• 한국방재학회 논문집
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• 제6권4호통권23호
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• pp.57-65
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• 2006

본 연구에서는 본류와 지류가 만나는 합류구간, 만곡 및 사행구간이 있는 자연하천과 동일한수리모형을 제작하고 합류부를 중심으로 본류와 지류의 유량비 변화에 따라 모형의 합류부 횡단면에서 발생하는 수위차의 변화를 분석하였다. 합류이전의 최하류단면 수위를 기준으로 하는 합류부 각 단면의 최대수위 변화에 미치는 유량비의 영향은 합류부 하류구간보다 상류구간에서 더 크게 나타난다. 횡단면의 최소수위에 대한 최대수위의 변화는 합류부 중심에 가까울수록 증가하며 합류부 중심 직하류에서 최대를 보인다. 또한 합류구간 횡단면의 수면경사는 단면형태에 따라 영향을 받으며 본류에 대한 지류의 유량비가 감소할수록 수면경사도 감소한다. 기존에 제안된 일정한 곡률반경과 정형화된 단면에서 도출된 횡단면 수위차 산정 공식이 평창강과 동일하게 제작된 모형수로에서 실측값과 약 60%의 차이를 보인 반면 본 연구에서는 실측값과 약 10%의 차이를 보이는 수위차 산정 공식을 제안하였다.

• 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.

• 한국농공학회지
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• 제37권E호
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• pp.55-62
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• 1995

The topographic influences for the hydraulic characteristics in the estuary were studied by the hydraulic model test. The upstream boundary is set up at the Kumkang estuary dike and the downstream boundary at the Kunsan outer port. The geometrical model scales in horizontal and vertical are 1/300 and 1/100 respectively so that the distorted ratio is 3. If there is no or little river flow through the gate, the highest water levels are varied with $\pm$ 5cm compared with those before the project. If there is a flood flow through the gate, the highest water levels in front of the estuary dike are reduced 5~2Ocm depending on the frequency of flood compared with those before the project. This means that there is no important risk of excessive water level rise after the dredging.

• 한국정보통신학회논문지
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• 제24권2호
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• pp.198-203
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• 2020

본 논문에서는 소규모 강의 범람 예측을 위한 인공 수위 예측 시스템을 제안한다. 강의 수위 예측은 홍수 피해를 줄일 수 있는 대책이 될 수 있다. 그러나 하천 범람에 영향을 미치는 강 또는 강우의 고유 특성으로 인해 범람 모델을 구축하기가 어렵다. 일반적으로 하류 수위는 상류의 인접한 수위에 영향을 받는다. 따라서 본 연구에서는 측정 지점에서 수위를 예측하기 위해 두 개의 상류 측정 지점의 수위를 순환신경망(LSTM)을 사용하여 인공 지능 모델을 구축했다. 제안 된 인공 지능 시스템은 수위 측정기를 설계하고 Nodejs를 사용하여 서버를 구축했다. 제안 된 신경망 하드웨어 시스템은 실제 강에서 6시간마다 수위를 잘 예측함을 알 수 있었다.

• 환경영향평가
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• 제21권1호
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• pp.81-91
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• 2012

In this study, it is grasped the status of nutrients through an investigation of release characteristics and physicochemical properties of sediments on reservoir. And then the effect of sediments is evaluated on the water quality in reservoir. In the results of physicochemical analysis, the pollution level of midstream is the highest, which shows the traits that the water is more deeper and takes place a deposition consistently. Then, the pollution level of upstream is higher than downstream's because inflow has influence on the upstream directly. The downstream is located near tidal gate so that the soil particles can be moved easily and are difficult to be deposited due to the distribution of seawater by control of tidal gate. Therefore, the downstream is showed the lowest pollution level than the others. Also, the concentration of SOD(Sediment Oxygen Demand) in the upstream which is influenced on the effect of inflow is highest than the others. When it analyzes under anaerobic and aerobic condition to understand the release characteristic of sediment, it shows that the release rate is low or negative under the aerobic condition. Whereas the release rate is usually positive under the unaerobic condition relatively. According to these results, it is necessary to maintain the proper environmental factors of water body for decreasing the release rate of sediment. Because the release rate is changeable under the different condition of water body. Therefore, proper strategies are required for increasing the self-purification of water as well as keeping the aerobic condition of sediment and managing a sediment layer directly to control the inner-pollution by the sediment of reservoir.

• 농업과학연구
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• 제50권3호
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• pp.331-347
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• 2023

The downstream submergence damages caused during the flood season in 2020, around the Yongdam-dam and five other sites, were analyzed using related dam management data. Hourly- and daily-data were collected from public national websites and to conduct various analyses, such as autocorrelation, partial-correlation, stationary test, trend test, Granger causality, Rescaled analysis, and principal statistical analysis, to find the cause of the catastrophic damages in 2020. The damage surrounding the Yongdam-dam in 2020 was confirmed to be caused by mis-management of the flood season water level. A similar pattern was found downstream of the Namgang- and Hapcheon-dams, however the damage caused via discharges from these dams in same year is uncertain. Conversely, a different pattern from that of the Yongdam-dam was seen in the areas downstream of Sumjingang- and Daecheongdams, in which the management of the flood season water level appeared appropriate and hence, the damages is assumed to have occurred via the increase in the absolute discharge amount from the dams and flood control capacity leakage of the downstream river. Because of the non-stationarity of the management data, we adapted the wavelet transform analysis to observe the behaviors of the dam management data in detail. Based on the results, an increasing trend in the discharge amount was observed from the dams after the year 2000, which may serve as a warning about similar trends in the future. Therefore, additional and continuous research on downstream safety against dam discharges is necessary.

• 한국수자원학회논문집
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• 제56권5호
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• pp.357-362
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• 2023

상류지역과 하류지역간 갈등은 우리나라의 대표적인 사회적 갈등이자 물갈등에 해당하는 사례로 이해당사자들에게는 재산권 침해와 수질보전 및 이용이라는 이념과 이익을 기반으로 경제적, 환경적 측면에서 이해관계가 첨예한 문제이다. 그러나 각 지역에서 느끼는 경제적 피해 및 편익에 대한 연구는 미흡한 실정이며 각 지역의 주장에만 근거하고 있어 갈등해결을 위한 방안을 도출하는데 어려움에 직면하고 있다. 본 연구에서는 우리나라의 주요한 물갈등의 하나인 상수원보호구역을 대상으로 상류지역의 재산권제약으로 인한 사회적 손실과 수질보전으로 인한 하류지역의 사회적 편익을 비교하여 상수원보호구역의 타당성을 검증하고 갈등해결을 위한 유역통합물관리 정책을 제언하였다.

• 한국수자원학회논문집
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• 제55권12호
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• pp.1021-1030
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• 2022

최근 우리나라의 물 관련 정책은 수량-수질-수생태 통합관리 방향으로 진행되고 있으며, 특히 하천의 자연성 회복이 주요한 이슈가 되고 있다. 이수기 댐 운영에 있어서는 가뭄, 물 수요 증가 등으로 용수공급 효과를 극대화시킬 수 있는 부족분 공급방식을 적용하고자하는 시도들이 이어지고 있다. 댐 운영에 부족분 공급방식을 적용하면 댐의 용수공급능력을 극대화 시킬 수는 있지만 하류 하천의 유량이 일정하게 유지된다는 특징이 있다. 자연하천은 오랜 시간동안 형성된 하나의 생태계로 유량의 변동성에 큰 영향을 받는다. 결국 부족분 공급방식을 적용한 댐 운영은 수량 관리에서는 효과적이지만 하천의 자연성 회복 및 수생태 측면에서는 부정적 영향을 미칠 수있다. 본 연구에서는 저수지 모의를 통해 보장량 공급방식, 부족분 공급방식, 선택적 부족분 공급방식 등의 댐 운영이 하류 하천 유황에 미치는 영향을 분석하고, 각 운영방식의 적용 효과에 대해 분석하고자 하였다. 그 결과 보장량 공급방식을 적용하면 하천의 유량 변동성은 크게 유지할 수 있으나 댐의 용수공급능력은 크지 않은 것으로 나타났다. 부족분 공급방식을 활용하면 용수공급능력을 증대시킬 수는 있으나 하류의 평수량과 갈수량의 차이가 매우 작아 유량의 변동성 측면에서는 매우 취약한 것으로 확인되었다. 선택적 부족분 공급방식을 적용할 경우 기간신뢰도를 95% 이상으로 유지하며, 하류 하천의 유황은 보장량 공급방식을 적용할 때와 유사하게 유지할 수 있는 것으로 분석되었다.

• 한국물환경학회지
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• 제22권5호
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• pp.887-894
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• 2006

Water quality in the Daecheong reservoir has been deteriorated by algal bloom every year. Algal bloom is propagated from eutrophicated tributary into the main body of the reservoir during the wet season. Nutrients from diffuse sources trigger the propagation of the algal bloom. This study is aimed to analyze relationship between the water current by the simulation and algae transport from the main body in the Daecheong reservoir including tributary where algal bloom has occurred seriously every year. Water quality model CE-QUAL-W2 was applied to analyze water movement in draught season (2001) and flooding season (2003). The result of simulation corresponded with the observed water elevation level, 63~80 m and showed stratification of the Daecheong reservoir. In the draught season, as velocity and direction off low in the reservoir was estimated to affect algae transport including nutrient supply from small tributary, algal blooms occurred in the stagnate zone of middle stream of the reservoir. On the other hand, in the flooding season, it was resulted in nutrient transport from upstream of main reservoir and nutrients were delivered up to downstream by fast water velocity. In result, algal blooms occurred in stagnate zone of reservoir downstream as the current of downstream was retarded according to dam outflow control.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
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• pp.486-492
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• 1999

One of the purpose of the reservoir operation is minimizing theinnudation area in the downstream reaches during flood period.l To execute the gate operation properly , it requires lots of real-time data such as rainfall, reservoir level, and water level in the downstrea. Gate operation model was developed with the flood discharge obtained from real-time flood forecasting model and the criterion prepared from the past history of gate operation. Water level in the downstream would be increased by the releasing discharge from the spillway and the area of paddy land flooded in a certain detph and time would be estimated usnig GIS map. Gate operation model was applied to the Yedang reservoir, and the flooded area, depth and time in the paddy land was estimaged.