Degree

Doctor of Philosophy (PhD)

Department

Civil and Environmental Engineering

Document Type

Dissertation

Abstract

The Mississippi Embayment aquifer system (MEAS) and the Coastal Lowlands aquifer system (CLAS) provide substantial groundwater resources for human activities in the U.S. Gulf Coastal Plain. However, the overexploitation has led to groundwater depletion in the MEAS and the CLAS, threatening sustainable groundwater use. Such concern highlights the crucial need for an advanced understanding of stratigraphy and groundwater in these aquifer systems, which is essential for effective regional groundwater management. This dissertation presents a comprehensive investigation of MEAS and CLAS in the Louisiana and southwestern Mississippi region, encompassing three fundamental dimensions: stratigraphy reconstruction, groundwater modeling, and groundwater stress assessments. A novel lithologic modeling method that integrates diverse types of geological data is proposed to construct the stratigraphy of MEAS and CLAS. The resulting lithologic model reveals intricate distributions and structures of aquifers, exposing their recharge zones and connections with surface water bodies. Based on the aquifer characterization, a high-resolution regional groundwater model for MEAS and CLAS was constructed. The research delves into the exploration and comparison of robust methods to address the challenging inverse problem of groundwater model calibration. The comparative analysis suggests an efficient iterative Ensemble Smoother method to facilitate inverse modeling. This study introduces a novel index approach for assessing groundwater stress in the MEAS and the CLAS. The assessment involves the regional groundwater model, providing unprecedented insights into groundwater availability, sustainability, and depletion across diverse spatial and temporal scales in Louisiana and southwestern Mississippi. This study not only significantly advances the knowledge of groundwater hydrology in the MEAS and the CLAS, but also contributes to the improvement of geologic and groundwater modeling techniques.

Date

3-14-2024

Committee Chair

Tsai, Frank

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