Urbanization and the groundwater budget, metropolitan Seoul area, Korea

The city of Seoul is home to more than 10 million people in an area of 605 km2. Groundwater is abstracted for public water supply and industrial use, and to drain underground facilities and construction sites. Though most tap water is supplied from the Han River, the quantity and quality of groundwater is of great concern to Seoul's citizens, because the use of groundwater for drinking water is continuously increasing. This study identifies the major factors affecting the urban water budget and quality of groundwater in the Seoul area and estimates the urban water budget. These factors include leakage from the municipal water-supply system and sewer systems, precipitation infiltration, water-level fluctuations of the Han River, the subway pumping system, and domestic pumping. The balance between groundwater recharge and discharge is near equilibrium. However, the quality of groundwater and ability to control contaminant fluxes are impeded by sewage infiltration, abandoned landfills, waste dumps, and abandoned wells.