263-9 Modeling the Impact of Projected Water Demand on Groundwater Flow and Transport in the Mahomet Aquifer, Central Illinois.

Session: Exploring Groundwater Recharge and Management: Managed Aquifer Recharge and Other Innovative Tools for Water Supply Development and Operations (Posters)

Presenting Author:

Authors:

Abstract:

The Mahomet Aquifer serves as a vital water source for approximately 14 counties in east-central Illinois, supporting municipal, agricultural, and industrial needs. With projected changes in climate, population growth, and increasing water demand, assessing the long-term sustainability of this aquifer is crucial. Elevated pumping rates to meet rising water needs may lead to declining groundwater levels and increased risks of contaminant transport. Understanding these interactions is essential for effective groundwater management. This study seeks to address two key research questions: (1) How will projected changes in groundwater demand affect water levels in the Mahomet aquifer? (2) How do groundwater withdrawal rates impact contaminant transport within the aquifer? The research objectives are to: (1) develop and calibrate a numerical groundwater flow model using historical water demand and groundwater level data, (2) simulate projected groundwater conditions under various demand scenarios based on Shared Socioeconomic Pathway-based Forcing Scenarios (SSP-RCPs), (3) analyze trends in groundwater level variations due to projected changes in demand, and (4) employ a particle tracking model to evaluate the effects of groundwater withdrawals on contaminant transport pathways. To achieve these objectives, a three-dimensional numerical groundwater model will be developed using MODFLOW to evaluate the Mahomet Aquifer's response to projected water demand and climate change. Particle tracking will be employed using MODPATH to assess the migration pathways of contaminants under varying pumping conditions. The model will incorporate hydrogeological parameters such as recharge rates, aquifer layer properties, and boundary conditions to simulate groundwater flow dynamics and contaminant transport in both confined and unconfined sections of the aquifer. Model calibration and validation will be performed using historical water demand and groundwater level data before running scenario-based simulations to assess future groundwater sustainability. It is expected that under high-demand scenarios, significant water level declines will lead to increased stress on the aquifer. Additionally, as groundwater levels drop, contaminant migration is anticipated to intensify, particularly in areas with high withdrawal rates. These findings will provide insights into balancing groundwater extraction while mitigating contamination risks. By integrating hydrological modeling with climate and socioeconomic projections, this study will aid in developing adaptive management strategies to ensure the continued reliability and quality of the Mahomet Aquifer as a long-term water source for east-central Illinois.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

© Copyright 2025 The Geological Society of America (GSA), all rights reserved.