Hydrogeochemistry & Hydrogeology Working Group

Members

The Earth's hydrological cycle fundamentally determines the biogeochemical, ecological, and climatic conditions of our planet. Hydrogeochemical research, particularly studies involving stable isotopes, aims to explore this cycle, the interactions within it, and the physical processes taking place (e.g., evaporation, condensation, mixing), as well as the origin of water. Isotopes of oxygen and hydrogen act as “fingerprints,” enabling the tracking of water derived from precipitation as it moves through surface and subsurface systems. The isotopic composition of precipitation provides fundamental information about rainfall in a given area and allows for deeper insights into atmospheric processes. In parallel, hydrogeological research analyzes the movement, distribution, and quantitative relationships of water within the hydrological cycle, including the spatial and temporal variability of precipitation. By combining hydrogeochemical and hydrogeological approaches, it becomes possible to achieve a deeper scientific understanding of the water cycle and to obtain key information essential for water resource management (e.g., mean residence time, effective infiltration period).

In Hungary, the protection of exceptionally rich water resources—both surface and groundwater—represents a significant responsibility for society.

Research themes

Isotope Hydrological Atlas of Hungary

Thanks to our collaboration with government bureaus between 2023 and 2026, we implemented a systematic sampling program including both surface and groundwater bodies throughout Hungary. The analysis of the stable hydrogen and oxygen isotope composition of the thousands of water samples collected is in progress. We publish the data for surface and groundwater in separate open databases. The most current version of the regularly updated database is available at https://hdl.handle.net/21.15109/CONCORDA/XRLKLY.

The database provides reference data on the average values and seasonality characterizing the stable isotope composition of surface and groundwater for any region in Hungary in the early 2020s, enabling not only future but also retrospective comparisons. The data may be useful not only in Hungary but also in hydrogeological research involving transboundary water bodies. The database is supplemented by a web-based visualization and browsing platform with a map-based interface that aids in the visualization and analysis of the underlying data in both spatial and temporal dimensions (izotopatlasz.elte.hu).

Projects:

Spatio-temporal changes in the isotopic composition of precipitation

Precipitation isotopes serve as benchmark data not only for hydrological research but also for various palaeoclimatological studies. Therefore, in addition to collecting primary data, we place a strong emphasis on methodological research related to quality control of databases archiving precipitation isotope data and to imputation methods for data gaps. In addition, we focus on creation of regional-scale isoscapes (isotopic landscapes) and the refinement of related methodological approaches. Another key research focus is the isotopic composition of precipitation, as well as the investigation of its origin and its relationship with other meteorological parameters.”

Projects:

Comprehensive geochemical and hydrogeological investigation of surface and groundwater

The aim of this research is to explore the connections between surface and subsurface water systems, as well as to determine the spatial and temporal variations of chemical and physical processes. We focus on natural factors (e.g., rock–water interactions, dissolution and precipitation processes) and anthropogenic impacts (agriculture, industrial pollution) that influence the development of water composition and physical state, as well as on a more precise determination of the water balance of a given area. The complex investigation is based on the integrated interpretation of remote sensing, meteorological, hydrogeochemical, and hydrogeological data, as well as the modeling of flow and transport processes.

Projects: