@inproceedings{01K8B1WZCVSVMNAWBFQSGTH6TV,
  abstract     = {{Groundwater plays a vital role in supporting domestic, agricultural, and industrial activities in the Gilgel Gibe and Dhidhessa watersheds of southwestern Ethiopia. This study aimed to investigate hydrogeochemical processes controlling groundwater chemistry and water quality assessment within the heterogenous volcanic aquifers. A total of 112 water samples were collected. Hydrochemical characterization  and isotopic analyses were conducted. 
The study revealed significant variations in cations and anions throughout the region. In hand-dug wells, springs, and surface waters (rivers, streams, and marshes), the cations and anions order is Ca²⁺ > Na⁺ > Mg²⁺ > K⁺ and HCO₃⁻ > NO₃⁻ > Cl⁻ > SO₄²⁻ respectively. In contrast, deep wells show a different order: 
Na⁺ > Ca²⁺ > Mg²⁺ > K⁺ and HCO₃⁻ > Cl⁻ > SO₄²⁻ > NO₃⁻. The dominant freshwater types in the region, 
based on the Piper diagram, are mainly Ca˗ HCO₃ and Ca˗ Mg˗ HCO₃, with highly mineralized Na˗HCO₃ waters in deep aquifers. Statistical correlations and bivariate plots indicate that the weathering of silicate minerals is the primary process influencing groundwater chemistry in this region. The constructed stability diagrams indicate that groundwater samples are in equilibrium with kaolinite ,Ca˗montmorillonite, and Na˗ montmorillonite, while microcline, anorthite, and albite are unstable and undergo weathering in the 
aquifer. The increasing ratios of [Ca2+]/[H+]2,[Na+]/[H+],  [K+]/[H+], and [H₄SiO₄] along flow lines reflect the progressive dissolution of aluminosilicate minerals. The difference in the shallow aquifer between the low chloride concentration in the active recharge areas at higher elevations and the high chloride concentration in the lowland depressions highlights the influence of evaporation processes. The scatter plots between Cl- and SO42-,Cl- and NO3- and elevated NO₃⁻ and Cl⁻ levels, reflected by the presence of Ca(NO₃)₂, NaNO₃, and CaCl₂ water types, indicate that anthropogenic processes further influence the water chemistry. Minerals such as dolomite, calcite, aragonite, alunite, illite , and K-mica are oversaturated, indicating potential mineral precipitation. In contrast, halite  with respective to  deep aquifers is undersaturated, suggesting ongoing dissolution processes that contribute ions to water chemistry. Stable isotopes revealed values ranging from -6.71‰ to -0.89‰ (mean: -1.78‰) for oxygen and -27.52‰ to +18.9‰ (mean: +1.89‰) for hydrogen. Most samples aligned closely with the global and  local meteoric water line, confirming the water in the catchments have meteoric origin. The study significantly advances the understanding of the region's hydrogeochemistry and water quality, offering crucial insights for policymakers, planners, and stakeholders in water resource management and development strategies of the studied area.
Keywords: Hydrogeochemical, isotope analysis, silicate weathering, water type, water quality}},
  author       = {{Kebede, Adisu Befekadu and Tufa, Fayera Gudu and Kitessa, Wagari Mosisa and Debela, Seifu Kebede and Gudeta, Beekan Gurmessa and Tumsa, Bekan Chelkeba and Fayessa, Fekadu Fufa and Hermans, Thomas and Walraevens, Kristine}},
  booktitle    = {{Groundwater Quality 2025, Abstracts}},
  keywords     = {{Hydrogeochemical,isotope analysis,silicate weathering,water type,water quality}},
  language     = {{eng}},
  location     = {{Bordeaux}},
  pages        = {{1}},
  title        = {{Hydrogeochemical characterization and water quality evaluation in the Gilgel Gibe and Dhidhessa watersheds, Southwestern Ethiopia}},
  year         = {{2025}},
}