TO:Andrew P. Powers, City Manager
FROM:Clifford G. Finley, Public Works Director
DATE:March 14, 2023
SUBJECT: Hill Canyon Treatment Plant Retaining Wall Project (CI 5444) RECOMMENDATION:
1. Approve Sixth Amendment to Professional Services Agreement No. 12377- 2020 with m6 Consulting, Inc. of Westlake Village, CA, for additional Construction Phase Services on the Hill Canyon Treatment Plant Retaining Wall Project (CI 5444) in the amount of $42,365 for a new revised not-to-exceed amount of $282,196.
2. Approve budget appropriation and expenditure in the amount of $42,365 from A/C #624-0000-341-9900 (Wastewater Fund, Net Position) to A/C #624-8250-682- 8300 (CI 5444, Hill Canyon Treatment Plant Retaining Wall Project).
3. Find that the project is Categorically Exempt from California Environmental Quality Act pursuant to 14 CCR §§ 15301, 15302, and 15304.
FINANCIAL IMPACT:
$42,365 Increase to FY 2022-23 Wastewater Fund Budget. $42,365 increase to Adopted FY 2022-23 Wastewater Fund Budget is requested for the Hill Canyon Treatment Plant Retaining Wall Project. $1,800,000 is available in the Adopted FY 2022-23 Wastewater Fund Budget. The total project cost is estimated at $1,842,365.
BACKGROUND:
Hill Canyon Treatment Plant (HCTP) treats wastewater from the community of Thousand Oaks. Constructed in the 1960s with major improvements over the following decades, HCTP provides tertiary level wastewater treatment. The treatment plant is located within a canyon environment. The plant is bordered on two sides by canyon walls with a creek running on the northwest side of the parcel. As the plant was expanded over the years, there were retaining structures installed on the southeast border of the plant (Attachment #1). Over time, the slope in some areas has overtopped the existing retaining wall sections and in
HCTP Retaining Wall Project CI 5444
March 14, 2023
5 4
3 certain areas the retaining wall has started to fail. Due to the special expertise required for retaining wall design, staff solicited proposals from engineering consulting firms to design and engineer the project scope of work, including removal and replacement of approximately 540 feet of existing retaining wall.
On May 12, 2020, City Council approved an agreement with m6 Consulting, Inc., (m6) of Westlake Village, CA, in the amount of $79,690 to perform engineering design services and preparation of construction contract documents for the Retaining Wall Project. Five amendments were issued to m6 during the project. Amendments No. 1 and No. 4 were contract time extensions. Amendments No. 2 through 5 covered additional scope of work associated with performing additional exploratory investigation to uncover existing utilities in the vicinity of the proposed improvements and for construction phase services. This brought the total agreement to $239,831.
The project plans and specifications were completed by m6 in December 2021, and the project was bid for construction in February 2022. On March 29, 2022, City Council approved a construction contract in the amount of $1,274,213, plus contingency of $127,421, with GMZ Engineering, Inc. (GMZ), of Westlake Village, CA for the construction of the retaining wall.
DISCUSSION/ANALYSIS:
The project is in the final closeout stages, to be finished by the end of March 2023. Unforeseen issues were encountered during the final stages of construction, such as utility conflicts and grade changes which led to extra construction time in the field during the months of December, January, and February. In addition, the final construction means and methods utilized by the construction contractor have alternative constructability approaches that entail extra field time for the placement of the piles and backfill of the retaining wall. As a result, additional consulting support services from m6 are required to complete the project, including additional construction inspection, engineering support, oversight, and materials testing. m6 will continue to provide support to the City until the project is closed out, which requires the additional funding requested herein.
Staff recommends City Council approve the Sixth and final Amendment to the Professional Services Agreement with m6 in the amount of $42,365 for these additional construction phase services (Attachment #2). m6 - Design Phase Services (previously approved) $ 79,690 Extra Design Services (previously approved) $ 7,791 Construction Period Engineering Support (previously approved) $ 152,350 Additional Construction Phase Services (this action) $ 42,365 Design and Engineering – Subtotal $ 282,196 HCTP Retaining Wall Project CI 5444
March 14, 2023
5 4
3 Community Outreach: Project work is limited to the HCTP and does not impact neighboring residences. The work will be at the north end of the plant and will have limited impact to plant operation. Construction-related impacts to hiking trail users will be minimal.
As part of the design efforts on the project, the Consultant prepared a Categorical Exemption memorandum in accordance with the California Environmental Quality Act (CEQA) guidelines per sections 14 CCR § 15301, 15302 and 15304. A Notice of Exemption (NOE) was prepared, and City staff had the document recorded by the County of Ventura in September 2021.
This project meets City Council’s Top Ten Priorities #9, “Public Works Infrastructure Investments.”
CIP PROJECT PRIORITY (as outlined in FY 2021-23 CIP Program Budget) Priority Two – Necessary, but not essential, and there could be consequences if deferred.
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: Nader Heydari, Deputy Public Works Director Attachments:
Attachment #1 – Vicinity and Location Maps
Attachment #2 – Sixth Amendment with m6 Consulting, Inc.
DPW: 850-20\ev\nh\etm\Council\2023\031423\CI 5444\ HCTP Retaining Wall staff report.docx