Design of microirrigation laterals on nonuniform slopes

A method for designing microirrigation laterals on nonuniform slopes was developed using the finite element method. Six representative nonuniform slope patterns were discussed in detail. The design principle was implemented based on the results of computer simulations. It was found that a single lateral is suitable for Pattern I while paired laterals are better for Patterns II similar to VI in most cases. The diameter of a single lateral or paired laterals may have two solutions for a required uniformity of water application and the length may have multiple solutions. When the required average emitter discharge, required uniformity of water application, and one parameter (either length or diameter) of a single lateral or paired laterals are given, the unknown parameter, best submain position (paired laterals) and operating pressure head can be accurately designed using personal computers. The design procedures are described.