Treffer: Modeling density-driven hydrogeological dynamics in arid endorheic basins: A numerical analysis of variable-density groundwater flow systems.

Human societies and ecosystems heavily rely on groundwater resources, yet their dynamics are complex and governed by both topography and density heterogeneity. This research focuses on the coupled effects of topographic and density forces on the evolution of groundwater flow systems in arid endorheic basins, employing advanced numerical modeling to quantify the synergistic effects of saline mass transport and hydraulic gradients on regional hydrogeological dynamics. A variable-density groundwater flow model has been developed based on a generalized hydrogeological profile of the Qaidam Basin, Tibetan Plateau. This study employed a Genetic Algorithm (GA) to invert and calibrate key hydrogeological parameters. Numerical simulations spanning 100,000 years elucidate the spatiotemporal effects of density gradients on regional groundwater flow dynamics and their controlling mechanisms. The results indicate a progressive salinization and density increase of groundwater in the basin center due to intensive evaporation, which elevates the equivalent freshwater heads in the discharge area by up to 47.86 %. This substantial change in heads weakens the hydraulic gradient from recharge area to discharge area, fundamentally altering groundwater flow paths within the terminal drainage area. Uncertainty analyses demonstrate that parametric uncertainties in diffusion coefficients (D) and hydraulic conductivity (K) moderately affect the density distribution patterns, but have negligible effects on the quantified driving force attenuation. The findings establish evaporative brine accumulation as the predominant control mechanism overriding sedimentary heterogeneity in shaping the long-term evolution of groundwater flow systems in arid basins. [Display omitted] • Density-induced suppression on groundwater flow system is assessed. • Evaporation-induced salinity increase significantly alters groundwater flow paths. • Evaporative brine accumulation governs groundwater flow system in arid basins. [ABSTRACT FROM AUTHOR]

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