Quantitative Simulation of Daily Groundwater Levels in the Mississippi River Valley Alluvial Aquifer Using GMS-MODFLOW

ORCID

Nekooei: https://orcid.org/0009-0003-8842-0500; Parajuli: https://orcid.org/0000-0002-4958-3302

MSU Affiliation

College of Agriculture and Life Sciences; James Worth Bagley College of Engineering; Department of Agricultural and Biological Engineering

Creation Date

2026-07-30

Abstract

Groundwater withdrawals in the Mississippi Delta have led to persistent declines in aquifer levels, particularly during peak irrigation periods. While seasonal groundwater level data are commonly used for modeling in the region, daily data remains underutilized despite their potential to enhance temporal resolution in simulations. This study evaluates the feasibility and limitations of simulating daily groundwater levels across the Delta using the GMS-MODFLOW platform, based on data from 11 USGS observation wells spanning the 2016-2021 growing seasons, periods characterized by the highest irrigation demand. Both steady-state and transient models were developed for each growing season to evaluate the feasibility and performance of daily-scale groundwater modeling under conditions of limited and inconsistent input data and observational coverage. The results revealed strong sensitivity of simulated groundwater levels to short-term variations in recharge rates, pumping estimates, and aquifer hydraulic conductivity. While the models performed well under steady-state conditions, the transient models struggled to reproduce daily variations due to challenges in accurately representing boundary conditions, particularly recharge and pumping data. This study documents the limitations and diagnostic challenges of using daily data in groundwater modeling for large-scale, data-scarce agricultural regions. It underscores the need for improved high-resolution datasets and better integration of natural variability and human-induced impacts. Future efforts should prioritize improved data availability and consistency before daily-scale transient groundwater modeling can be considered reliable to support more effective modeling and sustainable groundwater management in the Mississippi Delta and similar regions worldwide.

Publication Date

6-27-2026

Publication Title

Groundwater for Sustainable Development

Publisher

Elsevier

Rights

© 2026 The Authors

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Digital Object Identifier (DOI)

https://doi.org/10.1016/j.gsd.2026.101648