Item 07 - Sewer System Management Plan 2025 Update

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STATEWIDE SANITARY SEWER SYSTEMS GENERAL ORDER 2022-0103-DWQ • Identify and justify the amount (percentage) of its system for its condition to be assessed each year; • Prioritize the condition assessment of system areas that: o Hold a high level of environmental consequences if vulnerable to collapse, failure, blockage, capacity issues, or other system deficiencies; o Are located in or within the vicinity of surface waters, steep terrain, high groundwater elevations, and environmentally sensitive areas; o Are within the vicinity of a receiving water with a bacterial -related impairment on the most current Clean Water Act section 303(d) List; • Assess the system conditions using visual observations, video surveillance and/or other comparable system inspection methods; • Utilize observations/evidence of system conditions that may contribute to exiting of sewage from the system which can reasonably be expected to discharge into a water of the State; • Maintain documents and recordkeeping of system evaluation and condition assessment inspections and activities; and • Identify system assets vulnerable to direct and indirect impacts of climate change, including but not limited to: sea level rise; flooding and/or erosion due to increased storm volumes, frequency, and/or intensity; wildfires; and increased power disruptions. 8.2. Capacity Assessment and Design Criteria The Plan must include procedures to identify system components that are experiencing or contributing to spills caused by hydraulic deficiency and/or limited capacity, including procedures to identify the appropriate hydraulic capacity of key system elements for: • Dry -weather peak flow conditions that cause or contributes to spill events; • The appropriate design storm(s) or wet weather events that causes or contributes to spill events; • The capacity of key system components; and • Identify the major sources that contribute to the peak flows associated with sewer spills. The capacity assessment must consider: • Data from existing system condition assessments, system inspections, system audits, spill history, and other available information; • Capacity of flood -prone systems subject to increased infiltration and inflow, under normal local and regional storm conditions; ATTACHMENT D — SEWER SYSTEM MANAGEMENT PLAN REQUIRED ELEMENTS December 6, 2022 D - 8