Mathematical modelo of furrow irrigation

Abstract

A mathematical model of furrow irrigation is presented herein. The modal can be used to analyse and predict the efficiency of a sloping, open furrow irrigation system. This analysis is based upon the solution of the mass and momentum conservation equations, which govern the unsteady, nonuniform, varied flow of water in open channel flow. Consequently, the modal is called a hydrodynamic model. In addition, this paper shows that zero-inercia conditions can occur in furrow irrigation. Model input comprises the inflow discharge, furrow slope, cutoff time, furrow length, Manning roughness, infiltration parameters (K and a in Kostiakov equation), and furrow geometry. The output consists of: advance and recession curves, spatial distribution of water after irrigation, runoff volume, and application and storage efficiency. Dimensional analysis is used to reduce the number of parameters which govern the equations. Model performance is evaluated by comparison with field data, and the results show that the model predicts furrow irrigation satisfactorily.