Shallow Subsurface Stratigraphy Inferred from the Use of Vertical Electrical Soundings (VES) Survey in Central Chihuahua, Mexico

Vertical Electrical Soundings (VES) provide fast and economical measurements used in geophysical exploration. VES were carried out in El Sauz-Encinillas (ESE) aquifer, in northern Mexico, to determine apparent resistivity and geoelectrical units’ thickness. Despite it being one of the three main aquifers feeding Chihuahua city, a lack of available geophysical data prevails in its northern portion. The main goal of this study was the determination of the geoelectrical units in the subsurface stratigraphy via electrical-resistivity soundings. The ESE’ aquifer is located within alluvial Quaternary sediments, with varying granulometry and reaching from a few meters to more than 600 meters of thickness at the center of the valley. Forty-five vertical electrical resistivity soundings (Schlumberger array, maximum AB/2 distance of 500 m) were performed throughout ESE aquifer’s northern portion. Field data were analyzed using software. Results illustrate a wide variability in resistivity values throughout the study area. Five geoelectrical units were identified: 1) a hardpan topsoil, with resistivity values ranging from 200 - 800 Ω-m;2) an alluvial material mixture (sand/silt) with resistivity values ranging from 25 to 100 Ω-m;3) playa lake-type material (clay/evaporites mixture) with resistivity values ranging from 0.2 to 15 Ω-m;4) a gravel/sand mixture with resistivity values from 100 to 300 Ω-m;and 5) a partly fractured rock or conglomeratic material with resistivity values ranging from 400 to 3500 Ω-m. The electrical resistivity data, therefore gives reasonably accurate results that can be used to understand the subsurface stratigraphy and basement configuration in groundwater exploration.

Characterization of Subsurface Lithology and Aquifer Parameters Using Vertical Electrical Sounding(VES)for Groundwater Development in Igbo-Imabana,Southern Nigeria

Vertical Electrical Soundings(VES)using Schlumberger array was carried out at fifteen(15)different points to evaluate aquifer characteristics within Igbo-Imabana,Abi L.G.A of Cross River State.Resistivity meter and its accessories were used for data acquisition.The maximum current and potential electrode distance were 400 m and 20 m respectively.The field data were interpreted using Interpex software and three to five geo-electric layers encountered within the study area.The dominant curve type was H followed by K.From the result,geo-electric layers delineated were sandstone,clay,saturated sandstone,sandy shale,clayey shale,and shale with average apparent resistivity values of 2249.94Ωm,2.86Ωm,365.28Ωm,222.69Ωm,14.60Ωm and 59.02Ωm respectively.The top geoelectric layer was dominantly lateritic topsoil,with variation in degrees of compaction and having an average resistivity of 876.33Ωm with depth and thickness generally less than 5 m.The calculated aquifer parameters hydraulic conductivity(K_(c)),transmissivity,longitudinal conductance,and transverse resistance from the VES results show ranges values;3.86×10^(-4)to 4.69×10^(-2)m/day,2.95×10^(-3)to 2.82 m^(2)/day,2.95×10^(-3)to 2.81Ωm and 484.33 to 19444.83Ω^(2)m respectively.The aquifer thickness and depth values range from 3.60 m to 68.05 m and 5.20 m to 76 m respectively.The study reviewed that the area is made of heterolithic/heterogenous lithofacies,confined aquifer(s),shallow and deep aquifer.Also,from the models and aquifer parameters,the area is characterized by semipervious materials.This integrally explains why the area have have low transmissivity and majority of boreholes drilled in the area failed.

Vertical Electrical Sounding of Water-Bearing Sub-Surface of Issele-Azagba in Southern Nigeria

An electrical resistivity survey involving vertical electrical sounding (VES) technique was carried out in Issele-Azagba, Aniocha North Local Government Area of Delta State, Nigeria. This was aimed at investigating the lithologic boundaries and classification of the various subsurface formations. The data obtained were subjected to a twofold interpretative procedure involving initial partial curve matching and computer iteration. Results showed that a maximum of five subsurface layers was delineated from the geoelectric sections. This is made up of loamy topsoil underlain by relatively continuous sandy units composed of different compaction, wetness and clay content. The result also showed that the fifth substratum of the geoelectric section was the aquiferous sand relevant in groundwater development within the study area. Analysis of the result had shown that the aquifers identified in this study were vulnerable contamination percolating from the surface due to the absence of a protective aquitards.

Electrical Resistivity Sounding for Groundwater Investigation around Enugu Metropolis and the Environs, Southeast Nigeria

This report evaluates the use of electrical method and borehole data to investigate the subsurface to delineate the groundwater potential in Enugu metropolis and the environs, south-eastern Nigeria other than rely only on resistivity method which could lead to interpretation error. Integrating these 2 data sets is key in this study. The study area is located in the Anambra Basin and is underlain by Nkporo/Enugu Shale which is overlain by the Mamu Formation. It is bounded by Latitudes 6°2 0'00"N to 6°30'00"N and Longitudes 7°25'00"E to 7°35'00"E and covers surface area of about 342 m2. Thirty-one vertical electrical soundings (VES) were carried out across the area using the Schlumberger electrode array with current electrode separation from 2 to 500 m to identify the depths and resistivity values of the identified geo-electric layers. Through data analysis using WinResist software, the apparent resistivity, thicknesses and depths and the thicknesses of the aquifers were generated. The resistivity and depths were modelled to generate resistivity map and depth map. The resistivity of the aquiferous zone within the study area varied from 20.55 - 427.8 ohm-m at depths of between 10.7 - 40.05 m. Depth to the water table appears to be shallow at the south western part of the map. The interpreted geo-electric layers show a sequence of lateritic top soil, shale, sand and shale. The frequency distribution of the VES curves generated shows the presence of 3 to 5 layers with HK type as the highest. Also, a 2D model was generated using the correlation of VES to VES data and borehole data to VES data to show the underlying stratigraphy beneath the study area as well as the direction of ground water flow. Result of the VES curve analysis reveals that the sub-surface is underlain by three lithological layers namely: lateritic top soil, shale, sand and shales with NW direction of groundwater flow from the 2D model. Groundwater prospective zones can be seen along NW, SW and central parts of the study area which have low resistivity values.

Groundwater Potential Mapping in Lapan Gwari Community Using Integrated Remote Sensing and Electrical Resistivity Soundings

This research aims to address the pressing issue of failed and abandoned wells, causing water scarcity in Lapan Gwari Community, through an improved groundwater exploration approach integrating remote sensing and electrical resistivity soundings. The study area, located within the Zungeru Sheet 163 SE, spans Latitudes 9°30'00"N to 9°32'00"N and Longitudes 6°28'00" to 6°30'00". The surface geologic, structural, and hydrogeological mapping provided essential insights into the hydrogeological framework. Leveraging SRTM DEM data, thematic maps were created for geomorphology, slope, land use, lineament density, and drainage density. These datasets were then integrated using ArcGIS to develop a preliminary groundwater potential zones map. Further investigations were conducted using Vertical Electrical Sounding (VES) and Electrical Resistivity Imaging (2D VES) surveys at targeted locations identified by the preliminary map. Results show that the study area predominantly consists of crystalline rocks of the Nigerian Basement Complex, primarily comprising schist and granite with minor occurrences of quartz vein intrusions. Surface joint directions indicated a dominant NE-SW trend. The VES data revealed three to four geoelectric layers, encompassing the topsoil (1 to 5 m depth, resistivity: 100 Ωm to 300 Ωm), the weathered layer (in the 3-layer system) or fractured layer (in the 4-layer system), and the fresh basement rock characterized by infinite resistivity. The shallow weathered layers (3 to 30 m thickness) are believed to hold aquiferous potential. Hydrogeological interpretation, facilitated by 2D resistivity models, delineated water horizons trapped within clayey sand and weathered/fractured formations. Notably, the aquifer resistivity range was found to be between 3 - 35 m and 100 - 300 Ωm, signifying a promising aquifer positioned at depths of 40 to 88 m. This aligns with corroborative static water level measurements. Given this, we recommend drilling depths of a minimum of 80 m to ensure the acquisition of sufficient and sustainable water supplies. The final groundwater potential zones map derived from this study is expected to serve as an invaluable guide for prospective groundwater developers and relevant authorities in formulating effective water resource management plans. By effectively tackling water scarcity challenges in Lapan Gwari Community, this integrated approach demonstrates its potential for application in similar regions facing comparable hydrogeological concerns.

Hydrogeophysical and Structural Investigations Using VES: A Case Study of Dosso Region in the Southwestern Part of the Meso-Cenozoic Iullemmeden Basin (Southwestern Niger)

A regional study connecting geolelectrical surveys with geology and hydrogeology was carried out in the western part of the Iullemmeden basin, precisely in the Dosso region in Niger. One hundred and four (104) vertical electrical sounds have been realized, among them nineteen representative were thus be used as parametric surveys. The local resistivity values of the geological formations of Quaternary range from 100 Ω⋅m to 1000 Ω⋅m (sands and lateritic sandstones). The Oligo-Miocene formation of the Continental terminal (Ct) shows resistivity values ranging from 1 to 5 Ω⋅m (brackish groundwaters) to 1500 Ω⋅m (clay sandstones) while the Upper Cretaceous formation of the Continental “hamadien” (Ch) indicates values ranging from 20 Ω⋅m (sandy clay) to 5000 Ω⋅m (clayey sandstones). The geological formations of Paleocene have values from 2 Ω⋅m (marls) to 60 Ω⋅m (calcareous marl), while the Precambrian basement exhibits values of granite around 300 Ω⋅m to 60,000 Ω⋅m. The update of the structural settings reveals many faults in the study area which explain both the shape of the basin and the geometry of the aquifers. Tectonics is also consistent with the hydraulic characteristics of aquifers. In addition, brackish groundwaters were identified as perched aquifer groundwaters in different depths in Dosso region. They probably come from the marine brines during the regression of the Paleocene Sea.

Electrical geophysical evaluation of susceptibility to flooding in University of Nigeria, Nsukka main campus and its environs, Southeastern Nigeria

Flooding occurs when rainfall exceeds the absorption capacity of soil and causes significant environmental consequences.In this study,electrical resistivity techniques were employed to assess the flood susceptibility of the study area by examining variations in electrical properties.Prior to flooding,Vertical Electrical Sounding(VES)and Electrical Resistivity Tomography(ERT)profiles were conducted to determine the variations in resistivity within subsurface lithologies exposed to the injected current.The injected current penetrated the subsurface units characterised by resistivity ranging from 190.5Ω·m to 6,775.7Ω·m,42.3Ω·m to 7,297.4Ω·m,and 320.2Ω·m to 24,433.3Ω·m in the first,second and third layers,respectively.These layers were identified as lateritic topsoil,medium-coarse brownish grained sand,and coarse pebbly blackish sand,respectively.The calculated reflection coefficients between layers 1,2,and 3 reveal alternation in layers with values ranging from−0.04 to 0.66 and 0.36 to 0.95 for and,respectively.The transverse resistivity,longitudinal resistivity and anisotropy ranged from 243.59Ω·m to 24,115.42Ω·m,199.61Ω·m to 14,950.76Ω·m,and 1.02 to 2.14.Models derived from the ERT profiles reveal variations in resistivity,pinpointing areas of low resistivity which correspond to waterlogged and impermeable layers.The result of this study underscores the importance of integrated resistivity techniques in the study of floods,as it provides valuable insights into flood behaviour,and subsurface dynamics.

Groundwater Investigation Using Geoelectrical Method: A Case Study of the Western Region of Cameroon

A geoelectrical survey using the electrical resistivity method was carried out in some villages in the western region of Cameroon to investigate the sub-surface layers and evaluate the characteristics of aquifers. The direct current electrical resistivity method was utilized for the present study. Applying the Schlumberger array, a total of twenty four (24) Vertical Electrical Soundings (VES) were conducted. Quantitative and qualitative interpretations of data were carried out to determine the nature and thickness of the aquifer zone combined with existing litho-logs aided correlation of geoelectric sections to litho-logs. Four to five geoelectric layers were delineated from the survey area. The first layer which is the topsoil has resistivity values ranging from 6 - 949 Ωm and the thickness is between 0.2 - 4.2 m. The second layer which is made up of clay and laterite has resistivity values ranging between 9 - 1862 Ωm and thickness range from 1.0 - 16.4 m. The third and fourth geoelectric layers are made up of clay and granite/basalts with thickness varying from 2.2 - 39.5 m which corresponds to an aquifer horizon. Resistivity values of the aquifer ranges from 10 to 70,506 Ωm. The resistivity map drawn from these measurements shows the presence of a low resistivity zone which indicates the reflection in the direction of ground water from northeast to southwest with the recharge concentrated to the south of the study area. This study has revealed for this area, an average depth of the aquifer of 32 m with the average thickness of the aquifer being 22 m. The geoelectric sections of some VES stations demarcated corroborate very well with the geological description of the area.

Geo-Electrical and Borehole Investigation of Groundwater in Some Basalts on the South-Eastern Flank of Mount Cameroon, West Africa

The study area, located on the southwestern flank of Mt. Cameroon, is under-lain by basalts. The occurrence of groundwater in these rocks has been evaluated in order to determine their potentials as a source of water for a water bottling and soft drink plant. To achieve this, the constant separation traversing (CST) was used and the data qualitatively analyzed to determine the occurrence of fractures as most probable borehole sites. From this analysis, three sites were selected, sites at which a vertical electrical sounding (VES) was done and interpreted. Results obtained show a four layered earth profile model type KHKH, corresponding to a typical weathered/fractured confined aquifer type curve. This profile was later confirmed from borehole information after drilling at three of the selected sites. The comparison of VES data with geological sections is corroborative. A constant rate pumping test was done at rates as well as the investigation of other hydraulic properties. The results obtained for hydraulic properties investigated for all three boreholes reveal that productivity is very good and these results also reveal that at maximum exploitation rates, lowest tolerable drawdown for all three boreholes may not be reached after ten years. Chemical analysis done in-situ and on samples at the laboratory reveal that this water has a better mineralisation compared to other bottled water brands sold on the Cameroon market.

Aquifer Characterization and Groundwater Potential Using Integrated Geoelectric Sounding and Geoinformatics in West Maghagha Area, Minia Governorate, Egypt

The study area is located in the western extension of the Nile Valley near the boundary with the Western Desert, where the groundwater represents the potential water resource for future land development for both industrial purposes and agricultural reclamation. Historically, geoelectric methods proved prospective and practical in exploring for groundwater resources. In this study, 17 Vertical Electric Sounding (VES) were acquired and processed to reveal the subsurface distribution of the water bearing layers and identify the groundwater potential in West Maghagha area. After routine data analysis and calibration, the preliminary results are interpreted in light of the available geological data and indicated the presence of at least four geoelectric layers with model resistivity values up to 2000 Ω•m. The potential aquifer was encountered down to ~120 m depth with average thickness of 100 m and is made of argillaceous fractured carbonates. Despite the overall poor quality of this aquifer, the integrated geoelectric and hydrogeologic information indicated a possible potential occurrence of potable groundwater at the southern and northeastern parts of the study area. To improve understanding of the groundwater systems in the study area, detailed aquifer characterization is discussed through integration of the available geologic data, maps, and the geoelectric sections constructed from the VES.

Geophysical Study by Electrical Soundings of the Tartar Aquifer Unit, Boujdour Region, Morocco

The Tartar aquifer unit, is located at the SSO of the city of Boujdour, at a distance of nearly 86 km, and crossed (in its western part) by the National Road N1 connecting the towns of Boujdour and Lagouira passing through the vicinity of the city of Dakhla (PK40). It is exploited by rural settlements for domestic use (especially the inhabitants of fishing villages) and livestock watering, only through wells named Khtout Hobia (IRE 126/124) and Hassi Tartar known as Khtout Trayh (IRE 104/124). These wells have been tracked by a piezometric groundwater table and from 2011 to the present day. The interpretation of the electrical soundings in AB ≤ 2000 m allowed to differentiate the presence of two families of electrical soundings A and B, to establish the resistivity maps in AB = 200, 300 and 400 ihm&#8901m with qualitative aspects, to draw up the map of the isohypses of the roof of the intermediate Dt1 representing the impermeable floor of the aquifer and to highlight two types of discontinuities;electrical discontinuities corresponding to lateral facies changes (limit of erosion surfaces) separating the families A and B of electrical soundings and those corresponding to syn-sedimentary faults which structured the formations into horsts and grabens. The lithological sections of the existing water points and that of oil well 43-1 allowed the geological identification of the geoelectric layers highlighted by the electrical soundings diagrams. As a result, the sandstone and lumachelic formations constituting the aquifer are of Moghrebian-Pleistocene age represented by the resistant R (Family A), sometimes grouping, in its basal part, sandstone levels of the Miocene roof (Family B). These formations lie directly on the Miocene sandy marls represented by the intermediate Dt1. For the present work, we will focus only on the transverse geoelectric cross-section TA, with an SW-NE orientation, which characterizes all the longitudinal sections established following the correlation between the different electric sounding diagrams. It highlights the presence of the gravels G1 and G3 separated by the horst H1 where the resistant R is admitted as aquiferous at the level of the gravels G1 (Khtout Trayh well 104/124) and G3 (well 126/124) and sterile at the level of the horst H1.

Geoelectric Soundings for Delineation of Saline Water Intrusion into Aquifers in Part of Eastern Dahomey Basin, Nigeria

This study was aimed at mapping the subsurface extent of saline water intrusions into aquifers at the eastern part of Dahomey basin, Nigeria. The study adopted geoelectric sounding methods. 108 vertical electrical soundings (VES) and 9 induced polarization soundings (IPS) data were acquired using Schlumberger array technique. Three aquifer units were delineated across the study area. The resistivity of the first, second and third aquifer layers varies from 0.2 to 1569 ohm-m, 0.5 to 904 ohm-m and 0.4 to 665 ohm-m respectively, while depth to the top of first, second and third aquifer varies respectively from 0.7 to 151.5 m, 1.4 to 305.5 m and 12.9 to 452.9 m. The depth to the first aquifer layer is shallow (less than 5 m) in the coastal area which makes this area to be highly vulnerable to anthropogenic pollution while their proximity to Atlantic Ocean makes them susceptible to saline water intrusion. In all the three aquifer units, the coastal area, Agbabu and other few locations in the mainland are characterized by low resistivity values (below 60 ohm-m) indicating possible presence of brackish or saline water. IP sounding results showed that all the low resistive layers in the mainland are characterized by clayey materials. The integration of VES and IPS results enabled the delineation of the saline water lateral extent across the study area. There is a strong direct correlation (r2 = 0.8564) between location distance from the saline water source and depth to saline water in the study area. This can therefore serve as a predictive model to determine depth to saline water at any location within the saline water zone in the study area.

Electrical Resistivity Survey for Predicting Aquifer at Onicha-Ugbo, Delta State, Nigeria

A geoelectric survey employing the vertical electrical sounding (VES) was carried out in parts of Onicha-Ugbo in Aniocha North Local Government Area of Delta State using Abem Terrameter SAS 300C together with SAS 2000 booster. The study was carried out with the aim of delineating the subsurface geologic sequence present in the study area, determining their geoelectrical parameters (layer thicknesses and resistivities), and delineating the structural and geomorphological features present beneath the subsurface. The results of the survey suggest that the subsurface comprises of 5 - ?6 layers and that clay and silt content varies vertically and horizontally, thus influencing the apparent resistivity of the area. The geoelectric section developed shows that the subsurface units are dominantly sandy underlying loamy sandy topsoil which is relatively dry. The depth to water table from the sites is above 150 m and suggests that groundwater exploration is encouraging.

Geoelectric Investigation for Groundwater Exploration in YaoundéArea, Cameroon

Yaounde zone is originally characterized by the small number of aquifers and bad renewal capacity. Within the frame-work of the emergency program which aims at supplying the city with drinking water, seventeen Vertical Electrical Soundings (VES) were carried out using Schlumberger configuration in parts of Yaounde (latitude 3o- 5oN and longi- tude 11o-13oE) to determine the nature and thickness of aquifer zone and necessary geoelectrical parameters. Four to five geoelectric layers were delineated from the survey area. The first layer is the topsoil and has resistivity values ranging from 13 - 216 Ω·m and thickness is between 0.1 - 6 m. The second layer made up of clay sand and laterite has resistivity values ranging between 23 and 923 Ω·m and thickness ranged from 1 and 40 m. The third and fourth geoelectric layers consisting of clay and gneiss/migmatite with thickness varying from 1.7 - 63.3 m correspond to an aquifer horizon. Resistivity values of the aquifer ranges from 4 to 9215 Ω·m. The study indicates that average depth of the aquifer is 20 m and average thickness of the aquifer is 55 m. Soundings curves suggest several four layered geoelectrical sections KH, KQ, HK type and some five layered sections of the HKH, KHK types. KH type is dominant and can be used as reference for future studies. The resistivity survey reveals that the parameters obtained through interpretation of VES curves corroborate the litho logs of boreholes from the area.

Subsurface Structural Elements Delineation Using Electrical Resistivity Method—A Pointer to Groundwater Exploration:Case Study of Northcentral Part of Futa Campus,Southwestern Nigeria

Electrical resistivity survey was carried out as part of an integrated study of a portion of Federal University of Technology Akure,Campus,South-- western Nigeria—a Basement terrain,to unravel the rock types;delineate structural elements such as fractures and determine the ground water zones which could be pin-pointed for water borehole drilling. Thirty-three(33) Vertical Electrical Sounding(VES) along seven traverse lines using the

Geo-environmental Investigations for the Suitability of TSDF Site

A geo-environmental investigation is carried out to identify the suitability for treatment,storage and disposal facility(TSDF) in the industrial area at Perundurai,Tamilnadu(India).State industries promotion corporation of Tamilnadu(SIPCOT), Perundurai is a fast growing industrial centre therefore,needs a common utility i.e.TSDF site for safe management of the industrial wastes.

Characterization of Pan-African Aquifer Layers by the Least Squares Inversion Method Applied on Geoelectric Data

Geoelectric data obtained from forty (40) vertical electrical soundings collected with a Schlumberger device in the Adamawa plateau region, also known as the Cameroon water tower, have been treated by the least-squares inversion method. In order to study the nature and thickness of the aquifer and the necessary geoelectric parameters, quantitative and qualitative interpretations of the data were made. The results obtained showed that: about four to five geoelectric layers have been delimited in the study area with a dominance of the KH curve, which can be used as a reference for future studies. The first two layers constitute an association of clay and laterite with resistivity values ranging from 58 to 9122 Ω&middotm and whose thickness is between 0.6 and 13.4 m. The third layer is a potentially aquiferous laterite composed of clay, laterite and especially clay sand and cracked/good granite, with a dominance of sandy alteration whose resistivity values are between 81 and 960 Ω&middotm and its thickness between 12.2 and 26.8 m. The fourth and fifth layers are made up of cracked/good granite with a resistivity ranging from 12-10705 Ω&middotm with an average value of 1817 Ω&middotm. This study also shows that the North-East, South-West and South sectors could be the groundwater convergence zones and that the average depth of the basement aquifer roof is about 28.3 m. The geoelectric sections of certain demarcated vertical electrical sounding stations are consistent with the geologic description of the area.

Cyclostratigraphy Data as a Proxy for Geoelectrical Data Interpretation: Application to Phosphate Minerals Exploration in Matam (Senegal)

The vertical electrical soundings on the Matam region phosphates deposits are interpreted by inversion. To retrieve lithology from the obtained resistivities, mechanical drilling was performed to compare directly the lithologies and the geoelectrical resistivities. The obtained relation is not simple and is not sufficient to interpret all the VES. This situation motivated the collection of supplementary information from cyclostratigraphy. Geoelectrical and cyclostratigraphic?information is combined using fuzzy logic techniques to build a fuzzy inference system. The obtained results seem to be consistent with the stratigraphy of the investigated region and allow retrieving lithological succession. Further investigations are necessary for more accurate thickness determination.

Integration of Electrical Resistivity and Electromagnetic Radiation Methods for Fracture Flow System Detection

An electrical resistivity and electromagnetic emission survey was carried out involving the use of vertical electrical soundings (VES) and natural pulse electromagnetic field of the earth (NPEMFE). The use of this new methodology managed to detect the fracture flow system rupture zones in the underground, also answered the questions about the deferent subsurface water bodies. The present study focuses on Marsaba-Feshcha sub-basin in the northeast of the Dead Sea. Due to the scarcity of boreholes in the study area, several geophysical methods were implanted. The combination of these two methods (VES and NPEMFE) with the field observations and East-West transversal faults with the coordination (624437/242888) was determined, cutting through the anticlines with their mainly impervious cores with fracture length of >400 m. These transversal faults saddle inside Nabi Musa syncline (Boqea syncline), leading to a hydraulic connection between the Lower and the Upper Aquifer. Due to the identified transversal fault, the water of the Upper and Lower Aquifer mixed and emerged as springs at Ein Feshcha group.

Geoelectrical Investigation of Groundwater Potentials of Northern Paiko,Niger State,North Central Nigeria

Vertical electrical sounding（VES） was carried out in northern part of Paiko, North Central Nigeria, using Abem terrameter model SAS 4000 to determine the subsurface layer parameters（resistivities, depths and thickness） employed in delineating the groundwater potential of the area. A total of six transverses with ten VES stations along each traverse, at intervals of 50 m were investigated. It has a maximum current electrode separation（AB/2） of 100 m. Three to four distinct geoelectric layers were observed, namely, the top layer, the weathered layer, the fractured/fresh layer, and the fresh basement layer. The observed frequencies in curve types include 21% of H, 4.2% of HA, 2.4% of K, 4.2% of A, 1.67% of KH and 3% of HK. Eight VES stations were delineated as ground water potentials of the area, with third and fourth layer resistivities ranging from 191 to 398 ？·m. Depths range from 13.60 to 36.60 m and thickness varies from 9.23 to 30.51 m. A correlation of the borehole log with the VES lithology is in agreement. Viable boreholes for good portable water should be sited at VES stations J8 and J10 having a fine aquifer at a depth of 36.60 and 17.80 m respectively with thickness of 30.51 and 15.07 m, respectively.