Developing a pan-European high-resolution groundwater recharge map - Combining satellite data and national survey...

Area of Science:

• Hydrology
• Environmental Science
• Geoscience

Background:

• Groundwater recharge quantification is vital for sustainable water management but often limited in scale.
• Existing data lacks high-resolution, pan-European coverage for consistent groundwater resource assessment.

Purpose of the Study:

• To develop a harmonized, high-resolution (1 km x 1 km) dataset for groundwater recharge across Europe.
• To create a pan-European groundwater recharge map and associated datasets (evapotranspiration, effective precipitation, recharge coefficients).

Main Methods:

• Merged actual evapotranspiration from satellite data and the Budyko approach to estimate effective precipitation.
• Employed a Random Forest regressor machine learning model for mapping groundwater recharge coefficients using geological, soil, topographical, and climate data.
• Validated and trained models against seven national gridded datasets across diverse European hydrogeological conditions.

Main Results:

• Generated a high-resolution (1 km x 1 km) dataset of long-term average actual evapotranspiration, effective precipitation, recharge coefficients, and groundwater recharge for Europe.
• The pan-European groundwater recharge map shows good agreement with global hydrological models and national datasets.
• Provided locally relevant estimates for areas lacking prior detailed information.

Conclusions:

• The developed methodology successfully created a harmonized, high-resolution groundwater recharge map for Europe.
• The dataset enhances sustainable groundwater management by providing consistent and accessible data.
• The open-access data is available via the European Geological Data Infrastructure (EGDI).