Integrated Water Quantity–Quality Allocation for Mountain Railway Construction

Water resources along mountain railway corridors are characterized by limited availability, high ecological sensitivity, and stringent water quality requirements. These factors render them susceptible to degradation and wastage during construction. To address these challenges, in this study, an integrated dynamic allocation model considering water quantity and quality along mountainous railway sections is developed. The model is established on the basis of a joint allocation framework that considers both water volume and quality parameters holistically. Constrained by sectoral water consumption quotas, the assimilative capacity of water functional zones, and graded water supply standards, the objectives are to maximize the comprehensive benefits of water resource utilization and promote water savings. A gray wolf optimizer (GWO) algorithm is employed to identify high-quality solutions. The model is applied to a case study of water resource allocation in a specific section of a mountain railway. The results indicate that in both the pre- and postoptimization scenarios, total water consumption and water quality are maintained within permissible limits. After optimization, the comprehensive water use efficiency increased by 12.39%, the daily costs decreased by 81.34 USD, and water savings increased by 23.19%. The optimized allocation strategy alleviates water scarcity along the railway corridor, enhances overall water resource efficiency, and provides a reference for addressing quality-induced water shortages in mountainous regions.