Open AccessElectrical resistivity imaging of an enhanced aquifer recharge site
Author(s) -
Jon Fields,
Tyler Tandy,
Todd Halihan,
Randall R. Ross,
Doug Beak,
Russell Neill,
Justin Groves
Publication year - 2022
Publication title -
journal of geophysics and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.623
H-Index - 38
eISSN - 1742-2140
pISSN - 1742-2132
DOI - 10.1093/jge/gxac073
Subject(s) - aquifer , karst , groundwater recharge , sinkhole , geology , electrical resistivity tomography , groundwater , vadose zone , hydraulic conductivity , groundwater flow , hydrology (agriculture) , bedrock , geomorphology , soil science , geotechnical engineering , soil water , electrical resistivity and conductivity , engineering , paleontology , electrical engineering
Enhanced aquifer recharge (EAR) is defined as any engineered structure or enhanced natural feature designed to convey stormwater, surface water or wastewater directly into an aquifer (e.g. aquifer storage and recovery (ASR) wells) or into the vadose zone eventually percolating to an aquifer (e.g. spreading basins, dry well, etc.; USEPA 2021). Identifying the storage and flow capabilities of complex aquifers can improve the efficacy of many conceptual site models (CSM) for sites considered for ASR projects. In a karst setting, the EAR process may be able to take advantage of natural surficial features and the increased storage capacity of karst aquifers to improve recharge to groundwater. However, the suitability for an EAR project in a karst setting depends on the maturity of the karst and its preceding epikarst. The focus of flow within the epikarst causes enlargement of fractures and karst conduits. Thus, the storage and transmissivity within the karst vary greatly. Electrical resistivity imaging (ERI) is a well-known geophysical tool for mapping fractures and sinkholes, typical in karst settings. Locating enhanced water conveyance structures of a karst aquifer can improve the design and operation of an EAR site. This study investigated the hydraulic connection between shallow and deep groundwater using ERI to identify potential flow pathways and to improve our understanding of the storage mechanisms of the epikarst. The results presented in this paper validate the effectiveness of ERI in characterizing karst/epikarst and delineating soil, bedrock and local faults and fractures in the subsurface.