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100 <br />SEWER RATE STUDY I City of Santa Ana, CA <br />Figure B- 26: Pipeline Length by Number of Upstream Customer Laterals <br />Proximity to Critical Customers <br />The concern here is for increased risk due to possible environmental and inconvenience to nearby <br />critical customers. The City provided tabular lists of critical customer locations, including hospitals, <br />government facilities, and schools. Locations were geocoded by address data (if actual street addresses <br />were available) to identify the customer's location on a map. Using GIS spatial processes, all mains <br />within a 300 foot radius of each critical site was tagged. A count of nearby sites was then tabulated for <br />each main segment. The resulting values ranged between 0 and 2 occurrences. These values were then <br />multiplied by 5 to get the desired 0 — 10 range. Only approximately 10 percent of main segments were <br />within 300 feet of a critical customer. Note, other methods could be used to identify the impact of <br />nearby critical customers. However, based on the source data available, this approach was the most <br />logical. <br />Other CoF Criteria <br />Other CoF criteria have been used in assessments like this: such as proximity to major roads, water <br />intake sources, industry / business; public health and safety concerns; reputational damage; or other <br />financial impacts. Several of these were discussed at a risk workshop with the City. However, due to <br />limited source data available and /or schedule, these additional considerations were outside the scope of <br />this assessment. <br />Overall CoF Calculation <br />To produce an overall CoF score for individual pipe segments, weighted scores for each of the <br />contributing CoF criteria were added together. The resulting CoF scores are, by design, within the range <br />of 0 to 10. Because the Proximity to Critical Customers criteria was considered to be less important than <br />the other two criteria, it received a lower weighting. Therefore, the Pipe Diameter and Customer Impact <br />criteria were weighted at 42% each and the Critical Customer count was weighted at 16 %. By adjusting <br />these weights other assessment scenarios could be created. Table B 3 provides a summary of the CoF <br />criteria used in this analysis. <br />65B -259 <br />IM01TAI ,JIT— aw. 6m <br />