Model development for estimating irrigated water at Kandal province, Cambodia.

Water management is a critical global issue. In particular, broad-based management of irrigation water for paddy fields is important in terms of efficiency of water use. It is very difficult, however, to determine the amount of irrigated water and required irrigation water due to poor availability of local data. Thus, the aim of this study was to develop an estimation model for the amount of irrigated water and required irrigation water by using rice production. In the first step of modeling, a simplified structure and data sets were used. As there is little calibration data for the hydrological model, a specific method was applied to this model for estimating the amount of irrigated water and required irrigation water. First, rice production was calibrated by adjusting the tank model parameter values to reduce the calculation errors of two provinces. Second, in the case of optimized tank model parameter values, the amount of irrigated water was calculated and then the required irrigation water was estimated in sensitivity analysis. In this study, Kandal province in Cambodia was chosen as a sample area for the model and Siem Reap province in Cambodia was selected for adjusting the model parameter values. In the results, the amount of irrigated water at Kandal province was estimated to be approximately 8,000,000 m·year and at Siem Reap approximately 960,000 m·year. As the next step, this model should be applied to other places to check whether or not this method is beneficial, although reasonable results were obtained in this study.