Geostatistical techniques to evaluate groundwater contamination and its sources in Miryang City, Korea

Venkatramanan, Senapathi,Chung, Sang Yong,Kim, Tae Hyung,Kim, Byung-Woo,Selvam, Sekar Springer-Verlag 2016 Environmental Earth Sciences Vol.75 No.11

<P>Miryang City has high seasonal variations in precipitation and small number of surface reservoirs. It uses much groundwater for living and irrigation purposes. This study delineates the characteristics and the controlling factors of groundwater contamination using multivariate statistical analyses and kriging method. GIS spatial maps showed that groundwater contamination was occurred mainly in the central and southern areas and partly in the southwestern and northern areas. It may be attributed to the effect of residual saline water, irrigation, livestock wastes and municipal sewage. Ca-HCO3 water type was the most predominant in the groundwater of the study area. Ca-Cl-2, Na-Cl and Na-HCO3 water types were dominant in order, due to the influence of residual saline water and anthropogenic activity. Geostatistical techniques were applied to classify the groundwater samples and to identify the geochemical processes and sources controlling the groundwater geochemistry. The scatter diagrams of factor score versus topographic elevation and groundwater level represented that groundwater was influenced by saline water and NO3-N at <85 m of well elevation. The areas and degrees of groundwater contamination were understood from the spatial distribution maps of factor scores versus groundwater level. Chemical characteristics and contamination sources of groundwater were identified from cluster and factor analyses. Kriging method was useful for the production of distribution maps showing the degree and location of groundwater contamination. Thus, geostatistical techniques including factor analysis, cluster analysis and kriging method played very important roles in evaluating groundwater contamination and identifying contamination sources.</P>

지하수 자료를 이용한 경주지진(2016년 9월) 고찰

정상용,( Venkatramanan Senapathi ) 대한지질공학회 2016 대한지질공학회 학술발표회논문집 Vol.2016 No.2

The Characteristics of Hydrogeological Parameters of Unconsolidated Sediments in the Nakdong River Delta of Busan City, Korea

Elyorbek Khakimov,정상용,Venkatramanan Senapathi,HUSSAM ELDIN ELZAIN OSMAN ELZAIN,손주형 한국지하수토양환경학회 2017 지하수토양환경 Vol.22 No.3

This study dealt with the characteristics and the interrelations of hydrogeological parameters such as hydraulic conductivity, dispersivity and effective porosity of unconsolidated sediments for providing the basic data necessary for the planning of the management and preservation of groundwater quality in the Nakdong River Delta of Busan City, Korea. Groundwater quality in this area has been deteriorated due to seawater intrusion, agricultural fertilizer and pesticide, industrial wastewater, and contaminated river water. The physical properties (grain size distribution, sediment type, sorting) and aquifer parameters (hydraulic conductivity, effective porosity, longitudinal dispersivity) were determined from grain size analysis, laboratory permeability test and column tracer test. Among 36 samples, there were 18 Sand (S), 7 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 × 10−5 to 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.

Time series analyses of hydrological parameter variations and their correlations at a coastal area in Busan, South Korea

Chung, Sang Yong,Senapathi, Venkatramanan,Sekar, Selvam,Kim, Tae Hyung Verlag Heinz Heise 2018 Hydrogeology journal Vol.26 No.6

부산 낙동강 델타층의 지층구조와 지하수 환경

정상용(Sang Yong Chung),Senapathi Venkatramanan,Rajesh Rajendran,김민지(Minji Kim) 대한지질학회 2016 대한지질학회 학술대회 Vol.2016 No.10

The Characteristics of Hydrogeological Parameters of Unconsolidated Sediments in the Nakdong River Delta of Busan City, Korea

Khakimov, Elyorbek,Chung, Sang Yong,Senapathi, Venkatramanan,Elzain, Hussam Eldin,Son, JooHyeong Korean Society of Soil and Groundwater Environment 2017 지하수토양환경 Vol.22 No.3

This study dealt with the characteristics and the interrelations of hydrogeological parameters such as hydraulic conductivity, dispersivity and effective porosity of unconsolidated sediments for providing the basic data necessary for the planning of the management and preservation of groundwater quality in the Nakdong River Delta of Busan City, Korea. Groundwater quality in this area has been deteriorated due to seawater intrusion, agricultural fertilizer and pesticide, industrial wastewater, and contaminated river water. The physical properties (grain size distribution, sediment type, sorting) and aquifer parameters (hydraulic conductivity, effective porosity, longitudinal dispersivity) were determined from grain size analysis, laboratory permeability test and column tracer test. Among 36 samples, there were 18 Sand (S), 7 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 $9.2{\times}10^{-5}$ to $2.9{\times}10^{-2}cm/sec$ (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.

Application of Adaptive Neuro-fuzzy and Artificial Neural Network for the Assessment of Groundwater Contamination Vulnerability in Miryang City, Korea

( Hussam Eldin Elzain ),( Sang Yong Chung ),( Venkatramanan Senapathi ),( Kye-hun Park ) 대한지질공학회 2019 대한지질공학회 학술발표회논문집 Vol.2019 No.2

This study used the artificial intelligence methods of adaptive neuro-fuzzy (ANFIS) and artificial neural networks (ANN) to evaluate the groundwater contamination vulnerability in Miryang City, Korea. The original DRASTIC method for the evaluation has been using 7 factors of Depth to water, net Recharge, Aquifer materials, Soil media, Topography, Impact of vadose zone and Hydraulic Conductivity. In this study, the factor of land use was added to the original DRASTIC method because large agriculture fields extensively exist in the alluvial plain of the study area in addition to the industrial, urban, livestock and landfill areas. The models used 95 data of nitrate-nitrogen (NO3-N) concentrations from monitoring groundwater wells for training and validation purposes of ANFIS and ANN. The superiority of the two methods was examined by the graphical and statistical methods. The graphical method showed the correlations between ANN Index and ln (NO3-N), and between ANFIS Index and ln (NO3-N). The determination coefficients were 0.65 for ANN and 0.84 for ANFIS, respectively. The root means square errors (RMSE) of ANN and ANFIS were 0.071 and 0.059, respectively. Thus, ANFIS was more superior to ANN through graphic and statistical evaluations. By the level of importance based on the sensitivity analysis of the ANN model, hydraulic conductivity, land use and impact of the vadose zone were the most important factors in the order affecting the groundwater vulnerability in the study area.

개선된 DRASTIC 기법과 퍼지기법을 이용한 밀양지역 지하수오염 취약성 평가

정상용,후삼 엘딘 엘자인,벤카트라마난 세나파티,박계헌,권해우,유인걸,오해림,Chung, Sang Yong,Elzain, Hussam Eldin,Senapathi, Venkatramanan,Park, Kye-Hun,Kwon, Hae-Woo,Yoo, In Kol,Oh, Hae Rim 한국지하수토양환경학회 2018 지하수토양환경 Vol.23 No.4

The purpose of this study is to improve the Original DRASTIC Model (ODM) for the assessment of groundwater contamination vulnerability on the GIS platform. Miryang City of urban and rural features was selected for the study area to accomplish the research purpose. Advanced DRASTIC Model (ADM) was developed adding two more DRASTIC factors of lineament density and landuse to ODM. The fuzzy logic was also applied to ODM and ADM to improve their ability in evaluating the groundwater contamination vulnerability. Although the vulnerability map of ADM was a little simpler than that of ODM, it increased the area of the low vulnerability sector. The groundwater vulnerability maps of ODM and ADM using DRASTIC Indices represented the more detailed descriptions than those from the overlap of thematic maps, and their qualities were improved by the application of fuzzy technique. The vulnerability maps of ODM, ADM and FDM was evaluated by NO3-N concentrations in the study area. It was proved that ADM including lineament density and landuse factors produced a more reliable groundwater vulnerability map, and fuzzy ADM (FDM) made the best detailed groundwater vulnerability map with the significant statistical results.