Evaluation of hydrological zoning technique and its utilization in China

Hydrological zoning serves as a pivotal foundation for water resources planning and proves to be an effective method in data-deficient regions. In China, initial hydrological zoning primarily addressed the requirements of water resources planning. The national hydrological zoning emerged predominantly in the 1950s, while more refined provincial hydrological zoning was consolidated towards the close of the 20th century. At the core of hydrological zoning work lies the determination of zoning indicators and methods, which must be applied flexibly based on practical needs. Presently, hydrological zoning indicators predominantly encompass climate, hydrology, and underlying surface, with the clustering method being the primary approach for hydrological zoning. This method is instrumental in addressing the scarcity of hydrological data, and efforts have been made to enhance its ecological assessment through the development of ecohydrological zoning methods. In light of the current research landscape, the following avenues are proposed for future exploration: (1) integrating hydrological similarity theory into hydrological zoning, (2) delving into regional hydrological mechanisms and their applications in water resources, environment, and ecology, and (3) rigorously testing and scientifically interpreting hydrological zoning results. This study lays the groundwork for regional water resources planning, parameter transplantation, and ecological environment protection.