Calculation

O1: Water intensity = Total water intake / Normalisation factor

Unit of the indicator: m3/normalisation factor

 

Why this indicator is important

Although water covers over two-thirds of the earth’s surface and is renewable on a global scale, local shortages and quality problems are frequent. Water withdrawn for industrial processes, if not returned to the same water body in its original quantity and quality, could contribute to the depletion of rivers and lakes and the lowering of groundwater tables.

Water is not always consumed in the production process but it is often used for cooling, heating or washing. When water is consumed, such as when it is incorporated into beverages, it cannot easily be substituted or reduced. For that reason, the indicator calculates only the intensity of total water intake of the overhead and production process.

 

Interpretation

Especially in areas of insecure water supply, it is important to monitor both the intensity of water intake and the total amount of water taken in.

Most water, after re-circulation, is released back into the environment either directly to surface water (often at reduced quality) or through evaporation. Increasing the rate or re-circulation and avoiding evaporation will reduce the amount required to be withdrawn from municipal, groundwater or surface waters. It is advisable for facilities to measure how much water is being recycled or re-circulated.

 

Related issues

The quality of the discharged water is considered in the calculation of the Indicator O7: Intensity of residual releases to surface water. That is, the pollutants in the discharged water are accounted for in the overall releases to water.

In areas where water conservation measures are in force or there is a risk of depleting local resources, a more detailed accounting of water should be conducted. Although this is not included in the current version of the Toolkit, a more detailed accounting would include data on the water intensity of products, re-circulation, embodiment of water in products, evaporation, spillage, location and quality of discharge.

Additionally, it is important to also monitor the source of the water intake including water from surface water, ground water, rainwater, treated effluent (from another organisation), and municipal water.