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

Torrese, Patrizio; Rainone, Mario Luigi; Colantonio, Fabio; Signanini, Patrizio

doi:10.4133/sageep2013-112.1

Cited by 20 publications

(6 citation statements)

References 11 publications

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“…The aim of the current investigations is to further explore the location, shape, and course of the already detected northern canal and to provide evidence on the existence of a second canal described by Herodotus in the 5th century BCE. In the past, 2D Electrical Resistivity Tomography (ERT) was commonly applied to delineate sedimentological differences of the subsurface without soil disturbance (e.g., [14][15][16][17][18]). In particular, the combination of geoelectrical resistivity mapping (i.e., vertical electrical soundings, ERT) and drilling has been applied successfully in the Nile Delta and Nile Valley in related studies aiming to identify and localize buried channels (e.g., [19][20][21][22][23]).…”

Section: Introductionmentioning

confidence: 99%

The Sacred Waterscape of the Temple of Bastet at Ancient Bubastis, Nile Delta (Egypt)

et al. 2021

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Sacred water canals or lakes, which provided water for all kinds of purification rites and other activities, were very speciﬁc and important features of temples in ancient Egypt. In addition to the longer-known textual record, preliminary geoarchaeological surveys have recently provided evidence of a sacred canal at the Temple of Bastet at Bubastis. In order to further explore the location, shape, and course of this canal and to find evidence of the existence of a second waterway, also described by Herodotus, 34 drillings and five 2D geoelectrical measurements were carried out in 2019 and 2020 near the temple. The drillings and 2D ERT surveying revealed loamy to clayey deposits with a thickness of up to five meters, most likely deposited in a very low energy fluvial system (i.e., a canal), allowing the reconstruction of two separate sacred canals both north and south of the Temple of Bastet. In addition to the course of the canals, the width of about 30 m fits Herodotus' description of the sacred waterways. The presence of numerous artefacts proved the anthropogenic use of the ancient canals, which were presumably connected to the Nile via a tributary or canal located west or northwest of Bubastis.

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Section: Introductionmentioning

confidence: 99%

The Sacred Waterscape of the Temple of Bastet at Ancient Bubastis, Nile Delta (Egypt)

et al. 2021

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“…The first relates to sediment thickness: results from the geoelectrical surveys and borehole logs reveal a thickness of 2-5 m in the river channel and 10-15 m in the elevated areas inside the Limpopo river valley (Abi, 2018). Larger thicknesses could reveal the presence of paleochannels, as found at other sites with similar resistivity signals (e.g., Torrese and Rainone, 2013). Such channels are also expected to occur away from the main channel, in particular at the inner bends of migrating meanders.…”

Section: Limpopo Sand River Storage and Abstraction Potentialmentioning

confidence: 66%

Assessing Groundwater Dynamics and Hydrological Processes in the Sand River Deposits of the Limpopo River, Mozambique

et al. 2022

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Drought and water scarcity constrain the socioeconomic development of many (semi-)arid regions of Southern Africa. Moreover, due to the increase of water withdrawals upstream, the Limpopo River is no longer perennial in Mozambique. Fortunately, its river bed can store significant amounts of freshwater, because of the occurrence of thick and often coarse sand deposits formed through pronounced dryland weathering, erosion, and sedimentation in the river channel. Such so-called “sand rivers” exist in many parts of semi-arid Africa and have varying configurations and hydrological conditions. The current research aims to comparatively assess the Limpopo sand river aquifer in terms of recharge and discharge dynamics, storage potential, and interactions with the surface water flow, as a function of its specific hydrological conditions: its large size, location downstream of a dam releasing permanent ecological flow, and its relatively undeveloped state. For this purpose field investigations were carried out at two sites, involving groundwater level measurements, 2D geoelectrical surveying, water chemical and stable isotope analysis, and sediment classification. These investigations reveal the occurrence of medium to coarse sands with thicknesses that can reach 10–15 m, dropping to 2–5 m in the main river channel, underlain by less permeable clays and silts. Analysis of the river level shows that large parts of the sand river are flooded almost every year, providing optimal conditions for recurring and rapid recharge of the system (confirmed by infiltration tests) through two mechanisms: direct infiltration of surface runoff and lateral flow toward non-flooded areas of the river valley, also confirmed by the chemical and isotope study. During the dry season, groundwater provides base flow to the river and the average water level drop in the sand river system is about 1.8 m. The connectivity with the river margins is limited, due to the clayey nature of the river bank sediment, but local paleochannels can result in a continuation of sand layers. Hydrological processes controlling the water quality are evapoconcentration, mixing of discharging groundwater with the perennial surface water flow, and to a minor extent mineral dissolution, with the groundwater being of Ca-HCO3 type. The combination of the large size, high permeability, and frequent flooding of the sand river deposits provides optimal conditions for groundwater abstraction, requiring additional assessment of the impact on riparian vegetation and downstream users.

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“…A hybrid array sequence comprised of 1,295 measurements was developed by the combination of WS and PD array sequences. A 3D resistivity block was achieved by full inversion of combined 2D ERT data (TORRESE et al, 2012(TORRESE et al, , 2013. A 3D model 515 m x 203 m in size was achieved from this with a depth ranging between 70 m for the WS array and 100 m for the PD arrays.…”

Section: Methodsmentioning

confidence: 99%

3d Ert Imaging of the Fractured-Karst Aquifer Underlying the Experimental Site of Poitiers (France): Comparing Wenner-Schlumberger, Pole-Dipole and Hybrid Arrays

Torrese

Rainone

Signanini³

et al. 2014

Symposium on the Application of Geophysics to Engineering and Environmental Problems 2014

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Electrical Resistivity Tomography (ERT) surveys were undertaken to investigate the Dogger Limestone fractured-karst aquifer at the Hydrogeological Experimental Site (HES) of Poitiers, France. Three-dimensional resistivity imaging was obtained from full inversion of combined 2D ERT data collected along five parallel 470 m long profiles with a 50 m line spacing. A 3D block measuring 515 x 203 m in size with a maximum depth of 100 m was surveyed. Dogger Limestone occurs at a depth ranging between 30 and 120 m and is overlain by argillaceous limestone. This paper compares the imaging obtained from different array sequences. Calibration of the 3D resistivity block with well logs indicates that: the Wenner-Schlumberger (WS) array shows the tendency to enhance layering, to locate bodies at a shallower depth and to laterally extend them; the Pole-Dipole (PD) array shows larger lateral heterogeneities, more compact and vertically extended bodies and poor data fitting; the hybrid array sequence, obtained by the combination of WS and PD array sequences, despite a poor data fitting, similar to PD, shows a better correlation with respect to well log results. In this setting, the hybrid array sequence shows better imaging, due to the combination of the large vertical resolution of WS, large lateral resolution and penetration depth of PD. It allows passing through the thick, low resistivity shallow layer. Indeed, the results are affected by the occurrence of the shallow, 30 m thick, low resistivity argillaceous limestone that reduced the investigation depth as revealed by synthetic datasets modelling and sensitivity analysis. Modelling also revealed that the occurrence of the argillaceous limestone led to a severe underestimate of the Dogger Limestone resistivity values with respect to well resistivity logs; it also allowed verifying the detectability limits when investigating shallow karst limestone intervals located at depths of up to 50 m.

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

Cited by 20 publications

References 11 publications

The Sacred Waterscape of the Temple of Bastet at Ancient Bubastis, Nile Delta (Egypt)

The Sacred Waterscape of the Temple of Bastet at Ancient Bubastis, Nile Delta (Egypt)

Assessing Groundwater Dynamics and Hydrological Processes in the Sand River Deposits of the Limpopo River, Mozambique

3d Ert Imaging of the Fractured-Karst Aquifer Underlying the Experimental Site of Poitiers (France): Comparing Wenner-Schlumberger, Pole-Dipole and Hybrid Arrays

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