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.
WaterGAP is an open source software. The source code of the most recent model version WaterGAP 2.2e can be found at https://doi.org/10.5281/zenodo.10026943.
WaterGAP simulations regularly contribute to the simulation rounds of ISIMIP.

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