Statistical Approach for Drip Lateral Design

Abstract

ABSTRACT A design technique was developed using a statistical approach. This technique is based upon the coefficient of variation of pressure head along a lateral line and the variations of emitter flow caused by manufacturer. Considering the proportionality factor K, and the pressure head H in the emitter flow equation, q = KH^ as two random variables, an equation for mean emitter flow can be derived using Taylor's theorem. The coefficient of variation of K indicates the manufacturer's variation. The coefficient of variation of pressure head is determined statistically from the average and variance of pressure head which is affected by friction and slope changes along the lateral line. Once a design criterion of an emitter flow variation (expressed as the coefficient of variation) is set and a type of emitter is selected, the required coefficient of variation of pressure head for the lateral line can be calculated and the design length can be determined.