Refined Allocation of Water Resources in Pishihang Irrigation Area by Joint Utilization of Multiple Water Sources

Refined allocation of water resources is an important means of sustainable water resources utilization. Based on General Water Allocation and Simulation (GWAS), this study uses a Geographic Information System (GIS) to construct spatial topological relationships. A fairness optimal minimum was set as the objective function. Total quantity control, water supply potential, and quality-divided water supply were set as constraint conditions. Considering the dynamic mutual-feedback relationship between the middle-lower-reaches reservoir and the upstream reservoir, this study refines the allocation of water resources combined with the characteristics of "long cane knots melons" in the Pishihang irrigation area. Results showed that at 50%, 80%, and 90% frequencies in the base year, 2025, and 2035, respectively, the water deficient ratio is 0. For continuous drought years at 90% frequency, all water users are faced with different degrees of water shortage. In water source structures, water diversion in the irrigated area is the largest, followed by local surface water; reclaimed water and shallow groundwater are used as supplements. In the case of consecutive drought years, the water shortage degree can be reduced through rational development of local water and additional external water transfer. The model has thus been well applied. This study provides a more accurate method for optimizing water resources allocation.