• Korean Journal of Hydrosciences
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• 제4권
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• pp.11-19
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• 1993

The peak flood discharge at a downstream station and the flood travel time between a pair of dams due to a specific flood release from the upper reservoir are computed using a hydraulic river channel routing method. The study covered the whole large reservoir system in the Han River, Korea. The computed flood discharges and the travel times between dams were correlated with the duration and the magnitude of flood release rate at the upstream reservoir, and hence a multiple regression model is proposed for each river reach between a pair of dams. The peak flood discharge at a downstream location can be converted to the peak flood stage by a rating curve. Hence, the proposed regression model could be used to forecast the peak flood stage at a downstream location and the flood travel time between dams using the information on the flood travel time, release rate and duration from the upper dam.

• 융합정보논문지
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• 제11권12호
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• pp.115-126
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• 2021

본 연구에서는 내외수 범람을 동시에 고려하여 침수해석을 수행하는 시뮬레이션 모형을 개발하였다. 외수 침수해석을 위해 제방 월류 및 파제에 의한 하천범람 유입량을 고려할 수 있도록 하였고, 내수 침수해석을 위해서 이중배수체계 개념을 반영하도록 구성하였다. 지표면 침수해석과 관련하여 하천의 유동해석과 제내지의 유동해석을 통합적으로 수행하기 위해 유한요소법(FEM)을 적용하여 침수확산 해석을 수행할 수 있도록 하였다. 모형의 검증을 위해 우선 개념모델에 대해서 적용하였고, 이어서 실제 유역에 대해서 적용하였다. 본 연구를 통해 홍수로 인한 피해를 줄이고 홍수 피해를 저감하기 위한 효과적인 대책을 마련하기 위해 활용될 수 있을 것으로 기대된다.

• 한국농공학회지
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• 제21권1호
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• pp.13-23
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• 1979

The predictien of a design flood hydrograph at a particular site on a river may be based on the derivation of a discharge or stage hydrograph at an upstream section, together with a method to route this hydrograph along the rest of the river. In order to limit this investigation to cases where the assumption like uniform rainfall may be reasonably valid, the derivation of unit hydrographs has been limited to catchment with an area less than 500 km2. Consequently, flood routing methods provide a useful tool for the analysis of flooding in all but the smaller catchment, particularly where the shape of the hydrograph as well as the peak value is required. The author, therefore, will introduce here a flood routing method on the open channel with a peak discharge of the catchment area concerned. The importance of being able to route floods accurately is also reflected in the large number of flood routing method which have been developed since the year 1900. There are the modified puls method, Steinberg method, Goodrich method, Ekdahl method, Tatum's mean continuously Equation, wisler-Brater method, Muskingum, chung, and Muskingum-cunge (M-C) method and so on. The author will try to introduce a flood routing method which is revised Muskingum-cunge method. In calculating flood routing by the M-C method, whole variable parameters on the river were assumed to almost uniform values from the upstream to the downstream. In the results, the controlled flood rates at the 40km downstream on the river is appeared to decrease 22m$^3$/sec or 12 percent of the peak flood 170m$^3$/sec.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2016년도 학술발표회
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• pp.195-195
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• 2016

Kon - Ha Thanh River basin is the largest and the most important river basin in Binh Dinh, a province in the South Central Coast of Vietnam. In the lower rivers, frequent flooding and inundation caused by heavy rains, upstream flood and or uncontrolled flood released from upstream reservoirs, are very serious, causing damage to agriculture, socio-economic activity, human livelihood, property and lives. The damage is expected to increase in the future as a result of climate change. An advanced flood warning system could provide achievable non-structural measures for reducing such damages. In this study, we applied a modelling system which intergrates a 1-D river flow model and a 2-D surface flow model for simulating hydrodynamic flows in the river system and floodplain inundation. In the model, exchange of flows between the river and surface floodplain is calculated through established links, which determine the overflow from river nodes to surface grids or vice versa. These occur due to overtopping or failure of the levee when water height surpasses levee height. A GIS based comprehensive raster database of different spatial data layers was prepared and used in the model that incorporated detailed information about urban terrain features like embankments, roads, bridges, culverts, etc. in the simulation. The model calibration and validation were made using observed data in some gauging stations and flood extents in the floodplain. This research serves as an example how advanced modelling combined with GIS data can be used to support the development of efficient strategies for flood emergency and evacuation but also for designing flood mitigation measures.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2015년도 학술발표회
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• pp.173-173
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• 2015

The flood water level in tidal river is determined by the joint effects of flood discharge and tidal water levels at downstream boundary. Due to the variable tidal boundary conditions, the evaluated design water levels associated with a certain flood event can be significantly different. To avoid determining of design water levels just by a certain tidal boundary condition and remove the influence of variability in boundary condition from the evaluation of design water levels, a probabilistic approach is considered in this study. This study focuses on the development of a method to evaluate the realistic design water levels in tidal river with taking into account the combined effects of river discharge and tidal level. The flood water levels are described by the joint probability of two driving forces, river discharge and tidal water levels. The developed method is applied to determine design water levels for the tidal reach of the Han River. An unsteady flow model is used to simulate the flow in the reach. To determine design water levels associated with a certain flood event, first, possible boundary conditions are obtained by sampling starting times of tidal level time series; then for each tidal boundary condition, corresponding peak water levels along the channel are computed; and finally, design water levels are determined by computing the expectations of the peak water levels. Two types of tides which are composed by different constituents are assumed (one is composed by $M_2$, and the other one is composed by $M_2$ and $M_2$) at downstream boundary, and two flood events with different maximum flood discharges are considered in this study. It is found that (a) the computed design water levels with two assumed tides have no significant difference for a certain flood event, though variability of peak water levels due to the tidal effect is considerably different; (b) tidal effect can reach to the Jamsil submerged weir and the effect is obvious in the downstream reach of the Singok submerged weir; (c) in the tidally affected reach, the variability of peak water levels due to the tidal effect is greater if the maximum flood discharge is smaller.

• 한국수자원학회논문집
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• 제50권9호
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• pp.617-625
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• 2017

본 연구에서는 조석의 영향을 주기적으로 받는 임진강 하류부의 계획홍수위를 보다 합리적으로 산정하는 방안을 검토해 보았다. 우선 감조하천의 특성을 감안할 수 있는 부정류모의를 수행하여 홍수위의 변동을 살펴보았고, 수위 계산에 민감한 매개변수인 조도계수를 해당지역의 특성에 맞게 현실화하여 홍수위 변화를 분석하였다. 그 결과를 2011년 임진강하천기본계획보고서에서 고시한 임진강 하구 계획홍수위와 비교하고, 감조구간에서 홍수위 산정시 유의해야 할 점들을 정리하였다. 참고로 2011년에 고시된 계획홍수위는 대규모 하상 준설 단면을 입력자료로 하여 부등류모의를 통해 산정된 바 있다. 본 연구의 결과, 임진강 하구의 경우 홍수위 산정에 있어서 조도계수를 한강하구와 동일한 값으로 할당하고, 하구 조위를 감안할 수 있는 부정류 모의를 수행하면 하상 준설을 하지 않더라도 홍수위가 제방 여유고를 만족함을 알 수 있었다.

• 농업과학연구
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• 제46권4호
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• pp.843-856
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• 2019

Real-time flood prediction has an important role in significantly reducing potential damage caused by floods for urban residential areas located downstream of river basins. This paper presents an effective approach for flood forecasting based on the construction of a deep neural network (DNN) model. In addition, this research depends closely on the open-source software library, TensorFlow, which was developed by Google for machine and deep learning applications and research. The proposed model was applied to forecast the flowrate one, two, and three days in advance at the Son Tay hydrological station on the Red River, Vietnam. The input data of the model was a series of discharge data observed at five gauge stations on the Red River system, without requiring rainfall data, water levels and topographic characteristics. The research results indicate that the DNN model achieved a high performance for flood forecasting even though only a modest amount of data is required. When forecasting one and two days in advance, the Nash-Sutcliffe Efficiency (NSE) reached 0.993 and 0.938, respectively. The findings of this study suggest that the DNN model can be used to construct a real-time flood warning system on the Red River and for other river basins in Vietnam.

• 한국지반환경공학회 논문집
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• 제15권1호
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• pp.69-77
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• 2014

본 연구의 목적은 소하천 유역에 대한 홍수범람해석 모형을 비교하는 것이다. 검청천을 대상으로 1차원 수리모형인 HEC-RAS와 범람해석을 위한 HEC-GeoRAS, RAS Mapper, RiverCAD 모형을 적용하여 홍수범람해석을 수행하였다. 실측 강우량과 빈도별 홍수량을 적용하여 3가지 모형에 따른 홍수범람해석을 모의하였으며, 해석결과와 당시 조사된 침수흔적도를 비교하고 각 모형들의 빈도별, 침수심별에 따라 홍수범람면적을 비교하였다. 실측 강우량을 적용하여 해석된 홍수범람면적은 HEC-GeoRAS 모형의 결과가 침수흔적도와 비교적 유사하게 나타났다. 또한, 빈도별 설계홍수량을 적용하여 해석된 범람면적은 RAS Mapper 모형이 가장 크게 나타났으며, 3가지 모형의 전체 범람면적 차이가 10% 이내로 비교적 유사한 결과를 나타내었다. 침수심별 범람면적을 비교한 결과 침수심 2.0 m 이하 구간에서는 3가지 모형의 결과가 비교적 유사하게 나타났으며, 침수심 2.0 m 이상의 구간에서 RiverCAD 모형의 범람면적이 비교적 큰 차이를 나타내었다.

• 산업경영시스템학회지
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• 제38권1호
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• pp.118-123
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• 2015

There have been various studies on measurements of flood risk and forecasting models. For river and dam region, PDF and FVI has been proposed for measurement of flood risk and regression models have been applied for forecasting model. For Bo region unlikely river or dam region, flood risk would unexpectedly increase due to outgoing water to keep water amount under the designated risk level even the drain system could hardly manage the water amount. GFI and general linear model was proposed for flood risk measurement and forecasting model. In this paper, FVI with the consideration of duration on GFI was proposed for flood risk measurement at Bo region. General linear model was applied to the empirical data from Bo region of Nadong river to derive the forecasting model of FVI at three different values of Base High Level, 2m, 2.5m and 3m. The significant predictor variables on the target variable, FVI were as follows: ground water level based on sea level with negative effect, difference between ground altitude of ground water and river level with negative effect, and difference between ground water level and river level after Bo water being filled with positive sign for quantitative variables. And for qualitative variable, effective soil depth and ground soil type were significant for FVI.

• 한국습지학회지
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• 제9권3호
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• pp.25-34
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• 2007

본 연구는 도심지 유역인 경기도 부천 여월동 단지 내의 도시하천에 대해서 유출 및 홍수 특성을 분석하였다. 해당 유역의 하천은 차집 관로에 의한 생활하수와 흐름의 차단으로 인하여 평상시에는 매우 적은 유량만이 흐르고 있으나, 홍수 시에는 상대적으로 높은 홍수위로 인해 홍수 피해의 위험성을 보이고 있다. 홍수에 대한 안전성을 확인하기 위하여 유출 해석 모형을 적용하고, 또한 해당 유역에 대해 구축된 GIS 자료 및 하천 단면과 HEC-RAS를 이용, 홍수위를 예측하여 이를 바탕으로 해당 하천의 치수 안정성을 검토하였다. 검토 결과 다목적 소하천을 목적으로 설치된 하천 구조물로 인하여 홍수 피해 발생 위험이 있었으며, 하천 안정성에 대한 불안요소를 포함하고 있었다. 이러한 단지내 소규모의 도시유역에 대한 홍수 유출 해석에서는 홍수 유출 외에도 구조물에 의한 배수위 변동과 유속 등과 같은 여러 위험 요인에 대하여 함께 고려해야 할 것으로 판단된다.