• 한국수자원학회논문집
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• 제49권8호
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• pp.693-705
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• 2016

본 연구에서는 영주댐 하류하천에서 유사공급에 의한 하도의 지형변화와 그 효과를 수치실험을 통하여 분석하였다. 본 수치모형의 모의 결과는 실내실험에서 보여준 토사더미의 이송과 확산과정과 잘 일치하였다. 초기에 토사가 공급된 구간에서 수면이 불연속적으로 형성되는 현상이 발생하지만, 시간이 증가함에 따라 하상고가 저하되면서 완만한 수면형을 형성하였다. 유사공급을 효과적으로 수행하기 위하여 댐 직하류에서 여울이 형성된 만곡부를 유사공급 위치로 선정하였다. 시간이 증가함에 따라 공급된 유사는 하류로 쓸려 내려가고 하상고는 저하되었으며, 유속이 감소되는 하류지점에서 퇴적되었다. 시간이 증가함에 따라, 하상고의 변화가 증가하고, 상류보다는 하류에서 크게 변화하였다. 유량이 증가함에 따라 횡방향 하상고 변화를 나타내는 하상기복지수는 증가하였으며, 하도의 역동성과 유사공급 효과가 큰 것을 알 수 있다.

• Ocean and Polar Research
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• 제24권1호
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• pp.39-45
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• 2002

The seasonal patterns of sediment supply were investigated during the period of June 1999 to June 2000 on a coastal foredune of Seungbong Island, Korea. Sediment supply was determined from measurements of geomorphic changes in the foredune and beach along six lines. Most sands were deposited on the dunefoot and foredune area during the winter and spring, from November to April. The largest amount of sands was deposited along the lines 5 and 6 near the sea-dike in the southern tip of the dune area. In general, the sand on the beach was gradually eroded in spring, summer and fall but deposited in winter. Total sediment accumulation over the study period was $484m^3$ for the foredune and $345m^3$ for the beach. The volume of the foredune increased in the winter and spring, whereas the volume of beach increased in the winter. Variation in sediment deposition appears to be controlled primarily by variations in the seasonal wind regime.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2011년도 학술발표회
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• pp.17-17
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• 2011

As a method of countermeasure to bed degradation and armoring phenomena of bed material in the downstream area of dam reservoirs, sediment augmentation (replenished sediment) has been carried out in many Japanese rivers. In general, bed of the replenished sediment site is composed of rocks, because the site is located in the downstream area of the dams and sediment supply is very small. Bed deformation process has been researched by many researchers. As a method of countermeasure to bed degradation and armoring phenomena of bed material in the downstream area of dam reservoirs, sediment augmentation (replenished sediment) has been carried out in many Japanese rivers. In general, bed of the replenished sediment site is composed of rocks, because the site is located in the downstream area of the dams and sediment supply is very small. Bed deformation process has been researched by many researchers. However, most of them can treat movable bed only and cannot be applied to the bed deformation process of sediment on rocks. If the friction angle between the sediment and the bed surface is assumed to be the same as the friction angle between the sediment and the sediment, sediment transport rate must be smaller without sediment deposition layer on the rocks. As a result, the reproduced bed geometry is affected very well. In this study, non-equilibrium transport process of non-cohesive sediment on rigid bed is introduced into the horizontal two dimensional bed deformation model and the model is applied to the erosion process of replenished sediment on rock in the Nakagawa, Japan. Here, the Japanese largest scale sediment augmentation has been performed in the Nakagawa. The results show that the amounts of the eroded sediment and the remained sediment reproduced by the developed numerical model are $56300m^3$ and $26800m^3$, respectively. On the other hand, the amounts of the eroded sediment and the remained sediment measured in the field after the floods are $56600m^3$ and $26500m^3$, respectively. The difference between the model and field data is very small. Furthermore, the bed geometry of the replenished sediment after the floods reproduced by the developed model has a good agreement with the measured bed geometry after the floods. These results indicate that the developed model is able to simulate the erosion process of replenished sediment on rocks very well. Furthermore, the erosion speed of the replenished sediment during the decreasing process of the water discharge is faster than that during the increasing process of the water discharge. The replenished sediment is eroded well, when the top of the replenished sediment is covered by the water. In general, water surface level is kept to be high during the decreasing process of the discharge during floods, because water surface level at the downstream end is high. Hence, it is considered that the high water surface level during the decreasing process of the water discharge affects on the fast erosion of the replenished sediment.

• 한국지반환경공학회 논문집
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• 제15권12호
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• pp.109-115
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• 2014

본 연구의 목적은 산지에서 세립사가 포함된 유동체 혼합물이 다양한 경사 각도를 갖는 수로에서 공급유량의 변화에 따른 토사체적농도를 분석한 것이다. 수치모델은 질량보존 및 운동량 보존에 관한 방정식 그리고 세립토와 조립토 방정식에 기초하여 유한차분법을 이용하여 수행되었다. 비탈 경사면 각도 변화에 따른 토사농도 비교에서 경사가 급할수록 토사체적 농도의 급격한 변곡점이 나타났다. 공급유량의 변화에서는 공급유량이 많을수록 Fluctuation이 발생하였고, 토석류의 상태가 난류형으로 변하여 토사가 부유사 형태로 변화되었다. 이는 토석류의 이동속도가 빠르게 됨을 알 수 있다. 포화된 조립토의 변화에 따른 비교에서는 그 길이가 길수록 고농도가 발생하였으므로 사면 안정을 위해서는 사면에서의 침식 가능 여부를 먼저 판단해야 된다. 본 연구의 결과는 강우 변화에 따른 비탈면 하류단에서의 유동체 혼합물의 토석류에 의한 재해를 예측 및 다양한 경사의 비탈면을 갖는 산지 밑에서의 토석류에 의한 재해에 대한 정보를 제공할 것이다. 또한 사면 안정 시 효율적인 사면 경사각도로 설치하는 것과 사면에서의 침식 방지등에 있어 토석류와의 관계성 분석 및 토석류 재해를 막기 위한 다양한 대책을 세우는 데 효과적인 정보를 제공할 것이다.

• Geosciences Journal
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• 제22권6호
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• pp.903-919
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• 2018

This paper focuses on the depositional processes and environmental changes during initial marine flooding recorded in the lower Cambrian succession of the North China Platform in Shandong Province, China. In order to understand imbalance of accommodation and sediment supply in the initial stage of basin-fill, a detailed analysis of sedimentary facies was made for the lowermost siliciclastic deposits of the Liguan Formation. It reveals ten siliciclastic lithofacies in three large-scale outcrops (Jinhe, Anqianzhuang, and Zhangjiapo sections). These facies are grouped into four facies associations, representing siliciclastic foreshoreshoreface (S1), siliciclastic offshore (S2), distributary mouth bars (S3), and coastal plain (S4). The siliciclastic components occur in a linear belt, emanating from a major drainage system in the northeastern part of the platform. Deposition of siliciclastic sediments was largely controlled by regional topography of the unconformable surface and shoreline configuration as well as strong effect of waves and currents. With ensued rise in sea level and decrease in siliciclastic sediment supply, carbonate sediments prevailed, filling the accommodation created by epeirogenic subsidence and sediment loading.

• 한국환경과학회지
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• 제6권5호
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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.

• 한국지형학회지
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• 제28권1호
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• pp.13-33
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• 2021

Successful sediment management at the watershed scale requires an understanding of the erosion, transport and sedimentation processes at the specific site scale. However, studies on the sediment runoff characteristics in a small uppermost watershed, which serves as a sediment supply function, are very rare. Therefore, this study attempted to investigate the fluctuations in major sediment supply areas and sediment runoff in the uppermost mountain small watershed, and for this purpose, ArcSWAT (Soil and Water Assessment Tools with GIS interface) was applied to the Woldong reservoir catchment located in Gosam-myeon, Anseong-si, Gyeonggi-do. The model results were manually calibrated using the monitoring data of the Woldong reservoir sedimentation rate from 2005 to 2007. It was estimated that annual average of 34.4 tons/year of sediment was discharged from the Woldong reservoir basin. This estimate almost coincided with the monitoring data of the Woldong reservoir during the low flow period but tended to be somewhat underestimated during the high flow period. Although the SWAT model does not fully reflect the erosion process of gully and in-channel, this underestimation is probably due to the spatial connectivity of sediment transport and the storage and reactivation of the sediment being transported. Most of the forested hillslopes with a well-developed organic horizon were evaluated as having a low risk of erosion, while the places with the highest risk of erosion were predicted to be distributed in the logged area with some weeds or shrubs (classified as pasture) with relatively steeper slopes, and in the bare land. The results of this study are expected to be useful in developing strategies for sediment control and reservoir management.

• 한국수자원학회논문집
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• 제52권spc2호
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• pp.835-844
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• 2019

본 연구는 댐에 의해 유사공급이 제한되는 댐하류 하천에서 자연성 회복을 위한 근본적 방안으로서 댐 건설 후 감소된 유사의 공급과 이송능력을 회복하기 위하여 인공적으로 하천에 모래와 자갈과 같은 토사를 공급하는 하천 유사환원 연구 기술을 체계적으로 고찰하였다. 유사환원의 목적을 초기의 수질 개선과 어류의 인공산란처 조성에서부터, 이후 저수지 퇴사대책, 하천구조물 안전성 유지, 그리고 최근의 하천의 지형형성 과정 회복까지 다섯 개로 구분하여 제시하였으며, 이러한 사업 목적에 따른 공급토사의 크기, 공급량, 현장에서 적용되는 공급방법과 모니터링 방안을 국내외 연구사례를 들어 체계적으로 고찰하였다. 앞으로 국내 하천관리에서 환경유량과 유사환원이 연계된 통합 하천관리 기술발전에 기여하기를 기대한다.

• 물과 미래
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• 제9권2호
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• pp.67-75
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• 1976

With 9 existng reservoirs selected in the Sab-Gyo River Basin, the sedimentation of the reservoirs has been calculated by comparing the present capacity with the original value, which revealed its reduced reservoirs capacity. The reservoirs has a total drainage area of 6,792 ha, with a total capacity of 1,204.09 ha-m, and are short of water supply due to reduction of reservoirs capacity. Annual sedimention in the reservcire is relation to the drainage area, the mean of annual rain fall, and the slop of drainage area. The results of obtained from the investigation are summarized as follow; (1) A sediment deposition rate is very high, being about $9.19{m}^3/ha$ of drainage area, and resulting in the average decrease of reservoir capacity by 19.1%. This high rate of deposition could be mainly attributed to the serve denvdation of forests due to disor derly cuttings of tree. (2) An average unit storage of 415.8mm as the time of initial construation is decreesed to 315.59mm at present, as resultting, we could'nt supply water at 566.24ha. (3) A sediment deposition rate as a relation to the capacity of unit drainage area is as follow; $Qs=1.43 (c/a)^{0.531}$ (4) A sediment deposition rate as a relation to the mean of annval rainfall is as follow; $Qs=672.61 p^{0.024}$ (5) A sediment deposition rate as a relation to the mean slop of drainage area is follow; $Qs=267.21 S^{0.597}$

• 한국환경과학회지
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• 제2권2호
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• pp.153-160
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• 1993

산지유역에서 토사공급과 이동에 관한 문제는 동적지형학뿐만 아니 수문학적 순환의 입장에서 매우 중요하다. 토사유출 자연의 개변정도등 지형학적 요인에 크게 지배된다. 본 연구에서는 강우시 자연의 개변정도가 서로 다른 유역에서 유출되는 부류토량을 비교하여 부류토사 유출과정과 메타니즘을 알아 보았다. 강우강도가 유사한 30mm의 비가 내렸을때 채석장이 분포하고 있는 인공개변유역의 부유토사농도는 최고 27,000mg/l인 반면, 백연유역의 부유토사농도는 270mg/l에 불과해 100배 정도의 농도차이가 나타났다. 또 인공개역중에서도 인공개변도에 따라 최대부유토사양도 6,400mg/l에서 27,000mg/l까지 다양하게 관측되었다. 일반적으로 부유토사 공급원은 자연유역의 경우 하상, 하안, 그리고 하도주변하도입이며, 인공개변유역은 사면등의 하도외 지역이다.