Analytical Determination of Distribution Uniformity for Microirrigation Tapered Laterals Laid on Uphill and Horizontal Slopes

Abstract

The uniform distribution of water delivered through microirrigation emitters on a lateral line is an important objective that greatly affects a system’s efficiency. Among the various uniformity parameters, distribution uniformity (DU) is one of the most frequently used indexes in industry. In this study, an easy-to-use analytical method for directly calculating the DU of tapered microirrigation laterals laid on horizontal or uphill slopes is developed. The proposed equations are derived assuming that the system’s hydraulic characteristics and the ground slope are the only factors affecting the DU. A comparison test with a numerical stepwise solution indicates that the proposed analytical method is reasonably accurate and can be used to evaluate the system uniformity. The results also show that the accuracy of the method increases as the total number of outlets increases or the value of the emitter exponent approaches unity.