• Title, Summary, Keyword: sediment

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Sediment Estimation of Large Reservoir Using Daily Flowrate Analysis (일유량 분석을 이용한 대규모 저수지의 퇴사량 추정)

  • 정재성
    • Journal of Environmental Science International
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    • v.6 no.5
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    • pp.417-423
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    • 1997
  • The objective of this study Is to supply basic data for large reservoir sedimentation research In future and make suggestions to maintain and opera능 the reservoir more of efficiently. At first, previous studios about the estimation of sediment yield rate were reviewed in Korea. And the discharge rating curves of upstream stage gauging stations and the correlation between dam Inflow and stage discharge were analyzed. With the analysis results, the spec유c sediment rate of Soyanggang dam was estimated as 608 m3/km2/yr. It was similar to that of Soyanggang dam feasibility study and 1994's field surveys of the reservoir than that of 1983's field surveys. Because the sediment rating curves were derived under the low discharge conditions, It needs to be checked under the flood conditions. However, the suggested methods such as flowrate analysis and sediment estimation will be useful to the sediment studios In future. Key words . reservoir sediment, sediment yield rate, rating curve, flowrate analysis.

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A Study on Electricity Generation of Marine Sediment Cells (해양 퇴적토전지의 발전 특성에 대한 연구)

  • Lee, Eun-Mi;Kwon, Sung-Hyun;Rhee, In-Hyoung;Park, Byung-Gi;Cho, Dae-Chul
    • Journal of Environmental Science International
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    • v.20 no.5
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    • pp.647-653
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    • 2011
  • Sediment cell is renewable energy which produces electric energy using immanent ingredients or reducing power of marine sediment as natural resources. Also the cell has an advantage that environmental pollution can be reduced through conversion of organic and inorganic contaminants into inert matter with generation of the energy. In this paper, we compared characteristics of electricity generation of the two different sediment cells, and investigated the regeneration effect of the sediment cells with manipulation of the sediment such as mixing and re-positioning. The results showed that 14.1 $W/m^2$ of power was obtained with the aluminum electrode, and the mixing of the sediment could increase the power by 4 $W/m^2$ compared to the control. Also, mixing the sediment has kept electricity for 4 weeks at a relatively constant level, which implied 'fuel regeneration effect'. Meanwhile, the sediment cell was proved to be effective in reduction of COD, which was up to 28.6%.

Development and Evaluation of Sediment Delivery Ratio Equation using Clustering Methods for Estimation of Sediment Discharge on Ungauged Basins in Korea (국내 미계측 유역의 유사유출량 예측을 위한 군집별 유사전달율 산정식 도출 및 평가)

  • Lee, Seoro;Park, Sang Deog;Shin, Seung Sook;Kim, Ki-sung;Kim, Jonggun;Lim, Kyoung Jae
    • Journal of Korean Society on Water Environment
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    • v.34 no.5
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    • pp.537-547
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    • 2018
  • Sediment discharge by rainfall runoff affects water quality in rivers such as turbid water, eutrophication. In order to solve various problems caused by soil loss, it is important to establish a sediment management plan for watersheds and rivers in advance. However, there is a lack of sediment data available for estimating sediment discharge in ungauged basins.. Thus, reasonable research is very important to evaluate and predict the sediment discharge quantitatively. In this study, cluster analysis was conducted to classify gauged watersheds into hydrologically homogeneous groups based on the watershed characteristics. Also, this study suggests a method to efficiently predict the sediment discharge for ungauged basins by developing and evaluating the SDR equations based on the PA-SDR module. As the result, the SDR equations for the classified watersheds were derived to predict the most reasonable sediment discharge of ungauged basins with 0.24 % ~ 10.89 % errors. It was found that the optimal parameters for the gauged basins reflect well characteristic of sediment movement. SDR equations proposed in this study will be available for estimating sediment discharge on ungauged basins. Also it is possible to utilize establishing the appropriate sediment management plan for integrated management of watershed and river in Korea.

An Experimental Study on The Uncertainty of Suspended Sediment Pickup on Slope by Solitary Wave (고립파에 의한 경사면에서의 부유사 제승의 불확실성에 관한 실험적 연구)

  • Cho, Jae Nam;Jeong, Seok Il;Lee, Seung Oh
    • Journal of the Korean Society of Safety
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    • v.32 no.6
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    • pp.61-67
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    • 2017
  • Suspended sediment transport plays principal roles in morphological process of natural coastals. It is needed to understand the reason why interaction characteristics of solitary wave and suspended sediment. The present study shows that suspended sediment pickup derived on solitary wave celerity. The 2D prismatic open channel length is 12 m, width is 0.8 m, height is 0.75 m and slope is 1/6. Generation of solitary wave is used by rapidly opening the sluice gate. Bottom surface sediments are laid movable slope section by 0.03 m thickness and experimental sediments are used anathracite and jumoonjin sand. Techniques of suspended sediment pickup rate are designed equipment ASC(Absorptive Suspended sediment Collector). It could directly absorb 5 points suspended sediment by channel water depth. Solitary wave celerity is measued by ADV(Acoustic Doppler Velocimeter). Mounted two video cameras(Model No. : Sony, HDR-XR550) are used to image processing of suspended sediment concentration and turbidity. Suspended sediment pikcup rate(Einstein, 1950) is analyzed to nondimensionalization based on solitary wave celerity. The suspended sediment pickup rate is suggested that more effective plunging breaking type than spilling. The results indicates fundamental suspended sediment transport mechanism between solitary wave celerity and suspended sediment pickup based on laboratory experiments. Finally, the present study suggests that suspended sediment pickup rate by solitary wave is used only characteristics of sediment and solitary wave celerity.

Analysis and Suggestion of Estimation Equation for Sedimentation in Square Manholes with Straight Path (사각형 중간맨홀에서의 유사 퇴적 분석 및 산정식 제안)

  • Kim, Jung-Soo;Song Ju-Il;Rim Chang-Soo;Yoon, Sei-Eui
    • Journal of Korean Society of Water and Wastewater
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    • v.26 no.2
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    • pp.177-189
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    • 2012
  • Sediment load deposited in sewers and manholes reduces not only the capacity of pipes but also the efficiency of the whole sewer system. This causes the inundations of the low places and overflows at manholes, Moreover, sulfides and bad odor can occur due to deposited sediment with organic loads in manholes. Movements of sediment load in manholes are complicated depending on manhole size, location, inside structure, sediment load type, and time. Therefore, it is necessary to understand the movements of sediment load in manholes by experiments. In this study, experiments were implemented by a square manhole with straight path to measure deposited sedimentation quantity. The experimental apparatus was consisted of a high water tank, an upstream tank, test pipes, a sediment supplier, a manhole, and a downstream tank to measure the experimental discharge. The quantity of deposited sediment load was measured by different conditions, such as the inflow condition of sediment(continuous and certain period), the amount of inflow sediment, discharge, and the type of sediment. Jumoonjin sand(S=2.63, D50=0.55mm), general sand(GS, S=2.65, D50=1.83mm) and anthracite (S=1.45, D50=0.80mm) were employed for the experiment. The velocities in inflow pipe were 0.45 m/s, 0.67 m/s, and 0.9 m/s. Sediment load movement and sedimentation quantity in manhole were influenced by many factors such as velocity, shear stress, viscosity, amount of sediment, sediment size, and specific gravity. Suggested regression equations can estimated the quantity of deposited sediment in the straight path square manholes. The connoted equations that were evaluated through the experimental study have velocity range from 0.45 to 0.9m/sec. The study results illustrates that appropriation of design velocity ragne between 1.0 and 2.0m/sec could implement to maintain and manage manholes.

Occurrence of butyltin compounds in marine environment of Gwangyang Bay, Korea

  • Park, Hee-Gu;Kim, Sang-Soo;Moon, Hyo-Bang;Gu, Bon-Kyu
    • Journal of Environmental Science International
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    • v.11 no.8
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    • pp.793-800
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    • 2002
  • Butyltin (BT) compounds were measured in seawater, sediment, sediment core, settling solids, and plankton from Gwangyang Bay in 2001, Tributyltin (TBT) was detected in seawater from 1 out of the 7 seawater sampling sites and in sediment from 18 out of the 35 sediment sampling sites. The highest concentration of TBT was found in the sediment from the site near Yeosu Harbor (53 ng Sn/g dry wt), acting as the point source for TBT The mean concentrations of TBT were in the order of plankton> settling solids> sediment. The degradation indexes ([DBT]+[MBT]/[TBT]) for the plankton were less than 1, indicating the possibility of recent inputs of TBT. The indexes for the sediment and settling solids ranged from 1.14 to 8.73. The composition of the BT compounds found in the settling solids was similar to that found in the sediment. The vertical profile of the total BT compounds in the sediment was characterized by an abrupt decline from the surface. However, no butyltin compounds appeared below a depth of 10 cm, corresponding to the 1980s. Accordingly, the current results demonstrated that the levels of all butyltin species in the environment of Gwangyang Bay were relatively lower than those in other polluted coastal areas. The vertical profile also suggested a fairly recent history for the down-core.

Prediction of Watershed Erosion and Deposition Potentials (유역침식 및 퇴적 잠재능 예측모델 개발)

  • Son, Kwang-Ik
    • Journal of Korean Society of Hazard Mitigation
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    • v.7 no.1
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    • pp.67-72
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    • 2007
  • A model for predicting potentials of land erosion and deposition over a natural basin was developed based on the mass balance principle. The program was developed based on sediment mass balance principle for each cell in a GIS. Sediment yield from a cell was estimated with RUSLE. The outflow sediment from a cell was calculated by multiplying the sediment yield of the cell by the sediment delivery ratio (SDR) of the cell. The outflow sediment from the upstream cell becomes the incoming sediment of the downstream cell. Therefore the erosion and deposition potential of each cell could be determined from the sediment mass balance i.e., the difference between the incoming and outflow of sediments of each cell. The developed model was validated by comparing the predicted sediment yields for three basins with measured data.

Study on Sediment Runoff Reduction using Vegetative Filter Strips in a Mountainous Watershed (초생대를 이용한 산지유역 토사유출 저감에 관한 연구)

  • Son, Kwangik;Kim, Hyungjoon;Lim, Kyoung Jae;Jung, Younghun
    • Journal of Korean Society on Water Environment
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    • v.31 no.4
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    • pp.407-417
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    • 2015
  • Soil loss is one of the significant disasters which have threatened human community and ecosystem. Particularly, Korea has high vulnerability of soil loss because rainfall is concentrated during summer and mountainous regions take more than 70% of total land resources. Accordingly, the sediment control management plan are required to prevent the loss of soil resources and to improve water quality in the receiving waterbodies. In this regard, the objectives of this study are 1) to quantify the effect of the Vegetative Filter Strip (VFS) on sediment runoff reduction and 2) to analyze the relationship of rainfall intensity and sediment runoff. For this, SATEEC and VFSMOD were used to estimate sediment runoff according to rainfall intensity and to quantify the effect of VFS on sediment runoff reduction, respectively. In this study, the VFS has higher impact on sediment reduction for lower maximum rainfall intensity, which means that the maximum rainfall intensity is one of significant factors to control sediment runoff. Also, the sediment with VFS considered was highly correlated with maximum rainfall intensity. For these results, this study will contribute to extend the applicability of VFS in establishing eco-friendly sediment control plans.

A study on the measurement of nutrients release from sediment (영양염 용출 측정에 관한 고찰)

  • 김도희
    • Journal of Environmental Science International
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    • v.11 no.12
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    • pp.1333-1337
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    • 2002
  • A significant fraction of nutrients, such as nitrogen and phosphorus released from sediment are utilized by primary production in the shallow water of coast and lake. The purpose of this study is to introduce the mechanism of nutrients release from sediment and to introduce the methods of the measurement of nutrient released from sediment. One approach is to calculate nutrients released from sediment by a concentration gradient between sediment pore waters and overlying water based on the Fick's law. The other approaches of measurement are the undisturbed sediment core experiments and measurement of nutrient released from sediment by the in situ chamber equipment.

An Efficient Management of Sediment Deposit for Reservoir Long-Term Operation (1) - Reservoir Sediment Estimation (저수지 장기운영을 위한 퇴적토사의 효율적 관리(1) - 저수지 퇴사량 산정)

  • Ahn, Jae Hyun;Jang, Su Hyung;Choi, Won Suk;Yoon, Yong Nam
    • Journal of Korean Society on Water Environment
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    • v.22 no.6
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    • pp.1088-1093
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    • 2006
  • In this study, the method of annual sediment estimation for reservoir long-term operation is proposed. Long-term daily precipitation and evaporation are predicted by Markov Chain. Using these values, reservoir inflow is simulated by NWS-PC model. Reservoir sediment load is estimated by sediment rating relation curve which is observed. From the simulation results, it was found that each simulated value by Markov Chain and NWS-PC was well compared to the observed ones and also estimated reservoir sediment was appropriate to the compared values using empirical equations. It is thought that the proposed method for estimation of reservoir sediment can be useful used to operate the reservoir.