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· RWC Water Supply Reliability <br /> <br /> 3. Reliability: The Water Supply And Demand Balance <br /> <br /> Comparing the water supply data shown in Exhibit 1 with the demand data shown in Exhibit 2, it <br /> is obvious that RWC is in a high risk, Iow reliability situation at the moment. RWC has one of <br /> the lowest levels of reliability of the BAWUA members. I also believe RWC has one of the <br /> lowest levels of water supply reliability in Northern California, although obtaining accurate <br /> measures of reliability is difficult. As a consequence, I have not collected benchmarks for <br /> comparison at this time. <br /> <br /> The SFPUC water supply situation will remain unchanged until at least ~u!y 2009 when the <br /> existing Master Water Sales Contract and BAWUA / SFPI~. Interim ~e A~.hication Plan <br /> expire and are renegotiated. It is difficult to predict the outcome of the:Ivl~gotiations, but it is <br /> unlikely that RWC will improve its water supply reliability f~om this source. <br /> <br />4. Selecting A Proper Level Of Reliability <br /> <br /> What is the appropriate level of reliability? There is no exact engineering answer, but rather the <br /> appropriate level is a judgment call dependent on the level of risk RWC is willing to take, and <br /> how much RWC is willing to pay to minimize this risl~. <br /> <br /> Exhibit 3 graphically shows how water supply reliability increases with water supply additions <br /> of 1,000 AFY for water conservation and an additional 1,208 for water recycling (priority <br /> customers 1 and 2 in the Redwood Shores area identified by Kennedy/Jenks Consultants, Water <br /> Recycling Feasibility Study for Redwood Gity, August 2002). <br /> <br /> Focusing on scenario 3 (SFPUC cutback of 10%), RWC's cutback under current arrangements <br /> would be 17.5%. If 1,000 AFY of additiunal supplies could be obtained via conservation, the <br /> cutback would be reduced to 12.4%. With 1,208 AFY of additional supplies from recycling <br /> (2,208 AFY total), the cutback would be a very manageable 6.3%. <br /> <br /> Readers should note that the reliabilities presented are for existing water customers as of FY <br /> 2000/2001. As shown in Exhibit 2, water use is expected to grow 1,647 AFY over the next 20 <br /> years. The thirst of this new growth needs to be quenched from new water suvt)lies if the water <br /> reliability of existing customers is not to decay incrementally. <br /> <br /> Page 4 <br /> <br /> <br />