CITY COUNCIL MEETING AGENDA PACKET

City of Pleasanton, CA (0012108.00) 2-5 Woodard & Curran, Inc. Pleasanton Long-Term Sewer CIP October 6, 2025 projects were included from the Energy Master Plan in the long-term CIP, but these costs were assumed to be included as part of the mid- and long-term lift station rehabilitation work. 2.6 Generator Report (TJC) A separate generator report was prepared for the City in addition to the sewer lift station condition assessment. The goal of the report was to identify which pump/lift stations (including water, sewer, and storm) were most critical to the City and, in turn, recommend a reliable backup power source based on each asset’s priority. Priority was based on system importance with the most critical assets receiving a recommendation for stationary generators located at the lift stations to allow the station to run even if power was lost for up to 24 hours. Less robust systems were recommended for less critical assets. Costs for these upgrades to the sewer and storm drain lift station are included in the CIP (water pump station generator upgrades are captured in the water system long-term CIP). 2.7 Future Evaluation Efforts While the physical condition of most gravity sewers can be determined with standard CCTV inspections, several asset types require special considerations/techniques to determine their condition. This section presents several proposed methods for the condition assessment of large diameter trunk sewer pipelines, siphons, and force mains. Although these assets account for a small overall percentage of the system, their operation is critical to maintaining the City’s current level of service. 2.7.1 Large Diameter Trunk Sewer Condition Assessment The City does not currently have CCTV inspection data for their trunk sewers (considered to be any gravity sewer larger than 15 inches). These pipes are primarily located upstream of EALS, LS -8, and LS-6. Trunk sewers are typically more difficult to inspect than smaller diameter gravity sewers due to higher flow levels in the pipe. The additional flow can obscure view of the pipe wall, potentially causing inspection to miss defects in the pipe. Other issues include potential debris buildup in the pipe as grease and sediment deposit along the trunk line. In order to inspect these pipes, it is recommended that trunk sewers be inspected during nighttime hours, when the flow levels in the pipes are lowest, approximately 25 to 50 percent full based on hydraulic modeling results. During lower flow conditions like this, standard CCTV equipment could be used, and no flow bypass or flow plugs would be required. If significant flow or debris is present in the pipe, optional sonar measurements could be used to get a sense of the level of debris and condition under the water surface if pre-cleaning cannot remove the debris. Additionally, sewer trunk manholes are recommended for detailed inspection. Sewer trunk manholes are generally more prone to failure from Microbiologically Induced Corrosion (MIC) than typical gravity sewer manholes due to the higher likelihood of hydrogen sulfide present in trunk sewers compared to typical small diameter gravity sewers. Surface level visual observation could be used to inspect the manholes walls as part of this assessment. However, surface level inspection often provides limited information on the condition of the concrete in the lower sections of the trunk manholes where corrosion is more likely to be visible. Therefore, a more detailed man-entry or televised inspection is recommen ded, especially if MIC is noted in the pipe or manhole. It is recommended that a manhole inspection based on NASSO Manhole Assessment Certification Program (MACP) level 2 inspection be performed along the trunk sewer if manhole corrosion is a concern. Page 224 of 323