Ground Penetrating Radar Monitoring of Unconfined Aquifer Pumping Tests: Results from New Experiments

In this paper, we describe the result of a recent hydrogeological and geophysical investigation carried out within and around Aduramigba - Onibu-Eja Estate dumpsite with the aim of detecting evidence of contamination as well as depths to contamination of the groundwater after a previous study six years ago. Twenty water samples from shallow water wells and boreholes were analyzed for their physico-chemical constituents while five vertical electrical soundings and five electromagnetic ground penetrating radar surveys were conducted. The result shows high concentrations of anions of nitrates (NO3-), bicarbonates (HCO3-), chloride (Cl-) and sulphate (SO42-) with values of 73.97 mg/l, 91.5 mg/l, 331.2 mg/l, 222.4 mg/l respectively, cations values of Mg2+, Fe2+, Na+, and K+ having value of 25.44 mg/l, 6.23 mg/l, 37.31 mg/l and 35.41 mg/l, respectively, which were far above the World Health Organization (WHO) and Nigeria Drinking Water Quality Standard (NDWS). Heavy metal components such as Lead, Zinc, Copper and Nickel were also observed to be on the high side, having been contributed from effluents from rust metallic materials cum chemicals dumped within the dumpsite. Detailed geophysical study reveal the depth to contamination at between 4.1 meters in VES 3 to 5.9 meters in VES 2 with resistivity as low as 5.12 Ωm in VES 2 to 7.12 Ωm in VES 3 while ground penetrating radar (GPR) revealed that the leachate has permeated to a depth of 3.5 – 5.25 meters in traverse 4 and 4.0 – 6.0 meters in traverse 3 which correspond to the depth to unconfined aquifer within the dumpsite. The study conclude that this would pose a greater threat to residents living in this vicinity and as such, this might have contributed to the closure of the dumpsite.

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Surface Ground-penetrating Radar monitoring of water infiltration inside a ring infiltrometer

2012 14th International Conference on Ground Penetrating Radar (GPR) ◽

10.1109/icgpr.2012.6254948 ◽

2012 ◽

Cited By ~ 2

Author(s):

E. Leger ◽

A. Saintenoy

Keyword(s):

Ground Penetrating Radar ◽

Water Infiltration ◽

Ground Penetrating ◽

Radar Monitoring

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Seismoelectric imaging of the vadose zone of a sand aquifer

Geophysics ◽

10.1190/1.2773780 ◽

2007 ◽

Vol 72 (6) ◽

pp. A81-A85 ◽

Cited By ~ 69

Author(s):

J. Christian Dupuis ◽

Karl E. Butler ◽

Anton W. Kepic

Keyword(s):

Water Table ◽

Vadose Zone ◽

Ground Penetrating Radar ◽

Seismic Source ◽

Unconfined Aquifer ◽

Recording System ◽

Sedimentary Environments ◽

Sand Aquifer ◽

Weight Drop ◽

Ground Penetrating

We have acquired a [Formula: see text] seismoelectric section over an unconfined aquifer to demonstrate the effectiveness of interfacial signals at imaging interfaces in shallow sedimentary environments. The seismoelectric data were acquired by using a [Formula: see text] accelerated weight-drop source and a 24-channel seismoelectric recording system composed of grounded dipoles, preamplifiers, and seismographs. In the shot records, interfacial signals were remarkably clear; they arrived simultaneously at offsets as far as [Formula: see text] from the seismic source. The most prominent signal was generated at the water table at a depth of approximately [Formula: see text] and had peak amplitudes on the order of [Formula: see text]. A weaker response was generated at a shallower interface that is interpreted to be a water-retentive layer. The validity of these two laterally continuous events, and of other discontinuous events indicative of vadose-zone heterogeneity, is corroborated by the presence of reflections exhibiting similar characteristics in a ground-penetrating radar profile acquired along the same line.

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