Virtual water accounting for building: case study for E-town, Beijing

Virtual water as the overall water consumption of a building includes not only the on-site water use for constructing and operating, but also the off-site water used to supply the necessary manpower, material and equipment inputs required by the building. This paper advances a systematic virtual water accounting framework for building by employing a hybrid method as the combination of both process and input-output analysis. Based on the raw project data in the Bill of Quantities, a detailed case study is performed for the structure engineering of six landmark buildings in E-town, Beijing, supported by the virtual water intensity database for the Chinese economy in 2007. The total virtual water of the case buildings is quantified as 1.25E+06 m3, corresponding to an intensity of 20.83 m3 per square meter floor area. On-site tap-water supply, material inputs and manpower inputs contribute to 43.55%, 50.05% and 6.31% of the virtual water, respectively, indicating the fact that off-site water use plays a critical role in balancing the overall water budget of a building.