Intake Parameters from Advance and Wetting Phases of Surface Irrigation

Abstract

A volume balance approach to determine the parameters of the Kostiakov or modified Kostiakov infiltration equations in border and furrow irrigation is presented. The approach requires measured data from the advance phase, the postadvance (wetting) phase, or both, resulting in three different procedures to characterize infiltration. Using the entire field length the procedures provide infiltration parameters that are more representative of an actual irrigation. The volume balance computation performed by the end of the wetting phase makes it possible to determine the accuracy of each equation that can represent the infiltration process for a particular application. Inflow discharge, water front advance, average flow cross-sectional area, and outflow discharge are the required field data. Several mathematical approximations are suggested in order to simplify the field work and the amount of computation. The use of empirical factors to improve data fitting is discussed. By providing irrigation system performance information during an irrigation, this procedure can be easily adapted to guide decisions during real-time operation.