Causes of the changes in groundwater levels at Daegu, Korea: the effect of subway excavations

The paper presents the investigations into the decline in groundwater level recorded at national groundwater monitoring stations in Daegu Metropolitan City, Korea. The effect of precipitation and the pumping of wells in nearby areas was considered, but it was concluded that the main influence was the construction of a 1,110 m subway line some 250 m from the monitoring station. This was checked using a simplified conceptual model, which gave results consistent with field observations and suggested that groundwater levels may be depressed for a period of 10 years or more.