Consideration and Approval of Contract: Cooperative Purchase Contract with Garver, LLC for Wildcat Hill Wastewater System Professional Engineering Services in the amount of $656,067.60.

1. Approve the Cooperative Purchase Contract with Garver, LLC for Wildcat Hill Wastewater System Professional Engineering Services in the amount of $656,067.60; and
2. Authorize the City Manager to execute the necessary documents.

To address the needs of aging infrastructure at the Wildcat Hill Water Reclamation Plant, the voters approved the construction of a new Primary Effluent Pump Station (PEPS) in November of 2022. Garver, LLC prepared conceptual designs and construction documents that were finalized in May of 2022 for the new PEPS. This Cooperative Purchase Contract is for Professional Engineering Services that will advance the PEPS project.

This project and contract is funded through Water Services Capital Improvement Fund – Account #410-08-375-3443-3-4466 with a budget in FY2023-24 of $2,500,000, which leaves a remaining fund balance of $1,913,556.90.

Priority Based Budget Key Community Priorities and Objectives Carbon Neutrality Plan
Regional Plan

• June 20, 2023, Council approved the FY 24 Capital Improvement Plan, including the Wildcat Pumps Project.
• October 17, 2022 Joint City/County Work Session on Props 441 & 442.
• September 29, 2022 Council Retreat.
• August 23, 2022 City Council meeting on bond outreach plan for Props 441 & 442.
• June 7, 2022 City Council meeting.
• April 26, 2022 City Council meeting.
• November 2, 2021 City Council meeting.

1. Approve the Cooperative Purchase Contract with Garver, LLC for Wildcat Hill Wastewater System Professional Engineering Services in the amount of $656,067.60, as recommended; or
2. Do not approve the Cooperative Purchase Contract, direct staff to solicit design services through a Request for Statements Of Qualifications procurement. This alternative is not recommended, as it would add 6-12 months to the construction schedule; or
3. Do not approve the Cooperative Purchase Contract and continue to use the existing pump station at the Wildcat Hill Water Reclamation Plant. This alternative is not recommended, as the existing pump station is degrading and is close to or already has reached its useful life.

The Wildcat Hill Water Reclamation Plant was constructed as a trickling filter facility in 1976. The Primary Effluent Pump Station was constructed in 1980 as part of a plant expansion project and were originally designed to pump to biofilters. With the construction of the integrated fixed-film activated sludge process in 2007, the yard piping configuration was modified to redirect flow to the new treatment process using the existing pumps. The existing pumps in the lift station were installed in 2001.
 
In April of 2018, the City worked with Garver, LLC to complete a Wildcat Hill Primary Effluent Pump Station Improvement Evaluation to investigate alternatives to improving the reliability and operational flexibility of the PEPS including replacement of equipment in kind, and conversion to a submersible pump station. Garver, LLC has prepared a report and established the design basis and requirements necessary to complete improvements to the PEPS, including structural and building mechanical modifications.
 
To evaluate the efficiency of these modifications under current conditions, a system curve was developed and compared to pump curves provided for the existing pumps. Multiple pump curves were produced to analyze pump performance against system head. The pump efficiency is approximately 84% during high flow conditions but drops to approximately 32% during more typical low flow conditions. The original pump curves indicate that the existing configuration is capable of operating with one pump in standby as originally intended, but actual current field conditions require that all pumps operate during high flow conditions.
 
On several instances the PEPS has failed to operate and allowed the wet well to overflow and flood the Wildcat Hill Water Reclamation Plant with the last instance occurring in August of 2016. In 2023, Wildcat Hill Water Reclamation Plant saw influent flows in excess of twelve (12) million gallons per day. This flow required the use of all PEPS pumps to move the flow through the facility and prevent facility flooding. In June 2023, one PEPS pump experienced catastrophic bearing failure causing an emergency repair to restore full pumping capacity. This pump rebuild was the third rebuild in the last three (3) years.
 
In 2022, the PEPS was identified as a critical need for upgrade. The City moved the replacement project funding source to a general obligation bond that was approved by voters in November of 2022. Water Services staff continued working with Garver, LLC on a preliminary design and project scope. This preliminary design was completed in the spring of 2023.
 
Staff is requesting approval of the Cooperative Purchase Contract with Garver, LLC for Engineering for Professional Engineering Services. The City of Avondale Procurement Department conducted a competitive and open procurement process through Request for Qualification Solicitation No. PW20-051 that resulted in Contract No. 20-204C with Garver, LLC. The City of Flagstaff Purchasing Section has verified the cooperative purchase contract as valid and appropriate, and presents the best value to the City.