Great Lakes Virtual Water Accounting

An innovative approach to assess water resources



Alex Mayer, Principal Investigator

Victoria Pebbles, Outreach and Communications/ Project Lead

Accounting Our Water Resources for Tomorrow Workshop

Date: August 21, 2014

Location: Workspring, 30 West Monroe Street, Chicago, Illinois

What is Virtual Water Accounting?

Virtual Water Accounting is a method of assessing the true impact of water extraction on local water resources and ecosystem services. The approach provides a framework to account for the “Virtual Water”; water that is embedded in products during the production of goods for export (primarily through evaporative consumption) and is lost to the watershed: in this case, the Great Lakes Basin.

Virtual Water as concept requires that we “see” or consider all of the water that is being used in the production and export of that product as well as throughout the life of that product or service. For example, it takes about 900 liters of water to produce 1 kilogram of corn. 11 million bushels (141,590 kilograms) of corn is harvested, exported from the watershed of origin and brought to market in a different watershed. Therefore, the 127.4 million liters of water (incorporated into the corn) is lost to the watershed of origin and considered a virtual water export. Conversely, 1.4 million kilograms of bananas purchased and eaten in the watershed of origin (for the corn) are considered a virtual water import. An estimated 860 liters of water is needed to produce 1 kilogram of bananas, totaling 1,204 million liters of water imported. When only looking at corn and bananas in this watershed, the virtual water balance (-127.4 million liters [of corn] + 1,204 million liters [of bananas]) is a gain of 1,076.6 million liters.

VIEWR Approach

The Virtual Water Accounting project is using the “VIEWR” formula above to test a new framework that allows for a quantitative analysis of virtual water. The formula is being elaborated in different applications which are described in detail through a series of peer-reviewed journal articles. These original articles and a manager’s synopsis of those articles are linked at the right. The VIEWR approach will enable support more effective water conservation programs, water withdrawal management/regulations and cumulative impact assessments on water and related natural resources. The Great Lakes project will pilot the virtual water accounting approach in the Kalamazoo River watershed.

This study has been funded with generous support by the Great Lakes Protection Fund.


Journal Articles »

Water Scarcity at Multiple Scales

How can water be scarce in a water-rich region? The Great Lakes region is known the world over for its abundance of high-quality freshwater. This perceived abundance...


The ‘Fingerprints’ of Human Water Uses on Watersheds

How do many human socio-economic activities combine to impact freshwater ecosystems? The Study The ways in which people withdraw, consume, discharge, store, and...


Groundwater Scarcity and Availability

What is ecologically sustainable groundwater use? Groundwater is an important source of water for agriculture, public supply and other uses. But, how much is too...


Impacts of Economic Water Use on Freshwater Ecosystems

Why study these impacts? The impact of human water uses and economic pressures on freshwater ecosystems is of growing interest for water resource management worldwide....