Design of microirrigation laterals at minimum cost

Based on the design methods of finite elements and golden-section searches, a method was developed for designing microirrigation laterals at minimum cost. Characteristics of water application uniformity as affected by lateral diameters and lengths were analyzed. When the required average emitter discharge is known, the relationships of water application uniformity, best submain position (paired laterals), and operating pressure head as a function of the lateral diameter and length can be accurately determined using a personal computer. The lateral diameter and length can then be determined from a contour map representing water application uniformity as a function of the lateral diameter and length (computer calculation). The best submain position and operating pressure head for this lateral diameter and length is then determined by computer calculation. This method is suitable for designing microirrigation laterals on both uniformly and nonuniformly sloping fields.