The role of simulation models in understanding the processes in the soil-plant-atmosphere system has increased significantly in recent years. This is attributed to increased computing capabilities available today. Mathematical models, be it physically or empirically based, have the promising potential to explore solutions to water management problems. In the sub basin, frequent events of high and low rainfall, less work on soil conservation practice and deforestation are observed as causes of the changing climate and land degradation that make the need for improved and resilient agricultural water management to have a greater yield of the crop with environmental sustainability. Thus, taking, the Kuraz Sugar Development irrigation project in the sub basin, which is planned to irrigate sugarcane on 175,000 hectares of land as research area, we aim this research work to evaluate the performance of two computer-based agro-hydrological models (SWAP and CROPWAT) in simulating soil water balance components of a sugarcane cropped field under irrigation conditions. From the result of the performance of the models, the SWAP model result of actual evapotranspiration and irrigation water requirement is greater than the designed crop water requirement of the CROPWAT model output, which can be calibrated with the yield of sugarcane. The comparison of the two models shows that the SWAP model output indicates the actual evapotranspiration and irrigation water requirement is greater than the CROPWAT model output of the designed irrigation water requirement that can be made to conform to the yield reduction of sugarcane in the project area.

Keywords: Kuraz Sugar Development irrigation projectagro-hydrological models CROPWAT