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<br />I <br /> <br />I <br /> <br />I <br /> <br />C. Hydraulic Analysis <br /> <br />I <br /> <br />Hydraulic analysis of the water distribution system was performed using <br /> <br /> <br />a network analysis computer model. The model employs. a Hardy-Cross type <br /> <br /> <br />approach to determine unknown pressures and flow rates in each line. Simul- <br /> <br /> <br />taneous non-linear equations for each junctions are solved by a Newton-Raphson <br /> <br /> <br />iterative procedure. Standard operating conditions were analyzed as well as <br /> <br /> <br />a number of possible variations. Input parameters included pump characteristics; <br /> <br /> <br />line size, type and length; pipe equivalent lengths for fixture and valve losses; <br /> <br /> <br />elevations; and storage tank data. <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />I. Normal Operation and Future Demands - The distribution system can be <br />separated into three zones based on current operating procedures. These zones <br />are shown on Figures-6 and -7 (Pages 30 and 31). Zone A includes the area <br />served by Well No. I and Tank No. I; Zone B includes the area served by Well <br />No.4 and Tank No.2, and Zone C includes the area served by Wells No. 2 and <br />3 and Tank No.3. When distribution lines are in tact, each of these zones <br />is adequately served without transferring water between zones. Physical charac- <br />teristics of each zone and the water demand in each zone are presented in Table- <br />10 and Table-II, respectively. <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />The potential for transferring water between zones is assessed in the flow <br />rates section of this chapter. <br /> <br />I <br /> <br />Demands on the system were computed based on average flow rates assuming <br /> <br /> <br />a use rate of 80 GPCD. Peak flow rates of five times the average flow rate <br /> <br /> <br />were used to assess the adequacy of line sizes. Fire flow demands and the method <br /> <br /> <br />of fire protection are discussed on Page 42. <br /> <br />I <br /> <br />I <br /> <br />2. Pressures - Pressures in the water distribution lines are primarily <br /> <br /> <br />controlled by the water elevations in the storage tanks. The rate of water <br /> <br /> <br />flow and friction losses under normal operating conditions are relatively small. <br /> <br /> <br />The average flow velocity in the mains is less than one-foot per second which <br /> <br /> <br />results in minimum friction losses. Line pressures are only slightly higher <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />-44- <br />