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<br />1 Capital costs for materials at Riverside, California, were approxi- <br /> <br />2 mately $620/hectare where 76-mm ID laterals were used, and $740/hectare <br /> <br />3 where 102-mm ID laterals were used. This cost is considerably less than <br /> <br />4 solid-set drip or sprinkler systems that include pumps and filters. Be- <br />, , <br />5 cause the system is buried, labor costs for installation would be <br /> <br />6 greater than for drip systems, but probably less than for a buried-line <br /> <br />7 sprinkler system. The increased life expectancy of the buried system <br /> <br />8 over that of a surface drip system (~pproximately 20 vs. 10 years) <br /> <br />91 should more than repay the additional labor cost. <br /> <br />10 system can be installed with simple tools and the <br /> <br />The fact that the <br /> <br />flow regulated without <br /> <br />11 instruments, may make this closed-conduit, gravity system an attractive <br /> <br />12 alternative for developing countries. Once installed, water is pre- <br /> <br />13 cisely delivered to the field with an emission uniformity greater than <br /> <br />14 97% by simply maintaining water at the source at the proper level. <br /> <br />15 A similar buried lateral system designed to fill short furrows for row <br /> <br />16 crops (8) also shows promise. <br /> <br />17 These simple systems that have precise water control designed <br /> <br />18 ~,to ~bem may be only the beginning of what can be accomplished if <br /> <br />19 energy conservation and ease of operation are made valid strategies for <br /> <br />, <br />20 irrigation system development. But, any ~osed-conduit system, can <br /> <br />21 operate at its full potential for controlling water precisely only if <br /> <br />22 the farmer has water available on demand. The most easily operated and <br /> <br />23 ideal water supply providing this is a pipe distribution system res em- <br /> <br />2'1 bling a municipal water system. In this regard, Haletic and Langley <br /> <br />25 (9) stated <br /> <br />26 Operation of an irrigation water supply system on a <br /> <br />271 de~and basis rather tha~ on a conventional scheduled basis <br /> <br />U~I!.,I')OB- <br />-'~iJ .J <br />