Understanding the role of geological heterogeneity on the performance of managed aquifer recharge (MAR) in terms of effective groundwater storage is crucial to design MAR systems. Natural aquifers are affected by a variety of geologic strata and structures at different scales, which are responsible for wide ranging hydraulic properties. This study combines physical experiments and numerical modeling to investigate the effect of geologic structures commonly encountered in sedimentary environments, on MAR-induced groundwater flow patterns using injection wells. Models were conceptualized and parametrized based on the hydrogeological conditions of Tailan River basin in arid NW China, which hosts a typical, structurally complex, alluvial-fan aquifer system affected by sediment layering, clay lenses and anticline barriers, and is extensively studied for the strategic potential of MAR in addressing water shortages in the region. Results showed that, compared to a homogeneous scenario, high-permeability aquifer layers shortened groundwater ages, decreased the thickness of the artificially recharged water lenses (ARWLs), and shifted the stagnation points downstream. Clay lenses increased groundwater residence times but had little effect on spatial flow patterns due to their elongation parallel-to-flow direction. Overall groundwater ages, as well as the thickness of ARWLs created through injection on the upstream side of an anticline, increased, and this to a larger extent than through injection on the downstream side, which did not increase significantly compared to the homogeneous scenario. Results provide insights for MAR optimization in naturally heterogeneous aquifer systems, along with a benchmark tool for application to a wide range of typical geological conditions.
Bibliographical noteAcknowledgements We appreciate the constructive comments made by Marwan Fahs, an anonymous reviewer, and the editors, which helped to improve the manuscript.
Funding information This research was supported by the National Natural Science Foundation of China (41572210, U1803241, 51779230, 41572242), the Open Project Program of the State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering (Nanjing Hydraulic Research Institute, Grant NO. 2020nkms05), the Open Project Program of Key Laboratory of Groundwater Resources and Environment (Jilin University), Ministry of Education (Grant No.
202105002KF), the Science and Technique Foundation of He′nan Scientific Committee (No. 192102310248), and the National Key Research and Development Program of China (NO. 2016YFC0402809), by providing financial support for the collection of data and the publishing of the results.
- Groundwater flow
- Artificial recharge
- Geologic structures
- Lab-scale sand tank
- Numerical simulation