Articles | Volume 18, issue 17
https://doi.org/10.5194/gmd-18-5635-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/gmd-18-5635-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Development and technical paper
| 
04 Sep 2025
Development and technical paper |
| 04 Sep 2025
| 04 Sep 2025
The process and value of reprogramming a legacy global hydrological model
Emmanuel Nyenah
CORRESPONDING AUTHOR
Institute of Physical Geography, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
Senckenberg Biodiversity and Climate Research Centre (SBiK-F), 60325 Frankfurt am Main, Germany
Petra Döll
Institute of Physical Geography, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
Senckenberg Biodiversity and Climate Research Centre (SBiK-F), 60325 Frankfurt am Main, Germany
Martina Flörke
Institute of Engineering Hydrology and Water Resources Management, Ruhr University Bochum, 44801 Bochum, Germany
Leon Mühlenbruch
Institute of Engineering Hydrology and Water Resources Management, Ruhr University Bochum, 44801 Bochum, Germany
Lasse Nissen
Institute of Physical Geography, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
Robert Reinecke
Institute of Geography, Johannes Gutenberg-University Mainz, 55128 Mainz, Germany
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Denise Cáceres, Ben Marzeion, Jan Hendrik Malles, Benjamin Daniel Gutknecht, Hannes Müller Schmied, and Petra Döll
Hydrol. Earth Syst. Sci., 24, 4831–4851, https://doi.org/10.5194/hess-24-4831-2020, https://doi.org/10.5194/hess-24-4831-2020, 2020
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We analysed how and to which extent changes in water storage on continents had an effect on global ocean mass over the period 1948–2016. Continents lost water to oceans at an accelerated rate, inducing sea level rise. Shrinking glaciers explain 81 % of the long-term continental water mass loss, while declining groundwater levels, mainly due to sustained groundwater pumping for irrigation, is the second major driver. This long-term decline was partly offset by the impoundment of water in dams.
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Short summary
We reprogrammed the latest WaterGAP model (2.2e) to create a sustainable global hydrological model. By utilizing best software practices like modular design, version control, and clear documentation, the new WaterGAP supports collaboration across teams. It can be easily understood, applied, and enhanced by both novice and experienced modellers. Additionally, we share the reprogramming process to assist in the reprogramming of other large geoscientific research software.
We reprogrammed the latest WaterGAP model (2.2e) to create a sustainable global hydrological...
