Development of a pilot-Scale managed aquifer recharge facility that combines riverbank filtration, groundwater transfer, and injection in an intensively cultivated agroecosystem

Authors: O'Reilly, Andrew; Wren, Daniel; Locke, Martin; MIRECKI, JUNE - Mirecki Geoscience, Llc; Rossell, William

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/10/2026
Publication Date: 6/11/2026
Citation: O'Reilly, A.M., Wren, D.G., Locke, M.A., Mirecki, J.E., Rossell, W.B. (2026). Development of a pilot-Scale managed aquifer recharge facility that combines riverbank filtration, groundwater transfer, and injection in an intensively cultivated agroecosystem. Applied Engineering in Agriculture. 42(3):285-306. https://doi.org/10.13031/aea.16547.
DOI: https://doi.org/10.13031/aea.16547

Interpretive Summary: Sustaining groundwater resources for irrigated agriculture in the Mississippi Delta requires a new management approach before falling water levels causes uneconomical conditions.  Fertile soils and the highly productive Mississippi River Valley alluvial aquifer (MRVAA) of the Mississippi Alluvial Plain make this one of the most productive agricultural regions in the United States. However, irrigation water demands during the growing season have contributed to long-term groundwater depletion, adversely impacting farm productivity. To address groundwater irrigation sustainability concerns in the Delta region of northwestern Mississippi, a pilot-scale managed aquifer recharge (MAR) facility that combines riverbank filtration, groundwater transfer, and injection was conceived, built, and studied to understand the impact of this innovative combination of MAR technologies on the aquifer. After successful construction of the facility, studies showed an injection flow rate of 94.6 L/s (1,500 gal/min) for 24 hours could be achieved with water level increases of up to 1.48 m (4.85 ft) at the aquifer injection site. Importantly, water level impacts in the aquifer at the riverbank filtration extraction site were relatively minor with drawdowns up to 0.91 m (2.99 ft). Water sampling results indicate groundwater in the MRVAA at both the extraction and injection sites is similar in quality, which are conditions favorable for the mixing of recharge water obtained from the extraction well with ambient groundwater at the injection site. These findings provide a foundation to expand this type of MAR at a larger scale in the MRVAA in the Delta to support more farms. Additionally, this work serves as a template to pursue similar MAR technology in other intensively cultivated alluvial basins where groundwater level declines are impacting American farms and ecosystems.

Technical Abstract: Alluvial basins commonly contain both fertile soils and shallow high-yielding aquifers, forming highly productive regions for irrigated agriculture worldwide. The Mississippi Alluvial Plain in the Lower Mississippi River Basin of the United States is one such region, where irrigation demands during the growing season have contributed to long-term depletion of the Mississippi River Valley alluvial aquifer (MRVAA), adversely impacting farming operations in some areas. Managed aquifer recharge (MAR) is a technology for leveraging excess surface water resources by storing water in the subsurface for subsequent beneficial use. A pilot-scale MAR facility that combines riverbank filtration, groundwater transfer, and injection was conceived and built to address groundwater irrigation sustainability concerns in the Delta region of northwestern Mississippi, USA. This article establishes the need for the facility, describes the steps that led to the decision to pursue it, details the process of securing funding and permissions, and describes the construction and successful shakedown assessments of the facility. During testing of the facility at a flow rate of 94.6 L/s (1,500 gal/min) for 24 hours, water level increases of up to 1.48 m (4.85 ft) were measured in the MRVAA at the injection site, whereas water level impacts in the MRVAA at the riverbank filtration extraction site were relatively small with drawdowns up to 0.91 m (2.99 ft). Pre-operational water sampling results indicate groundwater in the MRVAA at both the extraction and injection sites is anoxic (dissolved oxygen 0.06–0.11 mg/L) and elevated iron (1.75–31.2 mg/L) and manganese (0.253–0.979 mg/L) concentrations indicate reducing geochemical conditions, suggesting chemically compatible conditions for the mixing of recharge water obtained from the extraction well and ambient groundwater at the injection site. Results provide a foundation to potentially expand MAR at a larger scale in the MRVAA in the Delta and an example to pursue similar MAR technology in other intensively cultivated alluvial basins where groundwater level declines are impacting farming and water resources.