ABSTRACT
Virtual water (VW) refers to the water used in the production processes of a commodity,
good or service (Hoekstra & Hung, 2002). Since its inception, the VW concept has been
used in various research topics and at varying scales. A growing number of researchers are
using the VW concept as a tool in water policy, management and/or global trade analysis,
and this requires accurate virtual water estimates. Studies have covered scales ranging
from the basin (Aldaya, Martı
´
nez-Santos, & Llamas, 2010; Dietzenbacher & Vela
´
zquez,
2007; Montesinos, Camacho, Campos, & Rodrı
´
guez-Dı
´
az, 2011), to the national (Guan &
Hubacek, 2007; Roth & Warner, 2008; Wichelns, 2001; Zhang, Yang, Shi, Zehnder, &
Abbaspour, 2011), to the global (Fader, Rost, Mu
¨
ller, Bondeau, & Gerten, 2010; Yang,
Wang, Abbaspour, & Zehnder, 2006).
