant Initial Study/MND. As part of the regulatory permit process, California Department of Fish and Wildlife (CDFW) has required compensatory mitigation of the impacts associated with the project. Landscape planting of native species is the recommended approach. Preparation of a construction ready set of plans and specifications for the mitigation planting needs to be prepared.
A First Amendment to the Contract was approved by City Council on February 11, 2025, in the amount of $2,805, increasing the not-to-exceed amount to $86,273.
The First Amendment covered additional environmental and monitoring services Unit W Wastewater Interceptor Improvements (CI 5445)
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and extended the agreement term until December 31, 2025. The Second Amendment to the Contract was executed using previously approved extra services funds under City Manager Authority on July 1, 2025, in the amount of $4,030, increasing the contract amount to $90,303. The Second Amendment covered additional work involving the preparation of an Arborist Report in accordance with Section 9-4.4201, Article 42 and Section 9-4.4303, Article 43 of the Thousand Oaks Municipal Code and Tree Protection Resolution No. 2010- 014. The Report assessed tree encroachment, trimming, and removal impacts at work areas and access routes.
DISCUSSION/ANALYSIS:
Environmental Review
As required under the provisions set forth in Section 15063 of the CEQA Guidelines, an Initial Study was prepared by the City for the Wastewater Interceptor Capital Improvement Project, Unit W (CI 5445). The Initial study evaluated the potential environmental effects of this project. Although the initial study determined that the project could have a potentially significant impact on the environment for specific receptors, the project design will reduce the impacts, and feasible mitigation measures have been identified that would either avoid or reduce impact to a level of insignificance or less than significant with mitigation. Based on these findings, an MND and a Mitigation Monitoring Reporting Plan were prepared for the proposed project in compliance with the provisions set forth in Section 15070 of the CEQA Guidelines. On February 22, 2022, City Council adopted the construction project MND.
Environmental Monitoring Services During Construction
Padre is the environmental/biological consultant of record and is providing construction support services required for the project. Padre’s construction support services include technical oversight to ensure the requirements of the environmental permits, as outlined in the CDFW Streambed Alteration Agreement (SAA) and other required CEQA mitigation monitoring requirements for the project, are met. Such mitigation and monitoring activities require services related to biological monitoring, breeding bird surveys, and permit compliance documentation, both during and after project construction. The extensive field construction phase for the project, and the volume of communication, reports, and correspondence with the permitting agencies requires additional services from Padre. Staff recommends approval of the Third Amendment to Contract No. 13560-2024 with Padre for $33,879.62 (Attachment #2) for a revised not-to-exceed amount of $124,182.62 to cover these additional services.
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The estimated overall project cost breakdown is as follows:
Design and Engineering Support w/AECOM (previously approved) $ 297,749 Design and Engineering Extra Services (previously approved) $ 39,170 Engineering & Project Management Support w/Phoenix (previously approved) $ 125,000
Isolation Valves Equipment (previously approved) $ 68,129 Unit W Construction Contract w/Toro (previously approved) $3,440,000 Unit W Construction Contingency (previously approved) $ 344,000 Construction Phase Support Services w/ AECOM (previously approved) $ 180,500 Habitat Restoration Design Services w/AECOM (previously approved) $ 72,400 Habitat Rest. Mitig. Design Services Extra Services (prev. approved) $ 7,200 Const. Phase Support Services Extra Services (prev. approved) $ 4,690 Const. Phase Environ. Monitoring w/Padre (prev. approved) $ 83,468 Const. Phase Environ. Monitoring- Amend. 1 w/Padre (prev. approved) $ 2,805 Construction Phase Environ. Monitoring- Amend. 2 w/Padre (prev. approved) $ 4,030
Amendment 3 for Environ. Monitoring (this action) $ 33,879.62 City Furnished Supplies and Materials (prev. approved) $ 5,000 Bank Letter of Credit for CDFW Permit Obligations (prev. approved) $ 550,000 Fee for Bank Letter of Credit for CDFW (prev. approved) $ 22,000 Plug Valves Equipment Purchase (previously approved) $ 126,555 Total Estimated Costs (through Previous and Current Actions) $5,406,575.62 Permitting and Inspection: CDFW (future) $ 25,000
Habitat Restoration as required by CDFW (future) $ 550,000 Total Estimated Project Costs (including Future Actions) $5,981,575.62 The overall project cost for the construction assessment project and the habitat mitigation project (including contingencies, design services during construction/testing, and project management) is estimated at $5,981,575.62.
The construction phase is expected to be fully completed by December 2025.
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This project meets City Council’s Top Ten Priorities #9, “Public Works Infrastructure Investments.”
Community Outreach: This project will be limited to work in the canyon adjacent to the HCTP, where the Unit W pipelines are located, and is not expected to impact any neighboring residences. The work will be located at the south end of the plant and will have a minimal impact on plant operations. Construction-related impacts to hiking trail users will be minimal.
CIP PROJECT PRIORITY (as outlined in FY 2025-26 and FY 2026-27 CIP Program Budget)
Priority Two – Necessary, but not essential, and there could be consequences if deferred.
LEVINE ACT (California Government Code § 84308):
This item is subject to the Levine Act. City Councilmembers who have received a campaign contribution of more than $500 (aggregated) within the preceding 12 months from a party or their agent/representative, or a financially-interested participant involved in this proceeding may do either of the following: (1) disclose the contribution on the record and recuse themselves from this proceeding; or if applicable (2) return the portion of the contribution that exceeds $500 within 30 days from the time the official knew or should have known about the contribution, and participate in the proceeding.
All parties and their agents/representatives must disclose on the record of this proceeding any aggregated contribution of more than $500 made to any Councilmember within the preceding 12 months. Councilmembers are prohibited from accepting, soliciting, or directing a campaign contribution of more than $500 (aggregated) from a party, their agent/representative, or a financially-interested participant during a proceeding and for 12 months following the date a final decision is made. In addition, a party, their agent/representative, or a financially- interested participant is prohibited from contributing more than $500 (aggregated) to a Councilmember during a proceeding and for 12 months following the date a final decision is made.
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COUNCIL GOAL COMPLIANCE:
Meets the following City Council goal:
F. Provide and enhance essential infrastructure to ensure that the goals and policies of the Thousand Oaks General Plan are carried out and the City retains its role and reputation as a leader in protecting the environment and preserving limited natural resources.
PREPARED BY: Paul Weinstein, Associate Analyst
Attachments:
Attachment #1 – Vicinity and Location Maps
Attachment #2 – Third Amendment to Contract No. 13560-2024 with Padre DPW: 850-20\ev\Council\2025\092325\CI 5445\ Unit W Interceptor Improvements staff report.docx