The Use of Ground‐Penetrating Radar to Accurately Determine Water Table Depths

1998 ◽  
Author(s):  
N. M. Trenholm ◽  
L. R. Bentley
Keyword(s):  
Water Table ◽  
Ground Penetrating Radar ◽  
Ground Penetrating

Seismic reflection and ground‐penetrating radar imaging of a shallow aquifer

Geophysics ◽  
1998 ◽  
Vol 63 (4) ◽  
pp. 1310-1317 ◽  
Author(s):  
Steven J. Cardimona ◽  
William P. Clement ◽  
Katharine Kadinsky‐Cade
Keyword(s):  
Water Table ◽  
Ground Penetrating Radar ◽  
Low Frequency ◽  
Shallow Aquifer ◽  
Cone Penetrometer ◽  
Gradual Change ◽  
Cone Penetration ◽  
Geotechnical Data ◽  
Radar Images ◽  
Ground Penetrating

In 1995 and 1996, researchers associated with the US Air Force’s Phillips and Armstrong Laboratories took part in an extensive geophysical site characterization of the Groundwater Remediation Field Laboratory located at Dover Air Force Base, Dover, Delaware. This field experiment offered an opportunity to compare shallow‐reflection profiling using seismic compressional sources and low‐frequency ground‐penetrating radar to image a shallow, unconfined aquifer. The main target within the aquifer was the sand‐clay interface defining the top of the underlying aquitard at 10 to 14 m depth. Although the water table in a well near the site was 8 m deep, cone penetration geotechnical data taken across the field do not reveal a distinct water table. Instead, cone penetration tests show a gradual change in electrical properties that we interpret as a thick zone of partial saturation. Comparing the seismic and radar data and using the geotechnical data as ground truth, we have associated the deepest coherent event in both reflection data sets with the sand‐clay aquitard boundary. Cone penetrometer data show the presence of a thin lens of clays and silts at about 4 m depth in the north part of the field. This shallow clay is not imaged clearly in the low‐frequency radar profiles. However, the seismic data do image the clay lens. Cone penetrometer data detail a clear change in the soil classification related to the underlying clay aquitard at the same position where the nonintrusive geophysical measurements show a change in image character. Corresponding features in the seismic and radar images are similar along profiles from common survey lines, and results of joint interpretation are consistent with information from geotechnical data across the site.

Measurement of Water Table Fluctuations in a Sandy Soil Using Ground Penetrating Radar

1992 ◽  
Vol 35 (4) ◽  
pp. 1161-1166 ◽  
Author(s):  
M. C. Smith ◽  
G. Vellidis ◽  
D. L. Thomas ◽  
M. A. Breve
Keyword(s):  
Water Table ◽  
Sandy Soil ◽  
Ground Penetrating Radar ◽  
Water Table Fluctuations ◽  
Ground Penetrating

scholarly journals Shallow Geophysical Techniques to Investigate the Groundwater Table at the Giza Pyramids Area, Giza, Egypt

2017 ◽  
Author(s):  
Sharafeldin M. Sharafeldin ◽  
Khalid S. Essa ◽  
Mohamed A. S. Youssef ◽  
Zein E. Diab
Keyword(s):  
Water Table ◽  
Ground Penetrating Radar ◽  
Seismic Refraction ◽  
Groundwater Table ◽  
High Resistivity ◽  
Electrical Resistivity Imaging ◽  
Shallow Seismic ◽  
Geophysical Techniques ◽  
Electrical Resistivities ◽  
Ground Penetrating

Abstract. Geophysical studies were performed along selected locations across the Pyramids Plateau to investigate the groundwater table and the near aquifer, which harmfully affected the existed monuments of the Giza Pyramids and Sphinx. Electrical Resistivity Imaging (ERI), Shallow Seismic Refraction (SSR) and Ground Penetrating Radar (GPR) techniques were carried out along selected profiles in the plateau. Ten ERI, twenty six SSR and nineteen GPR profiles were performed at the sites. The ERI survey shows that, the groundwater table is at elevations varying from 13 to 18 m above the sea level (asl) and low resistivity values near the surface at the Great Sphinx. ERI profiles, which were applied southeast of the Middle Pyramid (Khafre), show high resistivity values near the surface, and water table is located at elevations ranging from 22 to 40 m asl, while the ERI profiles conducted south of Menkaure, show almost high resistivity near the surface. The groundwater table is located at elevations ranging between 45 and 58 m asl. The aquifer layer shows electrical resistivities ranging between 10 and 50 Ohm.m. The considerable high change in the groundwater table is due to the rapid increases of topography from the Great Sphinx towards the Small Pyramids (Menkaure), where this part looks-like a scarp. The SSR Survey is transmitted to know the different velocities and types of the layers, which can help in knowing the saturated layers in the area. The GPR Survey is performed to delineate the water table, which gives good matching with the ERI results.

scholarly journals Englacial hydrology of Annette Plateau, a temperate alpine glacier, Southern Alps, New Zealand

2021 ◽  
Author(s):  
◽  
Kolja Schaller
Keyword(s):  
Water Table ◽  
Ground Penetrating Radar ◽  
Ice Core ◽  
Radar Data ◽  
Early Spring ◽  
Early Summer ◽  
Seasonal Temperature ◽  
Glacier Surface ◽  
Alpine Glacier ◽  
Ground Penetrating

<p>The movement of water through temperate glaciers is important for understanding fundamental issues within glaciology. These include glacier induced floods, glacier dynamics and run-off prediction. Traditional englacial hydrology is thought to consist of interconnected tubular channels that merge down-glacier and drain through the glacier to the bed. However, englacial hydrology is much debated as the links between the glacier surface and bed are not well understood. Ground penetrating radar (GPR) is a geophysical tool that is well suited for studying glaciated areas. Recent ice coring attempts in New Zealand’s temperate alpine glaciers were not successful in coring to bedrock due to the interception of water at depth. This highlights the need for a better understanding of the englacial hydrology of temperate systems. This study investigates the englacial hydrology at Annette Plateau where on three occasions the interception of water has prevented successful coring to the glacier bed. Ground penetrating radar was used to conduct two high-resolution surveys on Annette Plateau in early spring 2011 and early summer 2011. Across-glacier profiles were acquired at 20 m spacing to enable tracking of englacial reflectors between profiles. Models of temperate englacial features were made to aid feature identification within radar profiles. Radar data is compared with density, stratigraphy and chemistry results from the 45 m ice core obtained at Annette Plateau in winter 2009. The early-summer survey indicates an increase in the glacier’s water content compared with the early-spring survey. Englacial reflectors show evidence of (a) spatially continuous englacial conduits, (b) the formation of a water table feature which shallows down glacier, and (c) detailed bedrock topography. Hydropotential surfaces, calculated for the water table and bedrock horizons, show the direction of water flow. Ice core chemistry shows a correlation between the depth of the water table and a significant hiatus indicated by tritium dating. We infer that an extensive water table has formed on an old melt surface where ice from approximately 1930-1991 has been removed. This water table responds to seasonal temperature changes and hydrological inputs.</p>

scholarly journals Identifying a soil hydraulic parameterisation from on-ground GPR time lapse measurements of a pumping experiment

2012 ◽  
Vol 9 (8) ◽  
pp. 9095-9117 ◽  
Author(s):  
A. Dagenbach ◽  
J. Buchner ◽  
P. Klenk ◽  
K. Roth
Keyword(s):  
Quantitative Analysis ◽  
Numerical Simulations ◽  
Water Content ◽  
Water Table ◽  
Ground Penetrating Radar ◽  
Time Lapse ◽  
Radar Signal ◽  
Capillary Fringe ◽  
Ground Penetrating ◽  
Over Time

Abstract. We show the potential of on-ground Ground-Penetrating Radar (GPR) to identify the hydraulic parameterisation with a semi-quantitative analysis based on numerical simulations of the radar signal. A pumping experiment has been conducted at the ASSESS-GPR site to establish a fluctuating water table, while an on-ground GPR antenna recorded traces over time at a fixed location. These measurements allow to identify and track the capillary fringe in the soil. The typical dynamics of soil water content with a transient water table can be deduced from the recorded radargrams. The characteristic reflections from the capillary fringes in model soils that are described by commonly used hydraulic parameterisations are investigated by numerical simulations. The parameterisations used are: (i) full van Genuchten, (ii) simplified van Genuchten with m = 1 − 1/n and (iii) Brooks-Corey. All three yield characteristically different reflections, which allows the identification of an appropriate parameterisation by comparing to the measured signals. We show that these are not consistent with the commonly used simplified van Genuchten parameterisation with m = 1 − 1/n.

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