Design of Tapered Drip Irrigation Pipes in Non-Uniform Slopes

Abstract

Drip irrigation system design approach with tapered pipe segments (multi-diameter pipe segments) in a lateral or submain is a cost effective method. A new simple design method has been developed using Energy Gradient Line Approach (EGL) for the tapered pipes in non-uniform slopes. A non-uniform slope tapered pipe flow problem is divided into a series of uniform slope and uniform diameter pipe flow subproblems. An equation for determining the dripper discharge rates to determine the discharges of drippers for an uniform slope and uniform diameter pipe, with the flow occurring through drippers and also through the pipe beyond the last dripper, has been developed. The dripper discharges for each subproblem are considered as independent samples and the variation of discharges for the total pipe length is found out using the statistical equations. This method is demonstrated with a numerical problem and the results are compared with the step by step method of finding discharge rate in each dripper. This method has many advantages than the only manual method of Wu (1984), reported in the literature.