Delineation of weathered/fracture zones for aquifer potential using an integrated geophysical approach: A case study from South China

Hasan, Muhammad; Shang, Yanjun; Jin, Weijun

doi:10.1016/j.jappgeo.2018.06.017

Cited by 54 publications

(43 citation statements)

References 28 publications

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“…This may explain the recent introduction of the magnetic method as a reconnaissance tool in groundwater investigation in the basement complex environment (e.g. Hasan et al, 2018).…”

Section: Integrated Geophysical Methods and Techniques For Siting Promentioning

confidence: 99%

Integrated geophysical methods and techniques for siting productive boreholes in basement complex terrain of southwestern Nigeria

Olorunfemi¹,

Oni²

2019

Ife Journal of Science

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Electrical resistivity survey involving 2D Dipole-Dipole subsurface imaging and 1D Vertical Electrical Sounding (VES) and an integrated magnetic and electrical resistivity survey involving magnetic profiling and 1D VES/2D electrical imaging techniques were carried out at two sites underlain by grey gneiss and pegmatised schist, respectively, within the Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria. The surveys were carried out with a view to delineating the subsurface layers and determining the geoelectrical characteristics; identify geological structures such as faults, fractured, jointed and sheared basement zones that are favourable to groundwater accumulation and transmission and estimate hydrogeologically significant borehole drill depth in an area with previous experience of failed borehole drilling attempts. At the two sites (A&B) investigated, the 2D resistivity images identified suspected fractured basement zones as low resistivity vertical discontinuities within high resistivity fresh basement host rock. The magnetic profiles at site B displayed typical magnetic anomaly of a thick dyke (two magnetic lows with central high in low magnetic latitude) over each vertical resistivity discontinuity. The follow-up VES delineated maximum of five subsurface layers which include the topsoil/laterite, weathered layer, partly weathered/fresh basement, fractured basement and the fresh basement. The weathered/fractured basement constitutes the main aquifer unit with thicknesses varying from 17.7-125 m. Two boreholes, one per site, were drilled to 80 m at site A and 70 m at site B. Both boreholes encountered the predicted fractured basement zones and the borehole logs correlated well with the interpretation models of the drilled VES locations. The boreholes were very productive (yields of about 1.5 l/s and 2.2 l/s at sites A & B respectively). The study demonstrated the effectiveness of integrated geophysical methods and techniques in providing information on the subsurface sequence and the structural disposition required for a successful groundwater development through borehole drilling, in a borehole-failure-prone basement complex terrain.

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“…This may explain the recent introduction of the magnetic method as a reconnaissance tool in groundwater investigation in the basement complex environment (e.g. Hasan et al, 2018).…”

Section: Integrated Geophysical Methods and Techniques For Siting Promentioning

confidence: 99%

Integrated geophysical methods and techniques for siting productive boreholes in basement complex terrain of southwestern Nigeria

Olorunfemi¹,

Oni²

2019

Ife Journal of Science

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“…The changes in the physical parameters of the subsurface geologic layers make up the model of true resistivity [58]. True resistivity of rock mass depends on many factors such as porosity, clay content and water content, fault and fault zone, groundwater resistivity, and temperature [24]. Resistivity range for groundwater is from 10 ohm-m to 115 Ωm.…”

Section: Resistivity Model Curves and Lithological Calibrationmentioning

confidence: 99%

“…Calibration between the true resistivity and the litho logs was performed at nine wells to establish a unified layered-model appropriate to all resistivity modeled curves. This correlation depends on the local basis, that is, the hydrogeological information of the studied area [22,24]. The correlation between resistivity and borehole data constrained the subsurface formation into different layers, that is, dry strata with resistivity greater than 30 Ωm (above water table), clay containing saline water with resistivity less than 15 Ωm (below water table), clay-sand having brackish water with resistivity ranging from 15 to 25 Ωm (below water table), sand with fresh water containing resistivity range between 25 and 45 Ωm (below water table) and gravel-sand having fresh water with resistivity greater than 45 Ωm (below water table) as shown in Table 2.…”

Section: Resistivity Model Curves and Lithological Calibrationmentioning

confidence: 99%

“…Geophysical methods, especially the geoelectrical resistivity methods, have been adopted by many researchers to map the salinity and delineate the fresh-saline aquifer interface [10,[16][17][18][19][20][21]. Such techniques are commonly applied to characterize the groundwater zones mostly because of the close relation between subsurface resistivity, saturated subsurface materials and water salinity [22][23][24]. These methods have been very successful to distinguish between the fresh and saline aquifers due to their sensitivity to detect the variations in resistivity values of such aquifers [25].…”

Section: Introductionmentioning

confidence: 99%

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Delineation of Saline-Water Intrusion Using Surface Geoelectrical Method in Jahanian Area, Pakistan

Hasan

Shang

Akhter

et al. 2018

Water

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Groundwater is the main supply of fresh water in many parts of the world. The intrusion of saline water into the fresh water is a serious threat to groundwater resources. Delineation of fresh-saline aquifer zones is essential to exploit the potable fresh water. The conventional method to differentiate fresh-saline water interface is to collect and test groundwater samples from boreholes using a number of laboratory tests. However, such techniques are expensive and time consuming. A non-invasive geoelectrical method, in combination with borehole data and physicochemical analysis, is proposed to assess the fresh-saline aquifers. This investigation was conducted in Jahanian area of Pakistan with forty-five vertical electrical soundings (VES) using Schlumberger array, nine bore wells and fifty physicochemical samples. The fresh-saline aquifers are delineated by aquifer resistivity and Dar-Zarrouk parameters namely transverse unit resistance and longitudinal unit conductance. The aquifer potential of fresh-saline water zones is estimated by the aquifer parameters namely transmissivity and hydraulic conductivity. Integration of subsurface resistivity with hydrogeological information reveals the subsurface formation of five layered succession, that is, topsoil having dry strata with resistivity greater than 30 Ωm, clay containing saline water with resistivity less than 15 Ωm, clay-sand with brackish water having resistivity between 15 and 25 Ωm, sand containing fresh water with resistivity ranging from 25 to 45 Ωm and gravel-sand having fresh water with resistivity greater than 45 Ωm. The geoelectrical columns and geological cross-sections constructed by the aquifer resistivity provide effectiveness of the interpretations for the evaluation of fresh-saline aquifers. The results of physicochemical analysis using WHO guideline validate the fresh-saline aquifer zones delineated by the geophysical method. This investigation contributes towards predicting the fresh-saline water interface using inexpensive geoelectrical method.

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“…Evaluation of groundwater reserves is important because of an increasing demand for drinking, irrigation and industrial uses. The applications of many geophysical and hydrogeological methods, such as electrical resistivity, magnetic, electromagnetic, seismic, ground‐probing radar, pumping test and down‐hole logging, are required for the assessment of the groundwater (Hasan, Shang and Jin ). The groundwater flow system is explained by the spatial distribution of hydraulic parameters, such as specific yield, porosity, transmissivity and hydraulic conductivity.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of groundwater potential in Kabirwala area, Pakistan: A case study by using geophysical, geochemical and pump data

Hasan

Shang

Akhter

et al. 2018

Geophysical Prospecting

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Knowledge of hydraulic parameters (hydraulic conductivity and transmissivity) is essential for the delineation of groundwater potential zones. Conventionally, these parameters are measured using pumping tests carried out on boreholes. However, pumping tests are costly, labour intensive and require a considerable amount of equipment. The integration of geophysical methods with pumping tests provides efficient and cost‐effective alternative to calculate hydraulic parameters. Fifty electrical resistivity soundings were carried out in the study area using Schlumberger inter‐electrode configuration to obtain hydraulic characteristics that are estimated through the pumping tests. To apply this approach successfully, sufficient number of boreholes are used. Part of the boreholes, in which pumping tests were carried out, is used for both to constrain resistivity inversions and to establish the empirical relationship between the interpreted geophysical and hydraulic parameters. The rest of the boreholes without pumping tests are still used for constraining the inversions. Initially, aquifer parameters were measured using pumping tests at 12 water wells. Afterwards, transmissivity (T) and hydraulic conductivity (K) were correlated with transverse resistance (Tr) and the bulk resistivity (ρo) of the aquifer at other sites where pumping tests had not been conducted. In this way, the entire study area was covered to assess the groundwater reserves. The hydraulic properties obtained by the geophysical method fit pretty well to both the pumping and physicochemical data of the investigated area. The integrated study reveals five layers (i.e. topsoil, clay, clay sand, sand and gravel sand) and three potential zones (i.e. high, medium and low potential aquifer zones) with specific ranges of T, K, Tr and ρo. The results suggest that, in case of sparse well data, the aquifer parameters can be estimated using the relations depending on the specifications of the area.

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Delineation of weathered/fracture zones for aquifer potential using an integrated geophysical approach: A case study from South China

Cited by 54 publications

References 28 publications

Integrated geophysical methods and techniques for siting productive boreholes in basement complex terrain of southwestern Nigeria

Integrated geophysical methods and techniques for siting productive boreholes in basement complex terrain of southwestern Nigeria

Delineation of Saline-Water Intrusion Using Surface Geoelectrical Method in Jahanian Area, Pakistan

Evaluation of groundwater potential in Kabirwala area, Pakistan: A case study by using geophysical, geochemical and pump data

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