The research programme was carried out in the context of the
framework of the UNESCO-IHP Programme IV 'Water Interactions:
Systems at Risk and Social Challenges. What is virtual water?
Producing goods and services generally requires water. The water
used in the production process of an agricultural or industrial
product is called the 'virtual water' contained in the product.
For producing one kilogram of grain we need for instance one to
two cubic metres of water. Water is a scarce good and thus
should be treated economically. There is an urgent need to
develop appropriate concepts and tools to do so. A bridge has to
be built between water management practice and economic
thinking. In allocating and using water in an efficient way,
there are different levels of decision-making: Local water use
efficiency. At this level the user of the water plays a key
role. Local water use efficiency can be increased by creating
awareness, charging prices based on full marginal cost and by
stimulating watersaving technology.