Laserfiche WebLink
<br />1 eve 1. An increase of onfarm i rri gat ion effi c i ency to 60 percent by <br />constructing onfarm improvements would reduce the salt discharge to <br />the river, which would decrease the sal inity at Imperial Dam by an <br />annua 1 equi va 1 ent of approximately 6.0 mg/L at an annual equi va 1 ent <br />cost of $40,000 per mg/L. Lining the laterals would result in an <br />annual equivalent reduction in salinity at Imperial Dam of 1.6 mg/L, <br />at an annual equivalent cost of $360,000 per mg/L. A project involv- <br />ing accelerated flushing of salt from the Subarea for the first 20 <br />years by liberal application of water, followed by achievement of 60 <br />percent onfarm irrigation efficiency, was also investigated. The <br />possibility of surplus flows in the Colorado River during the next <br />decade 1 ed to thi s idea. It was found that such a measure woul d <br />result in a greater reduction in salt discharged beyond 20 years than <br />with efficiency improvement alone. However, the effect of the <br />increased salt di scharge duri ng the fi rst 20 years woul d far outwei gh <br />the effect of the reduction beyond 20 years. <br />This preliminary appraisal indicates that there is potential for <br />a salinity control project on a portion of the Palo Verde Irrigation <br />Di stri ct. The most cost-effective measure to reduce salt di scharge <br />appears to be the improvement of onfarm irrigation efficiency in the <br />Palo Verde Subarea, which has a relatively low capital cost compared <br />to conveyance system improvements. <br /> <br />Cooperation and Acknowledgements <br />This investigation was entered into as a cooperative venture with <br />the U.S. Soil Conservation Service, as established by a Memorandum of <br />Understandi ng between the Servi ce and the Water and Power Resources <br />Servi ce pursuant to Pub 1 i cLaw 93- 320. The State offi ce of the Soil <br />Conservation Service in Davis, California, and the Western Technical <br />Services Center at Portland, Oregon participated by drawing up plans <br />for investigating onfarm management practices, and provided consulta- <br />tion on aspects of irrigation water management. <br /> <br />002842 <br /> <br />4 <br />