• 제목/요약/키워드: Sediment management

검색결과 519건 처리시간 0.024초

Levels and Patterns of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans in Sediments from Korean Coast

  • Moon Hyo-Bang;Choi Hee-Gu;Kim Sang-Soo;Jeong Seung-Ryul;Lee Pil-Yong
    • Fisheries and Aquatic Sciences
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    • 제4권2호
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    • pp.51-57
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    • 2001
  • Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were measured in sediment samples from 19 stations in the coastal areas of Korea from February to July 2000. PCDDs and PCDFs were detected in all sediment samples. The concentrations of these con­taminants ranged from 18.2 to 804.0 pg/g dry weight and I-TEQ concentrations varied from 0.1 to 5.5 pg/g dry weight. Examination of homologue groups showed that octachlorinated dibenzo-p-dioxin (OCDD) was predominant congener in Korean coast. This pattern was similar to homologue profiles of marine sediments in which the main source of PCDDs/DFs was derived from the atmospheric deposition of particulate matters generated from various industrial activities. Grain size and total organic carbon (TOC) distribution are one of the important factors governing PCDDs/DFs concentration in this study.

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Spatially Distributed Model for Soil Loss Vulnerability Assessment in Mekong River Basin

  • Thuy, H.T.;Lee, Giha;Lee, Daeeop;Sophal, Try
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2016년도 학술발표회
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    • pp.188-188
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    • 2016
  • The Mekong which is one of the world's most significant rivers plays an extremely important role to South East Asia. Lying across six riparian countries including China, Myanmar, Thailand, Laos, Cambodia and Vietnam and being a greatly biological and ecological diversity of fishes, the river supports a huge population who living along Mekong Basin River. Therefore, much attention has been focused on the giant Mekong Basin River, particularly, the soil erosion and sedimentation problems which rise critical impacts on irrigation, agriculture, navigation, fisheries and aquatic ecosystem. In fact, there have been many methods to calculate these problems; however, in the case of Mekong, the available data have significant limitations because of large area (about 795 00 km2) and a failure by management agencies to analyze and publish of developing countries in Mekong Basin River. As a result, the Universal Soil Loss Equation (USLE) model in a GIS (Geographic Information System) framework was applied in this study. The USLE factors contain the rainfall erosivity, soil erodibility, slope length, steepness, crop management and conservation practices which are represented by raster layers in GIS environment. In the final step, these factors were multiplied together to estimate the soil erosion rate in the study area by using spatial analyst tool in the ArcGIS 10.2 software. The spatial distribution of soil loss result will be used to support river basin management to find the subtainable management practices by showing the position and amount of soil erosion and sediment load in the dangerous areas during the selected 56- year period from 1952 to 2007.

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논 경운방법에 따른 비영농기 질소.인 오염부하 (Runoff Loading of Nutrient from Paddy Fields According to Tillage Practices during Non-Cropping Season)

  • 윤광식;최진규;구자웅;손재권;조재영
    • 한국농공학회:학술대회논문집
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    • 한국농공학회 2001년도 학술발표회 발표논문집
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    • pp.484-487
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    • 2001
  • Runoff, sediments and nutrient losses were studied under different patterns of paddy field management: (1) fall and spring plowing (PL); (2) fall plowing for half of plot and spring plowing (SPL); (3) no-till for fall and spring plowing (NPL) during the non-cropping period in the southern Korea. Sediment losses from PL plot were 25% more than those from NPL plot. There was significant difference in nutrient losses via runoff water and sediment according to plowing practice (P < 0.01). Losses of total-N, ammonia-N, nitrate-N, total-P from NPL plot were larger than PL and SPL plots during study period. Sediment and total-P losses from SPL plot were close to those of PL plot.

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확률 신경망에 의한 해저 저질의 식별 (Classifying Seafloor Sediments Using a Probabilistic Neural Network)

  • 이대재
    • 한국수산과학회지
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    • 제51권3호
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    • pp.321-327
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    • 2018
  • To classify seafloor sediments using a probabilistic neural network (PNN), the frequency-dependent characteristics of broadband acoustic scattering, which make it possible to qualitatively categorize seabed type, were collected from three different geographical areas in Korea. The echo data samples from three types of seafloor sediment were measured using a chirp sonar system operating over a frequency range of 20-220 kHz. The spectrum amplitudes for frequency responses of 35-75 kHz were fed into the PNN as input feature parameters. The PNN algorithm could successfully identify three seabed types: mud, mud/shell and concrete sediments. The percentage probabilities of the three seabed types being correctly classified were 86% for mud, 66% for mud/shell and 72% for concrete sediment.

하천 퇴적물의 영양염류 모니터링 (Monitoring and Analysis of Nutrients in Sediments in the Riverbed)

  • 김건하;정우혁;이준배
    • 한국물환경학회지
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    • 제22권5호
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    • pp.838-845
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    • 2006
  • Characterization of sediment in the riverbed is of importance for effective water quality management, yet have not been monitored sufficiently. This paper reports monitoring results of nutrient concentrations of sediments. Surface waters and sediments were sampled four times during rainy season at five monitoring points. Organics of overlying water were increased after high flow condition followed by decreasing tendencies. Soluble phosphorus fraction among total phosphorus was increased after high flow condition while total phosphorus was in decreasing tendencies. Monitoring result suggested that more extended monitoring scheme for flow rate, scouring velocity, and suspended material is required for analyzing relationship between water quality and sediment.

댐하류의 하천환경 개선 (Improvement of river environment in the downstream reaches of dams)

  • Ozawa, Takashi
    • 한국환경생태학회:학술대회논문집
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    • 한국환경생태학회 2003년도 추계학술논문발표회 논문집
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    • pp.1-21
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    • 2003
  • I introduce the Flexible Dam Operation (FDO) and some of sediment control techniques In dams which are implemented as trials to avoid or reduce environmental impact of dams on the downstream reaches. The FDO is a dam management method to improve river environment in the downstream reaches by means of the flushing flow, the maintenance flow and so on utilizing a vacant portion of capacity for flood control without interrupting prime flood control function during the rainy/typhoon season. It Is suggested by the guideline of the FDO that EDO should be implemented regularly after the trial for about three years. The basic conception of the FDO is described here. The example of excavation of deposited sediments in check dams and placement of sand ana gravel immediately downstream of the dams and the example of coordinated sediment flushing are described as some of sediment control techniques in dams. Now they are at the stage of experiment and trial. Therefore, it is important to increase examples and establish the technical methodology and the environmental evaluation method for them.

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Long-term Sediment Discharge Analysis in Yongdam Dam Watershed due to Climate Change

  • Felix, Micah Lourdes;Kim, Joocheol;Choi, Mikyoung;Jung, Kwansue
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2020년도 학술발표회
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    • pp.327-327
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    • 2020
  • Increase in Earth's surface temperature, higher rainfall intensity rate, and rapid changes in land cover are just some of the most evident effects of climate change. Flooding, and river sedimentation are two inevitable natural processes in our environment, and both issues poses great risks in the dam industry when not addressed properly. River sedimentation is a significant issue that causes reservoir deposition, and thus causes the dam to gradually lose its ability to store water. In this study, the long-term effects of climate change on the sediment discharge in Yongdam Dam watershed is analyzed through the utilization of SWAT, a semi-distributed watershed model. Based from the results of this study, an abrupt increase on the annual sediment inflow trend in Yongdam Dam watershed was observed; which may suggests that due to the effects of climate change, higher rainfall intensity, land use and land cover changes, the sedimentation rate also increased. An efficient sedimentation management should consider the increasing trend in sedimentation rate due to the effects of climate change.

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기흥저수지 퇴적물에 대한 오염도 분석 (Analysis of Sediment Contamination Levels in the Giheung Reservoir)

  • 오경희;김성진;조영철
    • 한국물환경학회지
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    • 제34권1호
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    • pp.26-32
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    • 2018
  • In order to analyze the effects of sediment on the occurrence of algal bloom on the Giheung Reservoir, the contamination levels of sediments were evaluated. The concentrations of various organic compounds (ignition loss), as well as the total nitrogen, total phosphorus, and heavy metals (Zn, Cr, Co, Ni, Pb, As, Hg, Cd) were analyzed in the sediments taken at eighteen sites of the reservoir. The concentrations of ignition loss and total nitrogen tended to increase from upstream to downstream, and ranged from 4.38 to 12.93% and 2,153 to 4,723 mg/kg, respectively. Heavy metals were in the order of Zn>Cr>Co>Ni>Pb>As>Hg, and the contamination level of the heavy metals was not high as a whole. The concentrations of the total phosphorus were in the range of 765 ~ 3,238 mg/kg, which exceeded the contamination level of the "Sediment Quality Assessment Guideline of River and Lake Sediment (Rule No. 2015-687 of the National Institute of Environmental Research, Korea)" at two upstream sites, four downstream sites, and all downstream sites. These results indicated that the pollution level of the total phosphorus, which is the main factor related to algal bloom, was found to be serious. Therefore, it is necessary to establish a countermeasure for sediment management in order to control the algal bloom which occurs periodically in the reservoir.

SWAT-EFDC 연계 모델링을 통한 입장저수지의 유사 해석 (Modeling Sedimentation Process in Ipjang Reservoir using SWAT and EFDC)

  • 신샛별;황순호;허용구;송정헌;김학관;강문성
    • 한국농공학회논문집
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    • 제60권3호
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    • pp.135-148
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    • 2018
  • Reservoir sedimentation is a major environmental issue, and various sediment load controls and plans have been proposed to secure clean and safe water resources. The objectives of this study were to estimate soil loss in the upper basins and predict sediment deposition in Ipjang reservoir using hydrologic and hydraulic model. To do so, SWAT (Soil and Water Assessment Tool) and EFDC (Environmental Fluid Dynamics Code) was used to estimate soil loss in two upper basins and to predict spatial distribution and amount of sediment deposition in the Ipjang reservoir, respectively. The hydrologic modeling results showed that annual average soil loss from the upper basins was 500 ton. The hydraulic modeling results demonstrated that sediment particles transported to the reservoir were mostly trapped in the vicinity of the reservoir inlet and then moved toward the bank over time. If long-term water quality monitoring and sediment survey are performed, this study can be used as a tool for predicting the dredging amount, dredging location and proper dredging cycle in the reservoir. The study findings are expected to be used as a basis to establish management solutions for sediment reduction.

퇴적물 오염기준을 이용한 금강 하구역 표층 퇴적물내 유기물 및 미량금속 오염 평가 (Evaluation of Organic Matter and Trace Metal Contamination in Surface Sediments around the Geum River Estuary using Sediment Quality Guidelines)

  • 황동운;이인석;최민규;김숙양;최희구
    • 한국수산과학회지
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    • 제46권6호
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    • pp.930-940
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    • 2013
  • We evaluated contamination with organic matter and trace metals by analyzing grain size, ignition loss (IL), chemical oxygen demand (COD), acid volatile sulfide (AVS), and trace metals (Al, Fe, Cu, Pb, Zn, Cd, Ni, Cr, Mn, Hg, and As) in surface sediments at 28 stations around the Geum River estuary in July 2008. The surface sediments in the estuary were mainly composed of coarse sediment (sand and muddy sand), with mean grain size (Mz) ranging between $2-4{\O}$. The high concentrations of IL, COD, and trace metals were mainly found at stations in front of the Gusan outer port and industrial complex, and near the Seocheon coast with relatively fine sediments. In addition, the concentrations of IL and all trace metals, except Pb and As, showed good positive correlations with Mz, indicating that the concentrations of organic matter and trace metals were mainly dependent on sediment grain size. The concentrations of COD, AVS, and trace metals in most sediments did not exceed the sediment quality guideline (SQGs). Although the sediments in the study region are not polluted with organic matter and trace metals, there are many point sources of pollutants, such as Gusan port and industrial complex, Janghang refinery, and a thermoelectric power plant around the Geum River estuary. Thus, the management of coastal environments through periodic monitoring of organic matter and trace metals is required in the future.