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7. B. - Page 12 <br />Executive Summary <br />1! <br />B�tY �el� �r�ie <br />`wflj(RGO!/Kg 6 eOi[QaULCr(OK <br />Table ES -3. Summary of Recommended Seismic Improvement Programs <br />- .. ram Descriptio <br />Addresses the highest areas of seismic risk for low cost. This <br />$0.41VI program includes very small projects, such as <br />SIP -1 restraining and anchoring equipment. Due to the very high <br />$0.4 <br />benefit as compared to cost, this program is recommended <br />for implementation within the CIP timeframe. <br />Projects that continue to provide a benefit to cost ratio that is <br />greater than one. These programs include $1.71VI in <br />SIP -2 and SIP -3 <br />improvements at various pump stations and tanks, including <br />$1.7 <br />projects such as anchoring tanks, and pump station <br />equipment, and improving pump station structures. <br />Includes longer -term projects, would be desirable to address <br />seismic issues, but have a cost - benefit ratio less than 1. As a <br />SIP -4 <br />result, these projects are recommended for implementation <br />$0.1 <br />beyond the 20 -year CIP time frame. SIP -4 includes $0.11VI in <br />pump station improvement projects. <br />Total <br />$2.2 <br />The seismic analysis also identified major rehabilitation and replacement projects, including <br />rehabilitation of piles at Peninsula 1 and 2 Tanks, upgrades for Carson roof, and replacement of <br />Wilmington and Sequoia Tanks. These projects are addressed in the Pipeline and Facility <br />Renewal/Replacement Program. <br />The seismic analysis also found that pipelines in the Redwood Shores and Seaport Areas are <br />vulnerable during earthquakes. However, the BCR analysis indicated that preventative <br />replacement of these pipelines solely to address seismic issues would not be cost - effective. <br />ES.6.3 Pipeline and Facility Renewal /Replacement Evaluation <br />A replacement analysis was performed for pipelines using pipeline materials, age and leak <br />history to assess pipeline replacement needs. Other agency practices and American Water Works <br />Association (AWWA) guidelines were also evaluated. Benefit cost evaluations were performed <br />to compare the cost to continue to repair pipes as they age or to replace them. <br />Pipeline replacements were assembled into seven programs (PRP 1 through 7), two of which <br />would be implemented in the Master Plan timeframe, and five of which may include a small <br />portion of pipelines for replacement within the Master Plan timeframe, but are primarily <br />longer -term programs. Table ES -4 summarizes these programs. <br />A key conclusion of the analysis is that repair in lieu of replacement continues to be a <br />cost - effective strategy, based on current data. The analysis indicates that only a small number of <br />pipes with the highest leak history (3 to 4 leaks in the last 7 years) should be replaced. The <br />exception to this strategy is the recommended replacement of small (4 -inch and smaller) mains, <br />which present significantly reduced hydraulic capacity over time. The City should continue to <br />build its leak history database, and periodically review and tailor replacement needs accordingly. <br />WEST Y O S T ASSOCIATES ES -8 City of Redwood City <br />September 2011 Water System Master Plan <br />o\c\369\06-09-01 \wp\mp\05261 0_0ES <br />