Integration of airborne geophysical data and saltwater intrusion modeling to assess alluvial aquifer dynamics: salinization, upconing, and management implications

Document Type

Article

Publication Date

7-1-2026

Abstract

This study investigates the dynamics of groundwater flow along with salt plume migration mapped from airborne electromagnetic (AEM) surveys in the Mississippi River Valley alluvial aquifer (MRVA). A high‑resolution MRVA groundwater model, derived through AEM–borehole data fusion, was implemented in physics‑based modeling (MODFLOW 6) and integrated with the Mississippi embayment model to simulate inter‑aquifer groundwater exchanges. The MRVA groundwater model includes hydrologic variables, such as surficial recharge, stream-aquifer interactions, and groundwater withdrawals. An iterative ensemble smoother (iES) method was used for model calibration to estimate model parameters, and model performance was evaluated using spatially distributed error metrics. A density-varied two-way coupled saltwater intrusion model was employed to predict progressive saltwater upconing from 2025 to 2045 arising from the MRVA base due to groundwater pumping after the calibration period of 2020–2024. The MRVA geological framework and initial chloride distribution were informed by machine‑learning‑assisted interpretation of AEM, borehole data, and water samples; however, all long‑term predictions were performed using physics‑based groundwater flow and solute transport models within a hybrid machine learning–physics modeling framework. The simulation results show three distinct cones of depression in Arkansas and one in Louisiana. Saltwater upconing is likely to occur given the status quo of groundwater pumping in 2020 for the next 25 years. The study highlights the significant influence of groundwater pumping on MRVA groundwater levels and salinization and offers critical insights for effective groundwater management.

Publication Source (Journal or Book title)

Journal of Hydrology

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