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consideration soil conditions, existing underground utilities, high water tables or <br />excessive rock excavation. <br />The PIPE° computer model was used to rank each defect by priority number <br />(Appendix C). The priority number was determined by dividing the gallons of I/I <br />eliminated by the estimated rehabilitation cost. It should be emphasized that this <br />priority number is based on the amount of I/I observed or expected to enter <br />through the defect. Although structural defects may not currently contribute I/I, <br />and as such their priority number will be zero, they may impact the capacity of <br />existing lines and/or maintenance costs and are recommended to be included in an <br />overall rehabilitation program. <br />A prioritized ranking was determined for each individual manhole and line <br />segment based on the total I/I removed divided by the total rehabilitation cost for <br />that structure, assuming that all defects are repaired. Appendix B provides <br />prioritization of each manhole and line segment from the highest rank to the <br />lowest rank. Also, a prioritization of each manhole and line segment is included <br />based on the highest I/I removal to the lowest. <br />Presented for each identified problem is a method of rehabilitation and its <br />estimated cost (refer to the "Rehabilitation Methods and Costs", Table IV-2, page <br />IV-5). In addition, each defect in the priority number rankings (Appendix B and <br />C) can be identified in the field notes (Appendix E) by reference to the upstream <br />manhole number and sub-basin. <br />ADS Environmental Services, Inc. <br />IV-3 <br />