AgdaPkt 2003-09-08 - Laserfiche WebLink

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It - 4.1 C -3S I ES.3 Alternatives Development and Evaluation = preliminary attomadvss were developed for hydraulic; aradysis. The eight alternatives encompass a tuff range of passible system configundiom, so Miamn levels of service to the three geographical area and as;tomer priority levels could be Investigated. In addition, both centralized and decentralized storage and pumping options were Ixduded to investigate the 1 cost -Offectiveness Of ddfemd system configurations. The alternatives ranged from tenau systems (Priority 1 and 2 customers in Redwood Shores only) to City-wide systems (priority 1, 2, and 3 customers In all three geographical areas) Providing a range of now water supply from just over 1.100 AF/yr up to approximately 3.172 AP/yr. Preliminary estimates of capital Costs and Cost efladirarress (cost per ape -foot of water delivered) were developed for the eight preliminary aftematives based on pipeline sizes and ' lengths, storage and pumping capacity, treatment costs, and standby Connections. The conclusions drawn from the preliminary alternatives analysis are as follows. ' • The cost effectiveness of City -wide alternatives that serve only Priority 1 and 2 customers tends to be march laver than for altonativas that Include Priority 3 customers. When fie Priority 3 customers ers are added to City -wide distribution systems, the cost- effectiveness increases by about 3M This Is bei cruse Priority 3 customers male up a large percentage of total potential recycled water demand outside the Redwood Shores, and the transmission pipeline system becomes more post- efficlentwhen the Priority 3 ' customer demands are included. • Preliminary alternatives with centralized storage and pumping at SBSA are more cost ' effective than the alternatives with decentralized storage and pumping. The cost required for decentralized pump stations Is greater than the cost savings rearmed by reduced pipeline sizes In the transmission system. ' • In an attempt to Improve cost-effectiveness of a Cttyaeide project while maintaining a substantial recycled water supply, fine-tuning was performed by eliminating distribution pipelines to customers that appeared to be relatively expensive on a cost per AF/yr ■ delivered basis. A slight Improvement in cost eifectfvertess was realized in this fine- tuning. Based on the results of the preliminary alternatives evaluation, Mal attematives were developed to meet the range of the City's projected water supply treads, while providing the best value and preserving flexibility for future system growth and expansion. Ali of the final alternatives included some level of service to Priority 3 customers. The four Final Alternatives A through D are summarized in Figures ES-1 through ESA To preserve flexibility for future expansion of the recycled water system, the transmission pipelines are sized under each final aliemative to serve all of the Priority 1, Z and 3 customers in each of the three geographical areas (as in Alternative 8). ESA Recommended Project Based on an evaluation of cM -efrec mnen, view supply, and future flexibility considerations, Project Alternative D is recommended to the City for use In project planning and 1 1 Wafer Reeycfsxp Feasibility Study for Redwood City A'