scholarly journals Evaluation of Aquifer Protective Capacity and Groundwater Potential in Part of Iju, Akure-North, Ondo State, Nigeria

2020 ◽  
pp. 197-204
Author(s):  
A. Olajide ◽  
S. Bayode ◽  
T. Fagbemigun ◽  
A. Oyebamiji ◽  
J. Amosun ◽  
...  
Keyword(s):  
Geophysical Methods ◽  
Low Frequency ◽  
Groundwater Potential ◽  
Electrode Spacing ◽  
Protective Capacity ◽  
Value Range ◽  
Weathered Layer ◽  
Ondo State ◽  
Geological Units ◽  
Matching Techniques

Groundwater potential and aquifer protective capacity of the overburden unit was evaluated in part of Iju, Akure North, Ondo State using integrated geophysical methods involving Very Low Frequency Electromagnetic (VLF-EM) profiling and Vertical Electrical Sounding (VES). Four major traverses were established of varying length extents. The VLF-EM measurements were taken along the four major profiles of 10 m station interval.Forty two (42) Vertical Electrical Soundings were also conducted with half electrode spacing varying between 1 and 100 m and interpretation was done using the partial curve matching techniques and computer aided iteration. Five subsurface geological units were identified from geoelectric sections, consisting of the top soil, lateritic, weathered, partly weathered and fresh basement layers consecutively. For the first layer, resistivityranges between 23 and 323 Ωm with values of thickness ranging between 0.5 and 2.2 m. The resistivity and thickness of the second (lateritic) layer range from 132 to 430 Ωm and 1.6 to 4 m respectively. The resistivity of the weathered layer ranges from 4 to 94 Ωm and variable thickness between 10 and 24.4 m. The fourth layer has a resistivity value range of 65 to 120 Ωm and thicknesses between 20 and 30 m. The basement bedrock (fifth layer) has resistivity values between 770 and 820 Ωm. The depth to bedrock ranges from 1.8 to 31 m. The geophysical data and the basement aquifer delineated were then used to evaluate the hydrogeological setting and aquifer protective capacity of the study area. The observation from the results shows that close to 70 % of the study area falls within the zones of low groundwater potential, 25 % falls within medium potential zones while only 5 % make up the high potential zones. 75 % of the study area constituted the weak to poor protective capacity zones.  

scholarly journals Investigation of groundwater potential using integrated geophysical methods in Moloko-Asipa, Ogun State, Nigeria

2021 ◽  
Vol 11 (4) ◽  
Author(s):  
A. A. Alabi ◽  
S. A. Ganiyu ◽  
O. A. Idowu ◽  
A. F. Ogabi ◽  
O. I. Popoola
Keyword(s):  
Geophysical Methods ◽  
Low Frequency ◽  
Sampling Interval ◽  
Groundwater Potential ◽  
Groundwater Exploration ◽  
Protective Capacity ◽  
Southwestern Nigeria ◽  
Industrial Growth ◽  
Geoelectric Section ◽  
Weathered Layer

AbstractWater is essential for livelihood, development, and industrial growth. Its exploration in sufficient quantity is required where it does not freely occur on the surface. This research was aimed to delineate aquifer regions and provide information on the subsurface lithology of Moloko-Asipa Southwestern Nigeria. A combination of eight traverses investigated with very low frequency electromagnetic (VLF-EM) method at 5 m constant sampling interval and ten vertical electrical sounding (VES) were carried out in the survey. Measurements from the VLF-EM survey were processed with Karous and Hjelt filtering to give the resistivity contrast across the selected profiles. The VES data processing involved an automatic approximation of the initial resistivity and thickness of the geoelectric layers with IPI2Win and further filtering by WinResist iteration. Estimation of Dar-Zarrouk parameters was also employed to investigate the aquifer protective capacity of the area. The processed VLF-EM results showed the geology of the area to an average depth of 25 m. The geoelectric section of the VES data revealed minimum of 3 layers from sandy top soil to weathered layer and fresh basement with an average resistivity values of 1,816, 926 and 17,503 Ωm, respectively. The integration of VLF-EM and VES in the investigation revealed that the potential for groundwater exploration in the study area is poor due to the thin nature of the weathered layer and its shallow depth to basement. The aquifer protective capacity of the area was likewise inferred to be poor.

scholarly journals Hydrogeophysical investigation of groundwater potential and aquifer vulnerability prediction in basement complex terrain – A case study from Akure, Southwestern Nigeria

2016 ◽  
Vol 63 (1) ◽  
pp. 55-66 ◽  
Author(s):  
Opeyemi J. Akinrinade ◽  
Rasheed B. Adesina
Keyword(s):  
Low Frequency ◽  
Groundwater Potential ◽  
Aquifer Vulnerability ◽  
Hydraulic Gradient ◽  
Protective Capacity ◽  
Real Component ◽  
Southwestern Nigeria ◽  
Reconnaissance Survey ◽  
Transverse Resistance ◽  
Optimum Position

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.

scholarly journals HYDROGEOPHYSICAL AND AQUIFER PROTECTIVE CAPACITY OF ABAKALIKI/AFIKPO AREA AND ENVIRONS, SOUTHEASTERN NIGERIA USING GEO-SOUNDING DATA

2021 ◽  
pp. 53-72
Author(s):  
I Osi-Okeke ◽  
◽  
AI Opara ◽  
IC Oli ◽  
HM Udeh ◽  
...  
Keyword(s):  
Electrode Spacing ◽  
Model Parameters ◽  
Protective Capacity ◽  
Southeastern Nigeria ◽  
Longitudinal Conductance ◽  
Aquifer System ◽  
Transverse Resistance ◽  
Electrical Sounding ◽  
Depth Ranges ◽  
Matching Techniques

This work was carried out to evaluate the hydrogeological and geophysical properties of Abakaliki and Afikpo environs. Forty-seven (47) Vertical Electrical Sounding data were acquired with electrode spacing (AB/2) of 500m using Schlumberger electrode configuration. Conventional curve matching techniques were used to interpret the data and obtain initial model parameters. Results of the study showed 3-7 electric layers which indicate multiple aquifer system. QQH, QHK, KHK and QQHK models were the Vertical Sounding curves obtained. The aquiferous layers make up the third and fourth layers. The resistivity of the aquifer varies from 10.74Ωm to 13201Ωm with an average of 1013.58 Ωm. Aquifer depth ranges from 6.2m to 92.5m with an average aquifer depth of 27.07m, while the aquifer thickness varies from 2.3m to 55.87m with an average of 15.61m. Transverse resistance varies from 65.34Ωm2to 7079.14 Ωm2 with an average of 9966.29 Ωm2; and the longitudinal conductance varies from 0.00018Ω-1 to 1.65 Ω-1 with an average of 0.026 Ω-1. From the study, 49% of the study area falls under the poor protective rating while 21% falls under the weak rating with 25% and 5% which makes up the moderate and good ratings respectively. Using the average longitudinal conductance, it is observed that the study area is moderately protected.

scholarly journals Preliminary geophysical investigation for road construction using integrated methods

2018 ◽  
Vol 65 (4) ◽  
pp. 199-206
Author(s):  
Joel Olayide Amosun ◽  
Gbenga Moses Olayanju ◽  
Oluseun Adetola Sanuade ◽  
Tokunbo Fagbemigun
Keyword(s):  
Geophysical Methods ◽  
Low Frequency ◽  
Road Construction ◽  
Electrode Spacing ◽  
Geophysical Investigation ◽  
Near Surface ◽  
The Road ◽  
Geophysical Surveys ◽  
Integrated Methods ◽  
Resistivity Meter

AbstractIntegrated geophysical methods have been used to investigate the competency of the subsoil. The geophysical surveys conducted involve very low-frequency electromagnetic (VLF-EM) and electrical resistivity (ER) methods (dipole-dipole). ABEM Wadi and Ohmega resistivity meter were used to acquire VLF-EM and ER data, respectively, along two traverses. Station interval of 5 m was used for the VLF-EM survey, while inter-electrode spacing for dipole–dipole was 10 m; the inter-dipole expansion factor (n) ranged from 1 to 5. KHFFILT software was used to generate VLF-EM profiles and pseudosection, while DIPRO software was used for ER. Results from the ER method revealed the pattern of resistivity variations within the study area. The low resistivity values (11–25 Ohm-m) observed at the southern part of the study area could be attributed to changes in clay contents and degree of weathering in the subsurface. The results from the VLF-EM investigation revealed the presence of near-surface linear geologic structures of varying lengths, depths and attitudes, which suggest probable conductive zones that are inimical to the foundation of the road subgrade.

scholarly journals Hydrogeological appraisal of basement and sedimentary terrain in Ogun state using Geoelectrical methods

2020 ◽  
Vol 8 (1) ◽  
pp. 95
Author(s):  
Aladeboyeje Adegoke Ige ◽  
Coker Joseph Olakunle ◽  
Agbasi Okechukwu Ebuka ◽  
Inyang Namdie Joseph
Keyword(s):  
Groundwater Potential ◽  
Protective Capacity ◽  
Southwestern Part ◽  
Longitudinal Conductance ◽  
Northeastern Part ◽  
Ogun State ◽  
Overburden Thickness ◽  
Northwestern Region ◽  
Weathered Layer ◽  
Groundwater Potentiality

The coverage of the groundwater potential was estimated using the geometry calculator, the potential groundwater zones were validated using geophysical surveyed points of some selected locations in Abeokuta and Ewekoro. Generally, the result of the study shows that the higher the aquifer thickness and depth the better the groundwater potential. In the basement part of the study area (Abeokuta), the Northwestern region is characterized by increase in overburden thickness (28.1 m at VES-9), weathered layer resistivity (546 Ω m at VES-7) and longitudinal conductance unit (0.193 S at VES-3 and 0.218 S at VES-7), reflecting high aquifer potentials. In this regard, the Northeastern part of the study area can be categorized as good groundwater potential; moving towards the Southwestern part from the northern, groundwater potentiality changes from good to moderate while the Southwestern/ central part is categorized as area with poor groundwater potential. In the Sedimentary part of the study area (Ewekoro), the northcentral region is characterized by increase in overburden thickness (93 m at VES-10), longitudinal conductance unit (3.644 S at VES-6), reflecting high aquifer potentials. In this regard, the northcentral part of the study area can be categorized as good groundwater potential; moving towards the northeastern part of the study area, groundwater potentiality changes from good to moderate while the southwestern part is categorized as area with poor groundwater potential. The area showed very good protective capacity at VES’s 2, 3, 4, 5, 7 and 8; making 60% of the VES stations. Good protective capacity is observed at VES 1 and 6, making 15% of the VES stations in the town. The excellent protective capacity is observed at VES 9 and 10; making 15% of the study area.   

scholarly journals Assessment of Hydrogeological Potential and Aquifer Protective Capacity of Odeda, Southwestern Nigeria

2020 ◽  
Vol 66 (3) ◽  
pp. 199-209
Author(s):  
J.O. Aina ◽  
O.O. Adeleke ◽  
V. Makinde ◽  
H.A. Egunjobi ◽  
P.E. Biere
Keyword(s):  
Groundwater Resources ◽  
Electrode Array ◽  
Electrode Spacing ◽  
Protective Capacity ◽  
Clayey Sand ◽  
Southwestern Nigeria ◽  
Current Electrode ◽  
Ogun State ◽  
Weathered Layer ◽  
Longitudinal Unit Conductance

AbstractHydrogeological assessment of groundwater resources was carried out with a view to evaluate the potential of the aquifers to provide portable water supply and access the distribution of electrical parameters of hydrogeologic units in some areas in Odeda, Ogun State, Nigeria. A geophysical survey using vertical electrical sounding (VES) with the Schlumberger electrode array, with half-current electrode spacing (AB/2) varying from 1 to 132 m was carried out at 30 different stations in the study area. The VES data were interpreted qualitatively and quantitatively. Three-to-five sub-surface layers consisting of topsoil, weathered layer consisting of clay, sandy clay, clayey sand and sand layers, and fractured/fresh basement were delineated. Layer resistivities and thicknesses obtained on the curves within the study area showed one main aquifer type, which is the fractured basement. The longitudinal unit conductance (ranging from 0.049720 to 1.4520000 mhos) of the study area aided the protective capacity to be rated into good, moderate and weak. About 33% of the study area falls within the weak protective capacity, 57% falls within the moderate protective capacity and 10% falls within the good protective capacity.

scholarly journals Geoelectric Investigation of the Groundwater Potential of the Federal Housing Estate, Eastern Part of Ado-Ekiti, Southwestern Nigeria

2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Olayiwola G Olaseeni ◽  
Ajibola Oyebamiji ◽  
Oluwaseun Olaoye ◽  
Bosede Ojo ◽  
Ayokunle Akinlalu
Keyword(s):  
Subsurface Layer ◽  
Groundwater Potential ◽  
Vertical Electrical Sounding ◽  
Southeastern Part ◽  
Southwestern Nigeria ◽  
Type Curves ◽  
Overburden Thickness ◽  
Weathered Layer ◽  
Electrical Sounding ◽  
Matching Techniques

This study aimed at evaluating the potential for groundwater development in the eastern part of Ado-Ekiti, Southwestern Nigeria using Vertical Electrical Sounding (VES). Data were acquired with ABEM SAS 300 and processed through partial curve matching techniques and assisted with 1-D forward modelling. Geoelectric parameters were determined from the VES interpreted result. Seven (7) different VES type curves (H, A, HA, KH, HK, QH and HKH) indicating inhomogeneity of the subsurface layer beneath the study area were observed. Weathered layer resistivity map having values ranging from 3.2 – 272 Ωm, overburden thickness of value vary between 0 and 28m and  bedrock relief values range from 360 – 480 m were delineated. It was estimated from the result that the northwestern and southeastern part which constituted about 15%of the study area possess high groundwater potential while the remaining 85% of the study area exhibit low/moderate potentials for yielding substantial water. Hence, the groundwater potential rating of the area was considered generally low.Keywords- Geoelectric, Groundwater potential, Overburden thickness, Vertical Electrical Sounding

scholarly journals Hydrogeophysical characterization of aquifers in Upper Denkyira East and West Districts, Ghana

2021 ◽  
Vol 11 (7) ◽  
Author(s):  
Victor Ofori Agyemang
Keyword(s):  
Groundwater Potential ◽  
Electrode Spacing ◽  
Protective Capacity ◽  
Cape Coast ◽  
Regional Office ◽  
Current Electrode ◽  
Capacity Evaluation ◽  
Ground Investigation ◽  
East And West ◽  
High Level

AbstractHydrogeophysical assessment of aquifers in the Upper Denkyira East and West Districts of Ghana has been carried out for groundwater potential and protective capacity of the overburden rocks determination. The data for the study were obtained from the Regional office of Community Water and Sanitation Agency (CWSA), Cape Coast. A total of thirty-seven VES probed using a Schlumberger array with maximum current electrode spacing (AB/2) of 100 m at each point using the Abeam Terameter was used. The data were interpreted using the partial curve matching and WINRESIST computer iteration program techniques. The thickness and resistivities of the various overburden layers, basement resistivity, reflection coefficient and longitudinal conductance were used for the assessment of the groundwater potential and the protective capability of the overburden layers. The study revealed three-to-six layers with an average of four (4) layers including laterite (0.34–3.57 m); clay (0.64–8.84 m); sandy-clay (0.67–27.09 m) and slightly-to-highly weathered bedrock which includes phyllites and granite (3.09–86.89 m) that show high level of heterogeneity of electrical resistivity of the geologic materials within the study area. The weathered layers serve as the aquiferous zones. About 21.6%, 62.2%, 2.7% and 13.5% showed high, medium, low and very low potential for groundwater, respectively, with higher groundwater potentials at the western and south-eastern corner of the study area underlain by the Birimian and Tarkwaian formations, respectively, indicating that the two formations have similar groundwater potentials in the study area. The lowest groundwater potential was observed at the point underlain by the granitic intrusion. The assessment of the protective capacity of the aquifer showed very good (5%), good (27%), moderate (19%), weak (22%) and poor (27%) indicating that the study area is overlain mostly by materials of different protective capacities. This study presents information on the aquifer protective capacity evaluation by using geophysical technique and it has revealed that the Birimian formation has a good aquifer protective capacity than the Tarkwaian formation and has also confirmed the effectiveness of using geophysical techniques in ground investigation.

Integration of Multi-geophysical Approaches to Identify Potential Pathways of Heavy Metals Contamination - A Case Study in Zeida, Morocco

2020 ◽  
Vol 25 (3) ◽  
pp. 415-423
Author(s):  
Ahmed Lachhab ◽  
El Mehdi Benyassine ◽  
Mohamed Rouai ◽  
Abdelilah Dekayir ◽  
Jean C. Parisot ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Seismic Velocity ◽  
Seismic Refraction ◽  
Geophysical Methods ◽  
Low Frequency ◽  
Electrical Current ◽  
P Wave ◽  
Low Resistivity ◽  
Refraction Tomography ◽  
Geophysical Surveys

The tailings of Zeida's abandoned mine are found near the city of Midelt, in the middle of the high Moulouya watershed between the Middle and the High Atlas of Morocco. The tailings occupy an area of about 100 ha and are stored either in large mining pit lakes with clay-marl substratum or directly on a heavily fractured granite bedrock. The high contents of lead and arsenic in these tailings have transformed them into sources of pollution that disperse by wind, runoff, and seepage to the aquifer through faults and fractures. In this work, the main goal is to identify the pathways of contaminated water with heavy metals and arsenic to the local aquifers, water ponds, and Moulouya River. For this reason, geophysical surveys including electrical resistivity tomography (ERT), seismic refraction tomography (SRT) and very low-frequency electromagnetic (VLF-EM) methods were carried out over the tailings, and directly on the substratum outside the tailings. The result obtained from combining these methods has shown that pollutants were funneled through fractures, faults, and subsurface paleochannels and contaminated the hydrological system connecting groundwater, ponds, and the river. The ERT profiles have successfully shown the location of fractures, some of which extend throughout the upper formation to depths reaching the granite. The ERT was not successful in identifying fractures directly beneath the tailings due to their low resistivity which inhibits electrical current from propagating deeper. The seismic refraction surveys have provided valuable details on the local geology, and clearly identified the thickness of the tailings and explicitly marked the boundary between the Triassic formation and the granite. It also aided in the identification of paleochannels. The tailings materials were easily identified by both their low resistivity and low P-wave velocity values. Also, both resistivity and seismic velocity values rapidly increased beneath the tailings due to the compaction of the material and lack of moisture and have proven to be effective in identifying the upper limit of the granite. Faults were found to lie along the bottom of paleochannels, which suggest that the locations of these channels were caused by these same faults. The VLF-EM surveys have shown tilt angle anomalies over fractured areas which were also evinced by low resistivity area in ERT profiles. Finally, this study showed that the three geophysical methods were complementary and in good agreement in revealing the pathways of contamination from the tailings to the local aquifer, nearby ponds and Moulouya River.

Identifikasi Potensi Air Tanah untuk Kebutuhan Penyediaan Air Bersih dengan Metode Geolistrik: Studi Kasus di Kawasan Geostech, Puspiptek Serpong

2020 ◽  
Vol 21 (2) ◽  
pp. 204-212
Author(s):  
Heru Sri Naryanto ◽  
Puspa Khaerani ◽  
Syakira Trisnafiah ◽  
Achmad Fakhrus Shomim ◽  
Wisyanto Wisyanto ◽  
...  
Keyword(s):  
Geophysical Methods ◽  
Groundwater Potential ◽  
Clean Water ◽  
Rock Types ◽  
Groundwater Aquifers ◽  
Groundwater Aquifer ◽  
Groundwater Origin ◽  
Laboratory Facility ◽  
Potential Groundwater ◽  
Lower Depth

ABSTRACTGeostech Building, as an office and laboratory facility, requires a source of clean water from groundwater related to the limited supply of clean water from the PDAM. Due to the needs of freshwater from groundwater origin, data and information are needed regarding the potential groundwater in the area, including aquifer configuration, depth, and groundwater potential. The presence of groundwater is not distributed through every area, and it's related to the geological and geohydrological conditions. One of the geophysical methods that can describe subsurface is 2D geoelectric methods. This method can distinguish and analyze rock types, geological structures, groundwater aquifers, and other important information based on the characteristics of the electricity of rocks by looking at the value of the type of resistance. In this measurement, the Wenner Alpha configuration has been used, where the arrangement of A-B current electrodes and M-N potential electrodes have constant spacing. From the measurement results, it can be interpreted that there is a low resistivity layer containing porous groundwater as an aquifer. Based on regional geological data, it has been estimated that this layer is in the form of sandy tuff (0-1.5 ohm-m). The exploitation of groundwater with drilling is expected to reach the aquifer's upper layer at depth, starting from 11.5-13 meters. The groundwater aquifer thickness cannot be ascertained because of the penetration of the lower depth of 2D geoelectric measurements truncated by the constraint of a maximum stretch of cable. The upper layer of the aquifer contains a turned layer of fine tufa and medium tuff, which is impermeable, coarse tuff, and mixed soil with varying thickness at the upper layer.Keywords: 2D geoelectric, aquifer, potential groundwater, Geostech  ABSTRAKGedung Geostech sebagai sarana perkantoran dan laboratorium memerlukan sumber air bersih dari air tanah terkait dengan terbatasnya suplai air bersih dari PDAM. Kebutuhan air bersih berasal dari air tanah, maka diperlukan data dan informasi mengenai kondisi potensi air tanah di kawasan tersebut termasuk konfigurasi akuifer, kedalaman, dan potensi air tanahnya. Keberadaan air tanah tidaklah merata untuk setiap tempat dan sangat terkait dengan kondisi geologi dan geohidrologinya. Salah satu metode geofisika yang dapat memberikan gambaran kondisi bawah permukaan adalah dengan metode geolistrik 2D. Metode ini dapat membedakan dan menganalisis jenis batuan, struktur geologi, akuifer air tanah, dan informasi penting lainnya berdasarkan sifat kelistrikan batuan dengan melihat nilai tahanan jenisnya. Dalam pengukuran ini digunakan konfigurasi Wenner Alpha, dimana susunan elektroda arus A dan B dan elektroda potensial M dan N mempunyai spasi yang konstan. Dari hasil pengukuran dapat diinterpretasikan adanya lapisan dengan resistivitas rendah yang mengandung air tanah dan bersifat porous sebagai akuifer. Berdasarkan data geologi regional diperkirakan lapisan ini berupa tuf pasiran (0-1,5 ohm-m). Pengambilan air tanah dengan pemboran diperkirakan akan mengenai batas atas lapisan akuifer pada kedalaman 11,5-13 meter. Ketebalan akuifer air tanah tidak bisa dihitung karena penetrasi kedalaman pengukuran geolistrik 2D terbatasi oleh bentangan elektroda di permukaan. Lapisan di atas akuifer merupakan lapisan selang-seling tuf halus dan tuf sedang yang kedap air, tuf kasar, dan pada bagian paling atas merupakan tanah urugan dengan ketebalan bervariasi.Kata kunci: Geolistrik 2D, akuifer, potensi air tanah, Geostech  

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