Application of the mGROWA Water Balance Model in Slovenia: Structure, Key Outputs and Climate Change Use Cases

A reliable understanding of the water balance is essential for sustainable water management, especially under the influence of climate variability. The Slovenian Environment Agency (ARSO), in collaboration with Forschungszentrum Jülich (FZJ), has developed and applied the mGROWA water balance model for the entire territory of Slovenia. The model operates at a 100 m spatial resolution with daily and monthly temporal scales and has been fully validated using long-term hydrological data (1981–2010).

We will present the structure of the mGROWA model, the modeling scheme and key water balance components. The model integrates meteorological, hydrological, geological, and land use data and includes a snow module specifically developed for Slovenia, which enables detailed simulation of snowfall, snow cover, and melt dynamics. The core dynamic input of the model are climatic data.

Beyond standard simulations (from 1971 – present), the model has been used to assess climate change impacts on the Slovenian water cycle up to the year 2100, including scenarios of altered runoff, groundwater recharge, snow and drought risk. Results show regional differences in groundwater recharge trends and increased soil moisture stress under selected RCP scenarios. These simulations were part of national climate assessment project (OPS21 project).

The poster will provide a short visual overview of the model architecture, example outputs of key variables, and a short insight into the model’s application for future climate scenarios and operational forecasting. The mGROWA model is a valuable decision-support tool for integrated water resources management and a foundation for further climate adaptation efforts in Slovenia.