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. _."~'. .... '.'''~'''''''~'' ,~,."_,."'~.'h .0:,_" ,. 5. I c.. - 34- I RWC Water Supply Rebbllft)' 3. Reliability: The Water Supply And Demand Balance Comparing the water supply data mown in Exhibit 1 with the demand data shown in Exlnoit 2, it is obvious that RWe is ina high risk, low reliability situation attbe moment. RWC bas one of the lowest levels of reliability oCthe BAWUA mcmbeB. I also believe RWe has one of the lowest levels of water supply reliability in NOrthern California, although obtaining accurate measures of reliability is difficult. As a consequence, I have not collected benchmarks for comparison at this time. The SFPUC water supply situation will remain unchanged until at least July 2G09 when the existing Master Water Sales Contract and BAWUA / SFPUe Interim Shortage AlIocation Plan expire and are renegotiated. It is difficult to predict the. outcome oftbe renegotiatiofl$, but it is unlikely that RWC will improve its water supply reliability from this source. 4. Selecting A Proper Level Of Reliability What is the appropriate level of reliability? There is no exact enginecringanswer, but rather the appropriate level is a judgment call dependent en the level of risk RWe is wilimgte take, and how much R we is willing to pay to minimize this risk. Exhibit 3 graphically shows how water supply reliability increases with water supply additions of 1.000 AFY for water con.servation and an additional 1,208 for water recycling (priority customers I and 2 in the Redwood Shores area identified by Kennedy/Jenks Consultants, Water Recycling Feasibility Study for Redwood City, August 2002). Focusing on scenario 3 (SFPUCcutback of 10%), RWC's cutback under current arrangements would be 17.5%. If 1,000 A:FY of additional supplies could be obtained via conservation, the cutback would be reduced to 12.4%. With 1,208 AFY of additional supplies ti:om recycling (2,208 MY total), the cutback would be a very manageable 6.3%. Readers should norethat the reliabilities presented are for existing water customers as of FY 2000/200 I. As shown in Exhihit2, water use is expected to grow 1,647 AFY over the next 20 years. The thirst of this new growth needs to be quenched ti:om new water supplies if the water reliability of existing customers is not to decay incrementally. Page 4