We discuss a comparison between saturated hydraulic conductivity calculated with Electromagnetic Borehole Flowmeter (EBF) and water content obtained by Ground Penetrating Radar (GPR) Zero Offset Profile (ZOP

Arato, Alessandro

Basirico’, S.

Crosta, G.B.

Frattini, P.

Godio, Alberto

Villa, Alberto

English

We discuss a comparison between saturated hydraulic conductivity calculated with Electromagnetic Borehole Flowmeter (EBF) and water content obtained by Ground Penetrating Radar (GPR) Zero Offset Profile (ZOP) 

VILLA, ALBERTO

ARATO, ALESSANDRO

GODIO, Alberto

S. Basirico’

G. B. Crosta

P. Frattini

PORTO@iris (Publications Open Repository TOrino - Politecnico di Torino)

04 August 2020POLITECNICO DI TORINORepository ISTITUZIONALEFlowmeter and Ground Penetrating Radar: comparison between hydrogeological and geophysical methods / A. Villa; S.Basirico’ ; A. Arato; G.B. Crosta; P. Frattini; A. Godio. - ELETTRONICO. - 14(2012), p. EGU2012-11576. ((Interventopresentato al convegno EGU General Assembly 2012 tenutosi a Vienne nel April.OriginalFlowmeter and Ground Penetrating Radar: comparison betweenhydrogeological and geophysical methodsPublisher:PublishedDOI:Terms of use:openAccessPublisher copyright(Article begins on next page)This article is made available under terms and conditions as specified in the  corresponding bibliographic description inthe repositoryAvailability:This version is available at: 11583/2504765 since:Geophysical Research AbstractsVol. 14, EGU2012-11576, 2012EGU General Assembly 2012© Author(s) 2012Flowmeter and Ground Penetrating Radar: comparison betweenhydrogeological and geophysical methodsA. Villa (1), S. Basirico’ (1), A. Arato (2), G.B. Crosta (1), P. Frattini (1), and A. Godio (2)(1) Universita’ degli Studi di Milano - Bicocca, Dep. Scienze Geologiche e Geotecnologie, Milano, Italy(alberto.villa2@unimib.it), (2) DIGET, Geo-resources and Environment Department, Politecnico di Torino, ItalyA comparison between saturated hydraulic conductivity calculated with Electromagnetic Borehole Flowmeter(EBF) and water content obtained by Ground Penetrating Radar (GPR) Zero Offset Profile (ZOP) is presented.EBF technique permits to obtain permeability profiles along one borehole in the saturated zone by using the Moltz(1993) method. The analysis of ZOP data provides information about the water content (Topp, 1980) in the sectionbetween two adjacent boreholes. Water content profiles in the saturated zone can be related to the porosity of themedium which, together with the permeability from EBF measurements, is fundamental for any hydrogeologicalcharacterization.These two methods have been applied to three different test-sites located in the Northern Italy. A first site regardsa complex aquifer, characterized by a chaotic sequence of gypsum-marls. The other two sites are characterized byan alternation of sandy and silty-sandy layers. For each site, we adopted the EBF along screened boreholes with0.25 m spacing, under ambient and stressed conditions. The cross-hole georadar survey was performed within thesaturated zone by using 100 Hz borehole antennas with 0.25 m spacing.The results from the analysis of EBF and ZOP profiles show a general positive correlation between permeabilityand water content and porosity. This is reasonable for granular soils where the permeability is controlled bythe pore space available for water flow, i.e. the effective porosity. For this soils, where EBF permeability andZOP water-content profiles are in good agreement, the volume between the boreholes can be supposed to behomogeneous. On the other hand, a poor correlation suggests the presence of heterogeneity between the boreholes,which can be observed because the two techniques involve different volumes of soil: the EBF permeability refersto a portion of volume just around the borehole while the ZOP investigates the entire volume between the twoboreholes. The poor correlation could be enhanced when enlarging the borehole separation, because the differencein the involved volume between the two techniques increases. Finally, the degree of correlation between the EBFpermeability profile and the ZOP water content profile can indicate how much the volume investigated by EBF iseffectively representative of the entire volume between the boreholes.Molz, F.J. and S.C. Young, 1993. Development and Application of Borehole Flowmeters for EnvironmentalAssessment, The Log Analyst, 13-23.Topp G.C., J.L. Davis and A.P. Annan, 1980. Electromagnetic determination of soil water content: measurementsin coaxial transmission lines, Water Resources Research, 16, 574–582.

Flowmeter and Ground Penetrating Radar: comparison between
hydrogeological and geophysical methods

PORTO Publications Open Repository TOrino

Geophysical Research Abstracts
Vol. 14, EGU2012-11576, 2012
EGU General Assembly 2012
© Author(s) 2012
Flowmeter and Ground Penetrating Radar: comparison between
hydrogeological and geophysical methods
A. Villa (1), S. Basirico’ (1), A. Arato (2), G.B. Crosta (1), P. Frattini (1), and A. Godio (2)
(1) Universita’ degli Studi di Milano - Bicocca, Dep. Scienze Geologiche e Geotecnologie, Milano, Italy
(alberto.villa2@unimib.it), (2) DIGET, Geo-resources and Environment Department, Politecnico di Torino, Italy
A comparison between saturated hydraulic conductivity calculated with Electromagnetic Borehole Flowmeter
(EBF) and water content obtained by Ground Penetrating Radar (GPR) Zero Offset Profile (ZOP) is presented.
EBF technique permits to obtain permeability profiles along one borehole in the saturated zone by using the Moltz
(1993) method. The analysis of ZOP data provides information about the water content (Topp, 1980) in the section
between two adjacent boreholes. Water content profiles in the saturated zone can be related to the porosity of the
medium which, together with the permeability from EBF measurements, is fundamental for any hydrogeological
characterization.
These two methods have been applied to three different test-sites located in the Northern Italy. A first site regards
a complex aquifer, characterized by a chaotic sequence of gypsum-marls. The other two sites are characterized by
an alternation of sandy and silty-sandy layers. For each site, we adopted the EBF along screened boreholes with
0.25 m spacing, under ambient and stressed conditions. The cross-hole georadar survey was performed within the
saturated zone by using 100 Hz borehole antennas with 0.25 m spacing.
The results from the analysis of EBF and ZOP profiles show a general positive correlation between permeability
and water content and porosity. This is reasonable for granular soils where the permeability is controlled by
the pore space available for water flow, i.e. the effective porosity. For this soils, where EBF permeability and
ZOP water-content profiles are in good agreement, the volume between the boreholes can be supposed to be
homogeneous. On the other hand, a poor correlation suggests the presence of heterogeneity between the boreholes,
which can be observed because the two techniques involve different volumes of soil: the EBF permeability refers
to a portion of volume just around the borehole while the ZOP investigates the entire volume between the two
boreholes. The poor correlation could be enhanced when enlarging the borehole separation, because the difference
in the involved volume between the two techniques increases. Finally, the degree of correlation between the EBF
permeability profile and the ZOP water content profile can indicate how much the volume investigated by EBF is
effectively representative of the entire volume between the boreholes.
Molz, F.J. and S.C. Young, 1993. Development and Application of Borehole Flowmeters for Environmental
Assessment, The Log Analyst, 13-23.
Topp G.C., J.L. Davis and A.P. Annan, 1980. Electromagnetic determination of soil water content: measurements
in coaxial transmission lines, Water Resources Research, 16, 574–582.


Flowmeter and Ground Penetrating Radar: comparison between hydrogeological and geophysical methods

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Flowmeter and Ground Penetrating Radar: comparison between hydrogeological and geophysical methods

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