• Journal of Korea Water Resources Association
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• v.45 no.12
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• pp.1259-1273
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• 2012

In this study, a watershed-based surface water and groundwater integrated model, SWAT-MODFLOW was used to quantify the stream flow depletion due to groundwater pumping for the Sinduncheon watershed. Complex water use conditions such as water taken from a stream, sewage disposal release, irrigation from agricultural reservoir, groundwater pumping were considered for simulations. In particular, the model was revised to reflect the effects of reservoir operation and return flow from the used groundwater on streamflow variation. The simulated results showed that the groundwater pumping at current status has induced the decrease of more than 10% in annual average streamflow and 40% in drought flow at the outlet of the Sinduncheon watershed, The simulated results also revealed that the vast water withdrawals at green house areas during winter season have dramatically changed streamflow from April to June. The streamflow depletion was mainly attributed to pumping wells located within the distance of 300 m from the stream for Sinduncheon watershed.

• Journal of the Korean Society of Groundwater Environment
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• v.6 no.2
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• pp.53-58
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• 1999

This study was carried out evaluate to identify water quality and contamination characteristics of the shallow groundwater. and their seasonal variation in the rual area of the Yongin city. Groundwater sample were collected two times (in April and September) from a total of 19 well for domestic water supply. and surface-water samples from six locations. For cations, Ca and Mg predominated. In anion competition. the influence of Cl was obvious in the april samples. However. HCO$_3$ was a major component in the september samples. Electric conductivities and the concentrations of NO$_3$-N in groundwater samples significantly decreased from the april samples to the september samples This indicates a significant seasonal variation in the shallow groundwater composition. When the shallow aquifer is connected to the surface water. then metals sorbed on the stream sediments could occur at nearby wells through the induced recharge. Contaminants at ground surface appeared to be transported to the groundwater system infiltration during the spring melt.

• The Journal of Engineering Geology
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• v.23 no.3
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• pp.293-304
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• 2013

Because the present groundwater law broadly regulates a simple and impractical guideline ignoring aquifer characters and geology, general purpose facilities for protection of groundwater contamination is still considered unsatisfactory to ensure groundwater resources. In recent, there have been growing attempts in the packer development as crucial techniques and devices for groundwater protection. This study investigated the application of packer grouting techniques to contaminated groundwaters of two well sites in the Andong and Yeongi areas, both of which revealed a satisfactory effect with improved water quality: 94% decrease in turbidity at the Andong area and 60% decrease in $NO_3$-N, respectively. Based on aquifer characters including geology, weathering depth, fracture pattern, hydraulic gradient, and the flow path of contaminants, the integrated properties of groundwater contamination should be evaluated and treated with the help of accurate analyses such as bore hole imaging and monitoring data. Packer grouting and casing on well to ensure the useful aquifer free of contaminant are expected to play important role in inhibiting the inflow of contaminants when adequately applied. Therefore it is concluded that these can serve as reliable tools in remediation and protection of contaminated groundwater as well as efficient utilization of groundwater.

• The Journal of Engineering Geology
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• v.18 no.3
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• pp.331-338
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• 2008

A new ground water sampler was developed and evaluated for target depth sampling under most rigorous field conditions. This new concept sampler comprises an air-cylinder, a hypodermic needle and a sampling bottle. Pressurized air or nitrogen gas can be used as a mechanical power source to operate the sampler. The air-cylinder is used to jab the hypodermic needle into the rubber cap of the sampling bottle. The hypodermic needle functions as a pathway to inject groundwater into the sampling bottle. Field test was conducted in a seawater intrusion monitoring well located at Handong district of Jeju Island. Water qualities in this well are periodically changed from the effects of sea water. Water sampling fir the same target depth in this well were tried at various times, and variations in electrical conductivity and pressure at the inside and outside of the sampler were measured using CTD divers. We found that the device could collect water samples only when it was actuated, and the pattern and range of variations in electrical conductivities and pressures measured at the inside and outside of the sampler were nearly identical. These results indicate that water samples using the sampler presented in this study represent correctly water qualities in which the samplings were made at a specific target depth in a well.

• Journal of Wetlands Research
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• v.11 no.3
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• pp.1-8
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• 2009

The groundwater dependent ecosystem associated with a natural stream is the area where mixing and exchange of surface water and groundwater occurs due to large chemical and hydraulic gradients. Surface-groundwater interactions play an important role in biogeochemical processes in groundwater dependent ecosystems and make this area a hydro-ecological hot spot. The objective of this study is to characterize the groundwater dependent ecosystem in a natural stream where nitrate contamination of stream water is observed by means of hydrogeological, chemical, and biological methods. In this study, vertical flow exchange(hyporheic flow) rates between stream and groundwater were estimated based on vertical hydraulic gradients measured at mini-piezometers of various depths. To investigate the biological natural attenuation potential, biological analyses using polymerase chain reaction(PCR)-cloning methods were performed in this study. Results show that the veritical hyporheic water fluxes affect nitrate concentrations and bacterial densities in groundwater dependent ecosystems to some degree. Also, denitrifying bacteria were identified in hyporheic soils, which may support the biodegradation potential of the groundwater dependent ecosystems under certain conditions.

• Journal of agricultural medicine and community health
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• v.48 no.2
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• pp.71-80
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• 2023

목적: 2017년 지하수를 식수로 사용하고 있는 한 장기요양 정신병원(H병원)에서 A형간염 환자가 집단 발병하여 이에 대한 역학조사를 실시하고 조치 결과를 기술하고자 하였다. 방법: 노출기간 동안 H병원의 근로자 및 재원 환자 234명을 대상으로 사례군 조사 디자인으로 역학조사를 실시하였고, IgM, IgG 혈청검사 및 A형간염 바이러스(HAV)에 대한 PCR검사를 시행하였다. 또한 오염원으로 의심되는 지하수, 병원에서 제공되는 식품 및 인근 저수지의 물에서 HAV 검사를 실시하였고, 검출된 HAV는 유전형 검사를 진행하였다. 결과: H병원 환자 및 직원 234명 중 IgG 양성인 168명을 제외한 66명 중 19명이 최종적으로HAV 감염자로 확인되어 감수성자 중 발병률은 28.8%로 나타났다. 환자, 지하수, 식품(석박지) 및 저수지에서 동일 유전형의 HAV가 검출되어 지하수 오염에 의한 집단발병으로 결론 내렸으나, 최초 오염원은 확인하지 못하였다. 유행 종결 선언 이후 지하수에 대한 관리로 염소소독과 UV 조사를 하였음에도 불구하고 6개월 동안 지속적으로 HAV가 검출되어 새로운 관정을 개발하여 상황을 종결하였다. 결론: 본 연구에서 지하수를 식수로 사용하는 장기요양 정신병원에서 지하수 오염에 의한 19명의 HAV 집단발병을 조사하였다. HAV 항체가 없는 대상자 중에서 HAV의 높은 발병률을 확인하였다. 지하수 수질검사에서 바이러스 검사는 포함되어 있지 않기 때문에 지하수가 HAV에 오염시 HAV 집단발병 가능성이 높고 상당기간 지속적으로 검출되기 때문에 지하수에 대한 관리지침에 바이러스 검출을 위한 방안을 추가하고 관련 법을 정비할 필요가 있다.

• Economic and Environmental Geology
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• v.39 no.3 s.178
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• pp.269-284
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• 2006

Aquifer responses to the river stage fluctuations were analyzed between the groundwater level and the river stage in an alluvial aquifer. The auto-correlation and cross-correlation as a time series analysis were applied. Study site is a floodplain in the Mangyeong river. Groundwater levels in each depth representing the silt and sand(SS), gravel and sand(GS), and weathered zone(WZ) layer were monitored. The groundwater levels were more sensitive to the river stage fluctuations than rainfall. Since the river stages are influenced by the gate operations downstream and tide, show periodic patterns, and the correlation coefficients with rainfall is low. Cross-correlation function between groundwater level in each depth do not show any delay time, then response time is very short to each depth. Cross-correlation analysis were performed to estimate the response time of groundwater levels to river stage fluctuations. Groundwater levels respond to the river stage within 30 minutes to 1 hour in wells near the stream. Short time lag between groundwater level and river stage indicates the quick response. A different response time imply the hydraulic inhomogeneity of the site, and a probable high permeability zone between river and aquifer can be inferred. Mangyeong-river in study site is a gaining stream normally, and river stage rising by gate operation or floods makes river water flow into groundwater. The auto-correlation and cross-correlation functions as a time series analysis can be a good tool to interpret the aquifer responses to stream stage fluctuation

• The Journal of Engineering Geology
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• v.30 no.4
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• pp.469-483
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• 2020

The results of long-term groundwater level and quality monitoring can be used not only as the basic data for evaluating the impact of various disasters including climate change and establishing responses, but also as key data for predicting and managing geological disasters such as earthquakes. Some countries use groundwater level and quality monitoring for researches to predict earthquakes and to assess the impacts of the earthquake disaster. However, a few cases in Korea report on individual groundwater quality factors (i.e., dissolved ions) observed before and after the earthquakes, being different from other countries. To establish the abnormality criteria for groundwater quality in Pohang, groundwater samples were collected and analyzed five times from 14 agricultural or private wells existing in Shingwang-myeon and Heunghae-eup. As a result of the analysis, it was found that Ca2+ was the dominant cation in Shingwang-myeon, while Na+ was the dominant cation in Heunghae-eup. The elevated NO3- concentration in Shingwang-myeon is contributed to the agricultural activity in the area. A high concentration of Fe was detected in a well on Heunghae-eup; the concentration exceeded the drinking water standard by nearly 100 times. Relatively higher dissolved ions were observed in the groundwater of Heunghae-eup, and it is considered as the result of the flow velocity difference and water-rock reaction accompanying the difference in bedrock and sediment characteristics. The groundwater of Shingwang-myeon appeared to be most affected by the weathering of granite and silicates, while that of Heunghae-eup was mainly affected by the weathering of silicates and carbonate. The background concentrations (baselines) of groundwater Shingwang-myeon and Heunghae-eup was identified through the survey; however, the continuous monitoring is required to monitor the possible changes and the repeatability of seasonal variation.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.306-306
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• 2022

2015년부터 2019년까지 우리나라에서는 평균 18,521 ha의 경작지에 가뭄피해가 발생하였다. 이 중 평균 11,260 ha는 밭으로 피해의 60% 이상이 밭에서 발생하는 것으로 나타났다. 밭 가뭄 피해는 2016년과 2018년에 크게 발생하였으며, 제주에서 가장 큰 피해가 발생하였다. 또한 강원도, 충청남도의 여러 지역에서 지속적인 피해가 나타났다. 농업 가뭄을 대응하기 위하여 저수지와 지하수 관정 등을 활용하고 있지만, 밭에 대한 구체적이고 체계적인 가뭄 대응 방안은 미비하다. 따라서 본 연구에서는 밭 가뭄에 대한 취약성을 지역별로 평가하고 이를 기반으로 우선 관리지역을 선정하는 방안을 검토하였다. 밭 가뭄 취약성 평가에는 위협 요인, 피해 요인, 해소 요인을 평가 기준을 설정하였다. 밭 가뭄에 대한 위협 요인은 토양 수분량의 정도로 제시할 수 있으며 본 연구에서는 1995년부터 2014년까지 20년간의 강수량, 증발산량 등의 기상 및 토양 자료를 활용하여 분석하였다. 피해 요인은 피해를 입는 밭이 대상으로 행정구역 단위로 평가를 수행함에 따라 행정구역별 밭 비율을 산정하여 활용하였다. 해소 요인은 가뭄 피해를 감소시킬 수 있는 활동을 반영하는 평가 기준으로서 본 연구에서는 저수지와 지하수관정 등 밭 가뭄 저감에 활용할 수 있는 요소를 반영하였다.

• Economic and Environmental Geology
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• v.6 no.4
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• pp.231-233
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• 1973

1. 칠레의 중앙(中央)에 위치(位置)한 리오-아콘카우와 계곡(溪谷)은 600m 심도(深度)의 충적층(沖積層)으로 형성(形成)되어 있음. 2. 계곡(溪谷)의 물관리구역(管理區域)은 4 개구역중(個區域中) 3 개구역(個區域)에 걸쳐 있음. 3. 주요농업관개지역(主要農業灌漑地域)으로서 차카부퀴토에서 태평양연안(太平洋沿岸)까지의 거리(距離)는 113km가 됨. 4. 관개(灌漑)는 9 월(月)부터 5 월(月)사이에 도수로(導水路)와 관정(管井)에 의(依)하나 용수불족(用水不足)으로 저수지(貯水池)와 지하수개발(地下水開發)이 구상(構想)되었음. 5. 디지탈 모델 시험(試驗)은 제(第) 3 관리구역내(管理區域內) 약(約)7km의 거리(距離)의 히주에라스구간(區間)에서 이루어졌었음. 6. 시험결과(試驗結果) 가. 하천(河川)과 대수층(帶水層)과의 관련성(關聯性) 나. 다각도(多角度) 관개용수(灌漑用水)로 인(因)한 하천(河川)과 지하수(地下水) 저류(貯溜)의 효율성(效率性)의 확인(確認). 다. 지하수(地下水) 양수(揚水)에 의(依)한 지하수(地下水) 저류량(貯留量)의 감소(減少)와 라. 하천(河川)에의 재유입수량(再流入水量)이 관개(灌漑) 종료시(終了時)나 직후(直後)에 최대치(最大値)였음. 마. 리오 아콘카우와 계곡(溪谷)에 대(對)한 모델시험(試驗)을 제안(提案)하여 a) 장차(將次) 지하수개발(地下水開發)의 효과(效果)를 분석(分析)하고 b) 제안(提案)된 저수지(貯水池)의 효율(效率)과 c) 수자원(水資源)의 적절(適切)한 이용계획(利用計劃)을 수립(樹立)토록 하였음.