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ES.3 Alternatives Development and Evaluation <br /> <br />Eight preliminary altemstJves were developed for hydraulic analysis. The eight alternatives <br />encompass a full range of possible system configurations, so different levels of service to the <br />three geographical areas and customer priority levels could be investigated. In addition, both <br />cantmlized and decentralized storage and pumping options were included to investigate the <br />cost-effectiveness of different system configurations. The altamatives ranged from small <br />systems (Priority I and 2 customers in Redwood Shores only) to City-wide systems (Priority 1, <br />2, and 3 customers in all three geographical areas) providing a range of new water supply from <br />just over 1,100 AF/yr up to approximately 3,172 AF/yr. <br /> <br />Preliminary estimates of capital costs and cost effectNeness (cost per acre-foot of watar <br />delivered) were developed for the eight preliminary altamatives based on pipeline sizes and <br /> storage pumping capacity, costs, and standby connections. The <br />lengths, <br /> and <br /> treatment <br />conclusions c~rawn from the preliminary alternatives analysis are as follows: <br /> <br /> · The cost effectiveness of City-wide alternatives that serve only Pdority 1 and 2 <br /> customers tends to be much lower than for alternatives that include Priority 3 customers. <br /> When the Priority 3 customers are added to City-wide distribution systems, the cost- <br /> effectiveness increases by about 35%. This is because Priority 3 customers make up a <br /> large percentage of total potential recycled water demand outside the Redwood Shores, <br /> and the transmission pipeline system becomes mare cost-efficient when the Priority 3 <br /> customer demands are included.' <br /> <br /> · Preliminary altematives with centralized storage and pumping at SBSA ara more cost <br /> effective than the alternatives with decentralized storage and pumping. The cost <br /> required pump stations is greater than the cost savings realized by <br /> for <br /> decentralized <br /> reduced pipeline sizes in the transmission system. <br /> <br /> · In an attempt to improve cost-effectiveness of a City-wide project while <br /> maintaining <br /> e <br /> substantial recycled water supply, fine-tuning was performed by eliminating distribution <br /> pipelines to customers that appeared to be relatively expensive on a cost par AF/yr <br /> delivered basis. A slight improvement in cost effectiveness was realized in this fine- <br /> tuning. <br /> <br />Based on the results of the preliminary altematives evaluation, final alternatives were developed <br />to meet the range of the City's projected water supply needs, while providing the best value and <br />prese~ng flexibility for future system growth and expansion. NI of the final alternatives <br />included soma level of service to Priority 3 customers. The four Final Altemafives A through D <br />are summarized in Figures ES-1 through ES-4. To preserve flexibility for future expansion of <br />the recycled water system, the transmission pipelines ara sized under each final altamative to <br />serve all of the Priority 1, 2, and 3 customers in each of the three geographical areas (as in <br />Alternative r~). <br /> <br />ES.4 Recommended Project <br /> <br />Based on an evaluation of cost-effectiveness, water supply, and future fiexlbllity considerations, <br />Project Alternative D is recommended to the City for use in project planning and <br /> <br />Water Recycling Feasibility Study for Redwood City vi <br /> <br /> <br />