Water stress assessment integrated with virtual water trade and physical transfer water: A case study of Beijing, China.

Abstract

With the increase in population and economic development, urban water demand has increased significantly over the past decades, and physical transfer water (i.e., freshwater transported from water source regions to water intake regions through channels or pipelines) and virtual water (i.e., freshwater used in the production of goods and services along their supply chains, abbreviated as VW) have gradually become viable water sources for many cities to relieve water stress. This study used Beijing as the research object and systematically analyzed the impact of physical transfer water, VW, and local water on urban water stress from 2000 to 2016. The results show that VW inflow related to food trade has increased from 3.55 billion m3 in 2000 to 16.76 billion m3 in 2016, and that energy s VW inflow increased from 52.76 million m3 to 137.47 million m3 over the same period. Before 2011, Beijing s water demand was largely met by local water resources; however, after 2011, external water resources (including physical transfer water and VW) accounted for majority of the city s water demand, and VW s contribution increased from 47% in 2011 to 53% in 2016. Although Beijing has significantly reduced local water use in favor of external sources, its water stress index in 2016 remained considerable, far exceeding the upper limit of available water. This study also proposes some measures to ensure Beijing s water security based on the sustainability of external water supply.