Modelling surface runoff in a large-scale paddy field in Malaysia

A few models to simulate surface runoff generation at the agricultural field scale are available. However, most of the available models are developed for particular setup with certain assumptions, which preclude their universal use. There are no guidelines to choose a model best suited for a particular agricultural field. The major objective of this study is to estimate the surface runoff in the Muda irrigation scheme, by applying seven well-known hydrological models. The surface runoff amounts estimated using these models are compared with the observed runoff collected at an agricultural block in the scheme. The model performances are evaluated based on the mean runoff to precipitation ratio, relative mean absolute error, and the coefficient of determination criteria. The results suggest that the Smith-Parlange nonlinear model has matched satisfactorily with the observed surface runoff. The performances of the Philip, ARNO and Morel-Seytoux models are found to be close to the Smith-Parlange model. Thus, the mean runoff estimated by Smith-Parlange, Philip, ARNO, and Morel-Seytoux models can be regarded as the surface runoff in the study area.