A socio-hydrology model for Water-Urban-Land-Population-Production Nexus

The competition between urbanization patterns, agricultural practices, population dynamics, and economic production intensifies under limited water resources. To tackle this pressing issue, the Chinese government has issued a strategy of "Basing four aspects on water resources." The strategy aims to guide the scopes and scales of urban extension, land cultivation, population capacity, and economic production based on the constraints imposed by water availability, referred to as the Water-Urban-Land-Population-Production (WULPP) Nexus. While there is literature dealing with various water-related Nexus, few studies focus on WULPP Nexus. To understand the co-evolution and conflicts of WULPP Nexus between social development and water management, the study proposed a comprehensive framework and corresponding socio-hydrology model to address the WULPP Nexus. The model integrates the WULPP Nexus with the macro-economic Input-Output model and a multi-objective optimization (MO) solution to comprehensively explore the dynamic interactions between water and social development from the perspective of water, land, labor, products, and capital. The proposed model was fully applied in Yinchuan (YC), a pilot city for Ecological Protection and High-quality Development in the Yellow River Basin, to examine its effectiveness and sensitiveness as a case study. The results reveal a strong positive correlation between population growth and socio-economic development, with urban expansion offering both benefits and trade-offs, while land cultivation presents the most significant trade-off with other objectives. Water availability, especially under consumption constraints, is crucial to improve outcomes in wet years and intensify trade-offs in dry ones. These findings underscore the importance of a balanced approach to social development and water management, offering valuable insights for sustainable development in water-scarce regions globally.