• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.367-367
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• 2022

토지이용의 고도화에 따라 비점오염원 부하는 증가하는 추세이며 기후변화에 따른 강우강도 증가 등으로 지표면에 축적된 고농도의 비점오염물질이 하천으로 유출, 수질오염을 가중시키고 있어 비점오염원 관리가 필요하다. LID 기법은 자연적 기작(mechanisms)과 공정(process)을 이용하여 생태계의 물질순환(물순환 포함)과 에너지 흐름이 원활하도록 조성하는 기법으로, 불투수층면에서 발생되는 강우유출수를 관리 가능하다. LID 시설에는 전처리 시설을 두어 초기 고농도의 입자상 물질을 저감시키고, 강우유출수 저류공간을 통한 유출저감, 첨두유량 등을 저감시킨다. 이러한 전처리 시설에는 유기물질 및 영양소의 생물학적 제거를 위한 미생물 서식공간의 제공 등의 역할을 수행하기 위하여 다양한 여재를 적용하고 있다. 본 연구는 비점오염물질 유입이 LID 기법 전처리 시설 내 여재층의 물리·화학적 및 생물학적 환경을 평가하였다. 3개 시설 모두 100%의 불투수층에서 발생되는 강우유출수를 처리하는 LID 시설을 연구대상으로 선정하였으며, 각각의 전처리 시설에는 자갈, 우드칩, 쇄석 등이 적용되어 있다. 퇴적물의 경우 가장 상부에 존재하는 층으로 퇴적물의 오염물질 농도는 2~10.7배 이상 매우 높게 나타났다. 우드칩의 경우 다른 여재에 비해 높은 함수량과 유기물 함량을 보였으며 이는 우드칩의 수분을 보유하는 능력과 거친 표면공극에 오염물질이 부착되기 때문으로 나타났다. 또한, 같은 무기성 여재인 쇄석과 자갈의 경우 여재 크기의 차이를 보임에도 불구하고 미생물의 군집구성과 함수량의 차이를 보이는 것으로 평가되었다. 유기물의 함량이 낮은 강우유출수의 생물학적 처리능력을 향상시키기 위해서는 유기성 여재가 필요하며, 다공성 무기 멀칭재를 적용하고 하부의 토양은 적정 유기물을 배합하여 질산화 및 탈질화 유도가 가능하도록 설계가 필요한 것으로 분석되었다.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.108-108
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• 2015

준설이란, 물리적으로 수저의 퇴적물을 제거함으로써 하도관리에서 가장 확실하게 퇴적물을 제거하고 통수 단면적을 증가시킬 수 있는 방법 중 하나이다. 우리나라에서는 주로 해안이나 항만에서 주를 이루어져 왔으며, 하천에서는 주로 골재채취를 목적으로 하는 소규모 준설사업이 대부분이었다. 그러나 4대강 살리기 사업으로 인해서 건설된 다기능보는 수위 및 유량을 조절할 수 있다는 장점이 있는 반면, 흐름 및 유사의 연속성을 차단하여 유사퇴적이 발생할 가능성이 높아졌음으로 이를 위한 대책으로 유지준설이 이루어져야 한다. 준설은 대규모의 사업비가 투입되는 건설공사이면서, 수저의 퇴적물을 물리적으로 제거함에 따라 고탁도를 발생시키고 생태계를 교란시키는 등의 문제가 있다. 준설선진국인 미국의 경우, 이러한 문제점을 최소화하기 위한 일환으로 환경창(EWs; Environmental Windows)을 개발하여 미국 준설사업의 약 80%에 적용하여 관리하고 있다. 환경창이란, 준설 및 준설토 처분에 관한 작업이 이루어질수 있는 기간을 의미하여, 결정적으로 사회 환경적으로 준설에 따른 영향의 강도가 상대적으로 작은 기간을 선정하여 준설을 허용하는 기간이다. 본 연구에서는 이러한 환경창를 국내에 적용하기 위하여 어류, 조류, 친수시설 이용빈도, 홍수기를 이용하였다. 연구대상지역은 낙동강 유역의 금호강 합류점이며, 홍수기에는 준설하지 않는 것을 대전제로 하였다. 어류는 대표어종을 선정하여 연구를 진행하였고, 그 외 조류는 법적보호종인 흑두루미, 친수시설 이용빈도는 4대강 방문객 통계자료를 사용하였다. 엔트로피 가중치 산정방법을 통하여 각 속성별 가중치를 산정하여 최종적으로 한국형 환경창을 제시하였다. 본 연구에서 제시한 한국형 환경창은 기존의 환경창과 비교하였을 때, 영향의 정도를 수치로 표현하여 의사결정권자가 간편하게 환경창을 결정할 수 있도록 의사결정지원을 한다는 장점이 있다.

• Korean Journal of Ecology and Environment
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• v.55 no.2
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• pp.175-183
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• 2022

In this study, 46 reservoirs in South Korea were characterized based on heavy metal concentration in sediments. We analyzed the relationship between heavy metal concentrations, physicochemical water quality and hydromorphological factors in each reservoir. Study reservoirs were classified into five groups of reservoirs, by hierarchical cluster analysis based on the similarities of heavy metal concentration. Group 1 had the most severe sediment heavy metal contamination among the groups, whereas Groups 2 and 3 showed low levels of heavy metal contamination. Group 4 displayed high value of Ni, and Group 5 showed high contamination of Pb, Cu, Cr, Ni, and Hg. Groups 1 and 5, which had high concentration of heavy metals in sediments, showed a high density of mines in the catchment of reservoirs. Heavy metal concentration was high in reservoirs with large capacity or the ones located at higher elevation, and also highly related with number of mines in the catchment of reservoir. This study can contribute to the systematic management of sediment heavy metals in reservoirs.

• Nuclear industry
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• v.8 no.4 s.62
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• pp.72-75
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• 1988

화력발전플랜트에서도 원자력플랜트와 마찬가지로 물을 이용하여 열에너지를 기계에너지로 바꾸고 다시 전기에너지로 교환하고 있다. 이런 과정에서 물의 물성은 온도와 압력에 따라 크게 변화한다. 이 물의 물성변화는 부식과 스케일 퇴적에 큰 영향을 주어 수질관리상 여러가지 문제를 제기하고 있다.

• Journal of Korea Water Resources Association
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• v.39 no.5 s.166
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• pp.405-415
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• 2006

The deposition of sewer solids during dry weather in combined sewer systems results in a loss of flow capacity that may restrict flow and cause a local flooding and enhanced solids deposition. Sewer solid accumulations in drainage systems also create the 'first-flush' phenomena during wet weather runoff periods. In order to solve these problems, measurement of these loadings for a given sewer system for extended period is needed but this task is very difficult and extremely expensive. In this study, generalized procedures for estimating sewer sediment solid during dry weather in combined sewer systems developed by the U. S. Environmental Protection Agency were applied in a drainage system in Korea. As result, the appropriate equation can be selected and applied according to the available data. However, the estimated solid sediment shows considerable difference between methods which classified by model and estimation methods of variable. The estimated values using equations (1) $\sim$ (4) are greater than that of equations (5) $\sim$ (9) and intermediate models show greater values than elaborate or simplest models. The comparison between simulated and measured solid deposition is difficult due to the absent of measurement data, but this estimation method can be used usefully for the management of sewer solid with reduction of cost and effort if the measurement is carried out and the equation is adjusted according to the actual drainage systems in Korea.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.5
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• pp.467-473
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• 2015

In the present study, we investigated the physical characteristics of ground water behaviors and sediment properties in intertidal flat of Nakdong River Estuary. Variations in level and temperature of the groundwater depended on tides. And increase of river discharge led to increase in groundwater level and decrease in ground salinity at a depth of several ten cm. Difference in permeability of the intertidal flat sediments due to content of fine fraction affect velocity of groundwtaer level decrease at low tide. Furthermore, enhancement of groundwater flow due to the increase in permeability leaded to decrease of fine fraction in the intertidal flat sediments.

• Journal of the Korean Geographical Society
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• v.49 no.6
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• pp.812-832
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• 2014

We analyzed physical and chemical properties of sediments from 20 subtidal points and 9 beach points to define sedimentary environment between summer and winter of Shindu Marine Protected Area. Means of particle size in summer were generally finer than winter's. There was distinctively spatial pattern that particle sizes became increasingly fine as west direction and apart from beach in summer, but this pattern was not shown in winter. Coarse sediments were prevailed in winter. To explain these patterns, we propose possible two causes which are spatially different water depth condition related with seasonal wave climate or fine sediment input from an estuary located in south of this area during summer rainy season. Contents of exchangeable cations of sediment in summer were shown $Na^+$>$Ca^{2+}$>$Mg^{2+}$>$K^+$ in order, but those of winter were shown $Na^+$>$Mg^{2+}{\fallingdotseq}Ca^{2+}$>$K^+$. Contents of $Na^+$, $Mg^{2+}$, and $K^+$ were related with contents of fine sediment and showed high correlation in each other. These relations were not shown between $Ca^{2+}$ and others. Our results show that there are spatio-temporal unique sedimentary environments between subtidal zone, beach, and dune near Shindu Marine Protected Area. Therefore, we should consider these spatio-temporal patterns for environmentally sound management of Shindu coastal system.

• Journal of Wetlands Research
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• v.25 no.4
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• pp.306-314
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• 2023

Stream sediments are an important component of water quality management because they are receptors of various pollutants such as heavy metals and organic matters emitted from upland sources and can be secondary pollution sources, adversely affecting water environment. To effectively manage the stream sediments, identification of primary sources of sediment contamination and source-associated control strategies will be required. We evaluated the performance of machine learning models in identifying primary sources of sediment contamination based on the physico-chemical properties of stream sediments. A total of 356 stream sediment data sets of 18 quality parameters including 10 heavy metal species(Cd, Cu, Pb, Ni, As, Zn, Cr, Hg, Li, and Al), 3 soil parameters(clay, silt, and sand fractions), and 5 water quality parameters(water content, loss on ignition, total organic carbon, total nitrogen, and total phosphorous) were collected near abandoned metal mines and industrial complexes across the four major river basins in Korea. Two machine learning algorithms, linear discriminant analysis (LDA) and support vector machine (SVM) classifiers were used to classify the sediments into four cases of different combinations of the sampling period and locations (i.e., mine in dry season, mine in wet season, industrial complex in dry season, and　industrial complex in wet season). Both models showed good performance in the classification, with SVM outperformed LDA; the accuracy values of LDA and SVM were 79.5% and 88.1%, respectively. An SVM ensemble model was used for multi-label classification of the multiple contamination sources inlcuding landuses in the upland areas within 1 km radius from the sampling sites. The results showed that the multi-label classifier was comparable performance with sinlgle-label SVM in classifying mines and industrial complexes, but was less accurate in classifying dominant land uses (50~60%). The poor performance of the multi-label SVM is likely due to the overfitting caused by small data sets compared to the complexity of the model. A larger data set might increase the performance of the machine learning models in identifying contamination sources.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.7
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• pp.878-884
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• 2017

It is important to understand interactions in the sediment-water environment because nitrate (N) and phosphorus (P) nutrient fluxes released into overlying water can represent a significant fraction of the total nutrient requirement for primary productivity. In this study, we analyzed and estimated benthic nutrient fluxes at the sediment-water interface, investigating environmental conditions in Gomso and Geunso Bays. Also, we compared previously reported nutrient flux data to identify regional differences. As a result, benthic nutrient fluxes in Beopsan were DIN: $6.14mmol\;m^{-2}d^{-1}$ and DIP: $0.32mmol\;m^{-2}d^{-1}$ higher than other survey sites. Sediment COD were $4.0-10.8mg/g{\cdot}dry$, and environmental deterioration was observed due to organic pollution. If no solution is found for tidal flat farm management, problems such as a decrease in aquaculture production will follow. Therefore, long-term monitoring of tidal flat environments should be pursued to enable the sustainable use of biological resources.

• Journal of Environmental Impact Assessment
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• v.25 no.6
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• pp.466-476
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• 2016

Dredging is inevitably necessary for the management of water infrastructure such as waterways and polluted bottom sediment. Dredged material management options may be offshore dumping, wetland creation, beach nourishment and various other engineering uses depending on the given circumstances at the time of dredging. Among those options, wetland creation and beach nourishment are the preferred ones in Korea considering significant loss of wetland and beach erosion due to various development projects along the coastal region. In order to use dredged material beneficially, however, dredged material needs to be assessed its suitability with respect to its engineering purpose and environmental criteria. In this paper, we demonstrate that environmental risk of dredged material to be introduced into the marine environment can be easily assessed using biomarkers with relative low cost. Biomarkers can also compliment pollutant contents analysis that may not be specific to their impact on biological response. Biomarker information may be used to assist decision making process in selecting suitable treatment or beneficial use options for dredged materials.