What is "watergap"

The global freshwater model WaterGAP calculates flows and storages of water on all continents of the globe (except Antarctica), taking into account the human influence on the natural freshwater system by water abstractions and dams. It supports understanding the freshwater situation across the world’s river basins during the 20th and the 21st century, and is applied to assess water scarcity, droughts and floods and to quantify the impact of human actions on freshwater. Modelling results of WaterGAP have contributed to international assessment of the global environmental situation including the UN World Water Development Reports, the Millennium Ecosystem Assessment, the UN Global Environmental Outlooks as well as to reports of the Intergovernmental Panel on Climate Change. They were included in the 2012 Environmental Performance Index which ranks countries according to their environmental performance (index for impact of human water use on ecosystems).

WaterGAP (Water Global Assessment and Prognosis) has been developed at the University of Kassel (Germany) since 1996, and since 2003 also at the University of Frankfurt (Germany). It consists of both the WaterGAP Global Hydrology Model (WGHM) and five water use models for the sectors irrigation, livestock, households, manufacturing and cooling of thermal power plants. An additional model component computes the fractions of total water use that are abstracted from either groundwater or surface waters (rivers, lakes and reservoirs). All computations are done with a temporal resolution of 1 day and a spatial resolution of 0.5° geographical latitude × 0.5° geographical longitude, which is equivalent to 55 km × 55 km at the equator. Model input includes time series of climate data (e.g. precipitation, temperature and solar radiation) and physiogeographic information like characteristics of surface water bodies (lakes, reservoirs and wetlands), land cover, soil type, topography and irrigated area.