Chung-Mo Lee

A Comparative Study of Groundwater Vulnerability Assessment Methods: Application in Gumma, Korea

In the present study, several groundwater vulnerability assessment methods were applied to an agricultural area of Gumma in Korea. For the groundwater intrinsic vulnerability assessment, the performance of DRASTIC, SINTACS and GOD models was compared and an ensemble approach was suggested. M-DRASTIC and multi-linear regression (MLR) models were applied for the groundwater specific vulnerability assessment to nitrate of the study site. The correlation coefficient between the nitrate concentration and M-DRASTIC index was as low as 0.24. The result of the MLR model showed that the correlation coefficient is 0.62 and the areal extents of livestock farming and upland field are most influential factors for the nitrate contamination of groundwater in the study site.

Characterizing Hamangun Dohangri 6 th Tumulus Using Ground Survey

Hamangun Dohangri tumulus was characterized by using geological, geophysical, and geotechnical surveys in terms of the shape of the tombs, origin and geotechnical properties of tomb materials, safety of grave mound and burial chamber. The bedrock (Haman Formation sedimentary rock) forming the ground of the tomb, is weathered such that men can excavate the ground. The mound tomb is classified into soil part and rock part by low resistivity and high resistivity, respectively, through electrical resistivity survey. The burial chamber is mostly made by Haman Formation while some part is composed of granitic rock that is distributed in the most southern district of the study area. According to soil tests, the soil part of mound tomb shows low water content, low pore ratio, and proper unit weight that indicate highly compacted material. Additionally, the mound tomb is safe because the strength of the rock part of the mound tomb exceeds that of general rock.

Characteristics of South Korea's Geothermal Water in Relation to Its Geological and Geochemical Feature

The volcanic type of geothermal water is linked intimately to active or potentially active volcanoes and takes place near the plate boundaries. In contrast to the volcanic type, the geothermal water in Korea has a non-volcanic origin. Korea’s geothermal water is classified into the residual magma (RM) type and deep groundwater (DG) type according to the criterion of 35 o C. This study reviewed the relationship between the physical and chemical features of the 281 geothermal water sources in South Korea in terms of the specific capacity, water temperature, and chemical compositions of two different basements (igneous rock and metamorphic rock) as well as the geological structures. According to the spatial relationship between the geothermal holes and geological faults, the length of the major fault is considered a key parameter determining the movement to a deeper place and the temperature of geothermal water. A negligible relationship between the specific capacity (Q/s) and temperature was found for both the RM type and DG type with the greater specific capacities of the RM- and DG-igneous types than the RM- and DG-metamorphic types. No relationship was observed between Q/s and the chemical constituents (K + , Na + , Ca 2+ , Mg 2+ , Zn 2+ , Cl � , SO4 2� , HCO3 � , and SiO2) in the DG-igneous and DG-metamorphic types. Furthermore, weak relationship between temperature and chemical constituents was found for both the RM type and DG type.