Application of multi-criteria decision making (MCDM) and electrical resistivity tomography (ERT) techniques for identification of groundwater recharge zone(s) in granitic hard rock aquifer

Kumari, Archana; Kumar, Dewashish; Warwade, Pratibha

doi:10.1007/s12040-021-01577-3

Cited by 11 publications

(1 citation statement)

References 31 publications

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“…In the upper part of these deposits, high electrical resistivity values up to 5000 Ohm.m are imaged (Figure 10), indicating As for the upstream zone, the transition to the underlying granite basement is well imaged by an increase in resistivity at an elevation of around −20 to −30 m. Lateral variations of electrical resistivity illustrate the heterogeneous structures of this granite bedrock, which is likely related to fractures and alterations. In Figure 8c, the resistivity in the basement reaches 500 Ohm.m, possibly indicating unaltered granite [64][65][66]. Inversely, quite low resistivity ranging between 10 Ohm.m and 30 Ohm.m is observed in the upper part of the bedrock.…”

Section: Downstream Zonementioning

confidence: 92%

Imaging the Structure and the Saltwater Intrusion Extent of the Luy River Coastal Aquifer (Binh Thuan, Vietnam) Using Electrical Resistivity Tomography

Cong-Thi

Dieu

Thibaut

et al. 2021

Water

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With the growing population and the adverse effects of climate change, the pressure on coastal aquifers is increasing, leading to a larger risk of saltwater intrusion (SI). SI is often complex and difficult to characterize from well data only. In this context, electrical resistivity tomography (ERT) can provide high-resolution qualitative information on the lateral and vertical distribution of salinity. However, the quantitative interpretation of ERT remains difficult because of the uncertainty of petrophysical relationships, the limitations of inversion, and the heterogeneity of aquifers. In this contribution, we propose a methodology for the semiquantitative interpretation of ERT when colocated well data are not available. We first use existing wells to identify freshwater zones and characterize the resistivity response of clayey deposits. Then, we approximate the formation factor from water samples collected in the vicinity of ERT data to derive a resistivity threshold to interpret the saline boundary. We applied the methodology in the shallow aquifers of the Luy River in the Binh Thuan province, Vietnam, where water resources are under pressure due to agricultural, aquacultural, and industrial production. Twenty-one ERT profiles were collected and revealed a much larger intrusion zone, compared to the previous study. Saltwater is present in lowland areas of the left bank over almost the whole thickness of the aquifer, while the right bank is constituted of sand dunes that are filled with freshwater. At a larger distance from the sea, a complex distribution between fresh and saltwater is observed. Our methodology could be applied to other heterogeneous aquifers in the absence of a dense monitoring network.

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Section: Downstream Zonementioning

confidence: 92%