TO:Andrew P. Powers, City Manager
FROM:Nader Heydari, Public Works Director
DATE:August 26, 2025
SUBJECT: Hill Canyon Treatment Plant Slope Stabilization Project (CI 5736)
RECOMMENDATION:
1. Approve a Single-Source designation for the selection of Cotton, Shires and Associates, Inc. (CSA) (Thousand Oaks, CA) for consulting services related to the City’s Hill Canyon Treatment Plant (HCTP) Slope Stabilization Project (CI 5736).
2. Approve Professional Services Agreement with CSA in an amount not to exceed $119,000 for the preparation of construction-ready plans and specifications for the HCTP Slope Stabilization Project (CI 5736), plus extra services of $11,900, with a term ending December 31, 2026.
3. Authorize expense in the amount of $130,900 ($119,000 agreement plus extra services of $11,900) from A/C #624-8250-682-8300 (Wastewater Fund – Capital Improvements, CI 5736).
4. Find that this action is not a project as defined under the California Environmental Quality Act (CEQA).
LEVINE ACT ITEM: Yes
FINANCIAL IMPACT:
No Additional Funding Requested. $2,465,000 is included in the Adopted FY 2025-26 Wastewater Capital Fund Budget and an additional $130,000 carryover budget for a total available budget of $2,595,000 for CI 5736 HCTP Slope Stabilization Project. Additional funding for construction costs may be requested at the time of construction contract award depending on bids received.
BACKGROUND:
The City’s HCTP is located at 9600 Santa Rosa Road, in a canyon in the northwest section of the city, between two creeks in a natural, unimproved environment. The treatment plant's original construction included an access road along the bottom
HCTP Slope Stabilization Project (CI 5736)
August 26, 2025
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of a cliff adjacent to the creek boundary. In FY 2022-23, the City constructed a new retaining wall along the eastern edge of the HCTP, which required cutting of the existing slope.
The Slope Stabilization Project scope includes developing proposed long-term engineering solutions for stabilizing the slopes to protect the HCTP from the adjacent slopes (Attachment #1).
Staff previously solicited a formal Request for Proposals/Qualifications (RFP/Q) for the overall design and engineering services for the project, starting with the preliminary-design/design-phase services under the HCTP Slope Stabilization Project (CI 5736), to be followed by the final design and construction phase.
Proposals were received on July 31, 2024. After a thorough review of the firms’ qualifications and project approach, CSA was identified as the most qualified engineering firm to fulfill the City’s requirements for this project.
The City executed a Professional Services Agreement with CSA on September 16, 2024, in the amount of $66,500, with an additional $6,650 allocated for extra services, under the City Manager’s signature authority. The First Amendment to the Agreement in the amount of $10,500 was approved by City Council at the November 19, 2024, City Council meeting, for a revised not-to-exceed amount of $77,000.
CSA prepared a Preliminary Design Report (PDR) that outlines various stabilization techniques available for the slopes. The PDR recommended options for the City and provided estimates of probable construction costs to assist with budgeting for the improvements. Additional slope mediation/stabilization measures include removing and grading loose soil material from the slope to reduce the potential of future falling debris and may include a hillside soil and debris retention system in areas with significant loose soil and rock material. Overall, this project aims to reduce maintenance costs while improving safety.
DISCUSSION/ANALYSIS:
CSA completed the slope stability study and PDR phase in March 2025. The PDR recommended that the slopes within HCTP be protected by a network of rock anchors, and that a long-term mesh product be constructed to facilitate vegetative regrowth on the slope, allowing the mesh to be covered over time. The stabilization of the rock outcropping above the HCTP access road will be addressed in a separate proposal effort. At this time, long-term monitoring of the outcropping is recommended.
HCTP Slope Stabilization Project (CI 5736)
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CSA is uniquely qualified to complete the next phase of the project, to prepare the City’s construction-ready plans and specifications, as they are intimately familiar with the slope/project site, and they have studied this area extensively while preparing the PDR. This phase was included in the original RFP/Q and the intention had been for the selected consultant to also complete the plans. Due to timing, it was not possible to add this new scope through an amendment to the original contract. Therefore, staff recommends that City Council approve a single- source designation for the selection of CSA to complete this project.
Staff requested a proposal from CSA to prepare construction-ready plans and specifications detailing the recommended slope stabilization products/designs for the hillside areas within HCTP. Staff recommends approval of the Professional Services Agreement with CSA (Attachment #2) for a total not-to-exceed amount of $119,000, plus extra services of $11,900.
ESTIMATED PROJECT COST SUMMARY
Preliminary Design Report (previous) CI 5736 $ 66,500.00 First Amendment – Additional Design (previous) CI 5736 $ 10,500.00 Extra Services (previous) CI 5736 $ 6,650.00 Design and Engineering (this action) CI 5736 $ 119,000.00 Extra Services (this action) CI 5736 $ 11,900.00 Construction (future) CI 5736 $ 2,380,450.00
Total Estimated Project Cost for CI 5736 $ 2,595,000.00 The tentative schedule for completion of the project is as follows:
Preliminary Design Report (previous contract) Completed Design and Engineering Phase Summer 2025 - Winter 2026
Bid and Award Phase Spring 2026
Construction Phase Summer 2026 – Spring 2027
This action is not a project as defined under the CEQA because this action will not result in a direct or foreseeable indirect physical change in the environment [14 CCR 15060(c)].
Community Outreach: This project will be limited to work at the HCTP, including the access road and is not expected to impact any neighboring residences.
HCTP Slope Stabilization Project (CI 5736)
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This project meets City Council’s Top Ten Priorities #9, “Public Works Infrastructure Investments.”
CIP PROJECT PRIORITY (as outlined in FY 2025-26 and 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. The completed Levine Act form is included in Attachment #2.
COUNCIL GOAL COMPLIANCE:
Meets the following City Council goals:
C. Operate City government in a fiscally and managerially responsible and prudent manner to ensure that the City of Thousand Oaks remains one of California's most desirable places to live, work, visit, recreate, and raise a family.
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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 – Professional Services Agreement with CSA DPW: 850-20\ev\Council\2025\082625\CI5736\HCTP Slope Stabilization Project staff report.docx