Know Your Water Footprint

The blue water footprint is the total volume of fresh surface and groundwater needed to produce a commodity. Consumption of drinking water, irrigation water and industrial water can be considered as blue water footprint.

Blue water footprint can be defined as the gross water taken into the water transmission network from surface or groundwater resources for irrigated agriculture, industrial and domestic water uses. For example; for irrigated agriculture, evaporation loss can be expressed as the sum of water used by the crop and water drained. Blue water footprint in the industrial and drinking-utility water sectors can be defined as the water supplied to these sectors from the existing surface and groundwater bodies in a basin.

Irrigated Agriculture Blue Water Footprint (volume/time) = Evaporated Blue Water + Blue Water Included in the Product + Amount of Drainage

Green Water Footprint (volume/time) = Green Water Evaporated + Green Water Included in the Product

Grey water footprint is the amount of fresh water required to assimilate pollutants to meet water quality standards. Grey water footprint can be calculated for point and/or diffuse sources of pollution.
• Grey water footprint refers to pollution. It is defined as the volume of freshwater required to reduce the pollution load to natural background concentrations in the receiving water body.
• The grey water footprint is calculated by dividing the pollution load by the difference between the current water quality status in the environment as a result of pollution and the natural background concentration.
• The most important issue for grey water footprint calculation is the determination of water quality standard and natural background concentration.

Grey Water Footprint (volume/time) = Pollutant Load / (Maximum Measured Concentration in the Receiving Water Body – Natural Concentration in the Receiving Water Body)