How the water footprint is calculated

cómo se calcula la huella hídrica

One of the serious problems that exist in the world is water scarcity. It has become a critical problem in many regions, so understanding and monitoring the water footprint is essential to ensure sustainable use of this resource so essential for life. In this article we will learn how the water footprint is calculated.

What is the water footprint

The water footprint is an indicator that measures the total direct and indirect water use associated with the production of goods or services. 

Beyond measuring the water we consume directly, such as that we drink or use for bathing, the water footprint considers the water used throughout the life cycle of a product: from the production of raw materials to its manufacturing and distribution.

Main components

This indicator is broken down into three main components:

  • Green water footprint: Refers to rainwater that is absorbed by plants during their growth. Essentially, it represents the water that evaporates and transpires in the production of crops and vegetation.
  • Blue water footprint: This part considers the use of water from surface or underground sources for human activities, such as agriculture, industry or domestic consumption. Includes water extracted from rivers, lakes or aquifers.
  • Gray water footprint: Related to water contamination during production processes. Calculates the amount of water needed to dilute contaminants and restore the quality of the water used in production.

Importance of the water footprint

The water footprint serves as an integral tool to understand and manage sustainable water use. It provides valuable information about how our daily activities and the production of goods impact the availability and quality of water. In addition, it allows you to identify areas where water efficiency can be improved and waste reduced.

Its usefulness extends to different sectors:

  • Agriculture: Allows you to evaluate the impact of growing different foods on water use, promoting more efficient and sustainable practices.
  • Industry: Helps companies identify opportunities to reduce water consumption in their manufacturing processes and minimize water pollution.
  • Consumers and public policies: Facilitates making informed decisions. Consumers can opt for products with a smaller water footprint, and governments can establish policies to encourage responsible water use and conservation of water resources.

How the water footprint is calculated

The water footprint calculation It involves considering multiple variables and factors specific to each activity or product. Next, we will see how the water footprint is calculated.

Although its exact formula may vary depending on the approach and methodology used, there are general steps to calculate it:

  • System identification and limits: The system and its limits are established. To calculate the water footprint of a product, its complete production and consumption are determined.
  • Data collection: Collect detailed information on water use in all stages of the evaluated system. This includes the direct water used (green and blue footprint) and the amount of water needed to dilute the contamination (gray footprint).
  • Evaluation of the green water footprint: To calculate this part, the amount of water evaporated and transpired by crops or vegetation is analyzed. Precipitation, direct evaporation from the soil and plant transpiration are considered.
  • Calculation of the blue water footprint: Here the water extracted from surface or underground sources for specific uses in the evaluated system is quantified. Water used for irrigation, industrial processes or human consumption is considered.
  • Determination of the gray water footprint: The amount of water necessary to dilute the contaminants generated in the production process and return the water to its original quality is evaluated. This involves considering the levels and types of contaminants present.
  • Normalization and weighting: Once all the data is collected, it is adjusted to a common unit to be able to compare different products or activities. This involves normalizing values to unify measurement and, in some cases, applying weights to reflect local water availability or severity of contamination.
  • Interpretation of results: Finally, the results are analyzed to understand the total impact of water use and determine areas for improvement or strategies to reduce the water footprint.

Complex but necessary calculation

It is important to keep in mind that the calculation of the water footprint can be complex and often depends on the availability of accurate and reliable data at each stage of the evaluated process. 

Additionally, methodologies and standards may vary, resulting in slightly different results in different studies or evaluations. However, despite these complexities, the water footprint is a valuable tool for understanding and managing responsible water use in various sectors.

Our sustainability consulting Ecoterrae, we have a specialized team that will provide support and monitoring in the calculation of the water footprint to companies that require it.

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