Design of Microirrigation Submain Units using the Lateral Discharge Equation

A method was developed for designing microirrigation submain units. Hydraulic analysis is implemented by combining the lateral discharge equation, the back step method, the forward step method, and the golden section search. When the required uniformity of water application, the required average emitter discharge, one parameter of the lateral length and diameter, one parameter of the submain length and diameter, and the field conditions are given, the unknown parameters of the lateral and submain, the best submain position (paired laterals), and the operating pressure head of a submain unit can be accurately designed using a personal computer. The calculations in design procedures are simple and fast. It was found that the lengths of a lateral and submain may have two or three solutions and the diameters may have two solutions for some values of a uniformity coefficient of water application in slope conditions.