chapter  12
32 Pages

The blue, green and grey water footprint of rice from both a production and consumption perspective

ByAshok K. Chapagain & ArjenY. Hoekstra

ABSTRACT: The aim of this chapter is to make a global assessment of the green, blue and grey water footprint of rice, using a higher spatial resolution than earlier studies and using local data on actual irrigation. Evapotranspiration from rice fields is calculated with the CROPWAT model; the distinction between green and blue water evapotranspiration is based on data on precipitation and irrigation.Water pollution fromN-fertilizers is estimated based on application rates. The calculated green, blue and grey water footprints of paddy rice are converted into estimations of the green, blue and grey water footprints of derived rice products on the basis of product and value fractions. International virtual water flows related to trade in rice products are estimated by multiplying export volumes by their respective water footprints in the exporting countries. Per nation, the water footprint of rice production is estimated by aggregating the water footprints per production region. The water footprint of rice consumption is estimated for each nation by aggregating the water footprints in the regions where the rice consumed in a nation is grown. For rice importing countries, the water footprint related to rice consumption is thus partly (or fully) outside the country itself.