WaterGAP
The Global Freshwater Model

To support the sustainable development of the world's water resources, the global freshwater model WaterGAP computes water flows and storages as well as water withdrawals and consumptive uses on all continents. It is applied to assess the human – freshwater system under the impact of global change.
 
WaterGAP is being developed mainly at the Universities of Kassel and Frankfurt (comp. Wikipedia article). Its development and applications are documented in a large number of publications.

Water
flowing ... and stored
Rapids of the Nile River, Uganda Hardangerjoekulen (Glacier), Norway
Water
abundance ... and scarcity
Victoria Falls, Zimbabwe Etosha Pan, Namibia
Water
for human use ... and for nature
Irrigation of corn by a travelling sprinkler, Nebraska, USA Mont Tremblant National Park, Quebec, Canada
WaterGAP
model structure ... and C++ - code
Water flows and storages as computed for a WaterGAP grid cell C++ code of WaterGAP in an editor window
WaterGAP
results and applications
Change of total freshwater resources Groundwater resources of the world