Summary of Project Planning Guidelines for Basin Sample Clauses

Summary of Project Planning Guidelines for Basin. Groups 2, 3, and 4 The City is currently in the process of revising the project planning guidelines for Basin Groups 2, 3, and 4. Each Basin Group has been analyzed separately to determine the types of risk categories that most accurately identify reaches with elevated sewer overflow risk categories in each Basin Group. Analysis of sewer overflows in these Basin Groups has shown that the risk categories listed in Table 2-5 are the most effective at predicting the risk of sewer overflows within these basins. These risk categories were developed by analyzing CCTV data, age, material, and maintenance data to isolate factors that indicate elevated sewer overflow risk. Table 2-6 summarizes the Spill Factor for each risk category in each basin group. A Spill Factor greater than 1 indicates that the group of reaches has an above average risk of sewer overflows. Table 2-5. Definitions of Risk Categories for Basin Groups 2, 3, and 4 Risk Category Definitions of Risk Category Metal > 30 Years Cast Iron, Ductile Iron, or Steel pipe greater than 30 years old. “D” or worse Reaches with a Condition Ranking “D” or “E”. Major Defects Reaches that have at least one major defect. Major defects are primarily structural defects and include:  Severe bends, sags, and pipe deformation  All defects indicating missing pipe, broken pipe/joints, collapsed pipe, fractures, or large holes in the pipe  Open joints and severe offset joints  Severe corrosion  Severe infiltration  Severe protruding laterals Severe Roots Reaches that have at least one severe root defect in the pipe or at a joint. > 50% Medium Roots Reaches with medium roots defects in the pipe or at joints along more than 50 percent of the total reach length. Obsolete Structures1 Reaches that include terminal lampholes, clean-outs, non-operational flush tank mechanisms, chimney risers, or 6-inch drop connections.