Water - a Global Assessment and Prognosis



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WaterGAP is an integrated-environmental model, combining socio-economic drivers and climate change in a single, integrated framework.
It was developed to model water availability, use and quality on a global level. WaterGAP comprises of a hydrological module, used in determining global water resources and water availability, and a water-use module, which looks at consumption from different economic sectors, including a sub-model for an assessment of global irrigation requirements.
The model is mainly used for:
• assessing the impact of global developments (e.g. climate change on water availability and water demand;
• determining different water-stress conditions of different regions.

Input variables:

Global map of irrigation areas: Contains information about the area of each 0.5 degree cell (area 9.25 km by 9.25 km at the equator) that was equipped for irrigation around 2000. The dataset was developed by the Centre of Environmental Systems Research, Kassel University in 1999 and updated with the help of the Land and Water Development Division of the Food Organisation of the United Nations in 2007.

Global drainage direction map: The dataset describes the drainage direction of surface water, under the form of a map (spatial resolution of 30’ longitude by 30’ latitude).

Global lakes, wetlands and reservoir dataset.

Output variables:

impacts of global change on water availability and water demand, and to determine the development of water stress conditions on different spatial and temporal scales.

Documentation for the end user:

Scientific documentation:


Joseph Alcamo (Project Manager), alcamo@usf.uni-kassel.de