Embodied water for urban economy: A three-scale input-output analysis for Beijing 2010

The scheme of a three-scale input-output analysis is presented in this study to investigate the water use profile of the urban economy in Beijing. Defined as total water including direct and indirect water, embodied water for an urban economy supported by massive domestic and foreign trade can be decomposed into nine categories corresponding to three sources (local withdrawal, domestic imports, and foreign imports) and three destinations (local final demand, domestic exports, and foreign exports). Based on statistics for Beijing in 2010, the case urban economy is endowed with just 3.53 billion m³ of local water withdrawal, whereas the total embodied water demand is estimated up to 13.61 billion m³, almost quadruple the local water withdrawal. The extra 10.08 billion m³ of indirect water use is obtained via cross-boundary trade. Overall, Beijing's total water demand is satisfied mainly by domestic imports by a share of more than 60%, and partly by foreign imports by a share of around 20%. The unintentionally induced water embodied in domestic and global trade plays an essential role in satisfying the water demand, which has essential implications for decision making to ease urban water scarcity.