Introduction

Water is the symbol of life on earth having the most important value globally. There are many forms of water like precipitation, snow and underground aquifers with the quantum of water as a major source of water. Groundwater is contributing up to 0.61% globally (Fetter 1980). Pakistan, India, Afghanistan and China are the dependent countries on the Indus basin system. Increasing of industries, population, urbanization, environmental changes, and sedimentation in water reservoirs, irregular and over exploitation of water resources created the pressure on groundwater so there is a need of water resources management (Laghari et al. 2011). Khurshaid and Ahmed (2014) disclosed that the aquifers of Quetta Valley are under pressure by lowering the water table due to the increase in population growth rate and agricultural practices. The study was carried out on the Quetta Valley through vertical electrical sounding (VES) by using Schlumberger method; from 13 VES points only 11 VES points were surrounded within the Quetta Valley. In northern to the southern basin of the area, the maximum depth to bedrock is from 1500 to 1058 m, respectively. Khan et al. (2013) used Schlumberger method through VES that from 20 grid points only 6 points were observed as marginal fresh groundwater at Hayatabad, Peshawar. Groundwater was mostly available in soil layers as: sandy clay, sand and gravel having some amount of clay particles.

Up to 10% of groundwater is being utilized in Malaysia for the domestic purpose in arid areas due to unavailability of water supply schemes. More than 70% of groundwater is supplied on the exception rate basis, especially in Kelantan state (Abdullah 2010). Various research studies have been conducted to examine the groundwater potential and to detect freshwater quality through the use of multi-electrode resistivity survey by different scientists such as Owen and Gwavava (2005), Ewusi et al. (2009), Muchingami et al. (2012) and Redhaounia et al. (2016). However, Uchegbulam and Elijah (2014) conducted study on groundwater pollution by applying Wenner and Gradient method through ABEM SAS4000 Terrameter along with Lund imaging system by using sixty-four multi-electrodes.

By comparing the resistivity data with borehole data, it is observed that the first 10 m depth is composed of laterite materials and sand is present from 10 m up to 60 m. The high resistivity shows the hydrocarbon that indicates the pollution in the shallow aquifer that is 4- to 5-m groundwater level. Looking into the data, they recommended that bore well may be installed from 45 m depth.

Vertical electrical sounding (VES) is commonly used to solve many problems regarding groundwater assessment, investigation, exploration, quality/pollution, the boundary, thickness and depth of the aquifer with its different layers (Zohdy 1969; Kelly 1976; El-Waheidi et al. 1992; Young et al. 1998; Choudhry et al. 2001; Kaya 2001; Soupios et al. 2007). Gondwe et al. (2010) conducted study on hilly area which is composed of limestone at southeastern Yucatan Peninsula (southeastern Mexico). They state that the geophysical boreholes are time and financed burden as against of VES in the hilly area.

Asfahani (2011) conducted study at Khanasser Valley of Syria through VES to make it possible on the empirical relationship between earth and water resistivity. He defined in his results that over/extreme exploitation of freshwater might degrade the groundwater quality with saline water through upward movement. Further, Asfahani (2012) used the VES procedure as against the regular alternate pumping test approach on the quaternary aquifer transmissivity at the same place. The hydraulic conductivity values coincided with the results of pumping tests (i.e., 10−5 and 10−4 m/s); it suggested that this method (i.e., VES) is cheaper, faster and easily applicable in all the areas of the world.

Asfahani and Zakhem (2013) conducted survey study on hydro-chemical and geo-electrical to see the saline groundwater intrusion with fresh groundwater at Khanasser Valley in Syria. They interpreted the data received from 34 VES points to characterize about the salt water intrusion; horizontally and vertically with quantitative and qualitative approach. The results from study can be utilized for the management of water resources in those areas where the water is scarily available.

Amini and Ramazi (2011) investigated through the dipole–dipole electrode array with 2-D electrical resistivity imaging with three profiles of the soil were surveyed to identify the probable aqueduct tunnels with their depths having loose materials backfilled that made cavities, at the Pishva Hospital site of Iran. The main aqueduct tunnel was detected under the mid-portion of the study area.

AL-Fares (2016) conducted the study to identify the causes of failure of groundwater well drilled. Three types of survey data, such as VES, pseudo-2D and horizontal profiling, were interpreted data analyzed to maximize the reliability.

Giang et al. (2013) conducted the study on three boreholes from 40 to 60 m in depth through the methods: VES, 2D electrical resistivity imaging (ERI) and very low frequency (VLF). They suggested that both, the careful use of groundwater and reducing the pollution sources, can play the important role to prevent this natural source. The current study estimates the groundwater potential zones through a geological and resistivity survey of the study area. The study area is situated in the arid region of Sindh province and being developed for China Pakistan Economic Corridor, due to that the influence on the freshwater demand, the pressure would be increased on groundwater. To take this situation into consideration, the current study has been designed to investigate the potential of fresh groundwater aquifers.

Hydrogeology of the study area

Weather of the study area is generally classified as arid and hot. Temperature remains high during the summer season with a low precipitation and less humidity prevails in the area. Therefore, the area is sparsely vegetated. Mean annual rainfall in this study area is 150 mm with a variation of 25 mm. The rainfall period is very limited and mostly falls in the monsoon season which starts from July to September. Both the intensity and volume of rainfall in the monsoon are high and cannot be fully utilized. Short periods of intensive rainfall in areas of catchments with large areas of bare rocks and high dips of mountain limbs resulted in high runoff from the ranges. Moreover, the steep gradient of beds of streams ensures that there is fast flow, and thus, only a short period following rainfall providing little opportunity for infiltration of water into sediments or weathered rocks of ranges.

The aquifers are recharged by hill torrents. All the hill torrents (tributaries) are mainly non-perennial and originate seasonally from mountains. As a result, the soil of the plain areas is either poorly developed or entirely absent from the great majority of the area. There is no surface water resource to recharge the aquifers, rather than annual precipitation. Therefore, rainfall is only considered to recharge the aquifers in the area. Due to the absence of surface water, there is no other alternate than to exploit groundwater to meet all water requirements of the area. Groundwater is the main source to meet the requirements of the peoples for domestic and other purposes.

The runoff is mostly quick to leave the watershed/catchment areas and consequently stop a few hours after rainfall appears. Water accumulates in natural surface water reservoirs which are mostly in depressions in the area through which it gradually infiltrates into subsurface. Main streams and channels are originating from hill ranges of Nooriabad, dissecting the major structure of the hill ranges and eventually joining with the main tributaries which flow in north to south direction. Since, rainfall and flowing streams are the only sources to recharge aquifers. It is a possibility to detect and analyze the freshwater aquifer formation along these streams in the area.

There are some boreholes, dug well and natural lakes that are lying in the area. Water shortage is one of the main problems challenged by local communities in the area during drought season. Hence, the geophysical resistivity survey has been conducted to explore and exploit the freshwater aquifer reservoirs in the research study area. Water level was depleted in dry/summer season and consequently exaggerated the quality of groundwater.

Geological setting of the study area

The research study area located in the Laki range, which is the present in the lower Indus Basin and ranges in age from Eocene to Pleistocene. Lithologically, the area consists of alluvium, clay, silt, sand, gravel, limestone, sandstone, shale, conglomerates, etc. The major geological formations are Laki formation of early Eocene age, which contain main lithology of limestones with shales, sandstones and lateritic clay. The Laki formation in middle Eocene age, Tiyon formation is exposed in the study area, which contain main lithology, i.e., shales, marls and limestones. In Oligocene age, the Nari formation is exposed which contains mainly sandstone and marl deposit. In Miocene age, Gaj formation is exposed and contains limestone, sandstone, shales and minor conglomerates. In middle Miocene age, Manchar formation consists of the materials such as sandstones, shales, clay with subordinate conglomerate beds, and in Pliocene age, Dada conglomerate is exposed and mostly contains conglomerate, boulder, cobble. Most of the sweet-water aquifer pertains near the hill torrents having different depths (Figs. 1, 2).

Fig. 1
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Source: Khan (2012), Geological Survey of Pakistan

Geological map of the study area.

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Fig. 2
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Strait graphical chart of surveyed area showing lithological log (Brohi et al. 2009)

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Location and accessibility

The location of the study area lies in Sindh province, and it starts from Nooriabad (district Jamshoro) toward Karachi (district Malir). The study area touches with Thatta district in the south, and in the west there is Karachi Malir district, along with M-9 Motorway about 50 km long with 5 km on both sides. The geographic coordinate of the study area around from Nooriabad with Lat. 25.093988°N, Long. 67.567288°E and Lat. 25.080322°N, Long. 67.717537°E to Karachi Lat. 25.092969°N, Long. 67.608746°E and Lat. 25.118409°N, Long. 67.617525°E. Due to security risks, only twelve (12 VES) points were carried out in the study area.

Material and method

The purpose of electrical resistivity survey is to determine the subsurface resistivity distribution by making measurements on the ground surface. From these measurements, the resistivity of the subsurface can be estimated. The ground resistivity is related to various geological parameters such as the mineral and fluid content, porosity, permeability and degree of water saturation in the rock. In this study, SAS4000 Terrameter available at USPCASW, MUET, Jamshoro, has been used for VES to collect resistivity data for the subsurface geo-electric section which may be used to estimate the groundwater. Before assembling the instrument, it is overviewed to each VES at the study area to find out the flat lands on the hilly area to fix the stainless steel probes The resistivity measurements are normally made by injecting current into the ground through two current electrodes (C1 and C2), and measuring the resulting voltage difference with two potential electrodes (PI and P2). From the current (I) and voltage (V) values, an apparent resistivity (ρa) value is calculated.

$$\rho a = kV/I$$
$$\rho a = 2\pi a \times V/I$$

Here, ‘k’ is the geometric factor which depends on the arrangement of the four electrodes.

Resistivity meters normally give a resistance value, R = V/I, so in practice the apparent resistivity value is calculated by

$$\rho a = k*R$$

We used the Schlumberger configuration for data collection because it is a best and the simple method for getting good resistivity results of the subsurface. Schlumberger soundings generally have better resolution, greater probing depth and less time-consuming field deployment than the other configurations (Khan et al. 2013). The Schlumberger array consists of four collinear electrodes. The outer two electrodes are current (source) electrodes, and the inner two electrodes are the potential (receiver) electrodes. The potential electrodes are installed at the center of the electrode array with a small separation, typically less than one-fifth of the spacing between the current electrodes. The current electrodes are increased to a greater separation during the survey, while the potential electrodes remain in the same position until the observed voltage becomes too small to measure.

Results and discussion

There are twelve (12) probes on which data were collected through SAS4000 Terrameter and also water samples were collected from their premises, on the left side of M-9 Motorway from Nooriabad toward Karachi (50 km long and 10 km wide).

Geo-electric sections

The geo-electrical sections of 12 VES curves are generated and stacked along two section profiles based on the resistivity contrast of different lithologies (Figs. 3, 4). The thickness, depth and the respective resistivity of each layer, demarcated by VES, are isolated by IPI2win software. A visual inspection of all the sections revealed different lithological units across the area up to a depth of 300 m that include shale, clay, sandy clay fractured sandstone, and fractured limestone.

Fig. 3
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Location map of the study area

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Fig. 4
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Comparing the electrical resistivity and conductivity values found for Earth materials with common earth materials adopted from Palacky (1988), SAS4000 Terrameter (2010), and Carbajal (2014)

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VES-01 was carried out at (Lat. 25.141239°N, Long. 67.7766611°E) along the left side of M-9 Motorway along Nooriabad toward Karachi, which shows that total four lithological layers were demarcated in VES-01. The results present in the interpreted subsurface model show that the first layer with apparent resistivity of 11.6 Ωm up to the depth of 2 m (2 m thick) represents the alluvium or weather layer, second layer with resistivity of 26.5 Ωm up to the depth of 18 m (16.8 m thick) represents the low resistivity layer showing unconsolidated loose clay deposit of Tiyon formation, third layer with resistivity of 76 Ωm up to the depth of 29 m (11 m thick) represents high resistivity and shows lithology of limestone, fourth layer having the low resistivity of 24.5 Ωm up to the depth of 131 m (101 m thick) shows freshwater aquifer present in sandstone lithology of the Laki formation and great potential for tube well for a long time, and below freshwater layer resistivity values drop very low and show saline water up to the depth of 300 m.

VES-2 was carried out at (Lat. 25.145139°N, Long. 67.742073°E) along left side of M-9 Motorway along Nooriabad toward Karachi, which shows that the total four lithological layers were demarcated in VES-02. The results present in the interpreted subsurface model show that the first layer with apparent resistivity of 11.8 Ωm up to the depth of 1.88 m (1.88 m thick) represents the alluvium or weather layer, the second layer with resistivity of 25 Ωm up to the depth of 17.7 m (15.8 m thick) represents the low resistivity layer showing unconsolidated loose clay or deposit of Tiyon formation, the third layer having resistivity of 88 Ωm up to the depth of 26.9 m (9.26 m thick) represents high resistivity and shows lithology of limestone of formation Laki, fourth layer with low resistivity of 24.7 Ωm up to the depth of 127 m (100 m thick) shows freshwater aquifer present in sandstone lithology of the Laki formation and great potential for tube well for a long time, and below freshwater layer resistivity values drop in 1.1 Ωm very low and show saline water up to the depth of 300 m.

VES-3 was carried out at (Lat. 25.15069°N, Long. 67.725094°E) along left side of M-9 Motorway along Nooriabad toward Karachi which shows that total five lithological layers were demarcated in VES-03. The results present in the interpreted subsurface model show that the first layer with apparent resistivity of 40.1 Ωm up to the depth of less than 1 m (less 1 m thick) represents the alluvium or weather layer, the second layer with resistivity of 25.8 Ωm up to the depth of 1.8 m (1.0 m thick) represents low resistivity layer showing unconsolidated loose clay or shale of Tiyon formation, the third layer having resistivity 97 Ωm up to the depth of 5.16 m (3.33 m thick) represents high resistivity and shows lithology of limestone of Laki formation, the fourth layer with low resistivity of 1.3 Ωm up to the depth of 10.6 m (5.41 m thick) shows very low resistivity present in shale of Laki formation, fifth layer with resistivity 12.6 Ωm first layer up to the depth of 28.5 m (17.9 m thick) shows freshwater aquifer present in sandstone lithology of Laki formation and good potential for tube well for a long time, and below freshwater layer resistivity values drop in 1.23 Ωm very low and show saline water up to the depth of 300 m.

VES-4 was carried out at (Lat. 25.101862°N, Long. 67.597617°E) along left side of M-9 Motorway along Nooriabad toward Karachi which show that the total four lithological layers were demarcated in VES-04. The results present in the interpreted subsurface model show that the first layer with apparent resistivity of 6.54 Ωm up to the depth of less than 1.2 m (1.2 m thick) represents the alluvium or weather layer, second layer with resistivity of 137 Ωm up to the depth of 2.68 m (1.48 m thick) represents very high resistivity layer fractured limestone, third layer with resistivity of 6.37 Ωm up to the depth of 30.9 m (28.2 m thick) represents very low resistivity and shows lithology of shale of Tiyon formation, fourth layer having low resistivity of 11.2 Ωm up to the depth of 151 m (120 m thick) shows low resistivity freshwater aquifer zone present in sandstone of Laki formation that have good porosity and permeability and good potential for tube well, and below freshwater layer resistivity values drop in 1.23 Ωm very low and show saline water up to the depth of 300 m in Laki limestone.

VES-5 was carried out at (Lat. 25.094582°N, Long. 67.589702°E) along left side of M-9 Motorway along Nooriabad toward Karachi which shows that the total five lithological layers were demarcated in VES-05. The results present in the interpreted subsurface model show that the first layer with apparent resistivity of 4.04 Ωm up to the depth of less than 1 m (less than 1 m thick) represents the alluvium or weather layer, second layer with resistivity of 14.7 Ωm up to the depth of 2.67 m (1.48 m thick) represents loose unconsolidated clay material, third layer with resistivity of 3.14 Ωm up to the depth of 5.49 m (2.82 m thick) represents very low resistivity and shows shale lithology of Tiyon formation, fourth layer with very high resistivity of 214 Ωm up to the depth of 10.9 m (5.36 m thick) represents compacted lithology of Laki limestone member of Laki formation and fifth layer with resistivity 54.4 Ωm up to the depth of 300 m (274 m thick) shows low resistivity layer of freshwater aquifer zone present in fractured sandstone of Laki formation that have good porosity and permeability and good potential for tube well.

VES-06 was carried out at (Lat. 25.084359°N, Long. 67.572573°E) along left side of M-9 Motorway along Nooriabad toward Karachi which shows that the total five lithological layers were demarcated in VES-06. The results present in the interpreted subsurface model show that the first layer with apparent resistivity of 6.63 Ωm up to the depth of less than 1.82 m (1.82 m thick) represents the alluvium or weather layer, second layer with resistivity of 8.09 Ωm up to the depth of 2.04 m (less than 1 m thick) represents loose unconsolidated shale of Tiyon formation, third layer with resistivity of 6.19 Ωm up to the depth of 9.4 m (7.24 m thick) represents very low resistivity and shows lithology of clayey shale of Tiyon formation, fourth layer with resistivity of 46 Ωm up to the depth of 113 m (97 m thick) shows freshwater aquifer zone present in sandy clay material of Laki formation that have good porosity and permeability and good potential for tube well for long period of time, and below fifth layer with resistivity drops in 1.07 Ωm up to the depth of 300 m (198 m thick) represents saline water in limestone of Laki formation.

VES-07 was carried out at (Lat. 25.076057°N, Long. 67.519389°E) along left side of M-9 Motorway along Nooriabad toward Karachi which shows that the total five lithological layers were demarcated in VES-07. The results present in the interpreted subsurface model shows that the apparent resistivity of layer first is 19.1 Ωm up to the depth of 2.37 m (2.37 m thick) is representing the alluvium or weather layer, second layer with resistivity of 9.81 Ωm up to the depth of 13 m (10.6 m thick) representing shale of Tiyon formation, third layer with resistivity of 3.47 Ωm up to the depth of 30 m (17 m thick) represent very low resistivity and showing lithology of clayey shale of Tiyon formation, fourth layer with low resistivity of 27.1 Ωm up to the depth of 46.1 m (16 m thick) shows the freshwater aquifer zone present in clay material of Tiyon formation have good porosity and permeability and good potential for Tube well, and below fifth layer with resistivity drops in 4.12 Ωm up to the depth of 300 m (254 m thick) represents saline water in limestone of Laki formation.

VES-08 was carried out at (Lat. 25.033713°N, Long. 67.448123°E) along left side of M-9 Motorway along Nooriabad toward Karachi which shows that the total four lithological layers were demarcated in VES-08. The results present in the interpreted subsurface model show that the first layer with apparent resistivity of 15 Ωm up to the depth of less than 2.7 m (2.7 m thick) represents clay deposit, second layer with resistivity of 9.94 Ωm up to the depth of 30 m (27 m thick) represents shale lithology of Tiyon formation, third layer with resistivity of 3.92 Ωm up to the depth of 67 m (37 m thick) represents very low resistivity and shows lithology of clayey shale of Tiyon formation, fourth layer with resistivity of 70.7 Ωm up to the depth of 300 m (236 m thick) shows freshwater aquifer zone present in fractured sandstone of Laki formation that have good porosity and permeability and good potential for tube well (Figs. 5, 6).

Fig. 5
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Geo-electrical section of (VES 01 to 04) of the study area

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Fig. 6
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Geo-electrical sections of (VES 05 to 08) of the study area

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Pseudo-section and resistivity section

In order to obtain a clear picture of resistivity distribution and variation along various depths, two pseudo-section maps of six resistivity sections and two resistivity cross sections along with six VES are drawn. Pseudo-sections have been generated for all the VES profiles, which are colinear for generating a pseudo-section, Figs. 7 and 8, so as to portray the variation of resistivity across the VES, considered along the profiles. Three resistivity zones have been marked in pseudo-sections based on resistivity contrast, i.e., the low resistivity zone (0–10 Ωm), moderate resistivity zone (10–25 Ωm) and the high resistivity zone (> 50 Ωm). Low resistivity interpreted here saline or marginal saline water presents in limestone of Laki formation of Eocene age lies at the depth below average 150 m to 300 m depth. The saline water may be due to dissolution of calcium in Laki formation and affects the quality of water. Moderate zone is determined to be here fractured sandstone or sandy limestone, sandy clay accumulate here freshwater-bearing aquifers in Laki formation of Eocene age lies at the depth of 50 to 100 m and having good potential for installation of tube wells in study area. High zone interpreted here compacted limestone or sandstone which has the low porosity and permeability not recommended for drilling.

Fig. 7
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Pseudo-section of (VES-01 to VES-06)

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Fig. 8
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Pseudo-section of (VES-07 to VES-12)

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The resistivity cross section also interpreted here three zones that have been demarcated based on true resistivity contrast which are saline to marginal saline zone (ρ ≤ 20 Ωm), moderate freshwater zone (20 ≤ ρ ≥ 50 Ωm) and high compacted zone (50 ≤ ρ ≤ 100 Ωm). The resistivity cross section is generated for the same VES location to portray the changing true resistivity with depth (Figs. 9, 10). The overall trend of the cross section shows reducing downwards trend with steep drop. A total of three anomalous zones having a low resistivity are demarcated with a resistivity value of 0–10 Ωm along VES 03, 06 and 07, showing the presence of loose and conductive lithologies of altered materials like limestone. Moderate layer resistivity cross section at VES 01, 02, 04 and 08 showing good freshwater potential of water bearing strata and resistivity lies 10 to 25 Ωm. At surface, the resistivity values range from 50 to 100 Ωm indicating rock strata. The resistivity section and pseudo-section are in agreement with the general geology of the area and correlate with each others.

Fig. 9
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Resistivity section of (VES 01 to VES 06)

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Fig. 10
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Resistivity section of (VES 07 to VES 12)

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Statistical distribution curve (SDC) B

Statistical curves are generated to investigate the subsurface geology and hydrogeology with respect to changes in resistivity while increasing in the depth. The software IPIWIN is used to correlate the resistivity values with subsurface geology. We divide the section into two (SDC) layers VES 01-06 and VES 7-12 to detain the data of resistivity with changing of subsurface hydrogeology and geology with respect to depth (Figs. 11, 12). From SDC, it is observed that there is a steep downward trend with resistivity values between 0 and 3 Ωm within the depth of 0–5 m, which shows the presence of alluvium or weathered layer of topsoil.

Fig. 11
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SDC curve of the study area (VES 01 to 06)

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Fig. 12
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SDC curve of the study area (VES 07 to 12)

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With the increase in depth, linear horizontal trend is also observed from 3 to 15 m by an average resistivity value of 60 Ωm, resulting as clayey shale and fractured limestone of Laki formation. At a depth ranging between 15 to 50 m, the resistivity value varies from 10 to 25 Ωm that shows the lithology as clay and sandy clay with presence of freshwater aquifer zone; the curve follows as structural concordant. A abrupt upward change is observed at a depth which ranges from 42 to 100 m where the resistivity value rising from 20 to 50 Ωm indicates the presence of limestone and fractured sandstone which appears as groundwater potential reservoir with intercalation of limestone.

At 100 m depth, the resistivity shows a gentle downward trend with resistivity value drop below 10 Ωm at a depth of 300 m and is interpreted as a limestone of Laki formation which can dissolve water in salinity and saline water aquifers are interpreted. Overall, SDC shows the decreasing values of resistivity as we increase our depth, which show that the governing lithology at near surface is clay and shale that vary progressively to limestone and sandstone lithology up to the 40 m to 100 m depth.

Chemical analysis of water samples

Groundwater samples were collected from boreholes to investigate the accessible quality of groundwater in the research study area. A total of 12 groundwater samples were collected and analyzed at Soil and Water Laboratory, USPCASW, MUET, Jamshoro. Results show that electrical conductivity values of some location are above the WHO standard and affect the quality of water. EC values are high due to dissolution of calcium carbonate of Laki formation in water and which are also we mentioned in our resistivity section showing saline aquifer, pH, CO3, HCO3 are within WHO standards (Table 1).

Table 1 Chemical analysis of groundwater samples
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Conclusion

Result concluded on the basis of VES and previous knowledge of geology and hydrogeology of the area is summarized as follows:

  • Accumulation of groundwater is found to be controlled by geomorphology and geological structures of study area.

  • The area is chiefly divided into four basic lithological units: clay, sandy clay and shale of Tiyon Formation and limestone and fractured sandstone beds of the Laki formation of Eocene age.

  • The limestone of Laki formation can be considered to convey good aquifers because of its fractured and cavernous characteristics.

  • Confined and open aquifers are identified in sandstone and sandy limestone of the Tiyon and Gaj formation.

  • The quality of water in Laki formation aquifers is expected to be fresh to slightly saline.

  • The clay and shale beds give resistivity values ranging from 12–40 to 40–60 Ωm, due to their low porosity and permeability; these aquifers are not productive.

  • Fractured sandstone and limestone are the main water-bearing aquifers and are therefore a good source for groundwater reservoir and interpreted from a average resistivity value of 20–60 Ωm.

  • Freshwater aquifer zone lies at the average depth of 40 to 100 m and suitable for the installation of tube wells and potential for the long time.

  • Saline to marginal saline water aquifer zone exists in the Laki limestone as part of the Laki formation.

  • Clay mineralogy may prevent the percolation of water due to its low permeability, resisting the groundwater recharge.

  • Several saturated zones are encountered and confirmed within the sandstone units of Laki formation up to 100 m.

  • The extension of aquifer and its recharge remained the main concern and interest, if the aquifers’ production is successful. However, drilling will be preferred at the depth of 100 m; it will be beneficial to perforate the whole fractured sandstone zone for recharging purpose.

  • The conclusion of this research will be beneficial for the scientific study of groundwater management and prospecting for future and fruitful for community and industrial area.