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<br />GU0205 <br /> <br />. <br /> <br />The input data used for the Series II runs was the same as the final <br /> <br />Series I run with the exception of changes assumed in canal losses and <br /> <br /> <br />adjustments in ditch diversions as follows: <br /> <br /> <br />Series II-A run. The ultimate in reduction of canal seepage was <br /> <br /> <br />assumed in this set of runs--that is, zero canal seepage was assumed and <br /> <br /> <br />canal diversions were adjusted to deliver the same amount of water to the <br /> <br /> <br />farm turnouts as was received in the Series I or historical runs. The <br /> <br /> <br />water saved through nondiversion was made available to downstream canals <br /> <br /> <br />at such times as they were receiving less water than the computed irriga- <br /> <br /> <br />tion water requirement adjusted for the estimated on-farm efficiency. <br /> <br />The amount of water pumped from wells was assumed the same as during the <br /> <br /> <br />historical period and was taken into consideration as part of the total <br /> <br /> <br />water supply before calculating the amount of water that needed to be <br /> <br /> <br />diverted by the ditches during each week. <br /> <br />. <br /> <br />Series 11-8 run. In this run, canal seepage was reduced to zero in <br /> <br /> <br />selected locations. Those canals or sections of canals identified by Dr, <br /> <br /> <br />Skinner as having seepage losses of 25 percent or greater were soon to <br /> <br />be lined so as to reduce seepage losses to zero, Diversions by those <br /> <br />canals were reduced so that the deliveries to the farm headgates were the <br /> <br /> <br />same as received in the Series 1 runs, Water saved by such diversions was <br /> <br /> <br />made available to any downstream canals (according to priority) which <br /> <br /> <br />were then receiving less than the irrigation water requirement delivery <br /> <br /> <br />at the farm headgates adjusted for on-farm efficiencies, <br /> <br />Series III run--varyin~ on-farm efficiencies <br /> <br />The purpose of the Series III run was to evaluate the sensitivity of <br /> <br /> <br />irrigation water-use efficiency in the reach to changes in on-farm effi- <br /> <br /> <br />ciencies. The input data for Series III run were the same as for the final <br /> <br />Series 1 run with the exception of changes in on-farm efficiencies and <br /> <br /> <br />adjustments in ditch diversions as follows: <br /> <br />. <br /> <br />Series III-A run, In this run it was assumed that all on-farm effi- <br /> <br /> <br />ciencies which historically were estimated to be lower than 60 percent <br /> <br />were raised to the 60 percent level. Ditch diversions were adjusted so <br /> <br /> <br />that the crop received the same soil-moisture situation as in the Series <br /> <br /> <br />I or historical run. Any reduction in diversions resulting from this <br /> <br />-48- <br />