Towards realistic aquifer models: three-dimensional georadar surveys of Quaternary gravel deltas (Singen Basin, SW Germany)

Asprion, Ulrich; Aigner, Thomas

doi:10.1016/s0037-0738(99)00068-8

Cited by 92 publications

(46 citation statements)

References 33 publications

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“…It is also possible that layering of fine material was underlain here. Layers of fine sands can be marked by higher amplitudes in fluvioglacial deposits as was shown by Asprion and Aigner (1999).…”

Section: Discussionmentioning

confidence: 68%

Reconstructing migration phases of meandering channels by means of ground-penetrating radar (GPR): the case of the Obra River, Poland

Słowik

2011

J Soils Sediments

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Purpose The main goal of the study was to compare the potential of conventional and geophysical methods (ground-penetrating radar; GPR) to reconstruct the migration phases of a meandering lowland riverbed: the Obra River in western Poland. The purpose was to verify that the migration phases can be distinguished using the GPR measurement providing near-continuous imaging of alluvial structures and to discuss differences between the spatial extent of the migration phases distinguished using geologic data and GPR surveys. Materials and methods Historical maps from the eighteenth and the nineteenth century were analyzed to study transformations of the Obra River bed pattern. One hundred twenty tube sample borings were undertaken along five profiles to recognize the floodplain lithology. Granulation coefficients were determined using the method of moments to distinguish lithofacies of the alluvial deposits. The GPR measurement was performed using a georadar MALA ProEx equipped with shielded 100 and 250 MHz antennae. The GPR images were compared to geologic profiles to determine the depth scale and accuracy of the measurements. The depth scale of the GPR images was determined on the basis of the correlation of the radar reflections with the geologic profiles. Ten organic sediment samples were collected to determine the age of the migration phases.Results and discussion Point bars with layering of sand deposits, organic sediment fills, erosion surfaces, and gravel beds were distinguished using the 250 MHz antenna. However, some of sedimentary structures (e.g., inserts of fine sands in the organic deposits) were beyond the detection range of the antennae. The glacial/alluvial sediment interface was detected using the 100 MHz antenna which enabled the determination of the thickness of the alluvial fill. Traces of a period of early development of the Obra valley and three migration phases of the Obra River bed were distinguished. The research indicated that the Obra was a meandering river at least 7,000 years before present and that during the last 3,000 years, channel islands were formed within the studied section of the valley. Conclusions The GPR method allowed for the analysis of the spatial variability of alluvial deposits and helped to describe how meander bends were formed. The presented GPR images illustrate the spatial extent of the migration phases in a more detailed way than using only sedimentary information. However, geologic data are necessary for interpretation of the GPR images. It was shown that the GPR method gives useful results in spite of rough land surface and dense vegetation.

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Section: Discussionmentioning

confidence: 68%

Reconstructing migration phases of meandering channels by means of ground-penetrating radar (GPR): the case of the Obra River, Poland

Słowik

2011

J Soils Sediments

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“…Utilizing this knowledge is fundamental to achieve a geologically plausible description of heterogeneity, to delineate ranges of high-conductivity zones and for consistent re-interpretation of geophysical data (Stanford and Ashley, 1998;Asprion and Aigner, 1999;Hyndman and Tronicke, 2005;Iversen et al, 2008). Inclusion of such information in hydrogeological model calibration prevents non-realistic realizations of spatial hydraulic parameter distribution and exploits complementary knowledge to reduce ill-posedness of (geostatistical) inversion problems (Chen and Rubin, 2003;Maier et al, 2009;Dafflon et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional high resolution fluvio-glacial aquifer analog: Part 1: Field study

Bayer

Huggenberger

Renard

et al. 2011

Journal of Hydrology

100

106

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s u m m a r yDescribing the complex structures that exist in many sedimentary aquifers is crucial for reliable groundwater flow and transport simulation. However, hardly any aquifer can be inspected in such detail that all decimeter to meter heterogeneity is resolved. Aquifer analogs serve as surrogates to construct models of equivalent heterogeneity, and thus imitate those features relevant for flow or transport processes. Gravel pits found in excavation show excellent sections of the sedimentary sequence and thus offer direct insight into the structural and textural composition of the subsoil. This paper describes an approach to also inspect the third dimension: by mapping during the ongoing excavation it is possible to obtain a three-dimensional representation of the subsurface within a short period of time. A detailed description of a case study is presented and the findings from sedimentological, hydrogeological and geophysical analyses are compared. The gravel pit is located near the town of Herten in southwest Germany, where relatively young unconsolidated fluvio-glacial and fluvial sediments in the Rhine basin are mined. The excavated gravel body is built up by architectural elements typical for braided river deposits. The study generated a high-resolution data set of lithofacies, hydrofacies and ground penetrating radar (GPR) profiles. It represents the basis for a full three-dimensional geostatistical reconstruction presented in the second part

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“…Many authors (e.g. Asprion and Aigner 1999;Huisink 2000;Ekes and Hickin 2001) interpreted such signal as vertically accreted bed-load sheets or stratified sheetflood deposits. The horizontal reflectors appearing in the top part of Section 9 (Fig.…”

Section: Discussionmentioning

confidence: 99%

GPR and aerial imageries to identify the recent historical course of the Obra River and spatial extent of Obrzańskie Lake, altered by hydro-technical works

Słowik

2013

Environ Earth Sci

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Ground penetrating radar (GPR) measurements have been conducted to retrace the natural course of the Obra River and changes of spatial extent of Obrzańskie Lake (western Poland). The Obra River valley was subjected to intensive anthropogenic transformation. Three artificial canals were constructed here in the beginning of the nineteenth century. The GPR surveys were done using a georadar MALA ProEx equipped with 250 MHz antenna. The measurement was verified by coring and analyses of historical maps, aerial photographs, and satellite images. The research has shown that there are at least three elongated depressions preserved in the modern land surface near the village of Solec, situated in the middle course of the valley. Several structures suggesting functioning of a multi-channel pattern in the past have been detected inside and in the vicinity of the depressions. Filling the channels with silts and peats might have been the effect of flow deceleration caused by the construction of the Obra Canals. Moreover, situation of two of the retraced depressions suggests that the landforms might be the remains of a river bed disappearing in wetlands. Further studies including groundwater flux measurements in the area between the depressions are needed to confirm such hypothesis. Furthermore, the study allowed retracing the spatial extent of Obrzańskie Lake. The sediment structures detected by the GPR measurements and calibrated with coring were interpreted to be the traces of the lake shoreline. The interpretation was supported by the findings inferred from aerial and satellite images. It was shown that Obrzańskie Lake had had at least three islands and had been directly connected with a network of braided channels before the anthropogenic intervention. The spatial extent of the lake was significantly altered by the construction of the North Obra Canal. Disconnecting the lake from the Canal resulted in more than 50 % decrease of the lake surface.

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Towards realistic aquifer models: three-dimensional georadar surveys of Quaternary gravel deltas (Singen Basin, SW Germany)

Cited by 92 publications

References 33 publications

Reconstructing migration phases of meandering channels by means of ground-penetrating radar (GPR): the case of the Obra River, Poland

Reconstructing migration phases of meandering channels by means of ground-penetrating radar (GPR): the case of the Obra River, Poland

Three-dimensional high resolution fluvio-glacial aquifer analog: Part 1: Field study

GPR and aerial imageries to identify the recent historical course of the Obra River and spatial extent of Obrzańskie Lake, altered by hydro-technical works

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