The water footprint (as defined by the Water Footprint Network) is an indicator of freshwater use that looks at both direct and indirect water use of a consumer or producer. The water footprint of an individual, community or business is defined as the total volume of freshwater that is used to produce the goods and services consumed by the individual or community or produced by the business.
Water use is measured in terms of water volumes consumed (evaporated) and/or polluted per unit of time. A water footprint can be calculated for a particular product, for any well-defined group of consumers (e.g. an individual, family, village, city, province, state or nation) or producers (e.g. a public organisation, private enterprise or economic sector). The water footprint is a geographically explicit indicator, not only showing volumes of water use and pollution, but also the locations.
A water footprint measures three primary components:
Blue Water Footprint
The volume of surface and groundwater consumed as a result of the production of a good or service.
Consumptive water use refers to one or a combination of the following cases:
– Water evaporates
– Water is incorporated into the product
– Water does not return to the same catchment
– Water does not return in the same period.
Green Water Footprint
The volume of rainwater consumed during the production process.
This is particularly relevant for agricultural and forestry products (products based on crops or wood), where it refers to the total rainwater evapotranspiration (from fields and plantations) plus the water incorporated into the harvested crop or wood.
Grey Water Footprint
An indicator of freshwater pollution that can be associated with the production of a product.
It is defined as the volume of freshwater that is required to assimilate the load of pollutants based on existing ambient water quality standards. It is calculated as the volume of water that is required to dilute pollutants to such an extent that the quality of the water remains above agreed water quality standards.
For more information visit the website of the Water Footprint Network.