Water Footprint


Water Footprint (WF) concept was introduced by Arjen Hoekstra in 2002 during a meeting focusing on virtual water trade [1, 3]. It is defined as the measure of the amount of water consumed directly or indirectly for the consumption of human activities [1,2]. The water footprint of a product is shown in water volume per unit of product and it is the summation of all those steps that are required in product production [7]. There are different water footprints for individuals, communities, regions, and nations, as explained by [5]. These concepts start due to the human impact on the environment [4] and raise the awareness of a nation about the proper usage of water and show the global water resource management [1]. Water footprint not only shows the use of water but also indicate the degree of change in environments, like climate change [3, 5]. Water footprint was standardized by ISO standard 14,046, while in European Union it is defined under Water Framework Directive (FWD) to improve water production quality and deficiency [4]. WF is important as it is reported that human dependency on the water are increasing rapidly and used un-effectively which create water scarcity [5, 6]. It is estimated that 22% of the water consumption is related to trade through water [6]. The field of water footprint is very well explained as a new research area by [9] and emphasizes four key concepts. These concepts are described as;

  • The concept of virtual water trade (VWT): showing that freshwater is a global resource that effect on the global economy.
  • Limited amount of freshwater: this is explained by the limited rate of renewal for fresh water so a system will develop to study their production, consumption, and trade.
  • Understanding of natural resources: the use and impacts of water consumption, their supply chain, and life cycle.
  • Approaches towards freshwater: while following a comprehensive approach towards freshwater scarcity and its use, the consumers must consider blue, green, and gray water.

Recently it is reported by [10] that WF magnitude is highly affected by the type of soil, management of water, and change in the climate. The conceptual framework of the water footprint is summarized in Figure 1, (data taken from 3, 4, 5, 10, 12) showing the three types of water, qualitative and assessment approaches of WF, and the calculations of consumed water. The WFcon is achieved by two methods i.e. top-down and bottom-up. The former one is composed of WFpro + virtual water import (VWi) – Virtual water export (VWe).

Fig. 1. Illustration of the conceptual framework of water footprint.

Types/components of water

The scientist divvied the water resources into three types i.e. blue water, green water, and grey water [6]. Green water is the water of unstructured zones which are available for plants and mostly formed due to precipitation, while blue water is the commonly available water in various forms like river, lakes, and springs [3, 7]. Another type is grey water which act as indicator for water pollution and reflects the freshwater volume which is used in the assimilation of water pollutants [6]. In term of the consumptive and degradative concept, the former concept is associated with green water (rainwater consumption) and blue water (consumption of surface or groundwater), while the latter term explains grey water for the assimilation of water-related pollutants [9].

Traditionally the concept of water footprint were restricted to blue water but later other form were also included. These types of water are widely used for various purposes for instance, green water is the leading source for rainfed agriculture while blue water is mainly used in agriculture irrigation [3]. Green water is mostly the product of agricultural activities as they are evaporated from soil after rain, absorbed by roots, or transcribed from crops [4]. Gray water is used domestically, industrially, and commercially for various purposes [15]. 

Assessment of water footprint

Assessment of water can quantify the three forms of water and assess their sustainability, efficiency, and the approaches that are used to implement the water footprint effectively. In a broader sense, this concept covers hydrological, environmental, social and economic science [13]. The four key steps in water assessment are the following;

1-      Scope and goal: diversified and actionable goals are stetted.

2-      Data mining: once goals are stetted then data will be collected from various sources and analyzed. 

3-      Sustainability assessment: in this step water sustainability and efficiency are assessed.

4-      Response strategies: once enough data and other parameters are obtained then response strategies are formulated to achieve the target.

The assessment of water footprint is achieved by two pathways, the volumetric approaches of the Water Footprint Network (WFN) and the Life Cycle Analysis (LCA) [3, 4 ]. The first approach focus on the management of water and is concern with the quantification, sustainability, formulation and scope of water, while the second is product-based approach and focus on inventory and impact assessment, goal, and interpretation of water [4]. The quantification approaches are comprised of 5 types, namely Field Crop Water Requirement (FCWR), Regional Water Balance (RWB), Field Soil Water Balance (FSWB), Field Measured Water Balance (FMWB), and Remote Sensing (RS) as shown in fig.1 [10].

Importance of WF

Water footprint is important in various aspects; it cover all types of water in term of measurement and calculations, it is the main source of agriculture, mining, forestry, and fishing economy, it helps in the productions of goods, used in industry, help in construction etc. use for the transportation of goods and other substances and help in the production of food substances [6, 10]. WF also shows the water appropriation which indicates both water consumption and water assimilation [7].

Water footprint understanding can help nations to formulate their national policies [8].  The field of WF can interconnect both water resources and environmental science [9]. Currently, the root of water footprint is embedded in crops, foods, cheese, leather, milk, meat, and the municipal sector [9].  For water sustainability, the WF concept is crucial as they become an important parameter in water consumption and pollution [11]. 

As the freshwater amount is limited and how we human are using are vulnerable that leads to cause various environmental threats. Currently, such water sources are depleted in many parts of the world and causing damage to soil, ecosystem, and habitat and causing drastic climate change [12].  WF also shows the relationship between the production system and socio-economic activities which are the main factors of water assessment [14].

About the Author: Mr. Abrar Hussain holds a master's degree in chemistry/biochemistry from the University of Peshawar. He earned additional degrees in science education, including C.T., B.Ed., and M.Ed. from Allama Iqbal Open University. Recently, he completed his M.Phil./MS in biochemistry from HEJ Research Institute of Chemistry, focusing on probiotics research, particularly the assessment and validation of enterococcal strains. Abrar is a respected young researcher and speaker in the probiotics field, delivering numerous online lectures. He was recognized as a speaker at the 6th International Conference on Microbes and Beneficial Microbe for his talk on "Probiotics: Selection Criteria and Mechanism of Action." He is also committed to mentoring young researchers, emphasizing both scientific and moral development. His strong research and presentation skills have led him to engage with various organizations as a speaker.


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