TO: ADAM PIRRIE, CITY MANAGER
FROM: MARIA B. TIPPING, CITY ENGINEER
DATE: OCTOBER 13, 2026
Reviewed by:
City Manager: AP
SUBJECT:
Title
AUTHORIZATION TO ENTER INTO AN AGREEMENT WITH AKM CONSULTING ENGINEERS FOR A SEWER MODEL UPDATE (FUNDING SOURCE: SEWER FUND)
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SUMMARY
The City’s existing sewer model was developed in 2015 by AKM Consulting Engineers. The sewer model was developed with the InfoSewer software by Innovyze, using sewer flow data collected in 2013. Innovyze is no longer updating or supporting the software. Therefore, gathering updated sewer flow data and transferring the City’s sewer system to supported software is necessary. An updated sewer model is necessary to continue to evaluate sewer capacity and identify potential deficiencies in the system.
City staff has been coordinating with AKM Consulting Engineers to prepare a scope of work and schedule for the necessary sewer updates. AKM Consulting Engineers, in coordination with ADS Environmental, will collect updated sewer flow data through a four-month monitoring process that includes installation of flow meters and rain gauges. AKM will also coordinate with Golden State Water Company to obtain water use data to develop accurate parcel-level sewer demand estimates.
The existing sewer model will be transferred to Aquatwin Sewer and will be updated to incorporate current City-owned sewer pipes and manholes, along with relevant infrastructure information. Known proposed developments will also be incorporated into the model to evaluate future sewer flow conditions. The updated model will provide the City with a current planning tool to assess existing and future system capacity and identify potential deficiencies within the sewer system.
RECOMMENDATION
Recommended Action
Staff recommends the City Council:
A. Authorize the City Manager to enter into an agreement with AKM Consulting Engineers for a Sewer Model Update in an amount not to exceed $372,269; and
B. Appropriate $22,269 from the Sewer Fund to fully fund the agreement.
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ALTERNATIVE TO RECOMMENDATION
In addition to the recommendation, there is the following alternative:
• Request additional information from staff.
FINANCIAL REVIEW
The cost of services performed under the agreement is $372,269. Funding of $350,000 was included in the Engineering Division’s 2026-28 operating budget. Staff recommends appropriating $22,269 from the Sewer Fund’s available fund balance to fully fund the agreement.
The staff cost to prepare this report and administer this contract is estimated at $1,184 and is included in the operating budget of the Community Development Department.
ANALYSIS
The City’s existing sewer model was developed in 2015 by AKM Consulting Engineers. Sewer flow monitoring data was collected in May 2013 and was used to develop the sewer model. The model was created using InfoSewer software by Innovyze, which is no longer being updated or supported. Therefore, in addition to updating the sewer flow monitoring data, updating the sewer modeling software is also necessary.
AKM Consulting Engineers will work with ADS Environmental, as a subconsultant, to install flow monitoring and rain gauge equipment to collect updated sewer flow and wet weather data. A four-month monitoring period is proposed to capture wet weather conditions in accordance with the Waste Discharge Order for Sanitary Sewer Systems WQ 2022-0103-DWQ, adopted by the State Water Resources Control Board (SWRCB). The Waste Discharge Order requires agencies to establish procedures to identify the appropriate hydraulic capacity of key system elements for wet weather events that may cause or contribute to sanitary sewer spill events. It also requires agencies to assess the capacity of systems subject to increased inflow resulting from larger or higher-intensity storm events. In addition to the flow monitoring data, AKM will work with Golden State Water Company to obtain water use data to calculate sewer loads for individual parcels and develop accurate sewer demand information.
AKM will transfer the information from the existing InfoSewer model into the Aquatwin Sewer software. The updated sewer model will include all City-owned sewer pipes (excluding private laterals and private lines) and sewer manholes. AKM will transfer the existing sewer pipe information into the updated model, including the following attributes: unique pipe labels, upstream and downstream manhole labels, pipe diameter, pipe length, upstream and downstream invert elevations, slope, installation year, and pipe material. Manhole information will include a unique label, diameter, and rim elevation.
Lastly, City staff will work with AKM to account for future sewer loads associated with known proposed developments throughout the City. These future loads will be incorporated into the model to develop future flow conditions and assist in identifying potential deficiencies within the City’s sewer infrastructure. A final summary report of the findings is anticipated to be completed by December 2027, with monthly updates provided to the City by AKM Consulting Engineers.
RELATIONSHIP TO CITY PLANNING DOCUMENTS
Staff has evaluated the agenda item in relationship to the City’s strategic and visioning documents and finds that it applies to the following City Planning Documents: General Plan and the 2026-28 Budget.
CEQA REVIEW
This item is not subject to environmental review under the California Environmental Quality Act (CEQA).
PUBLIC NOTICE PROCESS
The agenda and staff report for this item have been posted on the City website and distributed to interested parties. If you desire a copy, please contact the City Clerk’s Office.
Submitted by: Prepared by:
Maria B. Tipping, P.E. Jasmin Hurtado, P.E.
City Engineer Associate Engineer