ABSTRACT
Improvements in the main climatic and hydrological databases on which Water Footprint calculations are based have been especially important. In an attempt to consolidate analytical approaches, the Water Footprint Network published the Water Footprint Assessment Manual. This sets out robust and standardised methods for calculating volumetric Water Footprint accounts and provides guidance on how to interpret them given variations in context. More practically, the varying water quality standards in different parts of the world make it difficult to account for grey Water Footprint. The other significant accounting Water Footprint challenge is linked to the concept of weighted Water Footprints. Anyone interpreting a Water Footprint Assessment needs to consider not only environmental factors relating to blue water resources but also land tenure, land allocation and social equity issues linked to green water. Weighted Water Footprint assessment is an attempt to reduce all of this complexity.
