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<br />Seismic Vulnerability Study <br /> <br />cast iron pipe substantially increase once the pipe hits 75-years to IOO-years of age? <br />There have been a number of technical studies of this sort in the industry, and to date, the <br />data does not indicate such a rapid change in leak rates. <br /> <br />504. For each pipe in the Redwood City system (as identified using the GIS ObjectID), we <br />will perform a benefit cost analysis ranking for pipe replacement. This will be prepared in <br />a software package that can be provided to Redwood City so that Redwood City can use <br />the software for its own purposes. The model will include the following factors: <br /> <br />. Cost to make repairs <br /> <br />. Cost to replace pipelines (in grouped areas) <br /> <br />· Locations of isolation valves (distances between) and number of customers <br />affected by outages due to leak <br /> <br />. Implied costs to residents due to leak repair (road closures, detours, etc.) <br /> <br />· Implied costs to customers due to water outages during the time needed to make <br />the leak repair <br /> <br />. Loss of revenue due to lost water <br /> <br />. Concurrence with BMPs (best management practices) <br /> <br />. Cost of capital <br /> <br />· Lifetime of existing or replacement pipes (which these may be long, they must be <br />considered for a complete lifetime analysis) <br /> <br />5.5 Using the model from Task 504, we will provide a benefit cost ratio for every pipe in <br />the Redwood City system. The results from the seismic analyses (Task 2) will be factored <br />into this model, in order to develop a more comprehensive BCR for each pipe. For <br />example, the BCR 9seismic alone) might be 004 (not worthy for upgrade), and the BCR <br />from leak-prevention might be 0.7 (not worthy for upgrade), but the combined BCR <br />would be 1.1 (assuming for this case that costs are the same), and thus worthy for pipe <br />replacement. <br /> <br />U sing these BCRs, all pipes can be ranked into a long term pipe replacement program, by <br />relative need. We will develop maps (in ArcGIS) that show the ranking of upgrade for <br />each pipe, suitably color coded to reflect ranking. We estimate that there will be about <br />12,000 pipe segments included in the analyses, using the data from the existing Redwood <br />City GIS for the pipe system. We will make recommendations as to how to group the <br />pipes into logical work packages. It is understood that WAY will develop the ultimate <br />selection of the upgrades, which in part will depend upon the annual capital budget for <br />Redwood City, as well as other upgrades that might be suitable for the water system <br />(seismic, fire flows, build out, etc.) <br /> <br />We will write a report with all findings and electronic databases and software. We will <br />provide to RWC (and WAY as suitable) the electronic databases and results. Depending <br /> <br />October 9, 2009 Page 8 <br />