Rice yields at the Sangker river basin in western Cambodia are simulated by a coupled model of the distributed hydrological model WEB-DHM and the rice growth model SIMRIW-rainfed. The results are validated by in-situ statistical data and FAOSTAT. Then, future rice yields are also simulated by using GCMs outputs. In addition, a simple irrigation model is introduced into the coupled model. By using this model, rice yields in consideration of climate change and irrigation are assessed.
In this study, effectiveness of irrigation in this river basin is shown for both of the present and future climates. The results showed that, by constructing irrigation facilities, a stable rice yield can be obtained even if no yield is obtained at rain-fed paddy fields. Also, this study showed that a variation of future rainfall pattern will affect a variation of rice yield.