Hydrogeochemical and Hydrodynamic Assessment of Tirnavos Basin, Central Greece

Ioannis Vrouhakis,Georgios Stamatis,Andreas Panagopoulos,Evangelos Tziritis

doi:10.3390/w13060759

Ioannis Vrouhakis, Georgios Stamatis + Show 2 more

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https://doi.org/10.3390/w13060759

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Journal: Water	Publication Date: Mar 11, 2021
Citations: 3	License type: CC BY 4.0

Affiliation: Agricultural University of Athens

Abstract

A combined hydrogeochemical and hydrodynamic characterization for the assessment of key aspects related to groundwater resources management was performed in a highly productive agricultural basin of the Thessaly region in central Greece. A complementary suite of tools and methods—including graphical processing, hydrogeochemical modeling, multivariate statistics and environmental isotopes—have been applied to a comprehensive dataset of physicochemical analyses and water level measurements. Results revealed that the initial hydrogeochemistry of groundwater was progressively impacted by secondary phenomena (e.g., ion exchange and redox reactions) which were clearly delineated into distinct zones according to data processing. The progressive evolution of groundwater was further verified by the variation of the saturation indices of critical minerals. In addition, the combined use of water level measurements delineated the major pathways of groundwater flow. Interestingly, the additional joint assessment of environmental isotopes revealed a new pathway from E–NE (which had never before been validated), thus highlighting the importance of the joint tools/methods application in complex scientific tasks. The application of multivariate statistics identified the dominant processes that control hydrogeochemistry and fit well with identified hydrodynamic mechanisms. These included (as dominant factor) the salinization impact due to the combined use of irrigation water return and evaporitic mineral leaching, as well as the impact of the geogenic calcareous substrate (mainly karstic calcareous formations and dolostones). Secondary factors, acting as processes (e.g., redox and ion exchange), were identified and found to be in line with initial assessment, thus validating the overall characterization. Finally, the outcomes may prove to be valuable in the progression toward sustainable groundwater resources management. The results have provided spatial and temporal information for significant parameters, sources, and processes—which, as a methodological approach, could be adopted in similar cases of other catchments.

Highlights

Groundwater is a critical natural resource that needs to be properly managed in order to sustain its paramount aspects of quantity and quality
Scientists need robust tools to efficiently evaluate the status of groundwater and decipher the governing factors that regulate its hydrogeochemical and hydrodynamic regimes
We focused on the Tirnavos basin, which is part of the greater Thessaly plain in central Greece and is among the most productive regions of the country

Summary

Introduction

Groundwater is a critical natural resource that needs to be properly managed in order to sustain its paramount aspects of quantity and quality. In service of this goal, rational groundwater management requires accurate information and adequate knowledge about the processes affecting groundwater evolution in time and space. Scientists (and eventually stakeholders) need robust tools to efficiently evaluate the status of groundwater and decipher the governing factors that regulate its hydrogeochemical and hydrodynamic regimes. The methodological approach of the present work dictated the synergetic and combinational consideration of various tools and methods, e.g., classic hydrogeochemical approaches, the use of bivariate plots and/or molar ratios [2,3,4,5,6], hydrodynamic characterizations [7,8,9], hydrogeochemical modelling [10,11,12], multivariate statistics [13,14,15,16,17,18] and environmental isotopes [19,20,21,22,23]

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Results

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