Hydrodynamic Modeling of Basin Irrigation

Abstract

In this study, a hydrodynamic model is presented for simulating basin irrigation. An explicit, second-order-accurate finite-volume technique is used for solving the two-dimensional governing equations of basin irrigation. The empirical Kostiakov-Lewis infiltration equation is used for the calculation of infiltration. The model is validated using field data and numerical results available in the literature. The proposed model was used for simulating a basin irrigation event in an irregular field with a high spot inside the computational domain. The resulting numerical error was smaller than that produced by previous models applied to the solution of this problem. The proposed model was also used for studying the effect of basin shape on the time of advance and to check the validity of one-dimensional flow assumption when the inflow to the field is provided only through a part of the edge. In the case of a rectangular field with a partial line inflow, the two-dimensionality effects become significant when the ratio of inflow width to the field width is less than a particular value. A simple subgrid technique was introduced to obtain a high grid resolution near the advancing front and maintain a low computational cost.