CITY COUNCIL MEETING AGENDA PACKET

City of Pleasanton, CA (0012108.00) 2-6 Woodard & Curran, Inc. Pleasanton Long-Term Sewer CIP October 6, 2025 The City’s system also includes a large diameter trunk, the East Amador Relief Sewer (EARS), that is not currently in use but could be used as an alternative/in addition to the EALS trunk sewer and lift station if some modifications are made to the system. The EARS trunk could provide a backup flow path while rehabilitation work is performed on the EALS line (if required), or a new lift station could be installed to supplement the EALS trunk and lift station. Analysis of these alternatives will require inspection of the EARS line and additional hydraulic modeling to determine the project’s feasibility. An analysis of the EALS and EARS capacity and condition assessment has been added to the CIP. As part of this effort an optional predesign for EARS could be conducted if the EALS lift station and/or trunk are found to be in poor condition and extensive rehabilitation is required. For the long-term CIP, it is assumed a specialty CCTV contractor would be hired to perform the large diameter trunk sewer and manhole inspections. A follow-up condition assessment using the same methodology outlined in the Gravity Sewer Condition Assessment would be used to determine if any rehabilitation or replacement of trunk sewers or manholes was required. For the purposes of the long-term CIP, several segments of pipe rehabilitation of the trunk sewer were assumed. This placeholder cost represents either several pipe segment replacements or a pipe lining projects but these costs are not sufficient for extensive rehabilitation of the trunk mains if they are found to be in poor condition. Based on the findings of the future condition assessment, assumptions for trunk sewer rehabilitation costs will be revisited and updated as needed. 2.7.2 Sewer Siphon Condition Assessment The City does not currently have CCTV inspection data for any of its sewer siphons. Siphons are also more difficult to inspect than smaller diameter gravity sewers since they flow full during typical operation, requiring the siphon to be drained prior to CCTV inspection. Also, due to the geometry of siphons, siphons can accumulate significant amounts of debris, further complicating inspections. Some siphons may also not be possible to inspect if the access points and the geometry of the pipe make it impossible to start/recover the CCTV camera. In these cases, sonar data could be used to determine if defects are present in the pipe (although this data will not be in NASSCO PACP format). It is assumed that specialty CCTV contractors would be hired to perform all siphon inspections. Siphon inspections would need to occur at night while the system flows are lowest. The siphon would be plugged, dewatered, and inspected in a single night. A follow-up condition assessment using the same methodology outlined in the Gravity Sewer Condition Assessment would be used to determine if any rehabilitation or replacement of sewer siphons would be required. 2.7.3 Force Main Condition Assessment Similar to sewer siphons, inspecting force mains is typically challenging because they operate under full flow conditions and cannot easily be dewatered, making standard CCTV inspection infeasible. Additionally, access points are often limited, further complicating the inspection process. To address these issues and focus future condition assessment efforts, the City will also include an engineering evaluation as part of its long-term CIP process. The evaluation will first include a desktop assessment of th e force mains, which will include a review of pipe attributes (alignment, age, material, etc.), geotechnical conditions in the proximity of the force mains, pump cycling data, and break history. This analysis will help identify feasible and appropriate inspection methods for each force main. Page 225 of 323