• 한국지하수토양환경학회지:지하수토양환경
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• 제26권6호
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• pp.118-129
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• 2021

The sediment transportation caused by soil erosion due to rainfall-discharge in the large watershed scale plays critical role in human society. The relationship between rainfall-discharge-sediment transportation is depending on the start time of rainfall and end of rainfall but, the studies related with rainfall characteristics are insufficient. In this study, The Soil and Water Assession Tool (SWAT) model was used to study the relationship between rainfall-discharge-sediment transportation at the Sook river watershed which is monitored by the Ministry of Environment. To do this, first of all, the sensitivity analysis about model attributes was performed using monitored data. The accuracy analysis of SWAT model was conducted using the model's efficiency index (Nash and Sutcliffe model efficiency; NSE) and the coefficient of determination (R²). After that, it was studied what results could be obtained according to changes in rainfall timing and end points. In the result of discharge simulation, the modified rainfall values (sum of total rainfall starting time and end time) showed more high accuracy values (R²:0.90, NSE: 0.8) than original rainfall values (R²:0.76, NSE: 0.72). In the result of sediment transportation simulation, during calibration had more resonable results(R²:0.87, NSE: 0.86) than compared with original rainfall values (R²:0.44, NSE: 0.41). However, validation results of sediment transportation simulation showed low accuracy values compared with calibration results. This results maybe cause monitoring periods of sediment flow compared with discharge monitoring periods. Nevertheless, since rainfall characteristic plays critical rule in model results, continuous research on rainfall characteristic is needed.

• 한국물환경학회지
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• 제29권6호
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• pp.813-824
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• 2013

In this study, sediment pass-through (SPT) from the Sangju Weir and Gumi Weir in the Nakdong River is analyzed numerically using CCHE2D. Sediment delivery is analyzed to predict the sediment discharge rate in the Sangju Weir and Gumi Weir. The sediment discharge from the Sanju Weir is 4,381 tons in the inflow of $3,857m^3/s$, which are 2 year frequency discharge, for 48 hours, and the sediment discharge is 2,766 tons in the inflow of $1,500m^3/s$. The maximum sediment delivery occurs in the immediate downstream of the weir. The sediment discharge from the Gumi Weir is 3,216 tons in the inflow of $5,400m^3/s$, which are 2 year frequency discharge, for 48 hours, and the sediment discharge is 73 tons in the inflow of $3,857m^3/s$. The maximum sediment delivery occurs in the weir. Therefore, the effectiveness of sediment delivery is high in the condition of the 2 year frequency discharge and the gate in the weirs fully are opened.

• International Journal of Ocean System Engineering
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• 제2권1호
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• pp.1-7
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• 2012

The cross-shore sediment transport in a coastal region causes the important changes in beach morphological properties. The accurate estimation of the cross-shore sediment transport is important for the designing of the marine structures such as seawalls, jetties, breakwaters etc, and the preventing coastal erosion and accretion due to on-off shore sediment transportation. In this study, the experiments on cross- shore sediment transport carried out in a laboratory wave channel for initial beach slopes of 1/8, 1/10 and 1/15. Using the regular waves with different deep-water wave steepness generated by a pedal-type wave generator, the geometrical characteristics of beach profiles under storm conditions and the parameters affecting on-off shore sediment transport are investigated for the beach materials having medium diameters of $d_{50}$=0.25, 0.32, 0.45, 0.62 and 0.80 mm. The experimental results obtained from this study compared with previous experimental work and found to be of the same magnitude as the experimental measurements and followed the expected basic trend.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.207-210
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• 2008

Recently many studys have been continued Nak-Dong river. This study recognized the importance about a rivers floor change. The Nak-Dong main river of railroad bridge(2.423Km) waegwan-eup, Cilgok-gun, Gyeongsangbuk-do analyzed to the SED2D-WES model. This study recognized the difference of the model according to the existence and nonexistence of the bridge piers. At a result of mean velocity current is higher in bridge option appeared in this case. As well sediment transportation model show that river bed change appear the part of velocity is low.

• 한국수자원학회논문집
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• 제50권9호
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• pp.587-595
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• 2017

본 연구에서는 낙동강에서 보운영에 의한 유사이송능력에 영향을 주는 수리학적 특성변화를 분석하고, 낙동강 주요 4개 지점(낙동, 구미, 왜관, 진동)의 유량-유사량 실측값을 분석하여, 각 지점별 지수형 유량-유사량 관계식을 유도하였다. 모든 지점에서 유사이송능은 감소할 것으로 예측되었으며 실제로 4대강 사업 이후인 2013년도 실측결과 사업 이전에 비해 유사이송 능력이 확연히 감소된 것을 확인하였다. GUIDE 프로그램에서 제공하는 9개 범용 유사이송능 산정기법의 적용성을 검토하여 4개 지점별로 적용 가능한 기법을 선정, 제시하였다. 주요 9개 지류를 포함한 낙동강 전 구간에 대한 유사수지분석 결과 전체적으로 퇴적이 우세한 것으로 나타났다. 유사이송능 산정기법으로는 Engelund-Hansen 공식이 가장 작은 오차를 보였으며 이는 4개 지점별 유사이송능 산정기법 적용성 검토 결과와도 일치한다. 한편 유사수지분석이 내포하는 오차가 낙동강 9개 지류로부터 유입되는 유사량 오차보다 더 작게 나타나 낙동강의 경우 지류의 유입유사량 산정기법에 대한 정밀도 향상이 시급한 과제임을 확인하였다.

• Journal of the korean society of oceanography
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• 제39권1호
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• pp.57-71
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• 2004

Based on the data obtained under the China-Korea joint project (1997-2001) and historic observations, the distribution, transportation and sedimentation of sediment in the southern Yellow Sea (SYS) are discussed, and the controversial formation mechanism of muddy sediments is also explored. The sediment transport trend analysis indicates that the net transport direction of sediment in the central SYS (a fine-grained sediment deposited area) points to $123.4^{\circ}E,\;35.1^{\circ}N$, which is a possible sedimentation center in the central SYS. The sediment transport pattern is verified by the distribution of total suspended matter (TSM) concentration and ${\delta}^{13}C$ values of particulate organic carbon (POC), the latter indicates that the bottom water plays a more important role than the surface water in transporting the terrigenous material to the central deep-water area of the SYS, and the Yellow Sea circulation is an important control factor for the sediment transport pattern in the SYS. The carbon isotope signals of organic matter in sediments indicate that the Shandong subaqueous delta has high sedimentation rate and the deposited sediments originate mainly from the modern Yellow River. The terrigenous sediments in deep-water area of the SYS originate mainly from the old Yellow River and the modern Yellow River, and only a small portion originates from the modern Yangtze River. The analytical results of TSM and stable carbon isotopes are further confirmed by another independent tracer of sediment source, polycyclic aromatic hydrocarbons (PAHs). Five light mineral provinces in the SYS can be identified and they indicate inhomogeneity in sources and sedimentary environment. The modern shelf sedimentary processes in the SYS are controlled by shelf dynamic factors. The muddy depositional systems are produced in the shelf low-energy environments, which are controlled by some meso-scale cyclonic eddies (cold eddies) in the central SYS and the area southwest of the Cheju Island. On the contrary, an anticyclonic muddy depositional system (warm eddy sediment) appears in the southeast of the SYS (the area northwest of the Cheju Island). In this study, we give the cyclonic and anticyclonic eddy sedimentation patterns.

• 한국농공학회지
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• 제22권4호
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• pp.96-107
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• 1980

This study is carried out to estimate the rate of sediment transportation both to measure the amount of suspended and bedload sediment that moves on or near the river bed and passes through the cross section of a river in unit time, with suspended and bed load samplers used for the Milyang river and to determine the most satisfactory and convenient formula of some formulas for sediment discharge by comparing the measured rate with the calculated rate. The results of this study are summarized as follows; 1) The interrelationship (1) between the total discharge and the total sediment discharge (2) between discharge and suspended sediment load and (3) between discharge and bed load in the Milyang river are (1) i) 4$\leq$Q$\leq$100 C.M.S. Qr=0. 00272 Q0.70 (kg/sec) ii) 150$\leq$Q$\leq$800 C.M.S. Qr=0. 4807 Q0.46 (kg/sec) (2) Qs~=0. 07576 Q1.02 (kg/sec) (3) QB=0. 00957 Q0.44 (kg/sec) 2) The rate of suspended sediment load to total sediment discharge is found to be about; 99%. The suspended load is shown to be almost wash load which consists of silt and clay. 3) The relation between the total discharge and the suspended sediment load that are measured at three medium and small rivers in Korea is Qs=0. 13831 Q0.97 (kg/sec) 4) Brown's formula is determined to be the most convenient formula for application and comparison with observed data obtained for the Milyang river.

• 한국환경과학회지
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• 제13권3호
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• pp.263-277
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• 2004

The purpose of this study is to analyze the characteristics of riverbed variation due to the sediment protection weir located on the estuary of the main stream of Taehwa river using I-D finite difference model, HEC-6 model, and the followings are the results of estimating sediment transport rate, amount of scour or deposition, and accumulated amount of deposit according to before and after of the sediment protection weir removal with various flow rates in the channel. Ackers-White transport function produced the greatest sediment transport rate while Meyer-Peter showed the smallest sediment transport rate at the most down stream area of the watershed through the sediment transport rate analyses for various flow rates according to the existence or nonexistence of the sediment protection weir. Toffaleti's and Colby transport function were closest to the average value, and the difference among the results of the sediment transport functions showed up to 8～9 times. Duboy's transport function produced the greatest riverbed variation while Toffaleti's showed the smallest variation through the riverbed variation analyses according to the existence or nonexistence of the sediment protection weir. Yang's was closest to the average value, and the difference among the results of the riverbed variation analyses ranged from 1.4 times to 11 times. It is thought that a sediment transport function must be selected very carefully with respect to the criteria of sediment yield estimation because the analysis results of the sediment transport rate and riverbed variation according to flow rates showed significant differences among the sediment transport functions, and the differences of sediment transport rate and riverbed variation according to the various sediment transport functions decreased as the flow rate increased.

• 한국수자원학회논문집
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• 제38권3호
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• pp.223-233
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• 2005

본 연구에서는 분포형 모형과 셀의 유입, 유출 및 저류량에 대한 질량보존의 법칙을 이용하여 토사의 이송 및 퇴적분포예측기법을 개발하였다. 모형은 (a) 토사침식 예측 (b) 흐름방향 및 유출량 산정 그리고 (c) 토사에 대한 질량보존의 법칙에 따른 셀별 토사이동량 산정의 세 단계로 구성되었다. 토양침식은 범용토양손실공식(USLE)을 활용하였으며 분포형 모형에서의 경사장(L) 산정은 일방향(SF)과 다방향 흐름 알고리즘(MF)을 사용하였다. 경사(S) 산정을 위해서는 Maximum Downhill Slope Method (MDS) and the Neighborhood Method (NBH) 기법을 활용하였고 셀별 토양의 이동은 Ferro등(1998)과 Swift (2000)의 토사전달률(DR)개념을 적용하였다. 개발된 모형은 시험유역의 실측 토사량과의 비교검토를 통하여 검증하였다. 3개의 농업용 저수지 유역에 적용한 결과, Ferro의 토사전달률 산정공식과 MDS, MF 기법을 이용한 해석이 저수지의 운영기록과 가장 유사한 결과를 제시한다는 사실을 확인할 수 있었다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2014년도 추계학술대회
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• pp.87-88
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• 2014

The Coastal sediment is highly contaminated due to ship transportation, industries discharges and urban sources. Various contaminants release into seawater and settle in marine sediment and it significantly affect marine eco system. In the present study evaluated the optimization of slow release biostimulant ball (BSB) in coastal sediment in busan. The effective variables like BSB size, distance and month variables on VS reduction was determined by using Response surface methodology(RSM). The analysis of variance (ANOVA) and coefficient determination (R2) of VS was 0.9369 and maximum reduction of VS was obtained in 3cm ball size and 5.5cm distance and 4 month interval time. This result revealed that the BSB in effective VS reduction in coastal sediment.