Mapping a Paleochannel System Controlling Contaminant Migration at a Wood‐Treating Facility Using Electromagnetics

Sandberg, Stewart K.; Corso, William; Levine, Jessica R.; Newhart, Gary; Powell, Greg

doi:10.4133/1.2922854

Cited by 3 publications

(2 citation statements)

References 2 publications

(2 reference statements)

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“…high resistivity), whereas finer-grained sediments (e.g. silt and clay) show high electric conductance (low resistivity) (Baines et al, 2002; Sandberg et al, 2001). The constructed geoelectrical cross-sections show three main geoelectrical layers.…”

Section: Resultsmentioning

confidence: 99%

Tracing Holocene channels and landforms of the Nile Delta through integration of early elevation, geophysical, and sediment core data

et al. 2020

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Intensification of anthropogenic activities and related processes have altered the morphology of modern deltaic systems. As a result, mapping of geomorphic features, such as paleochannels, using recently acquired digital elevation data has become increasingly difficult. Using the Nile River and delta as a test site, we developed and applied procedures to map the distribution of paleochannels that existed throughout the Holocene. A high-resolution digital elevation model (DEM) derived from an early, detailed topographic sheet collection was used to minimize the impact of recent man-made topographic artifacts. The DEM-inferred paleochannel distribution was verified using direct and indirect subsurface data. Using our adopted methodology, we identified 76 main and subsidiary paleochannels with a total length exceeding (by >500 km) previously mapped paleochannels. The overwhelming majority (>80%) of the reported historical and archeological sites (29 sites) in the Nile Delta were found to be proximal (<2.5 km) to the identified paleochannels, an observation that is not obvious in any of the previous paleochannel delineations. These observations suggest that the delineated paleochannel distribution of the Nile Delta can be a useful guide for locating ancient cities currently obscured by man-made structures or buried under thick Holocene deposits. Moreover, it can potentially enhance our understanding of the geological and archeological history of the Nile Delta and has societal benefits as these channels could act as preferred pathways for groundwater flow. The advocated methods can be readily applied to river deltas worldwide where high-resolution elevation datasets acquired before the onset of heavy anthropogenic activities are available.

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Section: Resultsmentioning

confidence: 99%

Tracing Holocene channels and landforms of the Nile Delta through integration of early elevation, geophysical, and sediment core data

et al. 2020

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“…The two sites were selected based on the interpretation of aerial photograms, which indicated the possible occurrence of paleochannels. Several geophysical methods can be used to investigate buried riverbeds: large scale rapid mapping with electromagnetic techniques (DE SMEDT et al, 2011;LEVSON et SAGEEP 2013 Denver, Colorado USA http://www.eegs.org SANDBERG et al, 2001;TORRESE et al, 2009), large scale identification of paleochannels with electrical resistivity depth sounding or profiling (SINHA et al, 2012), small scale identification of paleochannels and detailed imaging with reflection seismic (FRADELIZIO et al, 2008;HARRIS & STREET, 2006;MILLER et al, 1995;RAINONE and TORRESE, 2007), seismic tomography (DEEN and GOHL, 2002;SIGNANINI and TORRESE, 2004) and electric resistivity tomography (PILLA et al, 2010;TORRESE et al, 2012). Resistivity depth soundings were used to achieve electro-stratigraphic sections obtained by interpolating 1D inverted data with the objective of assessing the occurrence of paleochannels at a large scale.…”

Section: Introductionmentioning

confidence: 99%

Identification and Investigation of Shallow Paleochannels in the Chamelecon Valley (Honduras): 1d vs 2d Electrical Resistivity Surveys

Torrese

Rainone

Colantonio

et al. 2013

Symposium on the Application of Geophysics to Engineering and Environmental Problems 2013

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Electrical Resistivity Tomography (ERT) and resistivity depth sounding surveys were undertaken at two sites located along the Chamelecòn Valley (Honduras). The objective of the surveys was to determine the occurrence, geometry and lithological properties of the Chamelecòn River's shallow paleochannels. Following the interpretation of aerial photograms which indicated the likely presence of paleochannels, two sites were selected for the surveys. Resistivity depth soundings were used to achieve electro-stratigraphic sections obtained by interpolating 1D inverted data that would assist with assessing the occurrence of paleochannels at a large scale. The presence of paleochannels at the two sites was assessed through interpretation of the electro-stratigraphic sections. At Site 2, the abundant 1D data, the small distance between the soundings and the shallow target, allowed determining the course of the paleoriver as shown by resistivity and electrical transmissivity maps. The results from the 1D data, although affected by strong heterogeneities, are congruent with the 2D inverted models. ERT surveys confirmed the presence of paleochannels and allowed achieving detailed imaging of the alluvial geological bodies. Paleochannel deposits show resistivity values ranging between 70 and 100 ohm m at Site 1, while resistivity values range between 90 and 120 ohm m at Site 2. The latter resistivity values were affected by the presence of coarser deposits. Resistivity values suggest that at both sites paleochannel deposits have a clay content that is lower than 3 %. Other alluvial deposits in the area show resistivity values that range between 19 and 70 ohm m at Site 1, while resistivity values range between 30 and 90 ohm m at Site 2. These lower values suggest that clay content can be as high as 29 %. The presence of paleochannels assessed by means of 1D surveys and the lithological characterisation assessed by means of 2D surveys were confirmed by logs from boreholes drilled at the sites.

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Reconstruction of hillslope and valley paleotopography by application of a geomorphic model

Coleman

Niemann

Jacobs

2009

Computers & Geosciences

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Mapping a Paleochannel System Controlling Contaminant Migration at a Wood‐Treating Facility Using Electromagnetics

Cited by 3 publications

References 2 publications

Tracing Holocene channels and landforms of the Nile Delta through integration of early elevation, geophysical, and sediment core data

Tracing Holocene channels and landforms of the Nile Delta through integration of early elevation, geophysical, and sediment core data

Identification and Investigation of Shallow Paleochannels in the Chamelecon Valley (Honduras): 1d vs 2d Electrical Resistivity Surveys

Reconstruction of hillslope and valley paleotopography by application of a geomorphic model

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