Abstract

Water quality of Oseepchun, Dogye area, was investigated quantitatively for its origin and hydrogeochemistry in relation to the influence of groundwater. Groundwater appears to be the principal source of Oseepchun from the water-quality monitoring data including redox potentials, composition of dissolved ions and their correlations, hydrogen and oxygen stable isotopic ratios, and the distribution and occurrence of contaminants. Water-quality type of the surface water was grouped by the water-rock interactions as Ca-HCO₃ type originated from carbonated bedrocks in the Joseon Supergroup, (Ca, Mg)-SO₄ type related with dissolution of surfide minerals in coal beds of Pyeongan Supergroup, and (Ca, Mg)-(HCO₃, SO₄) type of the mixed one. Locally water pollution occurs by high SO₄ from mine drainage and NO₃ from waste-treatment facility. Intensive precipitation in summer has no effect on the water type of Oseepchun, but increases the inflow of nitrate and chloride originated from land surface. Results of this study direct that groundwater-surface water interaction is intimate, and thus surface-water resource management should begin with groundwater characterization.

Keywords Oseepchun, groundwater-surface water interaction, hydrogeochemistry, water-rock interaction, stable isotopes