What is the water footprint and why is it important?

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1,385 cubic meters, the equivalent of half an Olympic swimming pool. It is the average annual water footprint generated by each person, i.e. the quantity of fresh water that has been necessary for them to be able to feed themselves, dress themselves, move from one place to another.

In short, to develop your daily routine. Everything is going well that we use every day consume, directly and indirectly, a certain volume of water in their production and consumption process and this is what is called in terms of durability water footprint.

Thanks to this environmental indicator, can measure the human impact on the planet’s water resourcesas valuable as it is rare on the planet.

Concept

The concept was invented in 2002 by researchers from the University of Twente (Netherlands) Arjen Hoekstra and Mesfin Mekonnen, who established this variable to obtain valuable information on the actual consumption of water and the uses we make of itfrom surface and underground sources through the entire production and distribution chain to the final product.

Thus, it is possible to calculate the impact that we generate using a sheet of paper (10 liters), eating an orange (50 liters)implement a cup of coffee (140 liters) where to wear a pair of jeans (10,000 liters).

On a planet where the scarcity of fresh water will increase, mainly due to climate change, population growth and increased pressure on water resources, it is necessary to take measures to optimize and better manage the use of this vital resource.

Experts predict that in 2025 67% of the planet’s population will live in an area of ​​water stressi.e. the places where the demand for fresh water is greater than the quantity available (due to droughts, over-exploited aquifers, etc.) or where the use of this freshwater is restricted due to loss of quality (saline intrusion, contamination by nitrates or phytosanitary products, etc.).

How do we measure the water footprint?

The great discovery of Dutch researchers and its practical usefulness have allowed, since 2002, any organization, government or company to apply the formula to calculate the water footprintvery useful information, especially in the primary and secondary sectors.

To calculate its value measure the volume (liters or cubic meters) of water consumed, that which has been contaminated and that which has evaporated in the manufacturing process. The water footprint is therefore the result of three indicatorsdivided into colors, according to the origin of the water: green water footprint, blue water footprint and gray water footprint.

This was established in 2008 by Professor Hoekstra in the Water Footprint Networkthe platform created in collaboration with companies, civil society and academic organizations that includes a universal manual that differentiates:

  • Green water footprint (precipitation retained in the ground): It is that which comes from rainwater or snow incorporated into the product and which is stored in the ground superficially within reach of the plants, which return it to the atmosphere by evapotranspiration, than the returned to the atmosphere by evapotranspiration.
  • blue water footprint (rivers, lakes and aquifers): This is water that comes from or is captured from natural or artificial sources (surface or underground) by infrastructure or facilities. It is equivalent to the direct consumption of fresh water in the manufacturing processes of goods and includes irrigation water.
  • Gray water footprint (necessary for the receiving environment to assimilate the pollutants discharged): It designates the quality and it is the quantity of water contaminated in the processes and which subsequently requires treatment to comply with the sectoral regulations of the sector or the organization receiving the releases. the process.

Water footprint in the world and in Spain

Each country has a different water footprint depending on the quantity of goods and services it is able to generate and consume, the degree of availability of the resource and its quality, i.e. the degree of contamination or overexploitation. . At the World level China, India and the United States are the countries with the largest water footprint represent 38% of water consumption.

The water footprint per capita per year in the United States amounts to 2,842 m3, which is the equivalent of a daily expenditure of 7,786 liters per person per day and with which an Olympic swimming pool could be filled.

In China, this footprint amounts to 1,071 m3 per year and per inhabitant, or, which comes to the same thing, 2,934 liters per day and per person.

In India -where the water footprint amounts to 1,089 m3 per year and 3,000 liters per person per day-, the main problem lies in overexploitation of its groundwater and the trend is for it to get worse with lack of rain and deforestation.

What is happening in our country?

Despite Spain It is the driest country in the European Union, we occupy the second place -behind Portugal- with the largest water footprint in Europe with 2,461 cubic meters per capita per yearthe equivalent of expenses 6,700 liters per person per day.

Spanish agriculture requires an expenditure of 80% water, taking into account the blue and green water footprint, while industry accounts for 15%.

However, even if “Agriculture (food production) is the sector that uses the largest amount of water (70%), more than 99% is transpired, and returns directly to the atmosphere” noted Ignasi Servià, expert consultant on strategic and territorial irrigation issues at iAgua.

In addition, “If you bet on a efficient and highly technical agriculture the water footprint is considerably reduced, for example by spending only 31 liters to produce an apple compared to 69 liters if it is grown using a traditional method”, To add.

Main water footprints of goods and services

The the water footprint has necessarily a spatial and temporal dimensionthat is, knowing the water footprint of each region, each company or industrial facility over a period of time (normally measured in annual terms), allows to assess and improve the sustainability of its activities by putting implement more effective measures.

This is all the more relevant as the increase in population in the coming years will force to increase food production by 50% by 2030with the consequent conflict it can cause in other sectors, such as industry, and in general, with the availability and supply of fresh water throughout the planet.

For it it is necessary to know the impact of the water footprint in:

  • Food: Cereals, meat and milk These are the foods that require the most water in their production process. To get an idea: the production of a liter of milk requires 1,000 liters of water, a kilo of rice 3,400 liters, a kilo of corn 900 liters, a kilo of wheat 1,300 liters, a kilo of beef 16 000 liters.
  • Clothes and shoes: The water footprint of textile production is also one of the highest. For example, to obtain a kilo of cotton, you need about 10,000 liters, so, to make a cotton T-shirt of about 250 g, you need 2,500 liters, for a pair of jeans about 10,000 liters, for some sports shoes 4400 liters, and a single cotton swab requires 4 liters.

What can we do to reduce the water footprint as producers and consumers?

Producers:

  1. Apply efficient measures of water use, using technology available to us. “It consists of producing the maximum amount of food with the minimum amount of water thanks to localized irrigation systems, remote sensing, sensors, etc. “says Ignasi Servià.
  2. Adapt production linesby choosing local raw materials to reduce the water and virtual footprint, that resulting from travel: imports and exports.
  3. Promote a real circular economy in businesses and industries, returning a high percentage of the water used in manufacturing in pristine condition to the environment. This involves using essential amounts of water and reducing pollution in the process to avoid the so-called gray footprint.

Consumers:

  1. Consume local products in order to avoid the virtual water footprint. Just look at the label to know the origin of these products or garments, as in the case of clothing.
  2. Reduce consumption of certain foods more demanding in water, such as meat or processed foods and favor the consumption of fruits and vegetables. Also, do a responsible purchasing to avoid food waste, as this will help reduce the water footprint.
  3. assume the circular economy reduce consumption (extend the useful life of the products we use), reuse and recycle.
  4. raise awareness of a responsible use of water in our daily lives, such as using a dishwasher instead of washing dishes by hand, reusing water from boiling food to water plants, using the washing machine completely full, metering water from the cistern or using the shower instead of the bathtub to wash

Character font: Ana Caballero / Smart Planet – THE WORLD

Reference article: http://www.planetainteligente.elmundo.es/recursos-hidricos/que-es-la-huella-hidrica-y-por-que-es-importante

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