Title: Impact of alteration in soil hydraulic variables on collective infiltration using HYDRUS-1D

Authors: Ali Javadi; Kaveh Ostad-Ali-Askari

Addresses: Department of Water Science and Engineering, College of Agriculture, Isfahan University of Technology, Isfahan, 84156-83111, Iran ' Department of Civil Engineering, School of Engineering, American University in Dubai, Dubai, 28282, UAE; Department of Natural Sciences, Manchester Metropolitan University, Manchester, M1 5GD, UK

Abstract: Following HYDRUS-1D model calibration of the infiltration process, the impact of a 20% change in soil hydraulic parameters (0.8 to 1.2 parameter values) on cumulative infiltration was examined. Infiltration is most sensitive during the short irrigation period under intermittent irrigation when the soil is dried and wetted successively, whereas it is the most sensitive during the long irrigation period under daily irrigation when the soil is wetted continuously. In fact, as soil permeability increases, infiltration becomes more sensitive to parameter changes. The daily and intermittent irrigations with poor irrigation water quality, respectively, were found to have the highest and lowest values of the sensitivity index. The findings indicated that Ks was the parameter that was the most sensitive, followed by θ_s, n, α and θ_r with l being the least sensitive parameter. As a result, K_s and θ_s will be the only two parameters used to optimise the model.

Keywords: soil permeability; Genuchten-Mualem parameters; water quality; hydraulic parameters; irrigation management; HYDRUS-1D model; inverse modelling; sensitivity analysis; sensitivity index; intermittent irrigations.

DOI: 10.1504/IJW.2024.143305

International Journal of Water, 2024 Vol.16 No.2, pp.142 - 158

Received: 04 Jul 2023
Accepted: 14 Apr 2024
Published online: 12 Dec 2024 *

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