Date of Award
1-1-2023
Document Type
Thesis
Degree Name
M.S. in Chemistry
First Advisor
Lance Yarbrough
Second Advisor
Andrew O'Reilly
Third Advisor
Inoka Widanagamage
Relational Format
dissertation/thesis
Abstract
With long-term water level decline in the Mississippi River Valley Alluvial aquifer (MRVAA), the Groundwater Transfer and Injection Pilot project is analyzing the feasibility of Managed Aquifer Recharge (MAR) to increase groundwater availability in the Delta region of Mississippi. The MAR method chosen for this project included pumping water from a well adjacent to the Tallahatchie River using riverbank filtration, transferring the water through a 2-mile pipeline, and injecting the water into the MRVAA. However, by transporting river water into the aquifer, the water quality must be examined at both the river extraction site and the injection well site. The water quality of the MRVAA in other locations has been previously reported. However, these results do not reflect the water quality after riverbank filtration, transfer, and injection. Thus, a new collection of water quality data must be collected.
Water quality samples were collected at seventeen observation wells, the extraction well, two injection wells, and the Tallahatchie River. For each collection site, a multiparameter probe was used to determine the pH, specific conductivity, temperature, and dissolved oxygen concentration. A set of four collection bottles were also used to test for major ions, metals, and nutrients. The samples for the observation wells, extraction well, injection wells, and Tallahatchie River indicate water to be of calcium bicarbonate type. When comparing the data to the drinking water standards provided by the U.S. Environmental Protection Agency, the manganese and iron concentrations were noted to be above the secondary drinking guidelines. High iron levels are expected due to the geology of the MRVAA in the Delta. Agrochemical analysis was performed to determine possible aquifer contamination due to the Delta primarily serving as agriculture land. Agrochemicals were detected in groundwater and surface water samples collected. The U.S. Geological Survey geochemical software, PHREEQC, was utilized to calculate the saturation index of the groundwater quality samples. The groundwater samples were consistently supersaturated with primarily iron minerals. Based on the geology known about the Delta and previously reported groundwater sampling, elevated concentrations of iron and manganese in the groundwater are consistent with the presence of iron- and manganese-based mineral phases.
Recommended Citation
Ward, Alexandra Megan, "Determining the Geochemical Variability of Groundwater During Riverbank Filtration, Transfer and Injection in the Mississippi River Valley Alluvial Aquifer in Shellmound, Mississippi" (2023). Electronic Theses and Dissertations. 2776.
https://egrove.olemiss.edu/etd/2776