Modified Model for Simulating Water Flow in Furrow Irrigation

Abstract

Quantifying surface and subsurface water dynamics is essential to design and manage furrow irrigation systems. Many furrow irrigation models estimate infiltration using empirical functions without considering the variable ponding depth and the initial soil moisture. Other models, such as the detail coupled models, which describe subsurface flow with the 2D Richards equation, are complex and difficult to apply in practical use. In this paper, we propose a modified furrow irrigation model (MFIM) that couples the approximate furrow infiltration model with the zero-inertia model. The finite difference method and an iterative procedure were used to couple computations of surface flow and infiltration. The influence of time resolution on simulating results was also examined. Results showed that the simulated water advance of the MFIM agreed reasonably well with that of the detail coupled model. More accurate simulation results were obtained by using smaller time step size. The proposed model has shown high computational efficiency. The MFIM may be an effective alternative tool for furrow irrigation design and management.