WaterGAP (Water – Global Assessment and Prognosis) is a global hydrological model that simulates water flows and storage worldwide. It quantifies key components of the water cycle – including river discharge, groundwater storage, and soil moisture – while explicitly accounting for human impacts such as agricultural and industrial water withdrawals, consumption, and artificial reservoirs. As such, WaterGAP is a central tool for assessing water scarcity, identifying climate-vulnerable regions, and supporting sustainable water management at the global scale.

Due to its detailed structure, numerous parameters, and extensive data requirements, WaterGAP has a steep learning curve. The summer school equips international early-career researchers with the skills needed to apply the model confidently and correctly in their own research. Through hands-on training and direct interaction with expert developers, participants gain both technical proficiency and a solid understanding of the model’s hydrological concepts and assumptions.

In addition, the summer school fosters a collaborative learning environment that introduces participants to the WaterGAP open-source ecosystem. By engaging with the model’s architecture and workflows, participants are encouraged to move beyond model application and towards active involvement in its further development.

After the summer school, participants will be able to:

• understand the structure, assumptions, and limitations of the WaterGAP model
• set up, run, and evaluate WaterGAP simulations for different regions and applications
• analyze and interpret model outputs related to water availability, use, and scarcity
• work with the WaterGAP open-source codebase, including basic code modification
• apply best practices in version control and collaborative model development