S.Y. Chung
I am an Emeritus Professor in the Dept. of Earth Sciences, and interested in groundwater hydrology, AI methods to groundwater contamination vulnerability, and geostatistical applications to groundwater modeling and data estimation. I earned B.S. and M.S. from Seoul National University, Korea and Ph.D. from University of Nevada at Reno, USA. I published over 120 articles in International and Domestic Journals.
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Papers by S.Y. Chung
source of freshwater in the drought-prone Pudukkottai district of Tamil Nadu, India. Therefore, the search for groundwater potential zones (GWPZs) is critical. The present study focuses on the
investigation of potential groundwater zones using geospatial techniques. Geology, land use and land cover, geomorphology, soil, drainage density, lineament, and groundwater levels were obtained from state and non-state associations. ArcGIS version 10.8 was used to create all thematic layers and classified grids. The intensive use of groundwater in arid and semiarid regions is becoming a problem for the public to meet their freshwater needs. The condition of arid and semi-arid regions due to
intensive groundwater extraction has become one of the most important environmental problems for the public. In this study, a powerful groundwater potential mapping technique was developed using
integrated remote sensing data from GIS-AHP. Using AHP techniques, thematic layers for geology, geomorphology, and soil followed by drainage, drainage density and lineament, lineament density, slope, water level, and lithological parameters were created, classified, weighted, and integrated into a GIS environment. According to the results of the study, it is estimated that 14% of the groundwater potential in the study area is good, 49% is moderate and 36% is poor. A groundwater level map
was used to verify the groundwater potential. In addition, the model was validated with a single-layer sensitivity analysis, which showed that geology was the most influential layer and water level was the least influential thematic layer. The low-potential areas identified on the groundwater potential map can be used for further study to identify ideal locations for artificial recharge. In low-potential areas, the groundwater potential map can be used to find ideal locations for artificial
recharge. The water table in the area must be raised by artificial recharge structures such as infiltration basins, recharge pits, and agricultural ponds. Artificial recharge structures such as infiltration basins, recharge pits, and agricultural ponds can be used for groundwater development in low potential zones. The GWPZ map was successfully validated with three proxy data, such as the number of wells, groundwater level, and well density, obtained from well inventory information. The results of
this study will improve our understanding of the geographic analysis of groundwater potential and help policy makers in this drought-prone area to create more sustainable water supply systems.
region at southern part of Tamil Nadu state in India. The presence of excessive radium tracers revealed that the SGD was contributing to Ra desorption from the sediments and enrichment in the coastal waters. We estimated SGD of approximately 0.03–0.59 m3 m2 d1 for the Manapad region and relatively more homogeneous but comparatively less values in the Karameniyar estuary (0.03–0.34 m3 m2 d1). Higher average values of dis-solved inorganic nitrogen (DIN; 43.62 μmol L1) and soluble reactive phosphate (SRP; 1.848 μmol L1) suggested greater influence of SGD on the overall coastal water nutrient budget. This study also indicated simultaneous occurrence of fresh and saline SGD in this region
Gravelly Sand (gS), 5 Silty Sand (zS), 5 Muddy Sand (mS), and 1 Sandy Silt (sZ). Hydraulic conductivity was determined through a falling head test, and ranged from 9.2×10 −5to 2.9×10 −2 cm/sec (0.08 to 25.6 m/day). From breakthrough curves, dispersivity was calculated to be 0.35~3.92 cm. Also, effective porosity and average linear velocity were obtained through the column tracer test, and their values were 0.04~0.46 and 1.06E-04~6.49E-02 cm/sec, respectively. Statistical
methods were used to understand the interrelations among aquifer parameters of hydraulic conductivity, effective porosity and dispersivity. The relation between dispersivity and hydraulic conductivity or effective porosity considered the sample length, because dispersivity was affected by experimental scale. The relations between dispersivity and hydraulic conductivity or effective porosity were all in inverse proportion for all long and short samples. The reason was because dispersivity was in inverse proportion to the groundwater velocity in case of steady hydrodynamic dispersion coefficient, and groundwater velocity was in proportion to the hydraulic conductivity or effective porosity. This study also elucidated that longitudinal dispersivity was dependent on the scale of column tracer test, and all hydrogeological parameters were
low to high values due to the sand quantity of sediments. It is expected that the hydrogeological parameter data of sediments will be very useful for the planning of groundwater management and preservation in the Nakdong River Delta of Busan City, Korea.
parameters based on twenty-two groundwater samples from the coastal industrial city of Tuticorin in Southern India, taken before (10 and 11th February 2020) and during the lockdown (19 and 20th April 2020) periods. The physicochemical parameters compared are pH, total dissolved solids (TDS) and electrical conductivity (EC), ni-trate (NO3),fluoride (F), chromium(Cr), iron (Fe), copper (Cu), zinc (Zn), cadmium(Cd), lead (Pb), arsenic (As), and selenium (Se), and the bacterial parameters aretotal coliforms, fecal coliforms, E. coli,and fecal streptococci.Among the metals, the significant reductions in Se (42%), As (51%), Fe (60%), and Pb (50%)were noticed probably owing to no or very lesswastewater discharges from metal-based industries, seafood-based industries and ther-mal power plants during the lockdown. Reduction inNO3(56%),total coliform(52%) andfecal coliforms(48%) in-dicated less organic sewage from thefishing industries. Contents of Cr, Cu, Zn and Cd, however, remained similar and fluoridedidnot showany change, probably as they were sourced fromrock-water interactions. Similarly, we did not observe alterations inE. coliandfecal streptococci due to no significant change in domestic sewage production during the lockdown. The multivariate analyses aptly illustrated this and the principal component analyses helped to identify the sources that controlled water qualities of the lockdown compared to the pre-lockdown period. Our observation implies that groundwater is definitely under active interaction with surface waters and thus a quick revival could be observed following the seizing of anthropogenic activities
hydrological parameters were produced to evaluate their self-correlations. The ACFs of all hydrologic parameters showed a very good correlation over the entire time lag, but the PACF revealed that the correlations were good only at time lag Crosscorrelation functions (CCF) were used to evaluate the correlations between the hydrological parameters and the characteristics of seawater intrusion in the coastal aquifer system. The CCFs showed that EC had a close relationship with water pressure and precipitation rather than tide. The CCFs of water pressure with tide and precipitation were in inverse proportion, and the CCF of water pressure with precipitation was larger than that with tide.
and pollution load index values showed that the Vellar estuary was more contaminated by Zn, Pb and Cu than the Coleroon and Tirumalairajan estuaries. This study suggested that heavy metal input to the Vellar estuary should be regulated in the near future, particularly with regard to Zn, Cu and Pb on the basis of threshold effect level and effects range low benchmarks when compared to the other two estuaries. Comparative results with three estuaries suggested anthropogenic input rather than a natural process as a contamination source. This study will help in developing the effective strategies of pollution control and sediment remediation of the estuarine and marine environments.
source of freshwater in the drought-prone Pudukkottai district of Tamil Nadu, India. Therefore, the search for groundwater potential zones (GWPZs) is critical. The present study focuses on the
investigation of potential groundwater zones using geospatial techniques. Geology, land use and land cover, geomorphology, soil, drainage density, lineament, and groundwater levels were obtained from state and non-state associations. ArcGIS version 10.8 was used to create all thematic layers and classified grids. The intensive use of groundwater in arid and semiarid regions is becoming a problem for the public to meet their freshwater needs. The condition of arid and semi-arid regions due to
intensive groundwater extraction has become one of the most important environmental problems for the public. In this study, a powerful groundwater potential mapping technique was developed using
integrated remote sensing data from GIS-AHP. Using AHP techniques, thematic layers for geology, geomorphology, and soil followed by drainage, drainage density and lineament, lineament density, slope, water level, and lithological parameters were created, classified, weighted, and integrated into a GIS environment. According to the results of the study, it is estimated that 14% of the groundwater potential in the study area is good, 49% is moderate and 36% is poor. A groundwater level map
was used to verify the groundwater potential. In addition, the model was validated with a single-layer sensitivity analysis, which showed that geology was the most influential layer and water level was the least influential thematic layer. The low-potential areas identified on the groundwater potential map can be used for further study to identify ideal locations for artificial recharge. In low-potential areas, the groundwater potential map can be used to find ideal locations for artificial
recharge. The water table in the area must be raised by artificial recharge structures such as infiltration basins, recharge pits, and agricultural ponds. Artificial recharge structures such as infiltration basins, recharge pits, and agricultural ponds can be used for groundwater development in low potential zones. The GWPZ map was successfully validated with three proxy data, such as the number of wells, groundwater level, and well density, obtained from well inventory information. The results of
this study will improve our understanding of the geographic analysis of groundwater potential and help policy makers in this drought-prone area to create more sustainable water supply systems.
region at southern part of Tamil Nadu state in India. The presence of excessive radium tracers revealed that the SGD was contributing to Ra desorption from the sediments and enrichment in the coastal waters. We estimated SGD of approximately 0.03–0.59 m3 m2 d1 for the Manapad region and relatively more homogeneous but comparatively less values in the Karameniyar estuary (0.03–0.34 m3 m2 d1). Higher average values of dis-solved inorganic nitrogen (DIN; 43.62 μmol L1) and soluble reactive phosphate (SRP; 1.848 μmol L1) suggested greater influence of SGD on the overall coastal water nutrient budget. This study also indicated simultaneous occurrence of fresh and saline SGD in this region
Gravelly Sand (gS), 5 Silty Sand (zS), 5 Muddy Sand (mS), and 1 Sandy Silt (sZ). Hydraulic conductivity was determined through a falling head test, and ranged from 9.2×10 −5to 2.9×10 −2 cm/sec (0.08 to 25.6 m/day). From breakthrough curves, dispersivity was calculated to be 0.35~3.92 cm. Also, effective porosity and average linear velocity were obtained through the column tracer test, and their values were 0.04~0.46 and 1.06E-04~6.49E-02 cm/sec, respectively. Statistical
methods were used to understand the interrelations among aquifer parameters of hydraulic conductivity, effective porosity and dispersivity. The relation between dispersivity and hydraulic conductivity or effective porosity considered the sample length, because dispersivity was affected by experimental scale. The relations between dispersivity and hydraulic conductivity or effective porosity were all in inverse proportion for all long and short samples. The reason was because dispersivity was in inverse proportion to the groundwater velocity in case of steady hydrodynamic dispersion coefficient, and groundwater velocity was in proportion to the hydraulic conductivity or effective porosity. This study also elucidated that longitudinal dispersivity was dependent on the scale of column tracer test, and all hydrogeological parameters were
low to high values due to the sand quantity of sediments. It is expected that the hydrogeological parameter data of sediments will be very useful for the planning of groundwater management and preservation in the Nakdong River Delta of Busan City, Korea.
parameters based on twenty-two groundwater samples from the coastal industrial city of Tuticorin in Southern India, taken before (10 and 11th February 2020) and during the lockdown (19 and 20th April 2020) periods. The physicochemical parameters compared are pH, total dissolved solids (TDS) and electrical conductivity (EC), ni-trate (NO3),fluoride (F), chromium(Cr), iron (Fe), copper (Cu), zinc (Zn), cadmium(Cd), lead (Pb), arsenic (As), and selenium (Se), and the bacterial parameters aretotal coliforms, fecal coliforms, E. coli,and fecal streptococci.Among the metals, the significant reductions in Se (42%), As (51%), Fe (60%), and Pb (50%)were noticed probably owing to no or very lesswastewater discharges from metal-based industries, seafood-based industries and ther-mal power plants during the lockdown. Reduction inNO3(56%),total coliform(52%) andfecal coliforms(48%) in-dicated less organic sewage from thefishing industries. Contents of Cr, Cu, Zn and Cd, however, remained similar and fluoridedidnot showany change, probably as they were sourced fromrock-water interactions. Similarly, we did not observe alterations inE. coliandfecal streptococci due to no significant change in domestic sewage production during the lockdown. The multivariate analyses aptly illustrated this and the principal component analyses helped to identify the sources that controlled water qualities of the lockdown compared to the pre-lockdown period. Our observation implies that groundwater is definitely under active interaction with surface waters and thus a quick revival could be observed following the seizing of anthropogenic activities
hydrological parameters were produced to evaluate their self-correlations. The ACFs of all hydrologic parameters showed a very good correlation over the entire time lag, but the PACF revealed that the correlations were good only at time lag Crosscorrelation functions (CCF) were used to evaluate the correlations between the hydrological parameters and the characteristics of seawater intrusion in the coastal aquifer system. The CCFs showed that EC had a close relationship with water pressure and precipitation rather than tide. The CCFs of water pressure with tide and precipitation were in inverse proportion, and the CCF of water pressure with precipitation was larger than that with tide.
and pollution load index values showed that the Vellar estuary was more contaminated by Zn, Pb and Cu than the Coleroon and Tirumalairajan estuaries. This study suggested that heavy metal input to the Vellar estuary should be regulated in the near future, particularly with regard to Zn, Cu and Pb on the basis of threshold effect level and effects range low benchmarks when compared to the other two estuaries. Comparative results with three estuaries suggested anthropogenic input rather than a natural process as a contamination source. This study will help in developing the effective strategies of pollution control and sediment remediation of the estuarine and marine environments.