Grantee Research Project Results
2024 Progress Report: Development of Innovative Monitoring and Analysis Strategies for Rural Enhanced Aquifer Recharge Structures
EPA Grant Number: R840618Title: Development of Innovative Monitoring and Analysis Strategies for Rural Enhanced Aquifer Recharge Structures
Investigators: Halihan, Todd , Agnew, Robert , Beckmann, Sabrina , Xu, Tingying , Mace, Robert , Zhang, Yipeng , Sewell, Guy
Institution: Oklahoma State University , East Central University , Texas State University
EPA Project Officer: Harper, Jacquelyn
Project Period: August 1, 2023 through May 2, 2025
Project Period Covered by this Report: August 1, 2023 through July 31,2024
Project Amount: $1,991,613
RFA: Enhanced Aquifer Recharge Performance and Potential Risk in Different Regional and Hydrogeologic Settings Request For Applications (RFA) (2023) RFA Text | Recipients Lists
Research Category: Endocrine Disruptors , Aquifer , Aquifer Recharge , Clean Water
Objective:
The EAR project at the CAMARR site integrates various scientific disciplines to enhance understanding of enhanced aquifer recharge processes in a karstic system.
Progress Summary:
Work is progressing in multiple areas, including electrical hydrogeology, biogeochemistry, groundwater modeling, and siting and management of EAR structures. The electrical hydrogeology team temporal electrical resistivity imaging (TERI) data to better understand subsurface recharge and fault connectivity. A kilometer long TERI cable and six 168-meter temporary TERI lines were installed across interpreted fault lines to monitor groundwater movement during heavy rainfall and evaluate the impact of a siphon on groundwater discharge. While data analysis is ongoing, future work will include hydraulic testing, temporal resistivity comparison, and gas phase recharge monitoring to measure gas flux and composition. In the biogeochemical monitoring team, sediment and water sampling led to the discovery of seven microbial species capable of producing dark oxygen. These organisms could significantly alter the redox potential of the aquifer, a finding with substantial implications for developing the proposed novel Electrode-Monitoring System. Also, the presence of microbial species associated with chlorite dismutation, reactive oxygen species detoxification, and nitric oxide dismutation pathways is significant, and are not well understood in aquifer systems. Following a major flood event in May 2024, the geochemistry team collected groundwater, sediment, and rock samples, revealing high levels of metallic elements in some areas. Low dissolved oxygen and negative oxidation-reduction potential were correlated with the mobilization of these metals, suggesting that reducing conditions in the aquifer play a key role. Future research will involve analyzing solid samples using ICP-OES and synchrotron X-ray analysis to better understand the geochemical processes and the effectiveness of EAR structures. In the modeling and management team, a meta-analysis of managed aquifer recharge (MAR) techniques in the Edwards Aquifer of Texas has been completed, focusing on recharge methods and their application in karst systems. The team has also assessed the ethical implications of using EAR in karst aquifers, which will be expanded in future work to cover other global karst aquifer systems. Also, a steady-state simulation of the regional groundwater flow model for the Arbuckle Simpson Aquifer (ASA) has been completed, with particle tracking simulations showing that hydraulic conductivity contrasts must be carefully considered for successful recharge. The modeling team plans to integrate the conduit flow process (CFP) into site-specific models to capture hydrodynamic interactions during recharge events, using TERI to guide model configuration. The team have supported the field work, and researchers have engaged with stakeholders through conferences like OkaCon 2023 and site visits, strengthening relationships and discussing natural recharge and enhanced recharge options.
Future Activities:
Future efforts will include expanding geospatial data collection and supporting fieldwork, as well as organizing OkaCon 2024. Overall, this interdisciplinary research aims to advance the understanding of EAR in karst systems, with important findings on microbial activity, groundwater flow and metal mobilization. Future activities will continue to refine recharge models, explore fault system connectivity, and evaluate the impacts of episodic recharge events, enhancing the sustainability and management of groundwater resources.
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.