Modeling the nexus across water supply, power generation and environment systems using the system dynamics approach: Hehuang Region, China

Abstract

Nexus approaches address the complex interconnections across coupled systems, providing a new and effective way to identify the dynamics of coevolution process. The connections across water supply, power generation and environment (WPE) systems are increasingly tight and thus can be profiled as a WPE nexus. This paper aims to model the WPE nexus in the China’s Hehuang Region by using the system dynamics approach. Six nonlinear ordinary differential equations of storage, water supply, power generation, population, biomass, and environmental awareness are formulated to dominate the coevolution process. Their constitutive relations are then obtained from observed data to complete the WPE nexus model. The results show that the system dynamics approach is competent in modeling the WPE nexus of the Hehuang Region. The coevolution process is divided into four cyclic stages (i.e., exploitation, deterioration, depression and recovery stages) and terminates with a stationary cycling after thousands of years. The dynamics of state variables are explicitly interpreted to show how different driving variables affect the variations of system states. The observations obtained by modeling the nexus are insightful, improving the understanding of interactions across coupled systems.