An Analysis of Surface Water Hydraulics of Irrigated Paddy Field Using a Finite Volume Model

Abstract

A finite volume model is developed to simulate the surface irrigation and drainage at a paddy field. The model’s capabilities are validated through comparison with the observed data obtained by numerical experiment and various experimental test, i.e., basin irrigation test and irrigation and drainage test at two paddy fields. The model produced good results compared to the analytical solution and advance trajectory measured in basin irrigation. The model’s capability for simulation of surface irrigation and drainage at a paddy field was tested, and the simulated results were in good agreement with the observed inundating depths. The result of surface irrigation simulation shows that the longer the length of longer side of the paddy field becomes, the longer the advance and storage time is taken and the larger the inlet flow rate is required for water to reach the wanted ponding depth within allowed time. The result of surface drainage shows that the longer the width of the outlet is, the shorter the drainage time is taken, the more the number of drainage outlet is, the shorter the drainage time is taken, and the larger the size of the field becomes, the longer the drainage time is taken, and the field shape have little effect on drainage time.