Virtual Water Transfers in Major Us Cities from Domestic Commodity Flows

Open Access
Ahams, Ikechukwu C
Graduate Program:
Civil Engineering
Master of Science
Document Type:
Master Thesis
Date of Defense:
March 31, 2016
Committee Members:
  • Alfonso Ignacio Mejia, Thesis Advisor
  • Water Footprint
  • Virtual Water Content
  • US Cities
The domestic water footprint (WF) of consumption and production for 65 major US cities was estimated using available domestic commodity flow, water-use, and virtual water content data. For the WF estimates, 29 different commodities were considered, which account for ~51% by weight of the bulk, domestic US freight. Out of these 29 commodities, 5 are agricultural commodities and the remaining ones are industrial. The direct (blue) and indirect (green) water used in production for the agricultural commodities were taken into account while for the industrial commodities only the direct water used was considered. Additionally, the ability of WF estimates to follow urban scaling laws was assessed. Overall, it was found that there is significant variability in the spatial distribution of the urban WF of both consumption and production. It was also found that while most cities are net WF consumers (54 out of 65 cities), there are some net WF producers. Also, the analyzed cities consume, on average, 30% of their own WF of production but city self-dependency can vary greatly from city to city. The urban WF per capita and per gross domestic product (GDP) tend to decline with increasing population and GDP, respectively. Thus, large US cities tend, overall, to use less domestic water per capita and are more productive than smaller cities.