Understanding groundwater systems and system responses to external stimulations through the long-term monitoring

A total of 335 monitoring stations (497 of monitoring wells), organized the National Groundwater Monitoring Network (NGMN), has been established at 117 watersheds in Korea since 1995, and water-level, temperature and electrical conductivity (EC) have been recorded by every hour to every six hours. Basically the monitoring stations are implemented with two wells for alluvium and bedrock aquifer at depths of 6.1 m and 71.6 m, respectively. Using these long-term monitoring data, we have tried to understand the groundwater systems in Korea and the system responses to external stimulations such as precipitation events, earthquakes, and groundwater over-exploitation. In this study, water-level, temperature and EC data were analyzed for the Han-river, Geum-river, Yeongsan-Seomjin-river and Nakdong-river basins, Korea, for the three years from 2010 to 2012. Precipitation data were obtained from the automatic weather systems of Korea Meteorological Administration (KMA) at the same period of time. These data will be used to assess the relationship between groundwater and precipitation using the Genetic Mapping Tools (GMT) and Fast Fourier Transform analysis, and to calculate the recharge rate each rainfall event. At each monitoring stations, groundwater system will be defined based on the water-level responses to precipitation events, and their response rate will be calculated for specific amount of precipitation. Later, these data will be used for the calculation of sustainability of the watershed for long-term water resource management.