Spatial equilibrium model-based optimization for inter-regional virtual water pattern within grain trade to relieve water stress

Abstract

Realizing water usability and management sustainability represents one of the Sustainable Development Goals. Since grain cultivation consumes tremendous amount of water, the inter-regional grain trade causes virtual water flow, increasing water stress in certain water-scarce regions. As the second-longest river in China, the Yellow River bears increasingly severe water stress. Considering water and food security, this study proposes a spatial equilibrium model (SEM) that combines partial equilibrium theory and transport models to maximize net social revenue and to balance grain supply and demand, thereby optimizing inter-regional grain trade to relieve water stress. According to different natural, technical and social conditions, we conceive five scenarios to predict regional water stress characterizing with different water supplies, demographic structures, food demand compositions and water-saving technologies. Our simulation results suggest that the developed SEM can realize spatial equilibrium of food and water resources within the Basin, which is capable of resolving the problem of food demands in regions with varying extents (13%–55%), optimizing inter-regional grain trade and mitigating water stress. Finally, we recommend some constructive policies for different scenarios to relieve water stress.