• Journal of Korea Water Resources Association
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• v.55 no.12
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• pp.1021-1030
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• 2022

Currently, South Korea implements water resources management policies focusing on integrated water quantity, quality and hydro-ecology management. In particular, rehabilitation of natural rivers has become a major issue. As for reservoir operation during non-flood season, efforts have been made continuously to apply the Deficit Supply Method that can maximize water supply to address droughts and increase in water demand. When Deficit Supply Method is applied, the water supply capacity of reservoir can be maximized. However, downstream water flow would remain constant. In consideration that a natural stream, a long-time-created hydro-ecology, can be significantly influenced by flow variability, the Deficit Supply Method-based reservoir operation can generate effective water supply. Still, it may trigger adverse effects from the aspects of natural rehabilitation and hydro-ecology recovery. The main objective of this study is to analyze impacts on downstream flow duration through reservoir simulation by comparing the Firm Supply Method, the Deficit Supply Method and the Selective Deficit Supply Method, and examining each method's effects on reservoir operation. This study found that the Firm Supply Method could maintain water flow variability, but could not maximize water supply capacity. When the Deficit Supply Method was applied, water supply capacity could be increased while remaining vulnerable regarding water flow variability, as a difference between average flow and low flow was negligible at downstream. In comparison, the Selective Deficit Supply Method was found to sustain time-based reliability at 95% or higher, whereas downstream flow duration could be maintained at a level similar to the level generated by the Firm Supply Method.

• Korean Journal of Ecology and Environment
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• v.55 no.4
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• pp.320-329
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• 2022

Urban areas in watersheds increase the impervious surface, and agricultural areas deteriorate the water quality of rivers due to the use of fertilizers. As such, anthropogenic land use affects the type, intensity and quantity of land use and is closely related to the amount of substances and nutrients discharged to nearby streams. Riparian vegetation reduce the concentration of pollutants entering the watershed and mitigate the negative impacts of land use on rivers. This study analyzes the data through correlation analysis and regression analysis through point data measured twice a year in spring and autumn in 21 selected damaged tributary rivers within the Han River area, and then uses a structural equation model to determine the area land use. In the negative impact on water quality, the mitigation effect of riparian vegetation was estimated. As a result of the correlation analysis, the correlation between the agricultural area and water quality was stronger than that of the urban area, and the area ratio of riparian vegetation showed a negative correlation with water quality. As a result of the regression analysis, it was found that agricultural areas had a negative effect on water quality in all models, but the results were not statistically significant in the case of urban areas. As a result of the model estimated through the structural equation, BOD, COD, TN, and TP showed a mitigation effect due to the accumulation effect of river water quality through riparian vegetation in agricultural areas, but the effect of riparian vegetation through riparian vegetation was found in urban areas. There was no These results were interpreted as having a fairly low distribution rate in urban areas, and in the case of the study area, there was no impact due to riparian forests due to the form of scattered and distributed settlements rather than high-density urbanized areas. The results of this study were judged to be unreasonable to generalize by analyzing the rivers where most of the agricultural areas are distributed, and a follow-up to establish a structural equation model by expanding the watershed variables in urban areas and encompassing the variables of various factors affecting water quality research is required.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.spc
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• pp.23-29
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• 2022

To detect harmful chemical substances in seawater, we fabricated a prototype sensor and evaluated its performance. The prototype sensor consisted of a detector, housing, and driving circuit. We built the detector by printing an Indium-Tin-Oxide (ITO) nanoparticle film on a flexible substrate, and it had two detection parts for simultaneous detection of temperature and HNS concentration. The housing connected the detector and the driving circuit and was made of Teflon material to prevent chemical reactions that may affect sensor performance. The driving circuit supplied electric power, and display measured data using a bridge circuit and an Arduino board. We evaluated the sensor performances such as response (ΔR), the limit of detection (LOD), response time, and errors to confirm the specification.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.465-465
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• 2023

집중호우시 농경지에서 발생하는 흙탕물은 수질 및 수생태계를 오염시키며, 환경오염에 따른 사회·경제적 문제를 지속적으로 초래하고 있다. 정부와 지자체는 흙탕물 발생이 심각한 지역을 '비점오염원관리지역'으로 지정·고시하여 흙탕물 저감사업을 추진하였으나, 뚜렷한 성과를 나타내지 못하고 있는 실정이다. 최근 정부의 흙탕물 저감사업은 저감시설 설치 등과 같은 구조적 방법에서 발생원관리 중심으로 패러다임이 전환되고 있다. 농경지에서 발생하는 비점오염원의 발생원관리를 위해서는 주민들의 적극적인 참여가 필수적이나, 아직까지 주민들의 비점오염원에 대한 인식이 낮은 수준에 머무르고 있다. 따라서, 본 연구에서는 주민참여 거버넌스를 구축하여 주민들의 인식을 개선하고, 주민들의 참여를 유도하여 농촌지역 실정에 맞는 주민참여형 농업비점오염 관리의 기반을 마련하고자 하였다. 연구대상지는 강원도 비점오염원관리지역인 가아지구 내 강원도 인제군 인제읍 가아2리 마을일원으로, 본 연구의 참여농가는 총 10농가, 참여농지 면적은 21.81 ha이다. 참여농가를 대상으로2022년 10월 9일, 10월 16일, 10월 23일 총 3회에 걸쳐 주민 교육을 실시하였으며, 주기적인 설문조사를 통해 교육 진행에 따른 주민 인식 변화를 측정하였다. 설문조사는 교육참여자를 대상으로 3회 실시하였으며, 농업비점오염 개념, 최적관리기법의 이해, 비점오염저감 활동참여 의지에 관한 내용으로 구성하였다. 설문조사 점수에 대한 기준은 전혀아니다(1점), 그렇지않다(2점), 보통이다(3점), 그렇다(4점), 매우 그렇다(5점)로 선정하였다. 설문조사 결과 농업비점오염원의 대한 이해도는 1차 62점, 2차 66점, 3차 80점, 최적관리기법의 이해도는 1차 59점, 2차 64점, 3차 75점, 비점오염저감 활동참여 의지도는 1차 61점, 2차 73점, 3차 80점으로 나타났다. 1차 설문조사 결과 대비 3차설문조사 결과 농업비점오염의 개념 및 최적관리기법의 이해도는 22.5, 21.3% 증가하는것으로 분석되었으며, 비점오염저감 활동참여 의지도는 23.8% 증가하는 것으로 분석되었다. 조사 결과와 같이 교육을 통해 주민들의 인식이 전환된 것으로 분석되었으며, 비점오염원 저감활동에 대한 의지가 표준 이상으로 나타나 주민 참여 거버넌스 구축 연구를 통해 실질적인 농촌 비점오염 관리가 가능할 것이라 기대된다.

• Ecology and Resilient Infrastructure
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• v.10 no.3
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• pp.73-84
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• 2023

The objective of this study was to evaluate biodiversity and natural habitat environment of freshwater ecosystem. Our aim was therefore to produce a set of biodiversity and habitat indicators based on multi-parameters of water quality and biodiversity by analyzing the characteristics of the results by indicators. We selected four indicators a) anthropogenic disturbance, b) habitat diversity, c) biodiversity, d) ecosystem structure. The fishes cohabiting with Brachymystax lenok tsinlingensis were Rhynchocypris kumgangensis and Zacco koreanus. As a result of the anthropogenic disturbance evaluation, it was analyzed that vegetation embankment showed a more stable environment in the tributary than the main stream, and other disturbance was not confirmed As a result of the habitat diversity evaluation, it was analyzed that habitat evaluation index showed a high score of 200 more on average, showing an optimal habitat condition. As a result of the biodiversity evaluation, it was analyzed as a clean habitat condition with a high proportion of sensitive species, abundant dissolved oxygen, and little pollutants. As a results of the ecosystem structure, the ecological health condition metrics and appearance of endangered species showed large score deviation, but it was analyzed that the stream ecosystem health was generally excellent. There was a slight correlation between the habitat environment and the results of the nature habitat evaluation according to the appearance of the B. lenok tsinlingensis.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.506-506
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• 2022

비점오염원에서 배출되는 오염부하량(BOD, T-P)은 점오염원의 2배 이상을 차지하고 있어 비점오염원 관리에 대한 관심이 증대되고 있다. 이에 비점오염원의 효율적 관리를 위한 전략 및 추진과제 마련을 위해 제1차('04-'11), 제2차('12-'20) 비점오염원 관리 종합대책(이하 종합대책)이 수립 및 이행되었다. 이어 2016년 물환경보전법 개정에 따라 종합대책의 수립이 법제화되고 지난 2020년 말 제3차 비점종합대책('21~'25)이 수립되었다. 제3차 비점종합대책은 수질개선이 체감되는 비점오염원 관리라는 비전을 가지며 도시, 농·축산, 산림, 관리기반의 4개 분야에 총 71개의 세부 추진과제를 제시하고 있다. T-P 비점오염배출부하량 5% 감축, 불투수율 감축, 비점오염관리지역개소 확대, 고랭지 흙탕물 관리지역 구역 확장, 지역 거버넌스 구축을 대책의 목표와 각 분야별 관리지표로 제시하고 있다. 물환경보전법 제53조의5와 동법 시행령 제75조의3에 따라 환경부장관은 매년 이행사항을 점검 및 평가하여 그 결과를 비점오염원 관리 정책의 수립 및 집행에 반영해야 한다. 지난 제1·2차 대책의 경우 성과 점검 및 관리를 위한 체계가 부재하여 사업의 실효성 확보에 한계가 있었으며 이에 따라 소관별 이행사항 점검 및 평가체계의 필요성이 제기되었다. 따라서 본 연구에서는 종합대책 이행평가 전략 및 세부 추진체계를 마련하여 효율적인 소관별 이행사항 점검 및 평가를 도모하고자 하였다. 분야별 세부 추진과제는 매년, 대책의 목표와 각 분야별 관리지표는 대책 시행 후 5차년에 점검 및 평가할 수 있도록 구성하였다. 또한 종합대책의 최종 목표 달성 시뮬레이션을 통해 5차년 이후 원활한 평가가 이루어질 수 있도록 하였다. 본 연구에서 마련한 이행평가 체계를 통해 적절한 이행평가 및 효율적인 비점오염원 관리를 도모할 수 있을 것으로 사료된다.

• Clean Technology
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• v.15 no.3
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• pp.194-201
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• 2009

Reductive reactivity of zero-valent iron nanoparticles was investigated for removal of nitrate-nitrogen which is considered one of the major water pollutants. To elucidate the difference in reactivity between preparation methods, iron nanoparticles were synthesized respectively from microemulsion and aqueous solution of ferric ions. Iron nanoparticles prepared from microemulsion were deposited on aluminum by electrophoretic method, and their reaction kinetics was compared to that of the same nanoparticles suspended in aqueous batch reaction. With an approximation of pseudo-first-order reaction, rate constants for suspended nanoparticles prepared from microemulsion and dilute aqueous solution were $3.49{\times}10^{-2}min^{-1}$ and $1.40{\times}10^{-2}min^{-1}$, respectively. Iron nanoparticles supported on aluminum showed ca. 30% less reaction rate in comparison with the identical nanoparticles in suspended state. However, supported nanoparticles showed the superior effectiveness in terms of nitrate-nitrogen removal per zero-valent iron input especially when excess amounts of nitrates were present. Iron nanoparticles deposited on aluminum maintained reductive reactivity for more than 3 hours, and produced nitrogen gas as a final reduction product of nitrate-nitrogen.

• Economic and Environmental Geology
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• v.55 no.6
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• pp.717-726
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• 2022

This study was conducted to assess the geochemical contamination degree of As, Cd, Cu, Pb, Sb, and Zn in the soil and water samples from an abandoned gold mine. Enrichment Factor (EF), Geoaccumulation Index (Igeo), and Pollution Load Index (PLI) were carried out to assess the geochemical contamination degree of the soil samples. Variations of sulfate and heavy metals concentration in water samples were determined to identify the geochemical distribution with respect to the distance from the mine tailing dam. Geochemical pollution indices indicated significant contaminated with As, Cd, Pb, and Zn in the soil samples that areas close to the mine tailing dam, while, Sb showed similar indices in all soil samples. These results indicated that the As, Cd, Pb, and Zn dispersion has occurred via anthropogenic sources, such as mining activities. In terms of water samples, anomalies in the concentrations of As, Cd, Zn, and SO₄^2- was determined at specific area, in addition, the concentrations of the elements gradually decreased with distance. This result implies the heavy metals distribution in water has carried out by the weathering of sulfide minerals in the mine tailing and soil. The study area has been conducted the remediation of contaminated soil in the past, however, the geochemical dispersion of heavy metals was supposed to be occurred from the potential contamination source. Therefore, continuous monitoring of the soil and water is necessary after the completion of remediation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.2
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• pp.171-179
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• 2022

In this study, the characteristics of algae mitigation according to dam operation were quantitatively analyzed for Uiam Lake, where the Chuncheon Dam is located upstream of the main stream, Uiam Dam is located downstream, and Soyang Dam is located in the tributary stream. Nine dam operation scenarios were applied to the event of the summer of 2018 (at that time an algae alert occurred) using the EFDC model, which is capable of calculating three-dimensional hydrodynamics and water quality levels such as those associated with chlorophyll-a. The dam operation scenarios were set to generate a flushing effect via discharges in the form of pulse waves from the upstream dams and by lowering the water level at the downstream dam. At Uiam Lake, the flushing effect was different depending on the operation of the dam, and the amount of algae reduction at each point was different owing to topographic characteristics and the different base water temperatures from BukHan River and Soyang River. With regard to a point located on the left bank, it was predicted that the peak level of chlorophyll-a would be reduced by approximately 50 % or more upon pulsed discharge at 50 m³/s for three days at Soyang Dam. However, for the right bank, the amount of discharge from Soyang Dam had little effect on algae mitigation. Therefore, an appropriate dam operation could be effective for algae mitigation at specific points in the water body where large dams exist upstream and downstream, such as at Uiam Lake, in an emergency situation in which algal blooms rapidly.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.283-283
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• 2020

국가의 논의 타작물 재배 권장 정책과 농한기 수익을 위해서 동절기에도 농사가 가능한 시설농업이 발달했으며, 1990년 초부터 재배면적이 증가하여 2000년에는 10만 ha를 넘어섰고, 2018년에는 80만ha의 규모를 보이고 있다(농사로, 2019). 시설농업단지의 동절기 난방을 위한 에너지원으로 화석연료와 전기열원을 사용하고 있고, 특히 강변의 경우 지하수를 난방 열원으로 사용가능해 수막재배를 이용한 대규모 시설단지가 발달함에 따라 지하수의 이용량이 증가하고, 2015년 농업용 지하수 이용량은 연간 20억 톤에 이른다(GIMS, 2019). 난방이 필요한 동절기에 수막용수를 위한 지하수 이용량이 급증하여 계절적인 수위변화를 보이며, 특히 강변의 대규모 시설농업단지의 지하수의 부족현상이 빈번히 발생하는 실정이다(송성호, 2017). 본 연구지역은 낙동강 하구댐 설치 전만조 시 해수의 유입으로 암반지하수의 심도가 증가할수록 EC가 증가하는 특성을 보이는 곳으로, 지하수의 이용량이 급증하는 동절기에 특히 급격히 증가하여 지하수의 안정적인 수질관리를 위해 염분변화의 관리가 필요한 지역이다. 지하수의 계절적인 변화를 위해 시설농업단지내에 지하수 관측정이 설치되어 관측되고 있으며 본 연구에서는 관측정의 2013년 1월~2019년 1월까지 지하수의 EC변화를 관측하였다. 지하수의 수위(GL.m), 온도, EC를 1시간 주기로 관측하여 계적적인 변화를 분석하였고, EC의 증가가 큰 곳은 심도별로 센서(다중심도)를 설치하여 염도의 변화를 관측하였다. 지하수성분의 지질학적 기원분석을 위한 양음이온 분석을 연 1회 실시하였다. 또한 관측정의 심도별 변화를 알기 위해 동일지역에 충적, 암반 관측정을 따로 설치하고 관측하여 지표수와 지하수의 심도별 영향의 차이를 분석하였다. 동일지역의 관측결과 평균 5m이하의 수위변화를 보이나, 5m 이상의 수위변동을 보이는 관측망은 15년 14개소 17년 19개소로 증가추세를 보이며, 이는 주로 밀집된 시설하우스 단지의 수막재배를 위한 겨울철 지하수 사용량 증가가 원인인 것으로 판단된다. 본 연구지역은 강변지역에 밀집된 시설하우스단지의 동절기 수막재배를 위한 지하수 과다 사용으로 수위급감 및 수량부족현상이 반복되고 있어, 예방과 대책강구를 위해 지표수의 함양과 지하수사용량의 상관관계 분석과 자료축적 및 추가연구를 위한 장기관측이 요구된다.