Recharge and spatial distribution of groundwater hydrochemistry in the Geum River basin, South Korea

Groundwater in the Geum River basin is a major agricultural and domestic water resource. In the present study, we collected 128 groundwater samples from four candidate regions (KS, KJ, NS, and BO) for hydrochemical analyses to identify large-scale groundwater distribution. Only 5.5% of samples showed natural background levels of NO3-N and Cl, whereas about 65% of samples reflected the influence of external pollutants according to drinking water standards. Levels of tritium (H-3) in groundwater in the BO region indicated rapid recharge over a uniform time span (2.88 +/- 0.43 TU). The hydrochemical properties of water samples collected in this study suggest a sustainable water supply in the Geum River basin.