Irrigation water flowing into a holding pond, near Darlington Point, NSW

Measuring the water footprint of agriculture from 'paddock to plate'

A method for measuring the environmental impacts of water used in crop and food production is helping businesses develop more sustainable practices and consumers make wiser choices.

• 25 January 2011 | Updated 27 January 2012

• How a water footprint is calculated
• Research examples
• International standard for water footprinting

In many parts of the world, freshwater is already a scarce and over-exploited natural resource. Agriculture is the largest consumer of freshwater globally. The way we manage and develop our agricultural industries and farming techniques has significant implications for global food security.

CSIRO has jointly developed a method for 'water footprinting' with ETH Zurich that helps businesses measure the environmental impact of water use and identify where changes and savings can be made in the production system.

The method, based on a life cycle assessment approach, takes account of the type of water used across the full life cycle of the product as well as the local water scarcity where the actual production and water use occurs.

Food producers, manufacturers and retailers can then identify where changes need to be made in the production cycle and along the supply chain to reduce impact and improve the sustainability of our food systems.

'The research highlights the need to be careful about generalisations such as it takes 1000 litres to produce a particular product. The specific production system; the type of water used; and the scarcity of water in the production region needs to be considered to get a true picture of the environmental footprint', said scientist Dr Brad Ridoutt.

How a water footprint is calculated

The source of water is split into categories such as: natural rainfall over agricultural lands, and water taken from rivers, lakes and groundwater resources. Agricultural activities that capture rain, such as on farm dams, can also be important.

The impact of using this water is considered in the context of local water scarcity and expressed in an equivalent unit of water, H2Oe ('e' stands for 'equivalent').

This unit is similar to the unit of CO2e used in carbon footprinting. Using this way to express water footprints means comparisons can be made between alternative products and production systems that are produced in different areas under different climates.

An example of applying the method with Mars Australia

Work done with Mars Australia used an life cycle assessment (LCA) approach to examine the water footprints of two key products 250 g bag of Peanut M&M's™ and a 575 g jar of Dolmio™ pasta sauce. Researchers analysed the entire production chain, including agriculture, ingredient processing and food manufacturing through to the product use phase, packaging, and disposal of wastes. This study highlighted the importance of distinguishing LCA-based water footprints from other expressions of water use related to so-called virtual water.

The total amount of water required to produce the M&M's™ was 1153 litres compared to 202 litres for Dolmio™ pasta sauce. However, when the type of water being used and the local water scarcity was taken into account, the water footprint of Dolmio™ sauce was actually more than 10 times greater (350 litres compared to 31 litres H2Oe).

Furthermore, within the life cycle of the pasta sauce, 97 per cent of the potential to contribute to water scarcity was attributed to producing the agricultural ingredients themselves, in this case, tomatoes. Using this water footprinting approach enabled meaningful comparisons between different products and between different stages of a particular product's life cycle so that producers and food manufacturers could identify where they can best invest effort to reduce environmental impacts.

Research examples

Wheat, barley and oats

This water footprinting method has been applied to wheat, barley and oats in New South Wales, Australia.

The project for Sustainable Agricultural Initiative (SAI) Platform aimed to provide insights about the potential impacts on water resources using Australian grains sourced from various geographic areas. A summary report SAI Platform is available at: Water footprints of wheat, barley and oats in New South Wales.

Dairy products case studies

Recent work with Victoria's Department of Primary Industries has explored the use of the LCA-based water footprint method on milk products produced in South Gippsland, one of Australia's major dairy regions.

The researchers considered the type of water used on-farm as well as in the production of inputs brought onto the farm along with the local water stress where production occurred.

The research concluded that the average water footprint for the case study farms was 1.9 litres H2Oe per litre of fresh milk at farm gate, highlighting that it is possible for dairy products to be produced with minimal potential to contribute to freshwater scarcity. However, not all dairy production systems are alike and what is important is that LCA-based water footprinting represents a new way for agricultural sectors to explore their environmental footprint and take steps to minimise environmental burdens.

More information is available at ECOS: More accurate measure of food’s water footprint [external link].

Other water footprinting research projects

Projects underway are footprints of:

• lamb cuts produced in south-west Victoria, Australia and transported to the western USA
• beef production through analysing carbon footprints water footprints and landuse impacts on food production in case studies in New South Wales (Meat and Livestock Australia)
• rice.

International standard for water footprinting

Unfortunately the term 'water footprint' is being used to mean different things in different contexts and this is creating the potential for confusion and misunderstanding.

CSIRO is now contributing to the development of an international water footprint standard with ISO, the International Organization for Standardization (through Standards Australia).

An international water footprint standard will:

• make it simpler for Australian agriculture and food industries to meet the environmental reporting requirements which are increasingly required to participate in local and international value chains
• bring consistency to the meaning of the term 'water footprint'. This will overcome debate about the water footprints of agriculture and food products that are not based on a recognised water footprint calculation method.

Find out more about the Sustainable Agriculture Flagship.