Laserfiche WebLink
<br />, <br /> <br />Onfarm Improvements. In order to improve irrigation efficiency <br />with an irrigation scheduling program, the onfarm distribution system <br />and the fields themselves must be designed to permit uniform applica- <br />tion of the amount of water needed to replace soil moisture depleted <br />by the crop. <br />The farms of the Subarea have not been examined sufficiently to <br />determine the extent of improvements needed to permit the most effi- <br />cient irrigation. However, experience in the We11ton-Mohawk <br />Irrigation and Drainage District provides an indication of the extent <br />and magnitude of improvements that may be needed. <br /> <br />Effect on Salt Discharge. The present (1974) irrigation effi- <br />ciency of the Palo Verde Subarea is 42 percent, relatively low in <br />comparison with a number of other subareas of the District. The <br />improvement in efficiency that can be obtained through an IMS program <br />and associated onfarm improvements is not yet known. <br />Studi es in the Well ton-Mohawk Irri gation and Drai nage Di stri ct <br />i ndi cate a range of improvements is poss i b 1 e dependi ng on the 1 oca 1 <br />dedication to, and the degree of refinement of irrigation scheduling, <br />as well as the extent of onfarm improvements. <br />Based on the apparent similarities to the Wellton-Mohawk area, it <br />may be possible to achieve an efficiency of 70 percent or higher in <br />the Palo Verde Subarea. However, the Palo Verde Subarea is relatively <br />new in terms of i rri gat i on hi story, and some of the 1 and is still <br />undergoing the process of leaching out preexisting salts from the root <br />zone. Consequently, it may not be realistic to predict such a high <br />irrigation efficiency at this time, and the best that could be <br />achieved may be closer to GO percent. Accordingly, a GO-percent <br />efficiency was used for this preliminary evaluation. <br />Achievement of GO-percent irrigation efficiency would reduce the <br />initial net salt discharge from the Palo Verde Subarea as shown on <br />Table 1. The excess salt discharged from the Subarea would be reduced <br />by 70,900 tons i nit i a 11y, but the amount of excess salt di verted by <br />the Sundesert Plant would decrease by 5,300 tons. Additionally, the <br />002872 <br /> <br />28 <br />