• 한국환경보건학회지
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• 제8권1호
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• pp.31-43
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• 1982

Seventy-seven Mugil cephalus of spinal deformation, living in Hanam, Nogsan, and Myeongji area, the downstreams of the Nagdong River, were collected in order to determine their forms and the levels of heavy metal contamination between March and October, 1981. The specimens were examined by X-ray and content of cadmium, lead, copper, and zinc by atomic absorption spectrophotometer. The results were summarized as follows: 1. The rate of appearance of deformational fish to the total Mugil cephflus were 4.3% (13 fish), 5.7% (17 fish), relatively high in May and June (dry season). Meanwhile during March and October they were low by 1.0% (3 fish), 2.0% (6 fish). As far as the research areas are concerned, they appeared in larger numbers in downstreams than in upper streams Myeongji (39), Nogsan (25), and Hanam (13). 2. Concerning with fractured parts of vertebraes,86 percent (66 out of 77) had their caudal regions fractured and 72 percent (55) their first to seventh caudal regions fractured. 3. The average levels of cadmium, lead, copper, zinc detected from flesh were 0.26ppm, 2.06ppm, 6.35ppm, 0.85ppm on the other hand, they were 0.22ppm, 1.84ppm, 5.03ppm, 0.93ppm in normal fish. 4. The average levels of cadmium, lead, copper, zinc measured in the bones were 0.39ppm, 2.55ppm, 8.97ppm, 2.73ppm. Meanwhile, from normal fish they were 0.33ppm, 2.25ppm, 7.24ppm, 2.42ppm. 5. Compared with regional heavy metal contamination such as cadium, lead, zinc, Myeongji area had higher contamination content than Nogsan area Nogsan area than Hanam area. 6. Compared with heavy metal contamination level in their tissues, cadmium was highly found in bones Lead and copper were highly detected in viscera. Particularly in skeleton cadmium was 560 times, zinc 160 times in proportion to those in the downstreams of the Nagdong River.

• 환경영향평가
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• 제20권5호
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• pp.705-716
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• 2011

For the efficient discovery of knowledge and information from the observed systems, data mining techniques can be an useful tool for the prediction of water quality at intake station in rivers. Deterioration of water quality can be caused at intake station in dry season due to insufficient flow. This demands additional outflow from dam since some extent of deterioration can be attenuated by dam reservoir operation to control outflow considering predicted water quality. A seasonal occurrence of high ammonia nitrogen ($NH_3$-N) concentrations has hampered chemical treatment processes of a water plant in Geum river. Monthly flow allocation from upstream dam is important for downstream $NH_3$-N control. In this study, prediction models of water quality based on multiple regression (MR), artificial neural network and data mining methods were developed to understand water quality variation and to support dam operations through providing predicted $NH_3$-N concentrations at intake station. The models were calibrated with eight years of monthly data and verified with another two years of independent data. In those models, the $NH_3$-N concentration for next time step is dependent on dam outflow, river water quality such as alkalinity, temperature, and $NH_3$-N of previous time step. The model performances are compared and evaluated by error analysis and statistical characteristics like correlation and determination coefficients between the observed and the predicted water quality. It is expected that these data mining techniques can present more efficient data-driven tools in modelling stage and it is found that those models can be applied well to predict water quality in stream river systems.

• 한국물환경학회지
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• 제25권6호
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• pp.840-848
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• 2009

Spatial and temporal distributions of POC and DOC were surveyed in the North Han River system, Korea The proportion of algal cells was calculated in four reservoirs (Lakes Soyang, Paro, Chunchon, and Uiam). Monthly average DOC concentrations ranged from 1.5 to 2.3 mg C/L, and POC showed larger variation than DOC (range 0.3 to 1.9 mg C/L). The average proportion of POC in TOC was higher than those of typical natural lakes. Due to the influence of the Asian summer monsoon, the seasonal variation in POC concentration depended on heavy rain events occurring during the summer. POC concentrations increased during the summer monsoon season due to turbid storm runoff laden with debris, while DOC concentrations did not increase. The highest POC concentrations were observed in Lake Soyang in 2006 when a severe rain event occurred. In two deep stratified reservoirs (Lake Soyang and Paro) storm runoffs formed an intermediate turbidity layer with high POC and chlorophyll concentrations which is thought to originate from terrestrial debris and periphyton transported by inflowing streams. The proportion of algal cells in total POC was much lower than for most natural lakes, and it varied with season; low in the monsoon season and high in dry seasons with algal blooms. An analysis of POC concentration and chlorophyll a concentration showed that the ratio of POC/Chl.a varied from 24 to 80.

• 물과 미래
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• 제29권2호
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• pp.179-190
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• 1996

한강하류부 수질의 통계학적 해석을 통하여 수질 시계열자료의 기본 통계특성치, 지점별 및 계절별 변동성을 검토하였으며, 유량과 수질인자간의 상관성 분석을 실시하였다. 본류의 주요 6개 지점 및 3개 지류에 대한 통계특성치와 적정분포형을 산정하여 제시하였으며, 시간의존성 및 계절성을 검토하여 제시하였다. 또한, 수질 항목간의 상관성 검토를 통하여 상관성이 높은 수질, 항목간, 그리고 지점간의 상관식을 제시하였다. 추계학적 모의모형의 적용가능성을 확인하였으며, DO 항목은 전 지점간에 높은 상관성을 가지고 있었다. 유량과의 상관관계 검토에 있어서 DO, SS 항목은 유량보다는 수온에 민감하였으며, BOD, COD 항목은 유량이 적은 갈수기에는 유량에 민감한 것으로 나타났다. 수온에 밀접한 영향을 받는 DO 항목외에도 BOD, COD 항목은 계절적인 주기성을 가지고 있었으며, 상호상관 분석결과 DO, BOD, COD 항목 외의 수질 항목들에서도 각 수질 항목들에 내재된 주기성을 찾아볼 수 있었다.

• 한국수자원학회논문집
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• 제33권3호
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• pp.375-382
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• 2000

대유역의 지표면 수문현상은 추계학적 변동에 의해 야기되는 안정된 상태의 변이와 함께 몇 개의 발생빈도가 높은 안정된 상태의 영향을 받기가 쉬운데 그 이유는 지표면과 대기 상호관계의 밀접한 조합과도 관계가 있다. 따라서 각 안정상태에서의 체류기간 즉, 가뭄기나 홍수기의 지속기간이 중요한 연구 과제라 할 수 있으며 본 연구에서는 한강유역에 대하여 안정상태의 평균 변이기간을 분석하였다. 비선형 물수지모형을 한강 유역에 대하여 과거의 자료를 바탕으로 검정하였고 모형을 통한 물리과정의 추계학적 표현과 산정된 모형변수들로부터 안정상태사이의 평균 변이기간이 계산되었다. 본 연구는 안정상태 사이의 변이기간 혹은 거주기간, 즉 시스템이 주어진 안정상태에 머무는 기간(가뭄이나 홍수상태의 지속기간)의 예측과 밀접한 관계가 있다.

• 한국습지학회지
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• 제16권1호
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• pp.93-102
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• 2014

2000년대 후반 이래로 홍수터를 활용한 생태공원이나 체육시설 등과 같은 다양한 친수시설들이 조성되었다. 또한 최근 강우강도 및 홍수 빈도의 증가로 인해 관련 피해가 급증하고 있으며, 이는 홍수터에 설치된 공원과 같은 친수시설들의 침수피해와 직접적으로 연관되므로, 극한강우 시 홍수터에서의 수치해석이 필요하다고 판단된다. 본 연구에서는 홍수터에서의 수위상승과 하강에 따른 수리학적 영향을 분석하기 위해 마름/젖음 모의가 가능한 준부정류 흐름해석모형인 FaSTMECH와 부정류 흐름해석모형인 Nays2D 모형을 이용하여 각 모델간의 태풍 사상시 시간에 따른 침수심 및 유속분포를 비교 분석하였다. 태풍 사상시 홍수터에서의 유속분포는 주수로에서의 유속에 비해 매우 낮은 유속을 보이고 있었으며, 홍수터에서는 침식보다는 토사퇴적 문제가 더 높을 것이라 판단된다.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.787-790
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• 2008

SWAT(Soil and Water Assesment Tool) 모형은 장기간에 걸친 토양과 토지이용 및 관리 상태에 따라 복잡하게 반응한 대규모 유역의 물과 토사유출 및 농업화학물질로 인해 실제 토지관리가 수환경에 끼치는 영향을 예측하기 위하여 개발되었다. 일반적으로 하천은 유역의 개발 정도에 따라 도시하천과 자연하천으로 나뉘며 도시하천의 경우 도시화가 진행됨에 따라 토지이용상태 및 토지피복상태의 변화로 불투수면적이 증가함에 따라 도시하천의 건천화가 급속도로 진행된다. 본 연구에서는 장기유출모의가 가능한 SWAT 모형을 이용하여 도시하천의 유출량을 모의하고 특히 유역의 규모가 작은 소유역의 SWAT 모형의 적용성을 제시하고자 한다. GIS와 연계한 SWAT 모형을 이용하여 조만강 유역을 모의하였고, 모형의 민감도 분석을 통해 매개변수를 최적화시킴으로서 모델의 신뢰도를 평가하고자 하였다.

• Journal of Ecology and Environment
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• 제43권3호
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• pp.314-319
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• 2019

Background: The dramatic worldwide decline in the butterfly species Leptalina unicolor (Bremer & Grey) is largely the result of continuous habitat decline and disturbance by humans. The discovery of a narrow habitat in riverside wetlands utilized by L. unicolor raises the hope that such restricted key areas could be rather easily protected. Results: Here, we explain the environmental variables and habitat characteristics that primarily influence the distribution of L. unicolor discovered at the riverside areas along the Geum River. L. unicolor larvae were found at 9 of 13 study sites, and their abundance was strongly positively correlated with plant biomass. Our investigation showed that among four plant species (Miscanthus sinensis, Spodiopogon cotulifer, Setaria viridis, and Imperata cylindrica), L. unicolor larvae were the most abundant on the leaves of M. sinensis. They were not abundant on the leaves of S. cotulifer, S. viridis, or I. cylindrica. Interestingly, the number of L. unicolor larvae was positively correlated with the coverage area ($m^2$) of M. sinensis (F = 41.7, $r^2=0.74$, P < 0.0001). Conclusions: It appears that water (e.g., wetlands, ponds, and watersides) located along the riverside areas along the Geum River is important for the constant maintenance and conservation of L. unicolor. This is based on the habitat characteristics (water preference) of M. sinensis, which is used as a habitat by L. unicolor larvae. However, the waterside is dry and terrestrialization is in progress owing to the decreased water levels and water supply caused by an opened weir. Hereafter, this area will likely require management to secure a stable habitat for L. unicolor.

• 한국지반공학회논문집
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• 제24권4호
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• pp.67-78
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• 2008

본 연구에서는 시멘트의 고결효과를 정량적으로 파악하기 위하여 낙동강하상모래와 소량의 포틀랜드시멘트를 혼합하여 고결된 모래에 대하여 일축압축시험 및 배수조건과 비배수 조건의 삼축압축시험을 수행하였다. 시멘트혼합율의 증가에 따라 첨두강도 및 탄성계수는 증가하였고 시멘트의 결합력에 의하여 다일레이션 및 과잉간극수압이 억제되었으나 시멘트 결합력의 파괴 후 증가된 모래입자크기에 의하여 증가하였다. 그리고 배수조건의 응력-변형률 곡선은 연화거동이 나타났지만 비배수조건에서는 증가된 부(-)의 과잉간극수압에 의한 유효응력의 증가로 경화거동을 나타냈다. 각 조건에 대한 강도증가량의 예측을 위하여 선형을 가정한 다중회귀분석을 실시한 결과 제시된 경험식의 결정계수는 $0.81{\sim}0.91$로 나타나 신뢰성이 높은 것으로 평가되었으며 건조밀도의 경우 고결된 모래의 입도조건을 동시에 고려할 수 있어 고결된 모래의 강도를 결정하는데 중요한 변수로 분석되었다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2020년도 학술발표회
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• pp.169-169
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• 2020

According to the IPCC analysis, severe climate changes are projected to occur in Korea as the temperature is expected to rise by 3.2 ℃, the precipitation by 15.6% and the sea level by 27cm by 2050. It is predicted that the occurrence of abnormal climate phenomena - especially those such as increase of concentrated precipitation and extreme heat in the summer season and severe drought in the winter season - that have happened in Korea in the past 30 years (1981-2010) will continuously be intensified and accelerated. As a result, the impact on and vulnerability of the water management sector is expected to be exacerbated. This research aims to predict the climate change impacts on streamflow of Daecheong Lake area of Geum River in South Korea during the summer and winter seasons, which show extreme meteorological events, and ultimately develop an integrated policy model in response. We projected and compared the streamflow changes of Daecheong Lake area of Geum River in South Korea in the near future period (2020-2040) and the far future period (2041-2060) with the reference period (1991-2010) using the HEC-HMS model. The data from a global climate model HadGEM2-AO, which is the fully-coupled atmosphere-ocean version of the Hadley Centre Global Environment Model 2, and RCP scenarios (RCP4.5 and RCP8.5) were used as inputs for the HEC-HMS model to identify the river basins where cases of extreme flooding or drought are likely to occur in the near and far future. The projections were made for the summer season (July-September) and the winter season(November-January) in order to reflect the summer monsoon and the dry winter. The results are anticipated to be used by policy makers for preparation of adaptation plans to secure water resources in the nation.