Water Footprint and Virtual Water

Abstract

Freshwater is vital to life. As our population and prosperity grow, use of freshwater also increases. This is always a concern since water is already scarce in most parts of the world. People use lots of water for drinking, cooking and washing, but even more for producing things such as food, paper, cotton clothes, etc. This invisible use of water is called virtual water content. The adjective virtual refers to the fact that most of the water used to produce a product is in the end not contained in the product. The real water content of the product is generally negligible if compared to the virtual water content. Virtual water helps us realize how much water is needed to produce the goods we use and the food we eat. Water footprint is a popular method for demonstrating the total amount of water needed to produce a variety of goods and services. This concept was introduced in 2002 by Arjen Hoekstra of the United Nations Educational, Scientific and Cultural Organization (UNESCO) as a comprehensive indicator of water use. A water footprint is a comprehensive measure of freshwater consumption that connects consumptive water use to a certain place, time, and type of water resource. The water footprint includes the total amount of freshwater consumed along the supply chain of a product. 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. A water footprint differs from the typical measure of water use or water withdrawals, because a water withdrawal is a temporary diversion or drawl of water from surface or ground whereas water footprint accounts for consumptive water use that permanently withdraws water from its source and that water is no longer available because it has been evaporated, been transpired by plants, incorporated into products or crops or consumed by people or livestock. Water footprint accounts separately for three types of freshwater consumption: green water use, which is consumption from rainfall; blue water use, which is consumption from groundwater or surface water; and grey water use, which would be the dilution water required to reduce pollutant concentrations to acceptable values. Water footprint is an important concept in creating a public awareness of the amount of water that is used to make everyday items. It helps individuals, businesses and countries by revealing water use patterns, from the individual level all the way to the national level. It shows the water used in all the processes involved in manufacturing and production of our goods and services. Water footprint also accounts for how much water is contaminated during manufacturing and production process because that water become unusable and is taken out of the system. The water footprint gives a sound frame of reference and helps us all be more efficient and conservative with our water.