Extensive comparison of various infiltration estimation methods for furrow irrigation under different field conditions

Accurate estimation of infiltration coefficients in surface irrigation is essential for proper design, reducing water losses, preventing erosion and increasing water use efficiency. This study was conducted to evaluate various methods for estimating the coefficients of infiltration equations. We have selected 17 different methods with better performance based on previous studies, out of many methods which have been introduced for infiltration estimation. In order to compare the methods, 50 furrow data sets were selected which are different based on field and irrigation conditions. The results indicated that the performance of the infiltration estimation methods is variable because of various field conditions and required data requirements. Amongst the two-point methods, the Elliott and Walker method, with an average Relative Error (RE) of 16 %, the Vatankhah a al. method (RE = 16 %) between one-point methods and the Multilevel Calibration method (RE = 18 %) as compared with other computer-based models were concluded as the most accurate methods for estimating infiltration coefficients. The sensitivity analyses indicated that variations in relative error for estimating infiltration parameters are a function of soil texture, furrow length, inflow discharge and field slope.