• Journal of Korea Water Resources Association
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• v.49 no.11
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• pp.923-930
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• 2016

This study was to evaluate the stream depletion from groundwater pumping in shallow aquifer using the Hunt's analytical solution (2009) which considers a two-layer leaky aquifer-stream system. From the total 2,187 cases of simulations with combinations of various aquifer and stream properties, the streamflow depletion rates divided by the groundwater pumping rate showed the low values when the stream depletion factor (SDF) is higher than 1,000-10,000, and was more sensitive to the aquitard hydraulic conductivity than the streambed hydraulic conductivity. The comparison of the Hunt's solution (2009) with the Hunt's solution (1999) of a single layer aquifer indicated that the maximum difference between the dimensionless stream depletions calculated by using both solutions is above 0.3, and the stream depletion is significantly affected by the hydraulic properties of the $2^{nd}$ layer as the SDF of the first layer increases. The Hunt's solution (2009) was applied to the real shallow groundwater well that is located in Chunju-Si, and the results revealed that the groundwater pumping has significant effects on streamflow in a short period of time, showing that the dimensionless stream depletion exceeds 0.8 within a few days. It was also found that the shallow groundwater pumping effects on stream depletion are highly dependent on the stream-well distance for the locations with high hydraulic diffusivity of $1^{st}$ layer and low vertical leakance between $1^{st}$ and $2^{nd}$ layers.

• Economic and Environmental Geology
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• v.48 no.2
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• pp.131-145
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• 2015

Thermodynamic prediction of weathering products from primary aquifer minerals around underground disposal sites was investigated. The distribution of solubility quotients for kaolinite-smectite reactions showed the trend of reaching at equilibrium with Ca-, Mg-, and Na-smectite for deep groundwaters in granitic aquifers. The values of $10^{-14.56}$, $10^{-15.73}$, and $10^{-7.76}$ were proposed as equilibrium constants between kaolinite and Ca-, Mg-, and Na-smectite end members, respectively. On stability diagrams, most of deep groundwaters were located at equilibrium boundaries between stability fields of kaolinite and smectites or on stability fields of smectites and illite. Shallow groundwaters in basic rock aquifer were plotted at the same stability areas of deep granitic groundwaters on stability diagrams. The results indicated that the primiary mineralogical composition may be important to predict weathering products in deep aquifers.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.601-604
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• 2003

방사성폐기물 처분 연구의 일환으로 화강암지역내 500m 심도의 심부시추공이 착정되었으며, 다중패커시스템이 설치되어 장기적으로 심도별 지하수의 수리 및 화학특성이 모니터링 되고 있다. 지하수 수두값의 심도별 특성은 천부에서 심도 250m까지는 대체로 감소하는 경향을 보이며 250m이하에서 500m 심도까지는 증가하는 경향을 보여준다. 각 심도구간에서의 지하수 수두값은 장기적으로 일정한 값을 보여주지만, 장마기간동안 집중적으로 모니터링된 결과에 따르면 심도 370m 상부에서는 지하수 함양변화에 따라 지하수 수두가 변화되는 반면, 심부구간에서는 지하수 함양변화에 대하여 영향을 받지 않음을 보여준다.

• Journal of Korea Water Resources Association
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• v.35 no.1
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• pp.97-108
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• 2002

The use of land at the time of investigation of groundwater quality in the rapidly urbanized Bu-chon city is classified into 5 categories based on the change process of land use. The difference in groundwater quality according to the land use and its usage period is tested by non-parametric statistical procedures. The seven constituents of water quality with the highly frequent detection in the area for this study are used for the statistical test. The shallow groundwater quality within the areas of the same land use at the time of investigation varies significantly according to the period of land usage. The concentration of KMnO$_4$consumed and hardness is significantly higher in the old residential area (of more than 20 years old) than in the younger one (of less than 10 years old). The quality of the shallow groundwater is also significantly different among the three categories with the similar period of land usage (of more than 15 years old). The concentration of No$_3$-N, hardness and total solid is significantly higher in the residential area than in the agricultural one (namely, the area used as paddy fields 2 to 5 years ago). The median concentration of these constituents is 2.2 to 3.8 times higher in the residential area than in the agricultural one. The concentration of NO$_3$-N, KMnO$_4$, consumed and Cl is significantly higher in the industrial area than in the agricultural one. The median concentration of these constituents is 5.5 to 18 times higher in the industrial area than in the agricultural one. The concentration of KMnO$_4$consumed is significantly higher in the industrial area than in the residential area. The median concentration of these constituents is 12 times higher in the industrial area than in the residential one. The spatial distribution of shallow groundwater quality in the rapidly urbanized area is closely related to the period of land usage as well as the land use, which is presumed to be attributed to the difference in the concentration and leakage rate of the contaminants leaking from damaged sewer into shallow groundwater.

• The Journal of Engineering Geology
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• v.14 no.1
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• pp.1-20
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• 2004

This study focuses on the hydrochemical characteristics in goundwater affected by reclamation at 2000 Sydney Olympic Games site, Sydney, Australia. The Olympic Games site can be divided into three areas, i.e. reclaimed areas; landfill areas and non-infilled areas. In the current work, 'reclaimed areas' were previously estuarine, and were filled with waste materials and are now above present high tide level, whereas 'landfill areas' are areas where deposition of waste materials occurred above sea level. No deposition of waste took place in 'non-infilled areas'. This study was also evaluated by three different types such as deep boreholes, shallow boreholes and standpipes. The hydrochemishy of groundwaters in reclaimed and non-in-filled areas is characterized by Mg- and Ca-enrichment, whereas groundwaters in landfill areas are elevated in K and NO₃. Na, K and Mg are the dominant cations in groundwater from reclaimed areas and Na and K are the dominant cations in groundwater in landfill areas. Na and Mg are the dominant cations in groundwater in deep boreholes, whereas Na and K are the dominant cations in groundwater in shallow boreholes and standpipes. There is no distinct trend in heavy metals with electrical conductivity in the groundwater between the re-claimed, landfill and non-infilled areas. Fe and Mn in landfill areas with respect to reclaimed areas and non-infilled areas show a distinct increase in concentration with declining pH. Mean electrical conductivity values in the deep and shallow boreholes are higher than that of standpipes, but the minimum and maximum value of electrical conductivity in groundwater in standpipes shows remarkably different value, probably due to perched pond. There is no correlation between Cu, Pb, Zn, Cr concentrations in groundwater with pH, from deep boreholes, shallow boreholes and standpipes, except for Fe and Mn, which demonstrate increasing concentrations with declining pH. The results revealed a close association between elevated concentrations in groundwater and the presence of fill materials at the site. Trace metals teachability from re-claimed soils adjacent to estuary plays a significant role in determining their potential environmental risk to surrounding environment.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.100-104
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• 2006

58개 기상관측소에서 최근 22년간 측정된 천부 지중온도 자료와 국가지하수관측망의 169개 암반 및 95개 충적층 관측소에서 측정된 지하수 온도 자료를 이용하여 다음과 같은 연구를 수행하였다. 첫째, 우리나라 대기, 지면 및 지하수의 연평균 온도분포도를 제시하였으며, 다중회귀분석을 통하여 대기 및 지면온도를 추정할 수 있는 회귀식을 산정하였다. 둘째, 지면온도에 영향을 미치는 기상 요소로서 일사량, 지구복사, 강수량 및 적설량 자료를 분석하였다. 마지막으로 열전도 모델을 이용하여 심도별 열확산계수를 산정하고 통계 자료를 제시하였다.

• Economic and Environmental Geology
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• v.40 no.6
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• pp.833-841
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• 2007

The groundwater heat pump system(GWHP) is one of the most efficient ground source heat pump system(GSHP) which uses low grade and shallow geothermal energy for cooling and heating purpose. The GWHP system shall be designed properly based on peak block load performance and optimum pumping rate of groundwater comparable to ground coupled heat pump system(GCHP). The optimum pumping rate depends on groundwater temperature at a specific site, size of plate heat exchanger, and total head loss occurred by whole system comprising pumps and pipings. The required optimum flow rates of the system per RT are ranged from 3.8 to 9.8lpm being less than the typical building loop flow of 9.5 to 11.4lpm.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.215-218
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• 2002

The purposes of this research are to identify the source and the extent of contamination of nitrate in groundwater in a typical agricultural area. The study area has many livestock raising facilities, rice paddies and grape farms. In order to identify the hydrogeological character, we sampled groundwater and surface water in 27 locations and performed chemical analyses. Nitrate-nitrogen is the major contaminant in this area. Approximately 32 ~ 42% of groundwater samples are over the drinking water limit(10 mg/L) and 77% estimated to be entered from artificial sources. The nitrogen isotope analysis indicates animal waste being the major source of nitrate in water samples. Not only presently operating livestock facilities but also abandoned ones influence groundwater quality for a long time.

• Economic and Environmental Geology
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• v.36 no.5
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• pp.329-338
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• 2003

The purpose of this study is to identify the temporal and spatial variation of stable isotopic compositions of surface waters and shallow ground waters at a local watershed(100$Km^2$) near the Muju area. For oxygen and hydrogen isotope analysis, water samples were collected from 19-22 sites during August, October 2001, through April 2002. Seasonal variation in the isotopic compositions of surface waters was clearly shown. However, the degree of such isotopic variation was highly attenuated in shallow ground waters because of mixing with preexisting ground waters. Isotope values of surface waters and ground waters were very similar in each season, indicating that precipitation/ground water/surface water interactions were very active and continuous in the watershed. Stable isotopic ratios of surface waters in the study area were lighter than those of the downstream reach of Geum River on south, indicating “latitude effect”. Both “altitude effect” and “amount effect” were also shown in the stable isotopic ratios of surface waters in the study area as well as seasonal variation of stable isotopes.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.389-392
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• 2005

Visual MODFLOW를 이용하여 서울지하철 7호선 706공구에 계획된 터널 굴착에 따른 지하수 유동계의 변화를 모사하였다. 경계조건은 모델 영역 내 하천(굴포천)의 경우 일정수두경계, 터널 굴착 구간의 경우 $0.39{\sim}0.58m^2/day$의 전도계수를 갖는 배수경계(Drain), 터널 개착구간은 Inactive cell이 존재하는 일정수두경계 조건으로 설정하였다. 모델 보정은 현장시험을 통해 구해진 수리상수는 일정하게 유지하고 함양률을 변화시키면서 실시하였으며, 정류모사를 반복 수행하여 최적의 함양률(150 mm/yr)을 결정하였다. 모사 결과 터널 구간으로의 지하수 유입량은 굴착 및 개착 완료 시 $623m^3/day$, 터널 완공 후 정류상태의 경우 $584m^3/day$인 것으로 나타났다. Zone Budget을 이용한 유출입량 분석 결과 정류 상태 시 터널 내로 유입되는 지하수의 69%는 터널 인근 하천수의 유입에 기인하며, 나머지 31%는 주변 지역에서 함양된 지하수에 의한 것으로 나타났다.