Coupling ground-penetrating radar and flowmeter investigations for the characterization of a fissured aquifer

Abstract

We test the integration of ground-penetrating radar (GPR) borehole investigation and electromagnetic flowmeter surveys to characterize fissured or complex aquifers. Borehole GPR investigation allows assessment of the lateral continuity of the porous and permeable zones between closely spaced boreholes, whereas flowmeter tests are adopted to identify the inflow–outflow zones in the boreholes. We apply the coupled approach in a portion (between 10 and 20 m below ground surface) of a complex aquifer hosted in a calcareous–gypsiferous formation. The hydro-geophysical characterization was aimed to detect the most conductive levels and to estimate the hydrodynamic properties of the aquifer. The integration of single-hole flowmeters and GPR measurements accurately distinguished different productive levels of high porosity and permeability in the aquifer. Two aquifer systems characterized by a complex geometry of fissures and permeable layers have been recognized, establishing the role of the drilled boreholes in the short-circuiting of the two systems. Interpretation of the GPR survey in cross-hole configuration gave values of total porosity of the order of 0.35 and 0.5 in the two more productive levels, which were detected by the flowmeter investigation.

Borehole Flowmeter Logging for the Accurate Design and Analysis of Tracer Tests

“…In general, the GMF presents a widely variable permeability, related to both the complex and disturbed sedimentary sequence and fracturing. Core analysis and geophysical surveys suggest a flow pattern where groundwater moves preferentially along layers or thin intervals with very high hydraulic conductivity (Godio et al ). At the study site, we investigated the presence of hydraulically active layers intercepted by three boreholes (P1, P2, and P3), and their mutual connections in the region between boreholes.…”

Physical and Mechanical Properties of Turfy Soils under Confining and Axial Pressure Increases Stress Paths in Jilin Province, Northeast China

“…e low-lying plain is surrounded by low mountains, especially in the Jiangyuan and Jingyu areas, providing ideal terrain conditions for turfy soil formation [34]. e study was conducted in an area of seasonal frost, with a maximum frozen depth of around 180 cm [35,36]. Recent drill-hole results had revealed the distribution of a thick clay layer under the turfy soil layer, which prevented water infiltration into the turfy soil [33].…”