scholarly journals GEOPHYSICAL EVALUATION OF SUBSURFACE PROTECTIVE CAPACITY AND GROUNDWATER PROSPECT IN A TYPICAL SEDIMENTARY ZONE, EASTERN DAHOMEY BASIN USING ELECTRICAL RESISTIVITY TECHNIQUE

2020 ◽  
Vol 5 (2) ◽  
pp. 85-92
Author(s):  
Kayode Festus Oyedele ◽  
Olawale Babatunde Olatinsu

Subsurface protective capacity evaluation is important in groundwater prospecting. With the aid of Dar-Zarrouk parameters which show direct relationship with contaminants infiltration time and transmissivity, joint interpretation of vertical electrical sounding (VES) and 2-D resistivity imaging were employed to evaluate overburden protective capacity and groundwater potentials at Mowe in Obafemi-Owode LGA, southwest Nigeria. Total longitudinal conductance S, total transverse resistance T, longitudinal resistivity ρL and transverse resistivity ρT were computed. Sand/clayey sand was delineated at 70% of the area either as confined aquifers (78%) or unconfined aquifers (22%). S values in 87% of locations has moderate protective rating (0.2071 – 0.5630), one location has good protective rating (0.7736), others have weak protective ratings (0.1053 – 0.1814). The entire area is characterized by low overburden thickness H (7.9 – 25.6 m), which agrees with a correlation coefficient of 0.58 between S and H. T values is in the range 235 – 2046 Ωm2 with high values indicating high transmissivity zones, suggesting high probability of pollutant contamination of aquifer, also agreeing with moderate correlation coefficient of 0.69 between T and H. The study area was grouped into three regions on the cross plot of T versus S: low S and high T – poor protection and high contaminant transmission; moderate/good S and low T – good protection with low contaminants transmission; moderate/low S and low T – weak protective capacity and poor transmissivity. Excellent correlation (0.99) exists between ρL and ρT, with ρT slightly higher than ρL, and low ρL signifying the presence of conductive clayey materials in the overburden.

2020 ◽  
Vol 4 (2) ◽  
pp. 99-102
Author(s):  
Johnson C. Ibuot ◽  
Moses M. M. Ekpa ◽  
Doris O. Okoroh ◽  
Aniefiok S. Akpan Emmanuel T. Omeje

Geoelectric survey employing Vertical Electrical Sounding (VES) was carried out in order to assess the groundwater repositories. A total of seven soundings were obtained with their layer resistivity, thickness and depth within the maximum electrode separation. The geoelectric parameters obtained were used to estimate the Dar-Zarrouk parameters (longitudinal conductance and transverse resistance), hydraulic conductivity and transmissivity. The result shows the aquifer resistivity ranging from 77.14 to 784.76 Ωm, with thickness ranging from 28.78 to 80.04 m. The longitudinal conductance have values ranging from 0.071 to 0.825 Ω-1 while the values of hydraulic conductivity and transmissivity range from 1.087 to 5.881 m/day and 60.180 to 374.031 𝑚2/day respectively. The contour maps generated show the variation of these parameters across the subsurface, and areas with poor protective capacity were delineated. The results also delineate the groundwater potential of the study area as moderate, while the corrosivity rating indicates non-corrosive and slightly corrosive.


2020 ◽  
Vol 4 (2) ◽  
pp. 102-104
Author(s):  
Johnson C. Ibuot ◽  
Moses M. M. Ekpa ◽  
Doris O. Okoroh ◽  
Aniefiok S. Akpan Emmanuel T. Omeje

Geoelectric survey employing Vertical Electrical Sounding (VES) was carried out in order to assess the groundwater repositories. A total of seven soundings were obtained with their layer resistivity, thickness and depth within the maximum electrode separation. The geoelectric parameters obtained were used to estimate the Dar-Zarrouk parameters (longitudinal conductance and transverse resistance), hydraulic conductivity and transmissivity. The result shows the aquifer resistivity ranging from 77.14 to 784.76 Ωm, with thickness ranging from 28.78 to 80.04 m. The longitudinal conductance have values ranging from 0.071 to 0.825 Ω-1 while the values of hydraulic conductivity and transmissivity range from 1.087 to 5.881 m/day and 60.180 to 374.031 𝑚2/day respectively. The contour maps generated show the variation of these parameters across the subsurface, and areas with poor protective capacity were delineated. The results also delineate the groundwater potential of the study area as moderate, while the corrosivity rating indicates non-corrosive and slightly corrosive.


2018 ◽  
Vol 7 (2) ◽  
pp. 347-360 ◽  
Author(s):  
Olateju O. Bayewu ◽  
Moroof O. Oloruntola ◽  
Ganiyu O. Mosuro ◽  
Temitope A. Laniyan ◽  
Stephen O. Ariyo ◽  
...  

2021 ◽  
Vol 5 (1) ◽  
pp. 18
Author(s):  
Matthew Tersoo Tsepav ◽  
Aliyu Yahaya Badeggi ◽  
Obaje Nuhu George ◽  
Usman Yusuf Tanko ◽  
Ibrahim Samuel Ibbi

<p>Electrical resistivity method employing the Schlumberger array was used to occupy forty four (44) vertical electrical sounding points in Lapai town with the aim of determining the depth to aquifers, aquifer thicknesses and aquifer protective capacity. The G41 Geotron resistivity meter was used in obtaining the apparent resistivity data which was processed using Interpex 1XD resistivity interpretation software. The results revealed four lithologic sections which include top lateritic soil, sandy clay, fractured basement and fresh basement. Both confined and unconfined aquifers were identified within the area, with four classes of aquifer proactive capacities as high, moderate, weak and poor. While the aquifer at VES 20 was highly protected, twenty other aquifers were moderately protected, eight others had weak protection and fifteen aquifers were poorly protected. The aquifers were generally of good thicknesses and at varying reasonable depths, making them good reservoirs of water in appreciable quantity. The average aquifer thickness was estimated to be 48.36m while the average depth to aquifers was estimated to be 56.68m.</p>


Author(s):  
Dian Darisma ◽  
Ferdy Fernanda ◽  
Muhammad Syukri

Lam Apeng is a village with a majority of people living as farmers, which causes the need of water for agriculture is increasing. The water demand in this area continues to increase as the population increases, for various purposes. The objective of this study is to determine the distribution of the groundwater layer using the electrical resistivity method and to determine groundwater potential using hydraulic parameters. This research is conducted using 2 measurement line with a length of each line is 112 meters and distances of each electrode is 2 meters. The data invert using Res2Dinv software to obtain 2D subsurface lithology subsurface. At line 1, the aquifer (sand) layer is located in the second layer with a rock resistivity value of 12 Ωm - 18.6 Ωm at a depth of 8 m - 18 m. At line 2, the aquifer (sand) layer is also located in the second layer with a resistivity value of 4.6 Ωm - 18 Ωm at a depth of 5 m – 12 m. Based on the interpretation of the two measurement lines, it can be concluded that the type of aquifer in the research site is a semi unconfined aquifer. In this study, hydraulic parameters (hydraulic conductivity, longitudinal conductance, transverse resistance, and transmissivity) was calculated based on the resistivity value and the thickness of the aquifer layer. The average resistivity of the aquifer layer used is 15.3 Ωm and 11.3 Ωm, respectively for line 1 and line 2, indicating that the aquifer was moderately corrosive. Longitudinal conductance values are 0.65 Ω-1 and 0.62 Ω-1 which indicated moderate protective capacity. The transmissivity values are 6.78 m2/dayand 4.77 m2/day, which indicates that the designation in this area is low and the groundwater potential is local or only for personal consumption.


2019 ◽  
Vol 9 (8) ◽  
Author(s):  
Sixtus Nwachukwu ◽  
Rasaq Bello ◽  
Ayomide O. Balogun

Abstract An investigation has been made of the groundwater potentials of Orogun Town, Ughelli North Local Government Area of Delta State, Nigeria, using electrical resistivity survey. This study motivated to determine electrical resistivity parameters of the area. The aim of this work is to use electrical resistivity method to explore the groundwater potentials of Orogun Town with the determination of its Dar Zarrouk parameters. A total of eight vertical electrical sounding (VES) were conducted with maximum electrode spacing of 150 m. The data were acquired using ABEM SAS 4000 Terrameter and processed using IPI2win and Interpex softwares. The groundwater potentials of the area are evaluated based on the longitudinal conductance (S), transverse resistance (T), coefficient of electrical anisotropy (λ), resistivity for the formation ($$\rho_{\text{m}}$$ρm), reflection coefficient (RC) and resistivity contrast (FC). The results reveal four subsurface geoelectric layers in seven of the eight VES while one VES revealed three subsurface geoelectric layers. Resistivity values for all the layers in the study area are very high, higher than what is expected in a sedimentary basin as we have in the study area. The resistivity values range from 8470 Ωm (layer 1, VES 7) to 118,030,000 Ωm (layer 3, VES 8). Depth to aquifer in the study area ranged from 1.61 m (VES 2) to 12.41 m (VES 1), while resistivity values of the aquifer ranged from 64,182 Ωm (VES 3) to 118,030,000 Ωm (VES 8). The results from the formation parameters evaluated showed that the area has good groundwater potential but might have been highly contaminated, especially from hydrocarbon sources and other man-made pollutants. The suggested contamination of the aquifer is as a result of the high values of resistivity of the aquifer layers.


2016 ◽  
Vol 63 (1) ◽  
pp. 55-66 ◽  
Author(s):  
Opeyemi J. Akinrinade ◽  
Rasheed B. Adesina

AbstractThis study provides a model for the prediction of groundwater potential and vulnerability of basement aquifers in parts of Akure, Southwestern Nigeria. Hydrogeophysical surveys involving very-low-frequency electromagnetic (VLF-EM) profiling and electrical resistivity (ER) sounding, as well as evaluation of hydraulic gradient using three-point method, were carried out. Ten VLF-EM reconnaissance survey traverses, with lengths ranging from 55 m to 75 m, at 10 m station separation, and 12 vertical electrical sounding (VES) stations were occupied. Two-dimensional map of the filtered real component reveals areas of high conductivity, indicative of linear features that can serve as a reservoir or conduit for fluid flow. Interpretation of the VES results delineates three to four geoelectric units. Two aquifer zones were identified, with resistivity values in the ranges of 20 Ωm to 310 Ωm and 100 Ωm to 3,000 Ω m, respectively. Transverse resistance, longitudinal conductance, coefficient of anisotropy and hydraulic gradient have values ranging from 318.2 Ωm2 to 1,041.8 Ωm2, 0.11 mhos to 0.39 mhos, 1.04 to 1.74 and 0.017 to 0.05, respectively. The results of this study identified two prospective borehole locations and the optimum position to site the proposed septic system, based on the aquifer’s protective capacity and groundwater flow properties.


2021 ◽  
Vol 30 (1) ◽  
pp. 43-52
Author(s):  
Kenechukwu A. Ifeanyichukwu ◽  
Elizabeth Okeyeh ◽  
Okechukwu E. Agbasi ◽  
Onwe I. Moses ◽  
Ogechukwu Ben-Owope

In Nnewi, Anambra State Nigeria, twenty vertical electrical sounding (VES) were performed to delineate vulnerability and transmissivity of identified aquifer within the study area. Hydraulic parameters (transverse resistance, longitudinal conductivity, hydraulic conductivity and transmissivity) were delineated from geoelectrical parameters (depth, thickness, and apparent resistance). The geo- parameters of the aquifer: apparent resistance from 1000.590 to 1914.480, thickness from 42.850 – 66.490 m and 65.530 to 100.400 m of depth. The estimated hydraulic parameters of the aquifers are transverse resistance 54264.383 - 104568.898 Ωm, longitudinal conductance 0.029 – 0.062 mho, hydraulic conductivity 0.664 – 2.015 m/day and transmis- sivity between 4.167 and 13.963 m2/day. All aquifers have poor protective capacity, 40 percent of the aquifers have low classification with smaller withdrawal potential for local groundwater supply, while 60 percent of the delineated aquifer has intermediate classification and withdrawal potential for local groundwater supply. Due to its groundwater supply potential and protective capacity, the eastern part of the study area has stronger groundwater potential.


Warta Geologi ◽  
2021 ◽  
Vol 47 (2) ◽  
pp. 103-112
Author(s):  
S.N. Yusuf ◽  
◽  
J.M. Ishaku ◽  
W.M. Wakili ◽  
◽  
...  

Karlahi is largely underlain by granites and migmatites gneiss of the Adamawa Massif. The area lies west of Benue Trough and east of Cameroon volcanic line. The aim of this paper is to determine hydraulic properties of water bearing layer using parameters derived from Dar-Zarrouk equation and characterized them into groundwater potential zones. The resistivity values of the weathered and slightly weathered layers which make up the water bearing layers were added and an average was taken and used as the resistivity of the water bearing formation in computation of Dar-Zarrouk parameters in Karlahi area. The values of resistivity of water bearing formation ranged from 18 to 4963 Ωm with an average resistivity value of 549 Ωm and the thickness of the water bearing formation ranges from 21 to 32 m with an average thickness of 24.5 m. Conductivity values range from 0.000201 to 0.05509 (σ) while the longitudinal conductance range from 0.00483 to 1.2363 Ω-1, the transverse resistance ranges from 407 to 123504.3 Ωm2. The hydraulic conductivity and transmissivity values range from 0.14 to 25.87 m/day and 3.28 to 580.4 m2/day respectively. The longitudinal conductance values in Karlahi area revealed poor to good with an average longitudinal conductance value that is moderate. High transverse resistance values are located in the central and southern part of Karlahi area while low values are located in the eastern part. The spatial distribution map of transmissivity in the area revealed moderate to high transmissivity values in the north central part and a negligible to low transmissivity in southern part, extreme northeastern part. The groundwater potential map of Karlahi area shows negligible to weak potential groundwater zones in SW and SE, moderate potential in the central to northern part of Karlahi area.


Author(s):  
A. S. Ogungbe ◽  
O. O. Olajuwon ◽  
R. B. Adegbola ◽  
A. A. Alabi ◽  
E. O. Onori ◽  
...  

Geophysical and physiochemical investigations were carried out along Lagos-Badagry Expressway, Southwest, Nigeria on three locations dominated by highway runoff, with a view to monitoring the effect of highway runoff on nearby groundwater. The locations were: Iyana Isashi, Iyana Era and Agbara. An overview of the subsurface resistivity distribution was achieved employing Vertical Electrical Sounding (VES) using Schlumberger array and Two-dimensional (2D) resistivity imaging (Wenner array). The ABEM Terrameter SAS 1000 was used for both VES and 2D resistivity surveys and the data were analysed using IPI2win and RES2DINV, respectively. The VES results showed up to four geoelectric layers consisting of sand, clayey sand, clay and sandy soils. The resistivity at Agbara was found varying from 3.52 Ωm - 11 Ωm. This low resistivity value showed a high level of infiltration of highway runoff into the subsurface, thereby causing contamination of the groundwater. Iyana Isashi and Iyana Era have a relatively moderate resistivity values ranging from 103 Ωm to 178 Ωm. Physiochemical analysis of groundwater samples collected at the study locations revealed high electrical conductivity, total dissolved solids and pH values. The results of the borehole sample taken at 32 m away from the profile point at Agbara produced higher values of electrical conductivity and total dissolved solids than those of other locations, hence validating the electrical resistivity surveys, indicating that the groundwater sample from the survey point at Agbara is contaminated.


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