Integrated water assessment model for water budgeting under future development scenarios in Qiantang River Basin of China

Since conjunctive water use for agriculture is turning out to be a major environmental challenge in some river basins, there is an urgent need to quantify future water availability and water demand to identify whether there is a surplus or deficit of water. This is of great importance in developing water management plans for a basin or a state.In this paper, the Basin-wide Holistic IntegratedWater Assessment (BHIWA) model developed at the International Commission on Irrigation and Drainage (ICID) was used in an attempt to simulate the water balance of the study basin, the Qiantang River basin in China, as well as to analyse the impacts of land and water use on return flows of this basin. The model was run on a monthly basis, and was calibrated by comparing the calculated and observed data. Furthermore, the BHIWA model was applied to simulate historic conditions of the basin dating back to 1980 and for future scenarios to analyse the effects of water policies and multiple demands on water resources. The results calculated from this model indicated how the model could be a useful tool for basin-level integrated water assessment, particularly in small river basins.