• Journal of the Korean Association of Geographic Information Studies
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• v.7 no.1
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• pp.94-104
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• 2004

The purpose of this study is to analyze various hydraulic characteristics using SMS (Surface Water Modeling System) RMA2 model. It is based on 2-D finite element method. River reaches (13.8km) from Gyeongan gauge station to the inlet of Paldang lake was selected. Finite element was made by RIMGIS Data, and the analysis of river-changes was operated by unsteady flow. The sediment concentration and bed change was simulated using SED2D model. This River's velocity was distributed that 0.05~3.85m/s and bed change was changed about 0.0003~0.0135m.

• Journal of Wetlands Research
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• v.19 no.4
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• pp.542-550
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• 2017

The estimations of flow characteristics and river-bed erosion or sedimentation are very important for hydraulic structure design, floodplain management, and especially, river management. The objective of the study is therefore to estimate the change of flow characteristics and river-bed change due to a hydraulic structure construction. With 11.65 km study area of the Geum River which are located in downstream of Daecheong Dam, flow characteristics and river-bed change were estimated based on the RMA2 and SED2D model. As the result of the study, the increase of river-bed sedimentation in upstream and river-bed erosion in downstream were occurred by the construction of hydraulic structure.

• Journal of Korean Society of Disaster and Security
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• v.12 no.2
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• pp.35-45
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• 2019

The enlargement and reduction of river channels can not only change the flow of water but also alter sedimentation patterns, thus hindering smooth flood conveyance. Accordingly, this study aims to analyze the effects of the sudden enlargement of river channels on changes in the riverbed and river flow. For this purpose, as part of the "Hometown River" Construction Project, this study examined the local river Kyungpo-cheon, which a section of the river channel was widened by at least two- to three-fold, using RMA-2 and SED-2D models to simulate the changes in flow characteristics and riverbed variation due to the widening of the channel. The results of the study indicated that widening the Kyungpo -cheon river channel secured its dimensional stability in comparison to before widening. however, due to a flood frequency of more than once per year, future maintenance and management will be costly and time-consuming.

• Journal of Korea Water Resources Association
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• v.51 no.1
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• pp.61-70
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• 2018

This study examined how to determine the optimal sediment level in dam reservoir for efficient plan and operation of dam. Currently, Korea is applying a horizontally accumulated method for sediment level estimation for the safety design of dam and so the method estimated relatively higher level than others. However, the sediment level of dam reservoir should be accurately estimated because it is an important factor in assessing life cycle of a dam. The sediment level in dam reservoir can be determined by SED-2D model linked with RMA-2, horizontally accumulated method, area increment method, and empirical area reduction method. The estimated sediment level from each method was compared with the observed sediment level measured in 2007 in Imha dam reservoir, Korea and then the optimal method was determined. Also, the future sediment level was predicted by each method for the future trend analysis of sediment level. As the results, the most accurate sediment level was estimated by the empirical area reduction method and the future trend of sediment level variation followed the past trend. Therefore, we have found that the empirical area reduction method is a proper one for more accurate estimation of sediment level and it can be validated by the results from a numerical model of SED-2D linked with RMA-2 model.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.519-522
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• 2003

The purpose of this study is to analyze various hydraulic characteristics using SMS (Surface Water Modelling System) RMA2 model. It is based on 2-D finite element method. River reaches (13.8km) from Gyeongan gauge station to the inlet of Paldang lake was selected. Finite element was made by RIMGIS Data, and the analysis of river-changes was operated by unsteady flow. The sediment concentration and bed change was simulated using SED2D model.

• Journal of Korea Water Resources Association
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• v.47 no.8
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• pp.729-742
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• 2014

This study predicted long-term sediment distribution for 76 years by using RMA-2 which is two-dimensional numerical model and SED2D which is the sediment transport model to quantitatively analyze sediment distribution in the reservoir based on sediment intrusion and efficiently manage the reservoir. For water level-discharge-sediment data required in boundary conditions of the model, real-time data measured by the Korea Water Resources Corporation were used. The sediment input data was calculated using K-DRUM model. Sedimentation depth was compared with results of model by collecting cross-section core in the reservoir during the dry season. As the result of validation, the sediment depth in the reservoir was similar to actually measured value. For prediction of long-term sediment distribution, terrain data measured in 2012 was used as starting crosssection and simulations for 76 years until 2088 were made. As the results of simulations, sediment distributions of 1.63~1.26 m and 1.45~0.007 m were shown in upstream and downstream of Hapcheon Dam, respectively.

• Journal of the Korean Society of Hazard Mitigation
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• v.6 no.1 s.20
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• pp.69-81
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• 2006

The purpose of this study is to identify the downstream influences due to the dam discharge by using 2-dimensional model, SMS(Surface water Modeling System). RMA-2 and SED-2D in SMS were applied to Yongdam multipurpose dam watershed located in Gum river basin. Through the simulation, erosion and deposit quantitative analysis of sinuous channels and scour pattern analysis of bridges have been done. A differences erosion depths between deposit are simulated as $-102.4 mm{\sim}54.2 mm$ at No.176(1.4 km) and $-104.1 mm{\sim}28.9 mm$ at No.146(7.4 km), sinuous channel. The river bed at Kamdong bridge in straight channal is simulated as uniform erosion. However, the river bed at Dumdul bridge in sinuous channal has been shown as different erosion depths at each sides. Consequently, the parts that could not be simulated on the existing 1-dimensional model, can be improved results by using a 2-dimensional model, about weakness points for hydraulic modeling such as extreme bend, tributary confluence.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.908-911
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• 2004

The purpose of this study is to investigate the applicability of the two dimensional model in natural rivers. In this study, two dimensional unite element model, SMS, is used to simulate a complex flow along with the sediment movements in the natural river. The RMA-2 model embeded in SMS is used to simulate flow phenomena and SED-2D model is employed to simulate sediment transport. The model is applied to the confluence zone of the Gam River and mouth of Nakdong River. For model calibration, the result of the unsteady flow analysis is compared with the Typhoon 'Rusa' data. In addition, the runoff analysis was conducted for the determination of the project flood and the flood forecasting. The simulation results presented the characteristics of two dimensional flow with velocity vector and flow depth. The sediment transport characteristics are shown in terms of sediment concentration as well as bed elevation change. Accordingly, the SMS model in this study turned out to be very effective tool for the simulation of the hydrodynamic characteristics under the various flow conditions and corresponding sediment transports in natural rivers.

• Journal of Wetlands Research
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• v.16 no.1
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• pp.139-151
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• 2014

In this study, virtual confluence of $30^{\circ}$, $45^{\circ}$, $60^{\circ}$, $75^{\circ}$ type flowing into main channel was designed to comprehend occlusion phenomenon of the mouth of river, then performed numerical analysis using the RMA-2 and SED2D model of SMS according to application of 40m, 60m, 80m, 100m Training levee corresponding to main channel width ratio. Results of simulations analysis are summarized as follows. Applying appropriate Training levee length determined by numerical analysis results, Training levee dimension for occlusion reduction was studied through the analysis of velocity, water level, bed variation at the Gamchen confluence and Wichen confluence.

• Journal of Wetlands Research
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• v.14 no.4
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• pp.715-723
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• 2012

The Hoelyongpo in the Naeseong River as tributary basin of the Nakdong River is broadly well-known a tourist attraction, which is made of sandy beach, and is called "Island of Inland". But Construction of the Dam was planned at upstream of river. In other words, an influx of sediment is blocked from upstream of river. In this situation, through sediment discharge coming from tributary of the Naeseong river, the whether to go ahead of sand beach of the Hoelyongpo is analyzed by using 1-D and 2-D model. The sediment discharge is estimated through ratio raw with basin area, and the instream flow requirement of river coming from dam and the flow rate and sediment coming from tributary are inputted for model. The 1-D model uses HEC-6 and the 2-D model uses SMS(RMA2 and SED2D). The analysis using the HEC-6 is performed from cross section data 10 year ago to the present cross section. Consequently, Yang equation presenting similar result to the present cross section data is determined, using this, the prediction is conducted for the cross section after 20 years. The 2-D analysis is conducted for the present cross section data. The value of distinction between a deposition and erosion with the results presented in the 1, 2-D models is occur, however, the appearance between the deposition and the erosion is similar.