A Nonlinear Model for Evaluating Dynamic Resilience of Water Supply Hydropower Generation-Environment Conservation Nexus System

Undesirable disturbances (e.g., extraordinary drought) are prone to cause cascading failures of water supply-hydropower generation-environment conservation (WHE) nexus system. Simulating a dynamic resilience of the nexus system can provide opportunities for pre-disturbance effective prevention and post-disturbance recovery from the cascading failures. Previous dynamic resilience simulating is often based on the linear assumption which is not applicable for the WHE nexus system that involves nonlinear processes. To improve simulation accuracy of the dynamic resilience of the WHE nexus system, a novel nonlinear dynamic resilience model that incorporates both a WHE nexus model and a second-order Volterra (SOV) model is proposed. The WHE nexus model simulates amount of impact propagated by an original disturbance event on each subsystem, while the SOV model captures nonlinear relationship between the amount of impact and a corresponding dynamic resilience. The proposed model was applied to the Liuchong River Basin, China, under different dry year scenarios. The results show that the dynamic resilience simulated through the SOV model performs better than that through a first-order Volterra model which is suitable for a linear system, with Nash-Sutcliffe efficiencies of water supply, hydropower generation, and environment conservation subsystems increasing by 36.8%, 70.9%, and 17% respectively. Among the WHE nexus system, the water supply subsystem is found to be the least resilient. Moreover, the proposed nonlinear model is more suitable for simulating and predicting dynamic resilience when a severer water resources drought occurs. The proposed model helps to guide resilience management of water resource system by combining nexus and resilience thinking.