Replacement of Saline Water through Injecting Fresh Water into a Confined Saline Aquifer at the Nakdong River Delta Area

Coastal aquifers provide fresh drinking water to over 20% of the world&#8217;s population. In recent times, they have come under immense pressure due to salinization. This study aims to investigate the origin of groundwater salinity and elucidate the major&#160;processes&#160;controlling&#160;shallow&#160;groundwater&#160;(depth of 0~50m) evolution in the Luanhe River Delta since&#160;the Holocene. Rapid increase in Electric Conductivity (EC) profile was observed in the area, as such, based on the vertical distribution of EC and&#160;sedimentary history, shallow groundwater was generalized into two zones&#160;for analysis: the groundwater&#160;in Holocene stratum (HSG) and groundwater in Late Pleistocene stratum&#160;(PSG). The isotopic (&#948;18O, &#948;2H and 14C) analyses showed that the HSG is recharged by modern surface water, while the PSG having enriched isotopic values could have been recharged during a warmer Holocene transgression period. The hydrochemistry analyses demonstrated that seawater is the major source of salinity in groundwater and overtime a series of geochemical processes (mineral weathering and/or cation exchange) modified the chemistry of the groundwater. The combined use of Cl-&#160;and &#948;18O&#160;yielded four classes of groundwater (fresh water, brackish water, saline water and brine), while the mixing phenomena between fresh water and seawater was identified to be the main evolutionary process of the shallow groundwater. To improve understanding of evolution of multiple groundwater types in a spatial context, a conceptual model was developed integrating the results derived from the presented study in a vertical cross-section. The conceptual model shows that the residual seawater mixes with freshwater from surface recharge at the shallow aquifer of the delta plain where the lagoon environment provides salinity concentration conditions for the formation of hyper-saline water. Due to&#160;the precipitation and accumulation of the salinity from hyper-saline water, some brine might form&#160;formed in late Pleistocene continental stratum.

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Corrigendum to “sediment properties of lithologic units and their correlation within the lower delta plain of the Nakdong River Delta, southeast Korea” [Quat. Int., https://doi.org/10.1016/j.quaint.2019.02.044]

Quaternary International ◽

10.1016/j.quaint.2019.06.035 ◽

2019 ◽

Vol 525 ◽

pp. 159

Author(s):

Boo-Keun Khim ◽

Seungwon Shin ◽

Jin Cheul Kim ◽

Hiroyuki Takata ◽

Sangmin Hyun ◽

...

Keyword(s):

River Delta ◽

Nakdong River ◽

Sediment Properties ◽

Delta Plain ◽

The Nakdong River

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

Water ◽

10.3390/w10111548 ◽

2018 ◽

Vol 10 (11) ◽

pp. 1548 ◽

Cited By ~ 11

Author(s):

Muhammad Hasan ◽

Yanjun Shang ◽

Gulraiz Akhter ◽

Weijun Jin

Keyword(s):

Fresh Water ◽

Cross Sections ◽

Saline Water ◽

Groundwater Resources ◽

Physicochemical Analysis ◽

Saline Aquifers ◽

Water Interface ◽

Saline Aquifer ◽

Borehole Data ◽

Dar Zarrouk Parameters

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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