• 한국환경과학회지
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• 제24권4호
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• pp.471-480
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• 2015

Hydrologic component analysis was conducted to investigate water budget characteristics the Oedocheon watershed, Jeju Island. For this purpose, integrated SWAT-MODFLOW model was applied to this watershed for continuous surface water-groundwater modeling. Pasture and forest-deciduous are the major land use types and these affect general hydrologic component ratio. The spatio-temporal groundwater recharge can be obtained from SWAT and then distributed groundwater recharge can be reproduced by MODFLOW. The groundwater level variation was simulated with distributed groundwater pumping data. The water budget in this watershed was compared with the previous estimated result by Jeju-Do(2013). As this result considered discharge to the coastal side, the discrepancy was found. However, it was found that the overall tendency of both analyses were similar.

• 대한토목학회논문집
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• 제35권6호
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• pp.1259-1267
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• 2015

우리나라에서는 기존에 경험하지 못한 농촌의 지하수 개발문제가 새로운 도전으로 대두되고 있다. 이른바 수막재배(Water Curtain Cultivation : WCC)라 불리우는 동절기 농업활동이 주된 이슈이다. 본 연구에서는 대상지역인 충북 청원군 수막재배지역내 충적대수층의 물수지를 검증하기 위해 3차원 유한차분모형인 MODFLOW를 구축하였다. 세계적인 추세인 학제간 융합방식을 현장규모에 맞게 도입한 지하수 모델링을 수행하였고, 특히 정밀한 지하수 함양량의 입력을 위해 SWAT모형을 이용한 소유역 지하수 함양량을 계산하였으며 양질의 현장자료를 기반으로 모형의 신뢰성을 확보하기 위한 검보정이 진행되었다. 본 연구의 목표는 하천의 보와 배수 시스템과 같은 인위적인 경계조건하에서 지하수 양수가 진행될 때 하천과 대수층의 다양한 상호작용을 모의하는 것이다. 또한 부지내의 누적 물수지의 계절변화를 분석함으로써 지하수 고갈과 회복량을 정량화할 수 있었다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권3호
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• pp.41-50
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• 2015

Hydrogeologic environment of the Mega City such as Seoul, suffers from rapid changes caused by urbanization, construction of underground subway or buildings, and contaminant loading by diverse anthropogenic activities. Understanding the present condition of groundwater environment and water budget is necessary to prevent natural and manmade disasters and to prepare for sustainable water resource management of urban environment. In this study, regional groundwater flow and water budget status of Seoul was analyzed using numerical simulation. Modeling result indicated that groundwater level distribution of Seoul generally followed the topography, but the significant decreases in groundwater level were observed around the subway network. Steady-state water balance analysis showed groundwater recharge by rainfall and leakage from the water supply network was about 550,495 m³/day. Surface water inflow and baseflow rate via Han River and major streams accounted for 799,689 m³/day and 1,103,906 m³/day, respectively. Groundwater usage was 60,945 m³/day, and the total groundwater leakage along the subway lines amounted to 114,746 m³/day. Modeling results revealed that the subway could decrease net groundwater baseflow by 40%. Our study result demonstrated that the subway system can have a significant influence on the groundwater environment of Seoul.

• 한국지하수토양환경학회지:지하수토양환경
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• 제22권4호
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• pp.49-59
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• 2017

This study estimated the nitrogen budget, including gaseous nitrogen oxides ($NO_x$), of South Korea in 2012~2014. The nitrogen budget was classified into three categories: agricultural and livestock, forest, and city. To estimate the nitrogen budget, several input and output parameters were investigated, including deposition, fixation, irrigation, chemical fertilizer use, compost, fuel, denitrification, volatilization, runoff, crop uptake, leaching, and $NO_x$ emissions. The annual nitrogen inputs from 2012 to 2014 were 6,202,828, 6,137,708, and 6,022,379 ton/yr, respectively. The corresponding annual nitrogen outputs were 1,393,763, 1,380,406, and 1,360,819 ton/yr, respectively, signifying a slight decrease from 2012 to 2014. $NO_x$ was the parameter contributing to the nitrogen budget to the greatest extent. The annual ratios of $NO_x$ emissions by vehicles, power plants, and businesses were 0.31, 0.31, and 0.30 in 2012, 2013, and 2014, respectively. A change in government policy that prohibited the disposal of livestock manure and sewage sludge in the ocean from 2012 affected nitrogen budget profile. As a result, the ocean disposal ratio completely diminished, which differs from previous studies.

• 한국환경과학회지
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• 제20권9호
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• pp.1165-1182
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• 2011

The evaluation of potential submarine groundwater is an important research topic for exploring an alternative water resource. Two different approaches, water budget analysis and Rn mass balance method, were employed to investigate the annual variation of submarine groundwater discharge in 2010 at a marine watershed located at the south-eastern part of Korean Peninsula. In order to obtain reliable hydrological data during study period, temporal and spatial variations of rainfall and soil moisture had been collected and hydro-meterological data such as temperature, humidity and wind speed were collected The runoff response was simulated using SCS-CN method with spatial distributions of landuse and soil texture from GIS analysis. Six different methods were used to estimate the monthly variation of evapotranspiration and field measurements of soil moisture were used to account for the infiltration. Comparisons of infiltration and surface runoff between simulation and water balance with measurements showed coincidence. The water budget analysis and Rn mass balance method provide mean daily submarine groundwater as 5.35 and 4.07 $m^3/m/day$ in 2010, respectively.

• 지질공학
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• 제27권3호
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• pp.313-322
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• 2017

본 연구의 목적은 지표수-지하수 통합 모델을 통해 모델 영역과 시설농업단지(밀양들)의 지표수/지하수 유동을 모의하고 모델 영역의 물수지 분석을 통해 지하수 함양량을 산정하는 것이다. 지표수 유동 모델 결과에서는 밀양강 상류(북동쪽)에서 하류(남동쪽)로 약 1~5 m의 수심으로 지표수가 유동하고 있으며, 모델지역 상류의 M01 지점에서는 지표수 유량 관측값과 모델값이 일치하고, 모델지역 하류의 M02 지점에서의 지표수 유량은 1% 정도의 차이를 보인다. 지하수 유동 모델에서는 지하수 심도가 하천에서는 표고와 유사하며 산림 지역으로 갈수록 높아지고, 지하수 양수를 고려한 지하수 심도는 모델값이 관측값보다 1.5 m이내의 범위로 높게 나타난다. 지표수-지하수 통합모델에서는 지하수의 함양 면적이 모델 면적의 90% 정도이고, 지하수 함양량은 $1.92{\times}10^5m^3/day$인 것으로 나타난다. 연평균 물수지 분석에서는 단위 면적당 지하수 함양량이 503.9 mm/year로서 연평균 강우량의 39% 정도로 추정된다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제16권5호
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• pp.82-89
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• 2011

Understanding snowmelt movement to the watershed is crucial for both climate change and hydrological studies because the snowmelt is a significant component of groundwater and surface runoff in temperature area. In this work, a new energy balance budget algorithm has been developed for melting snow from a snowpack at the Central Sierra Snow Laboratory (CSSL) in California, US. Using two sets of experiments, artificial rain-on-snow experiments and observations of diel variations, carried out in the winter of 2002 and 2003, we investigate how to calculate the amount of snowmelt from the snowpack using radiation energy and air temperature. To address the effect of air temperature, we calculate the integrated daily solar radiation energy input, and the integrated discharge of snowmelt under the snowpack and the energy required to generate such an amount of meltwater. The difference between the two is the excess (or deficit) energy input and we compare this energy to the average daily temperature. The resulting empirical relationship is used to calculate the instantaneous snowmelt rate in the model used by Lee et al. (2008a; 2010), in addition to the net-short radiation. If for a given 10 minute interval, the energy obtained by the melt calculation is negative, then no melt is generated. The input energy from the sun is considered to be used to increase the temperature of the snowpack. Positive energy is used for melting snow for the 10-minute interval. Using this energy budget algorithm, we optimize the intrinsic permeability of the snowpack for the two sets of experiments using one-dimensional water percolation model, which are $52.5{\times}10^{-10}m^2$ and $75{\times}10^{-10}m^2$ for the artificial rain-on-snow experiments and observations of diel variation, respectively.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2002년도 학술발표회 논문집(II)
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• pp.1034-1040
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• 2002

A rainwater recharge model, which is combined with the quasi-three dimensional unconfined groundwater flow, is proposed in the present paper. The water budget in the catchments of the planned new campus of Kyushu University is evaluated by the present method that calculates both the surface runoff and groundwater flow simultaneously. The results obtained in the present study reveal that the calculated monthly and annual runoff discharges agree reasonably well with the observed discharge. Combining the rainwater recharge model, the two-phase groundwater flow equation is numerically solved f3r the entire area including the low land where the salt water intrusion is observed. The calculated depth of the salt-fresh interface agrees reasonably well with the observed ones at several cross sections. On the other hand, however, it is found that the calculated water budget remains uncertain because of lack of information on the accurate potential evapotranspiration including rainfall interception. In conclusion, however, it is found that the proposed method is applicable for the areas where the horizontal flow is dominant and the interface is assumed to be sharp.

• 자원환경지질
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• 제44권1호
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• pp.49-57
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• 2011

금강유역의 지하수계 내 물수지 분포를 파악하기 위하여 지하수 물수지 분석을 수행하였다. 유역의 2002년에서 2006년까지 강우량, 하천 유출량, 증발산량 및 상수도 유입량, 댐 저류변화량을 산출하였고 이 값들을 바탕으로 유역 내 유출입량을 고려하여 금강유역 내 물수지 잔류량을 산정함으로써 년도 및 소 유역별 수자원의 분포 양상을 검토하였다. 분석 결과 2003년에 가장 많은 강우량이 기록되었고, 2006년의 강우량이 가장 적었으며 강우량 대비 유출률은 5개년 평균 60.44%로 산출되었다. 년도 별 증발산량은 큰 편차를 보이지 않았으나, 주로 금강 하류 지역에서 다량의 증발산이 산출되었다. 산정된 값들을 토대로 물수지를 분석한 결과 각 년도 별 유역 내 물수지 잔류량은 2002년 133.36, 2003년 77.64, 2004년 -19.40, 2005년 -82.25, 2006년 -128.07 mm로 시간의 흐름에 따라 유역 내에 잔류되어있는 수자원의 총량이 적어지는 양상을 나타내었다. 또한 금강 유역 물수지 잔류량은 대체로 금강의 상류와 금강 본류인 공주 부근에서 많이 산출 되었고, 청주 인근의 미호천 유역과 논산이 위치한 금강 하류 유역으로 갈수록 유역 내 잔류량이 적어지는 것으로 분석되었다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2004년도 학술발표회
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• pp.691-695
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• 2004

In recent years, mary studies for efact estimation of groudwater recharge has been performed. They can be categorized into three groups : analytical method by means of groundwater recession curve, water budget analysis based on watershed, and the method using groundwater model. Since groundwater recharge rate shows the spatial-temporal variability due to hydrogeological heterogeneity, existing studies have various limits to deal with these characteristics. The method of estimating daily recharge rate with spatial-temporal variation based on rainfall-runoff model is suggested in this study for this purpose. This method is expected to enhance existing indirect method by means of reflecting climatic conditions, land use and hydrogeological heterogeneity.