scholarly journals Time-lapse imaging of subglacial drainage conditions using three-dimensional inversion of borehole electrical resistivity data

2006 ◽  
Vol 52 (176) ◽  
pp. 49-57 ◽  
Author(s):  
Bernd Kulessa ◽  
Bryn Hubbard ◽  
Giles H. Brown
Keyword(s):  
Electrical Resistivity ◽  
Hydraulic Conductivity ◽  
Three Dimensional ◽  
Clay Content ◽  
Time Lapse ◽  
Sediment Layer ◽  
Bulk Resistivity ◽  
Resistivity Data ◽  
Hydrological Cycles ◽  
Subglacial Drainage

AbstractWe recorded electrical resistivity data at the base of four boreholes drilled through Haut Glacier d’Arolla, Switzerland. The data were acquired repetitively every hour over two diurnal hydrological cycles in the late melt season, separated by 10 days. Constrained three-dimensional (3-D) data inversion allowed reconstruction of hourly variations in bulk resistivity in the subglacial sediment layer. Inverted resistivity models reflect the establishment of channelized subglacial drainage in the study area between the two hydrological cycles, in agreement with previous work. Daily variations in bulk and water resistivity are in phase, and bulk resistivity amplitudes decrease away from the subglacial channel. Using selected electrical–hydraulic relationships, we estimate metre-scale changes in the hydraulic conductivity and porosity of the subglacial sediment layer, accounting for increasing clay content and decreasing median grain radius with distance from the channel. Hydraulic conductivity and porosity were respectively calculated to decrease from (6.4 ± 2.1) × 10–2ms–1 and 0.34 ± 0.01 at the channel to (3.3 ± 2.2) × 10–2ms–1 and 0.26 ± 0.01 at a distance of 5m from it. The hydraulic conductivity estimates are in agreement with previously inferred values, and the porosity estimates fall within the expected range for unlithified subglacial sediments. We conclude that collection and inversion of repeat 3-D subglacial resistivity data is feasible and has the capacity to generate multidimensional images of subglacial hydraulic processes and properties.

Estimation of Soil Hydraulic Conductivity on Clay Content, Determined from Resistivity Data

2006 ◽  
Author(s):  
Vladimir Shevnin ◽  
Omar Delgado‐Rodríguez ◽  
Aleksandr Mousatov ◽  
Albert Ryjov
Keyword(s):  
Hydraulic Conductivity ◽  
Clay Content ◽  
Soil Hydraulic Conductivity ◽  
Resistivity Data ◽  
Soil Hydraulic

Seasonal Shifts in Surface Water-Groundwater Connections in a Ferricrete-Impacted Stream Estimated from Electrical Resistivity

Geophysics ◽  
2021 ◽  
pp. 1-55
Author(s):  
Ariel Rickel ◽  
Beth Hoagland ◽  
Alexis Navarre-Sitchler ◽  
Kamini Singha
Keyword(s):  
Electrical Resistivity ◽  
Surface Water ◽  
Hydraulic Conductivity ◽  
Hyporheic Zone ◽  
Time Lapse ◽  
Breakthrough Curves ◽  
Low Flow ◽  
High Discharge ◽  
Storage Area ◽  
And Storage

The efficacy of the hyporheic zone (HZ) — where surface water and groundwater mix — for processing nutrients or uptake of metals is dependent on streambed hydraulic conductivity and stream discharge, among other characteristics. Here, we explore electrical resistivity tomography (ERT) of hyporheic exchange in Cement Creek near Silverton, Colorado, which is affected by ferricrete precipitation. To quantify flows through the HZ, we conducted four-hour salt injection tracer tests and collected time-lapse ERT of the streambed and banks of Cement Creek at high and low flow. We installed piezometers to conduct slug tests, which suggested a low permeability zone at 44-cm depth likely comprised of ferricrete that cemented cobbles together. Based on the ERT, the tracer released into the stream was constrained within the shallow streambed with little subsurface flow through the banks. Tracer was detected in the HZ for a longer time at high flow compared to low flow, suggesting that more flow paths were available to connect the stream to the HZ. Tracer was confined above the ferricrete layer during both the high- and low-flow tests. Mass transfer and storage area parameters were calculated from combined analysis of apparent bulk conductivity derived from ERT and numerical modeling of the tracer breakthrough curves. The hyporheic storage area estimated at low discharge (0.1 m2) was smaller than at high discharge (0.4 m2) and residence times were 2.7 h at low discharge and 4.1 h at high discharge. During high discharge, in-stream breakthrough curves displayed slower breakthrough and longer tails, which was consistent with the time-lapse electrical inversions and One-dimensional Transport with Inflow and Storage (OTIS) modeling. Our findings indicate that ferricrete reduces the hydraulic conductivity of the streambed and limits the areal extent of the HZ, which may lower the potential for pollutant attenuation from the metal-rich waters of Cement Creek.

scholarly journals Estimation of hydraulic conductivity on clay content in soil determined from resistivity data

2006 ◽  
Vol 45 (3) ◽  
pp. 195-207
Author(s):  
Aleksandr Mousatov ◽  
Albert Ryjov
Keyword(s):  
Hydraulic Conductivity ◽  
Clay Content ◽  
Resistivity Data

El contenido de arcilla en suelos areno-arcillosos influye sobre la permeabilidad hidráulica (coeficiente de filtración). Sepresenta una revisión de datos experimentales publicados que relacionan el coeficiente de filtración con el tipo litológico delsuelo y el tamaño de las partículas. A partir de cálculos teóricos, se modifican las conocidas fórmulas que relacionan el coeficientede filtración con el contenido de arcilla. Se estima el contenido de arcilla a partir de los datos interpretados por el método SEV,y se propone un procedimiento para la estimación del coeficiente de filtración: (a) cálculo del contenido de arcilla a partir de laresistividad del suelo y de la salinidad del agua subterránea, (b) estimación del coeficiente de filtración a partir del contenido dearcilla. Se presentan algunos ejemplos de la aplicación de esta metodología.

scholarly journals Geophysical Investigation Using 3-Dimensional Grid-Formation for Subsurface Lithology Characterization (A Case Study of Ovia North East, Edo State, South South Nigeria)

2021 ◽  
pp. 182-194
Author(s):  
O. J. Airen ◽  
P. S. Iyere
Keyword(s):  
Electrical Resistivity ◽  
Three Dimensional ◽  
Geophysical Investigation ◽  
Clayey Sand ◽  
Resistivity Data ◽  
North East ◽  
Lateral Distance ◽  
Lateral Plane ◽  
Resistivity Model ◽  
Edo State

Geophysical investigations using three-dimensional (3D) grid formation was carried out in Ovia North East Local Government Area of Edo State, Nigeria for subsurface lithology characterisation so as to generate a comprehensive basemap of the study area. Twelve (12) traverses in form of a rectangular grid were occupied for the 2D Electrical Resistivity Imaging (ERI) using the Wenner array. The 2D were all collated to form the 3D grid. The 2D Electrical Resistivity data was processed by the inversion of the 2D apparent resistivity data using the DIPRO software to generate the 2D inverted resistivity section while the 3D inverted resistivity model was done by inverting all the twelve traverses using 3DEarthimager software to model the 3D cube. The results of the 2D ERI revealed three (03) to five (05) resistivity structures across the twelve traverses indicating clay/clayey sand, sand and sandstone on a 200 and 300 m lateral distance and corresponding depth of 39.6 and 57.3 m across each traverses. Resistivity values generally varies from 16.8 – 45302 Ωm across Traverse 1 – 12. The layer horizontal depth slices of the 3D inverted resistivity distribution are in six layers, which are; 0 - 5 m, 5 – 10.8 m, 10.8 – 17.4 m, 17.4 – 25 m, 25 – 33.7 m and 33.7 – 43.8 m. The 3D inverted resistivity model within the study area covered lateral plane (the roll axis), 300 m, in the x plane (the pitch axis), 200 m lateral distance was covered and in the depth plane (the yaw axis), a maximum depth of 66 m is imaged. The inverted 3D Resistivity values generally vary from 189 - 6149 Ωm across the study area. The resistivity structures delineated from the 3D model are clayey sand and sand.

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