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<br />.. <br /> <br />a <br />'....-l <br />r __"I <br />~ <br />c.n <br />w <br /> <br />. <br /> <br />PRELIMINARY <br />.SUBJECT TO REVI:!JN <br /> <br />4. Based on the general weighting factors discussed above. the <br /> <br /> <br />alternative plans considered in this analysis consider only Kaplan propeller <br /> <br /> <br />turbine of varying installed capacities. Kaplan units were found to be the <br /> <br /> <br />best suited for the heads and flows at the project and at the same time lower <br /> <br /> <br />in cost than other types of turbines. <br /> <br />V. Power Production. ./ <br /> <br />A. VAriation of Flow and Hp-~d. ~ <br /> <br />1. Since the operation of John Martin Dam allows releases only during <br /> <br /> <br />the irrigation season. which normally occurs from about April through October. <br /> <br /> <br />and considering that the available head is reduced dramatically through this <br /> <br /> <br />period. it was deemed appropriate to evaluate power production on a monthly <br /> <br /> <br />rather than annual basis. Both flow-duration and pool elevation-duration <br /> <br /> <br />curves were developed for each month of the irrigation season based on the <br /> <br /> <br />1948 through 1981 period of record. These curves are shown on Plates 4 and 5. <br /> <br />B. Dp-sii" and Avpr~ep Hpad. <br /> <br />/ <br /> <br />1. By assuming that the selected Kaplan turbine can operate <br /> <br /> <br />satisfactorily in a range of 60 to 140 percent of the design head. an <br /> <br /> <br />empirical review of the monthly pool elevation-curves indicated a design head <br /> <br /> <br />of 70 feet would most effectively utilize the available head of- the 'site. <br /> <br /> <br />Therefore. the assumed design head for each alternative plan was made equal to <br /> <br /> <br />70 feet. <br /> <br />2. The average pool elevation for a given month was determined by <br /> <br /> <br />measuring the area under the portion of the pool elevation-duration curve <br /> <br /> <br />bounded by the operating limits of the turbine. An assumed tai1water <br /> <br /> <br />elevation of 3740 was subtracted from the average pool elevation to obtain the <br /> <br /> <br />average operating head. For this analysis. it was assumed that hydraulic <br /> <br /> <br />losses encountered between the conduit inlet and the turbine would result in a <br /> <br /> <br />three percent head loss. The average net operating head was therefore set <br /> <br /> <br />equal to 97 percent of the average operating head. <br /> <br />8 <br />