AgdaPkt 2004-01-26 - Laserfiche WebLink

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, - ._.....~..,._=.,..'""''''''. .__""""e~~'''>''', ~",..;.", 5. \ c-- 2>4 It I I ES.3 Aftema~es Development and Evaluation Eight preliminary alteml.lives ware developed for hydrauDc analysis. The eight altematlves I encompass a full range of possible systemconflm.ntions. so different levels of service to the 1hree geographical areas and aJStomer priOrity \evel$COIJld be investigated. In addition, both centralized and decentralized storageand pumping options were included to Investigate the . eost..effectiveness of different system configurations. The altematlves ranged from small systems (Priority 1 and 2 customen; in RedWl)od Shores only) to aty,.wide systems (Priority 1. 2. and 3 customers In all threl!Jg&Qgfllphical areas) providing a range of new water supply from I just, over 1,100 AF/yr up to approximately 3.172 AF/yr. Preliminary eslImales of capilal.c:;osts and cost effectiveness (~ per 8C78-foot of water I delivered) were developed for the eight pI9llmlnary alternatives based on pipeline slz&s and lengths, storage andpwnplng capacity, treatment costs,and&tandby connections. The conclusions drawn from 1he prellmInary ,alternatives analysis areas follows: I . The cost effeetiveJle$S of CIty-wlde altematives,lhat serve ooly Priority 1 and 2 customers tends to be ITIUCh lower than for atIematives that Indude Priority 3 customers. When the Priority 3 customers are added to CIty-wide distribution sy$tems, the cost- I effeetivenesslncreases by about 35%. This1s because Prlority3 custometsmake up a lal'98 percentage of total potential recycled water demand.outskIe the ~ Shores. and 1tle transmission pipeline system becomes more cost-efficient When the Prlority 3 I customer demands are included.' Preliminary altematlves with centralized ston:Jge and pumping at SBSA are more cost . I effective than tile altematives with decentralized storage and pumping. The cost required for decentralized pump stations Is greater than the cost savings realized by reduced pipeftne slzas In the transmission system. I . In an attempt to Improve cost-effectiveness of a CI~-wide project While maintaining a substantial recycled water supply, fine-tuning was performed by eflminating distribution pipeUnes to customers that appeared to be relatively expensive on a cost per AF/yr I delivered basis. A slight Improvement In cost effectivel'le$s was realized in this fine- tuning. I' Based on the results of the prenmlnaryaltematives evaluation. final alternatives were developed to meet the range of the City's projecte<S water supply need$, while providing the best value and preserving flexibility for future system growth and expansion. AD of the finalaltematives , included some level of service to Priority 3 customers. The four F"lI1al Alternatlves A through D are summarlzed In Figures ES-1 through ES-4. To preserve t1exlbility for future expansion of the recycled water system, the transmission pipelines are sized under each final alternative to 1\ serve aU of the Priority 1, 2, and 3 customers In each of the three geographical areas (as in Alternative B). I ES.4 Recommended Project Based on an evaluation of cost-effectiveness, water supply, and future f1eldblllty considerations, I Project Alternative D Is recommendad to the CIty for use in project planning and I Water RscycJ1ng Feaslbmty Study for Redwood CIty vi ,'""""",,,,,,,,,,"'"