20.500.12556/DiRROS-23833 Integrated approach for characterizing aquifer heterogeneity in alluvial plains Alluvial aquifers serve as vital groundwater resources worldwide. Due to their complex heterogeneity, accurate characterization requires the integration of multiple data types. This study presents a systematic framework to address aquifer heterogeneity through hydrofacies analysis, combining borehole data, electrical resistivity tomography (ERT) and stochastic modeling. The approach was tested in the Varaždin aquifer, where geostatistical and stochastic tools were used to simulate the spatial distribution of four hydrofacies: gravel (G), gravel, sandy to clayey (Gsc), sand with gravel, clayey to silty (Sgcs), and clay to silt, sandy (CSs). As the thin and electrically conductive lenses of Sgcs-CSs material below 20 m depth limited the ERT resolution, synthetic models were used to infer their possible geometry and resistivity magnitudes, estimating a model of the hydrofacies distribution up to 35 m depth, consistent with field-data based model. The resulting dimensions of the lens-shaped structures revealed the horizontal extent of the hydrofacies, and were incorporated into horizontal Markov chain models. The 3D Markov chain models were used to generate 10 stochastic realizations of the hydrofacies distribution. Validation identified the representative hydrofacies model for the Varaždin aquifer with a prediction accuracy of 63 %. Results from simulations focused on the Vinokovščak wellfield area show that incorporating ERT-derived lens lengths into the model development slightly improved hydrofacies prediction accuracy by 0.3 % to 5.0 %, depending on hydrofacies model grid resolution. The analysis of different grid resolutions demonstrates that increasing model detail beyond the characteristic lens dimensions provided no accuracy improvement, suggesting that the optimal cell size is closely related to the estimated lens lengths. In contrast, coarser grids provide a simplified hydrofacies model, potentially increasing prediction accuracy but losing spatial resolution. This methodology forms a basis for integrating spatial heterogeneity into groundwater models, providing a useful tool for sustainable management in alluvial and similar sedimentary environments. alluvial sediments aquifers groundwater water resources hydro-facies wells geophysical investigations modelling true false true Elsevier Angleški jezik Ni določen Neznano 2025-10-10 03:40:32 2025-10-22 15:16:19 2025-10-24 03:55:09 0000-00-00 00:00:00 2025 0 0 str. 4969–4982 iss. 19 vol. 29 2025 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 2025-10-06 556.3 1607-7938 10.5194/hess-29-4969-2025 252454659 hess-29-4969-2025.pdf hess-29-4969-2025.pdf 1 1FACE84582F6E4A5767DF8AF4858674A b53961f999eb5ac89e12eb563393285452ea3b63d166ca7ac6e2d7b2606a9ae2 0cc4ff23-af4a-11f0-9bb7-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=35487 Geološki zavod Slovenije 0 0 0