Item 07 - Sewer System Management Plan 2025 Update

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y of Santa Ana Section 4: Operation and Maintenance Pro, 4.1.2 Storm Drain System The locations of all the storm water conveyance facilities are available to field crews as a separate GIS layer which can be overlaid with collection system mapping layers to reveal important relationships between the two systems. While not responsible for the O&M of the storm drain system, City O&M staff is trained to understand the storm drainage network to supplement spill response actions. 4.2 Preventive Operation and Maintenance Activities The City's sewer collection system Operations and Maintenance Program consists of critical proactive, preventive and corrective measures for the City's gravity sewer system and lift stations. The details of the City's O&M Program are summarized below with further detail and specific procedures set forth in the City's Sewer System Operations and Maintenance Manual. 4.2.1 Gravity Mains The City of Santa Ana cleans the majority of the sewer system on an 18-month cycle, and corresponding areas that are similar. However, the City does collect field observations and data during routine maintenance activities, which factor into maintenance frequencies. This utilization and analysis of field data allows the City to optimize maintenance activities throughout the sewer system. This process can result in more sections of gravity pipelines being cleaned less frequently than the traditional 18-month cycle. The City has identified areas of the collection system that require more frequent cleaning— known as enhanced maintenance locations (EMLs) — which are cleaned on a monthly or quarterly interval. EMLs include, but are not limited to, inverted siphons that run under flood control channels and commercial areas with a high density of food service establishments. The City executes the collection system maintenance program with two sewer cleaning trucks, each staffed with a two -man crew. The gravity mains within the City are divided into two discrete zones with one crew assigned to each zone. In general, the gravity mains are cleaned in a Northeast to Southwesterly direction, following the natural gravity flow of the sewer system. To control root growth within the sewer system, the City performs as -needed root control activities. The root control activities include the use of root -killing foam that is approved by the U.S. Environmental Protection Agency for this use. Closed-circuit television (CCTV) inspections are often used to evaluate the root growth and determine the appropriate mitigation measures for each stretch of impacted sewer mainlines. CCTV inspection of the City's entire sewer system was completed in 2022 to assess the system condition in detail. The City assigned each sewer segment one of six structural severity ratings established by the National Association of Sewer Service Companies (NASSCO) to classify the condition of sewer lines. Defect severity refers to the degree of damage or degradation, such as cracks, fractures, root intrusion, offsets, and FOG accumulation, in the sewer line. The rating ranges from Grade 5 for the most severe to Grade 0 for the least severe or no defect identified. Sewer maintenance activities are scheduled and tracked using the GIS-based computerized maintenance management system (CMMS). For each line segment cleaned, the maintenance crews complete a report detailing the date, time, location, and key observations during the maintenance activities. Field observations include assessment of the type (e.g., roots, FOG, debris) and quantity (e.g., light, medium, and heavy) of materials removed during the line cleaning process. These observations are analyzed and factor into determinations of maintenance frequency adjustments. Additionally, observations of "heavy" accumulation are prioritized for CCTV inspection and/or other source control actions. 2025 4-9