Impact of land-use/cover changes due to urbanization on groundwater recharge by precipitation in South Korea

Due to urbanization, land use and cover change (LUCC) are considered one of the concerns in groundwater recharge by precipitation because urban development increases impermeable surfaces. The main objective of this study is to investigate the effects of LUCC on groundwater recharge by precipitation in South Korea. Ten monitoring wells were selected based on a significant difference in LUCC using Arc-GIS software. Then lag-time between precipitation and groundwater level response was estimated based on correlation coefficients computed from cross-correlation function (CCF) and moving average (MA) for 3 years before and after LUCC. As a result of the estimated lag-time, monitoring wells were classified into two groups: group Ⅰ (n = 3) with more than 30% increase in the impermeable surface and group Ⅱ (n = 7) with less than 30% increase in the impermeable surface. Group I showed a significant increase in lag-time computed from MA (28 to 127 days) and CCF (6 to 19 days), while group II showed no significant difference in lag-time. The results of this study indicate that groundwater recharge is regulated by the occurrence of the impermeable surface, interrupting direct groundwater recharge from rainwater infiltration.