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<br />, <br /> <br />001286 <br /> <br />Coachella Valley service area are very low, since the entire <br />distribution system consists of pipelines. There are some <br />conveyance losses in Imperial Valley from unlined ditches; <br />however, the district is continuously improving these channels. <br />In following Chairman Holmer's classification of water <br />losses, I have discussed those which take place during the <br />storage and conveyance of water. This brings me to the third <br />class of water losses, that is, loss of water during its <br />utilization. <br />I have previously discussed in general terms irrigation <br />losses and the problem of measuring these losses in terms of <br />irrigation efficiency, by stating that much of the excess applied <br />water percolates to ground water and becomes available for reuse. <br />Turning again to the Imperial and Coachella Valleys, gross annual <br />diversions of Colorado River water for use in these valleys aver- <br />age about 6.5 acre-feet per acre. Because this water contains <br />about 850 parts per million of total dissolved solids at the <br />headgates--and depending on the soil and crop characteristics-- <br />considerably more water than is normally needed for consumptive <br />use must be applied in order to maintain a favorable salt balance <br />in the soil. An example of the effectiveness of the leaching <br />program is the increase in alfalfa yields in some locations from <br />3 tons per acre to 10 tons per acre. The total dissolved solids <br />in the drainage water by comparison is about 2,600 parts per <br />million, a level which is unsuitable for further irrigation <br /> <br />-10- <br />