In order to design water policy as part of a strategy for sustainable development, an insight into the dynamics of the water system is necessary but not sufficient. It is hypothesized that understanding today's water policy issues requires integrated analysis of hydrology, water quality, water demand and water supply in relation to land use changes, soil degradation, element cycles and climate change, as well as in relation to food and energy supply, human development and economics.
The analytical tools for water policy analysis presently available only partly meet the requirements of such integrated analysis. To fill this gap, the new modelling framework AQUA has been developed. AQUA is part of the more extensive modelling framework TARGETS: a Tool to Assess Regional and Global Environmental and health Targets for Sustainability. This report discusses the policy issues to be dealt with by AQUA, the main structure of the tool and the underlying definitions and assumptions.