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Redwood City Sanitary Sewer Master Plan Executive Summary FINAL August 2008 6 Project Priorities and Flow Confirmation Levels Table ES-1 also indicates project priorities and flow confirmation levels. The recommended projects were divided into four priority groups based on the relative magnitude of predicted capacity deficiencies under existing conditions. The priorities range from Priority 1 – the highest priority – which means the model predicts an overflow, to Priority 4 – the lowest priority – which means the project was not needed under existing conditions. The recommended projects were likewise assigned a flow confirmation level, which indicates the relative level of confidence in the model predictions based on actual flow monitoring data. Flow confirmation level 1 represents the highest level of confidence in the model predictions. This confirmation level means that a flow meter located along the project reach surcharged during a metered storm, effectively providing field confirmation that a project is needed in the area. The lowest confirmation level, level 3, indicates that there was no flow meter on the project reach. Project Implementation Recommendations The City should begin implementation of the Capital Improvement Program recommended in this Master Plan, starting with the highest priority projects. This plan does not specify an implementation schedule, as the City will need to balance sewer improvements with the need for other capital projects. The following items should be considered in project scheduling and design, and in future updates of the Master Plan. Move forward with further planning and design of the Priority 1 projects. Flow monitoring should be performed to verify the modeled flows and capacity deficiencies unless adequate monitoring has already been performed in the vicinity. Further planning or pre-design work should include consideration of alternative routes for new sewers. The potential for combining projects 8, 10, 11, and 12 should be reviewed to avoid building multiple projects in the same area and to identify more cost-effective solutions. The alignments and sizes of all recommended projects should be verified with detailed predesign analyses, including topographic surveys, geotechnical investigations, utility research, and constructability reviews. All projects detailed in this report are based on pipe replacement. The decision to parallel or replace existing sewers should consider the physical condition and remaining useful life of the existing pipelines; the availability of pipeline corridors for new sewer construction; and operation and maintenance concerns. The hydraulic model has been developed to assist the City in performing capacity analyses and updating the Master Plan in the future. The model should be kept up-to-date with any changes to existing sewer connections, development plans, and sewer system facilities. The City should continue with the current sewer inspection and condition assessment program, identifying sewers that should be replaced due to poor condition. To the extent possible, these improvements should be coordinated with the recommended capacity-related improvements. Additional field investigation, such as smoke testing, should be conducted in high I/I areas to identify possible opportunities for I/I reduction. Chapter 7 includes additional information and recommendations regarding I/I reduction. The City should assess its connection fees and evaluate financial alternatives to fund the recommended capacity assessment CIP. In addition to the project implementation recommendations listed above, the City should continue to address I/I through continued CCTV inspection and rehabilitation of sewer mains and lower laterals. Additionally, since a significant amount of I/I is thought to enter collection systems through private laterals, the City should explore the possibility of implementing a private lateral compliance program that 6.2.A. - Page 222