• Journal of Soil and Groundwater Environment
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• v.14 no.6
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• pp.73-77
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• 2009

Two different aquifers with different characteristics developed in the study area - a lower and upper aquifer zone. Nitrate contamination of the lower aquifer zone was likely due to infiltration of nitrate-contaminated groundwater of the upper aquier zone through abandoned groundwater wells. In order to evaluate the feasibility of a preliminary packer designed to prevent nitrate migration through abandoned groundwater wells NO3-N concentrations of the upper and lower part of preliminary packer installed at four sampling sites were measured. Nitrate concentrations of the and lower part of Yechun sinwolri were 10.3 mg/L and 5.0 mg/L, respectively. Yechun eosinri, Yechun jeowooriis, and Andong hoegokri were $NO_3$-N concentrations in the upper (11.3, 11.0, and 14.6 mg/L) and lower (8.8, 1.6, and 8.0 mg/L), respectively. $NO_3$-N contents of all groundwater samples in the lower part after the preliminary packer installation showed 22~85% lower than those of the upper part.

• Economic and Environmental Geology
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• v.13 no.3
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• pp.185-192
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• 1980

The rocks exposed in the investigation area are andesite of Late Cretaceous age, and syenite and aplitic granite of Bulgugsa Series of Early Cretaceous Period, which is intruded in the older andesitic rock. The strike and dip of major joint is $N10^{\circ}$ to $60^{\circ}E$, and $70^{\circ}SE$ to vertical respectively. According to seismic exploration, lower velocity zone, deemed to be fractured and/or crushed zone, is appeared along the gully center of east flank of the area. Test drilling shows that andesite bedrock is mostly very hard, massive, and very fine to medium grained and has almost 100 percent RQD and core recovery. In comparision with andesitic bedrock, intruded syenite cores show that it is highly crush especially at the depth from 55m to 63m.