Potential benefits of increased application of water to paddy fields in Taiwan

The potential benefits of increased application of water to paddy fields in Taiwan are investigated in this paper. A conceptual model is used to repre sent the hydrological system of the paddy field. A technique is presented t o estimate the parameters of the model. Field experiments also are performe d for parameter estimation and model verification. The simulated results ar e in good agreement with the observed during model verification. With param eters estimated from the field data, the model is used to simulate the effe cts of applying water beyond current practice. The simulation results show that the downward percolation increases when the irrigation water increases . However, the percolation reaches a capacity rate no matter how large die amount of water applied. This phenomenon results from the existence of a ha rd layer below the paddy field. The effects of raising the height of levees around paddy fields are also studied. Copyright (C) 2001 John Wiley & Sons , Ltd.