OVERVIEW

A.Y. Hoekstra introduced the water footprint concept in 2002; it has been developed as an indicator, used to express the total amount of volume of fresh water consumed to produce a particular good, or to provide a service.

The main objective of assessing the water footprint of goods is to analyze how their production is affecting water resources (and pollution), and how these processes can be more sustainable (from a water perspective).

The water footprint is composed of three components: green, blue, and gray water footprint. The blue water represents the volume of water, which is withdrawn from surface (sea, lake, and river) or grand-water, and does not return to the same basin of catchment, or to the sea.

The green water is the rainwater, the soil moisture adsorbed, and the evapotranspiration of the plant. As it is easy to imagine this component of water footprint is of particular relevance toward the agriculture sector in comparison with the industry sector (just in the case in which they have green roof, but, even in that case, is usually not significant).

The last component of the water footprint, the gray water, represents the amount of water, which is necessary to dilute the load of pollutants/emitted substance from the production chain, in order to make them harmless.

The water footprint can be expressed in a variety of ways, according to what is most relevant to underline in the assessment. For instance, it can be expressed as water volume per piece (when the product is countable), or as water volume per product unit (mass, money, piece, unit of energy, etc.). However, the classical way of its representation is in the form of water volume per unit of time (m³/ton, or l/kg).

The water footprint can be calculated on different scales, starting from the individual consumer to companies, products, and even entire countries. Such categories are usually divided into direct and indirect water footprints; for example, an individual is composed by the water consumed at home (direct) and the one comprised from the consumption of products and services (indirect). As for companies the operational represents the direct consumption, while the suppliers/production chains the indirect [1].

The last concept that is worth mentioning about water footprint is that of water neutrality.

This concept is relatively new and was defined for the first time in 2007 by a heterogeneous group of six organizations. The group defined three main criteria characterizing this idea, being:

1. Defining, measuring, and reporting one's “water footprint” (this is not always considered mandatory, especially for actors different from organizations).
2. Taking all actions that are “reasonably possible” to reduce the existing operational water footprint.
3. Reconciling the residual water footprint (amount remaining after a company does as much as possible to reduce the footprint) by making a “reasonable investment” in establishing or supporting projects that focus on the sustainable and equitable use of water.

Unless these points have still some unclear aspects—such as what is reasonable, how to measure improvement and accounting for loss of water in different areas—the water neutrality concept can still be considered a useful tool to decrease the overall water consumption and increase the efficiency of use within the production chain [2].

GUIDELINES FOR MEASURING THE WATER FOOTPRINT

At the contrary of what is the situation for the calculation of the carbon footprint, for which there are plenty of different methodologies to use, for the water footprint the choice is significantly smaller. Indeed, the most used framework is the one provided by the Water Footprint Network, which gives guidelines on how to assess the water footprint of a product. According to it a complete water footprint assessment is made of four different phases:

1. Setting the goals and scope—In order to define what is to be measured (consumption of water for the supply chain, one stage of production, final consumer, etc.).

   The first thing to determine is which type of water footprint to calculate (product, consumer, production step, etc.), and to what level of detail. Then the boundaries should be set, defining what is included in the study and what is not, for example, which component of the water footprint (green, blue, gray), spatial–temporal borders, direct or indirect consumption, etc. The sustainability assessment, which is usually based on geographic perspective, enables the analyst to link the hot spot and issues to a particular place or reality. Finally the response formulation, here is particularly important to individuate who should be involved and participate to the “solution” process started by the water footprint analysis.

2. Water footprint accounting—Here the water consumption is quantified and located in space and time.

   Its aim is to measure the human appropriation of freshwater in a determinate catchment area—expressed in volume. The water, which composes the water footprint typically, originates from the one catch by evapotranspiration and runoffs. The water footprint of a single process-step is the basic measure for every accounting of water footprint; then the intermediate or final product calculation can also be done, and add to the total accounting. The accounting of water footprint (which is “the water footprint of a product is defined as the total volume of fresh water used directly or indirectly to produce the product”) is therefore calculated by including the consumption and contamination of water in all the stages of the production chain (this process will almost always be the almost the same, no matter the sector).

3. Water footprint sustainability assessment—Is where the environmental, social, and economic aspects are evaluated.

   The suggestion given by the guideline considers the assessment of the sustainability process of the catchment of water according predominately by two parameters: the location in time and space within a catchment or river basin, and from which kind of process or group it is addressed (i.e., producer or consumer). For the calculation of the sustainability of the water collected, different impacts within environmental, social, and economic spheres are taken into consideration (once relevant criteria are identified). Then precise suggestions on how to calculate the sustainability of processes, products, and consumers are given.

4. Water footprint response formulation—In which a strategy is trying to be developed.

   The guideline is intended to be a useful tool to understand in which direction solutions should come and go. The main actors which are addressed are consumers, companies, farmers, investors, and governments; and for each of them suggestions are given on how they can act and undertake initiatives to reduce the consumption of water, and therefore the water footprint. Lastly there is also a short mentioning on how it should be preferable to have clear targets of reduction instead of an offsetting program to reach water neutrality [1].

Another interesting tool that is under development and should be released within 2012 is the ISO 14046 or water footprint—requirements and guidelines, developed by the International Organization for Standardization (ISO). The work of ISO is aimed at integrating the standards of Life Cycle Assessment (LCA), and the carbon footprint standard ISO 14067 (which is also under development by ISO). The purpose of this guideline is to include:

• Principles and guidelines for a water footprint metric of products or organizations.
• How different types of water (green, blue, and gray, as well as ground and surface water) should be considered together with the socio economic and environmental issues.
• How to communicate on water footprint.
• Make it compatible with the other standards of the ISO 14000 family [3].

WATER FOOTPRINT AND LCA

At the moment the most commonly used framework to calculate water footprint is the guideline released by the Water Footprint Network, which is assessed mainly through water inventory and accounting.

Indeed water footprint is sometimes criticized for the absence of “characterization factors,” which should weight its components according to their impact, and will be appreciated for an LCA methodology (and perspective). But this, according to the Water Footprint Network, will go to influence the impact on social and environmental impacts, since it will lead to the omission of important key indicators—such as the variability in time and space.

To agree on both the purposes of Water Resources Management and LCA the steps usually undertaken for the calculation of the water footprint should be approached differently in an LCA perspective. To do so the accounting stage will be part of the inventory of LCA, while the impact assessment and aggregated impact assessment will be part of the life cycle impact assessment. But this, according to the authors, will still invalidate the effectiveness of the water footprint meaning [3].

CASE STUDY: COCA-COLA COMPANY

Coca-Cola is a leading company in the beverage industry with particularly interesting initiatives related to sustainability [4]. Water is one of the most important ingredients for the production of the final product and special attention is paid to its management in the context of the establishment of a sustainable business on a global scale. Most efforts are focused on the areas with the highest impact on people's health, communities, environment, and market places, thus contributing to United Nations Sustainable Development Goal 6: Clean Water and Sanitation.

In particular, the sectors that are the core of the company's strategy are the following: improving water-use efficiency and reuse in bottling plants, managing wastewater, and storm water discharge to prevent pollution, replenishing the water used in finished beverages across communities and watersheds and helping manage water resources in agricultural ingredient supply chain. Global water risk assessments are carried out at the plant-level and each of the 800 Coca-Cola installations is required to assess local vulnerabilities to implement plans to address them. And this is because a clear precondition for water management is the clear understanding of the origin of water, its availability to local communities, current, and expected future pressures on supply and quality, as well as ways of contributing to addressing common challenges in watersheds of operation [5].

REPLENISHING THE WATER USED

Coca-Cola is trying to refresh 100% of its water in the final beverages back to communities and nature, a target it met for the first time in 2015. Community water projects are carried out with the expertise and support of many important partners and focus on improving safe access to water for human consumption and sanitation, the protection of catchment areas by improving the capture, storage, and quality of water, and the supply of water for productive use, such as increased water availability or water efficiency in agriculture.

IMPROVING WATER-USE EFFICIENCY AND REUSE IN BOTTLING PLANTS

A key process for water management is managing the use of water in bottling plants worldwide. The goal is to reduce the water use ratio by 2020, while increasing the volume of units of the company so that profitability improves by 25% compared with 2010 levels. In recent years there has been a significant improvement in the water efficiency, while about US$1 billion (from 2011 to 2020) can be saved across the water acquisition system, domestic handling, and discharge fees.

WATER IN AGRICULTURE

A fundamental pillar of water stewardship and overall sustainability of water resources is to improve water management in agriculture through integrated farm operations. In this context, support is being given to projects aimed at improving the productive use of water, especially in areas with high risk of water stress or pollution. These projects are aimed at reducing water drainage and improving water efficiency in agriculture or reducing the use of pesticides and runoff in order to reduce water pollution. Partnerships to promote nature assessment work are just as important, as in the case of cooperation with the global partner, WWF, to help rural communities determine which sustainable farming practices provide the greatest benefits for the protection of watersheds. Lastly, suppliers play a key role in addressing farmers' water hazards with global and extensive supply chains. Sustainable Agriculture Guiding Principles (SAGPs) and Supplier Guiding Principles ensure good water management practices.

ENGAGING IN WATER POLICY REFORM

Because the ultimate responsibility for more sustainable and equitable water resource management lies with governments and public authorities, Coca-Cola is available to provide valuable information on relevant discussions and subsequent policies to solve water supply, quality, and access gaps. With great experience on this precious resource, operating in more than 200 countries and territories, the company is working with international policy cooperation platforms such as CEO Water Mandate and 2030 Water Resources Group to help reform water policy.

NESTLE

Nestle has developed a drip irrigation project in Nicaragua, to develop a low cost irrigation system to use in the coffee plantations. This project took place during a three years period (2007–2010), and Nestle developed it in collaboration with ECOM, Rainforest Alliance, and IDE, and it estimated the participation of 1500 small coffee producers.

The purpose of the project was to provide the coffee crops with a supplementary irrigation system during water stress periods (and flowering periods), since this has showed to increase the productivity, the growth of the plant, and the quality of the crop. Indeed, during the critical growth period, a lack of irrigation could have a strong negative impact on coffee performance and quality. To do so Nestle introduced, improved, and recorded a low cost dripping system, as part of a process of embedding sustainability within its value chain.

The project started with the installation of a drip irrigation system in 11 different plantations in Nicaragua. The increase of production was registered the same year, for an amount estimated between 40% and 60% of the yield of the previous year, and at the same time young plants grow faster. These results were confirmed during the following years of the projects, which also allowed observing that irrigated plants of two years were producing similarly to plants that hadn't been irrigated over a period of three years.

Since the successful results of this project, the system of irrigation has been implemented in other plantations in Nicaragua (32 in total), and also in Honduras (9 systems), El Salvador, and Guatemala [6].

The Dole Food Company, which is the world's biggest producer of fruit and vegetables, has introduced a new method to reduce the use of water consumed during the packing process of bananas. To allow a sensitive reduction of water consumption, Dole has implemented different types of water recycling systems during the packing process in the last two decades.

The use of water in the packing stage takes place mainly in the following three different phases: to remove dirt and insects from bananas, to hold and carry bananas while they are selected, and for the removal stage. This traditional way of packing bananas requires around 150 l/box (18.14 kg).

A first measure that Dole undertook at the beginning of the nineties was the adoption of sand and other gravel filters inside a partial recirculation system in order to reduce the amount of water per produced box to 100 l. In addition a Mobile Banana Processor was also developed which allowed a reduction of 97% of water use, which distributed in remote areas of the Philippines.

After a few years Dole installed 120 new systems, which completely recycle and re-circulate the water for the packing process in Ecuador, bringing the water consumption for banana boxes down to 18 l. Afterwards, this system was applied in water scarce areas in Honduras Colombia, and Costa Rica.

The last improvement that Dole designed was part the “New Millennium Packing Plant.” In this new system, rather than using water pools (as is common practice), most of the activities take place in the banana crop, leading to a 90% decrease of water use (and 50% less energy) in comparison with a traditional system. Dole's specific initiative has been awarded with an “honorable mention” from the Scientific Committee of the World Water Week in Stockholm in September 2010 [7].

WATER FOOTPRINT VERSUS CARBON FOOTPRINT

The numerous “footprint” indicators that have been born in the last few years have been intended as complementary indicators of the environmental impact of human activities, since they focus on different issues.

Both water and carbon footprint are two really useful tools for the quantification of the emission or consumption of the respective resources, as well as of the improvement that they can lead during their assessment. However, both footprints communicate just the final value of the study. This can be really deceptive (particularly for water), since the amount of water consumption communicated is not related to the hydro geographical area; therefore it is not necessarily synonymous of water stress in the area. Indeed, if we compare with the carbon footprint, where we assume that any quantity of CO₂ emitted (and other greenhouse gas (GHG)) is increasing the greenhouse effect (therefore it has a “negative” impact), we cannot say the same for the water consumption. In fact a high consumption of water in a particular region/basin should not automatically lead to a water stress situation. As a consequence, it is easy to understand how it can be difficult to communicate effectively the assessment of the footprint undertaken.

Regardless of the communication problem, the water footprint and the carbon footprint remain really valuable tools for companies wishing to find their major point of consumption and waste, in order to quantify and try to reduce their water consumption (e.g., through the identification of hot spot). A challenge regarding the future use of different footprints, which is recognized by different experts, is the development of a framework that would be able to integrate all these different analysis in a comprehensive and useful manner.

The last point of difference between these two “footprints” can be found in their way of offsetting. Indeed both of them have developed a system, which allowed offsetting and neutralizing the emissions or consumption through projects, in order to reach the “neutrality” balance. Here the only difference among the two strategies of offsetting is that the one for water has not yet developed an exchange system of quote among nations or companies since water is a local resource.

ISSUES FOR LEARNING AND DISCUSSION

1. Does the product water footprint include the water consumed and the water polluted?
2. Does the water footprint of a product include the use phase of the product as well?
3. Can a water footprint be calculated for a product and an organization?
4. Which are the three components of water footprint?

REFERENCES

1. 1.  Hoekstra AY, Chapagain, A.K., Aldaya, M.M. & Mekonnen, M.M.. The Water Footprint Assessment Manual—Setting the Global Standard. The World Bank Group; 2011.
2. 2.  BSR (Business for Social Responsibility). 2008. Water neutrality. Available at http://www.bsr.org/reports/Coke_Water_Study_March_2008.pdf. Accessed 2019 Oct 28.
3. 3.  Arjen Y. Hoekstraa, Winnie Gerbens-Leenesa, and Theo H. van der Meerb. 2009. Water footprint accounting, impact assessment, and life-cycle assessment. Available at http://www.waterfootprint.org/Reports/Hoekstra-et-al-2009-WaterFootprint-LCA.pdf. Accessed 2019 Oct 28.
4. 4.  Coca Cola company. 2018. 2017 sustainability report the Coca-Cola Company. Available at https://www.coca-colacompany.com/2017-sustainability-report. Accessed 2019 Oct 28.
5. 5.  Coca Cola company. 2018. 2017 water update: investing in water quality and availability. Available at https://www.coca-colacompany.com/stories/2017-water. Accessed 2019 Oct 28.
6. 6.  Nestle. 2019. Available at https://www.nestle.com/csv. Accessed 2019 Oct 28.
7. 7.  Dole Food Company. 2011. Available at http://dolecrs.com/sustainability/water-management/water-recycling-programs-for-banana-packing. Accessed 2019 Oct 28.