April 15, 2025, Item #11
AGENDA REPORT CityofPoway
DATE:
TO:
FROM:
CONTACT:
SUBJECT:
Summary:
April 15, 2025
Honorable Mayor and Members of the City Council
Eric Heidemann, Director of Public Works
Robert Weber, Principal Civil Engineer, Public Works -Utilities (858) 668-4717 or [email protected]
Water Infrastructure Improvement Program Update
CITY COUNCIL
This report presents a background and status update on the Water Infrastructure Improvement Program and the associated individual projects, their status, and a look ahead of upcoming activities.
Discussion:
With the goal of increasing the reliability of drinking water for water customers now and for generations to come, the City of Poway (City) is undertaking its largest capital improvement program in the City's history, referred to as the Water Infrastructure Improvement Program (Program). The Program was presented to the City Council as an informational item, to provide updates and to request approval of the various components on March 18, 2020; June 16, 2020; October 20, 2020; November 17, 2020; March 16, 2021; April 20, 2021; June 1, 2021; July 20, 2021; August 17, 2021; April 5, 2022; October 18, 2022; February 7, 2023; May 16, 2023; August 15, 2023; September 19, 2023; and November 19, 2024. A comprehensive summary of the project background and status. including photos and recent time lapse construction video can be found on the project webpage:
https://poway.org/water-projects.
Program Overview
Poway inherited its water distribution system when it became a city in 1980. Safety standards have evolved over time and while the city conscientiously budgeted for water infrastructure improvements, this Program addresses key improvements identified in a mutual agreement with the State of California Water Resources Control Board Division of Drinking Water (DDW). It includes the following three projects:
Phase I -Clearwell Bypass Project
The Clearwell Bypass Project consists of temporary and permanent bypass pipelines, a temporary pump station, a pressure regulating station and two temporary bypass tanks. Each tank has a storage capacity of 1.4 million gallons (MG). The bypass pipelines, pump station and pressure control facility are located within City property at the Lester J. Berglund Water Treatment Plant (Berglund WTP) site, 1 of 10
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as well as the Public Works Operations Yard and parking lot. The two temporary tanks are located on the softball field at Lake Poway Park. This bypass system allows the Clearwell to be taken offline for replacement.
Phase II -Clearwell Replacement Project
The Clearwell Replacement Project consists of replacing the existing lined and covered embankment style Clearwell with two new 4-million-gallon prestressed concrete tanks. The existing Clearwell had reached the end of its useful life and needed replacement to maintain reliable service to Poway residents. The overflow structure of the Clearwell will also be replaced with a new structure designed with industry standard air gaps.
Phase Ill -Treated Water Facilities Project
The Treated Water Facilities Project provides Poway with its first treated water connection and is a cooperative project with the Ramona Municipal Water District (Ramona). The project includes flow bifurcation control valves, a pump station, forebay and a transmission pipeline providing redundancy to the existing single transmission pipeline on Lake Poway Road.
Completed Activities and Current Status
The following is a summary of completed activities and status of each project:
Phase I -Clearwell Bypass Project
The first project in the Program, the Clearwell Bypass Project, is an enabling project for subsequent phases of work. A project overview map is provided as Figure 1. The original Clearwell was an embankment style lined and covered facility originally constructed in 1964. There was no means of bypassing the facility to construct the replacement Clearwell, hence, construction of the bypass project, consisting of above and below ground pipelines, a temporary pump station, a temporary pressure regulating station and two temporary bolted-steel tanks was completed in September 2022.
The project includes a permanent 36-inch diameter cement mortar lined and coated (CML&C) steel bypass pipeline, a temporary pump station to pump water up to the two 1.4 MG temporary tanks, temporary 24-inch diameter bypass piping and a pressure control facility. The bypass system operates by sending treated water through the permanent bypass pipeline to both the distribution system and the temporary pump station from where the temporary tanks are filled, and water is then drawn out of the temporary tanks through the pressure control facility and out into the distribution system in response to demand. System Operators at Berglund WTP control the overall rate of flow through the bypass to mimic the deeper volumetric fill and draw cycles that were performed by the original Clearwell. The bypass system was tested and has been successfully operating since November 2022. This infrastructure enables bypassing the existing Clearwell and facilitated taking it offline for replacement. The Clearwell Bypass Project was completed under budget.
Phase II -Clearwell Replacement Project
The Clearwell Replacement Project is replacing the former Clearwell with two 4 MG circular prestressed concrete tanks. A project overview map is provided as Figure 2. The dual tanks provide redundancy and operational flexibility, allowing one tank to be taken offline for future maintenance and repairs while the other provides continuous, uninterrupted service. The prestressed concrete tanks also provide superior seismic performance and a longer asset life of approximately 75 years.
With this project, the overflow structures will also be constructed with physically separated air gaps, in accordance with the agreement with DOW. This phase of work began in January 2024 with demolition of the existing Clearwell, demolition and removal of conflicting sections of old pipe, mass 2 of 10
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grading and earthwork along with soil processing for subsequent onsite reuse of material, realignment of two large diameter storm drains outside the footprint of the new Clearwell tanks, construction of site retaining walls, construction of a new drain vault and outlet control valve vault, installation of new CML&C steel pipe, subgrade preparation and liner installation, and concrete tank construction. The Clearwell Replacement project is approximately 50% complete and recently reached a significant milestone with initiation of concrete placement for the North Tank floor and walls. Challenges during the project included weather delays in early 2024 and 2025 and the presence of rock throughout the site. However, the project is currently on schedule for commissioning in late Spring of 2026.
Phase Ill -Treated Water Facilities Project
The Treated Water Facilities (TWF) Project will provide Poway with its first treated water supply. A project overview map is provided as Figure 3. The TWF project will fulfill two important reliability and redundancy principles: (1) provide a secondary source of drinking water to the City in the event of either an interruption to the untreated supply or unplanned outage at Berglund WTP, and (2) allow for planned outages at the Berglund WTP to facilitate maintenance and rehabilitation work. Future maintenance and rehabilitation work at Berglund WTP is not currently within the scope of the Program and the TWF project is an important enabling project toward this goal.
The TWF project was originally conceptualized as a new Flow Control Facility (FCF) connected to the San Diego County Water Authority (SDCWA) Ramona Pipeline, which terminates on Espola Road near the Blue Sky Ecological Preserve, a new treated water pipeline on Espola and Lake Poway Roads, and a forebay and pump station on Lake Poway Road. A new pump station is needed to boost pressure from the pressure available in the Ramona Pipeline to the elevation of the new Clearwells. During design it was determined the projected cost of this project configuration was prohibitively high; which prompted staff, the Program Manager, and the Design Consultant to review other options.
In parallel with the determination of the prohibitively high cost of the original TWF project configuration, staff learned that the SDCWA 2024 Master Plan was considering the possibility of converting one of its two existing untreated water pipelines that run through Poway to a treated water pipeline. Had this conversion occurred, the need for new facilities to be constructed for the TWF project would have been significantly reduced. Unfortunately, the SDCWA did not advance this project in their 2024 Master Plan due to water quality degradation concerns.
Staff, the Program Manager, and Design Consultant developed a new TWF project configuration that maximizes use of existing facilities by constructing a connection to the Ramona system immediately downstream of the existing RAM-3 Flow Control Facility (Figure 3) and using existing Ramona and Poway pipelines to deliver SDCWA treated water to the new Clearwell. These existing pipelines were originally constructed so Poway could provide Ramona with an emergency source of treated water from the Berglund WTP during short term outages on the SDCWA treated water system. The proposed TWF project will construct facilities to enable flow of treated water from the SDCWA Ramona pipeline to Poway during times when Poway needs treated water (i.e., when the Berglund WTP is off-line for maintenance or in an emergency) and from Poway to Ramona (i.e., when the SDCWA system is down for maintenance or when Ramona desires to purchase water from Poway). The project includes pipeline modifications, the new forebay and pump station on Lake Poway Road, and a redundant treated water pipeline between the new pump station and the new Clearwells. A Memorandum of Understanding (MOU) with Ramona which sets forth the framework to cooperate during project design was approved by the Council on November 19, 2024. The TWF project is currently on schedule; 3 of 10
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the next steps over the coming months will include negotiating a water exchange agreement with Ramona and final design and environmental compliance.
Related Projects -Interconnections with the City of San Diego In accordance with the City's agreement with DOW, two treated water interconnections to the City of San Diego's system will be constructed. Emergency Interconnection No. 1 will be located on Avenida La Valencia at the Bridle Trail near Pomerado Road and Emergency Interconnection No. 2 will be located on Poway Road from Springhurst Drive in San Diego to Francine Terrace in Poway. Project overview maps are provided as Figures 4 and 5, respectively. These projects, together with the TWF project, will provide treated water in the event of an unplanned outage affecting Berglund WTP.
Emergency Interconnection No. 1 is currently in the design phase and Emergency Interconnection No. 2 will begin design later in 2025.
Next Steps/Look Ahead:
The Program will continue with construction of the Clearwell Replacement Project over the remainder of 2025 and into early 2026. Commissioning the new Clearwell is anticipated in late Spring of 2026 and decommissioning of the bypass and restoration of the Lake Poway softball fields by Fall 2026.
Design and environmental compliance for the TWF project will continue and is anticipated to conclude in late 2025. Design of both emergency interconnections with the City of San Diego will be performed in 2025 into early 2026. Staff will continue to keep the City Council informed of project status and developments.
Recommended Action:
This is an informational item and there is no recommended action.
Environmental Review:
This action is not subject to review under the California Environmental Quality Act (CEQA).
Fiscal Impact:
None.
Public Notification:
None.
Attachments:
Figure 1 -Clearwell Bypass Project
Figure 2 -Clearwell Replacement Project
Figure 3 -Treated Water Facilities Project
Figure 4 -Emergency Interconnection No. 1
Figure 5 -Emergency Interconnection No. 2
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Reviewed/Approved By:
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Assistant City Manager
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Reviewed By:
Alan Fenstermacher
City Attorney
Approved By:
Chris Hazeltine
City Manager
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I Existing J
(clearwell
Temporary Pressure
Control Valves
FIGURE 1
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Existing Water Pipeline
Existing Storm Drain
• • • • • • Proposed Buried Water Pipeline
Proposed Above•Ground Water Pipeline
Proposed Above•Ground Overflow Pipeline
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FIGURE 2
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FIGURE 2 -CLEARWELL REPLACEMENT PROJECT
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FIGURE
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FIGURE
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EMERGENCY
INTERCONNECTION
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FIGURE 5
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