• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.3
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• pp.13-21
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• 2007

Recently, very short-term rainfall forecast using radar is required for regional flash flood according to climate change. This research is to evaluate the feasibility of GIS based distributed model using radar rainfall which can express temporal and spatial distribution in actual dam watershed during flood runoff period. Vflo model which was developed Oklahoma university was used as physical based distributed model, and Namgang dam watershed ($2,293km^2$) was applied as study site. Distributed rainfall according to grid resolution was generated by using K-RainVieux, preprocess program of radar rainfall, from JIN radar. Also, GIS hydrological parameters were extracted from basic GIS data such as DEM, land cover and soil map, and used as input data of distributed model(Vflo). Results of this research can provide a base for building of real-time short-term rainfall runoff forecast system according to flash flood in near future.

• Journal of Korean Society on Water Environment
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• v.36 no.3
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• pp.229-244
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• 2020

Hydrologic models, as a useful tool for understanding the hydrologic phenomena in the watershed, have become more complex with the increase of computer performance. The hydrologic model, with complex configurations and powerful performance, facilitates a broader understanding of the effects of climate and soil in hydrologic partitioning. However, the more complex the model is, the more effort and time is required to drive the model, and the more parameters it uses, the less accessible to the user and less applicable to the ungauged watershed. Rather, a parsimonious hydrologic model may be effective in hydrologic modeling of the ungauged watershed. Thus, a semi-distributed hydrologic partitioning model was developed with minimal composition and number of parameters to improve applicability. In this study, the validity and performance of the proposed model were confirmed by applying it to the Namgang Dam, Andong Dam, Hapcheon Dam, and Milyang Dam watersheds among the Nakdong River watersheds. From the results of the application, it was confirmed that despite the simple model structure, the hydrologic partitioning process of the watershed can be modeled relatively well through three vertical layers comprising the surface layer, the soil layer, and the aquifer. Additionally, discussions were conducted on antecedent soil moisture conditions widely applied to stormwater estimation using the soil moisture data simulated by the proposed model.

• Journal of Korean Society on Water Environment
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• v.28 no.4
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• pp.582-594
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• 2012

A simple ecohydorlogic model that simulates hydrologic components and vegetation dynamics simultaneously based on equations of soil water dynamics and vegetation's growth and mortality is discussed. In order to simulate ungauged watersheds, the proposed model is calibrated with indirected estimated observation data set; 1) empirically estimated annual vaporization, 2) monthly surface runoff estimated by NRCS-CN method, and 3) vegetation fraction estimated by SPOT/VEGETATION NDVI. In order to check whether the model is performed well with indirectly estimated data or not, four upper dam watersheds (Andong, Habcheon, Namgang, Milyang) in Nakdong River watershed are selected, and the model is verified.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.724-728
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• 2010

강우강도의 증가와 식생대의 변화 등 기후변화로 인한 저수지내 대형탁수와 조류대발생으로 사회적 문제가 야기되고 있다. 이에 유역대책 평가와 저수지내 유체거동 및 영향평가를 위한 수단 확보가 절실한 상황이다. 본 연구에서는 국내 저수지에 대한 3차원 수리해석기술의 적용성을 검토하고자 하였다. 이를 위해 낙동강의 주요지류 중 하나인 남강에 위치한 남강댐에 대해 미 EPA의 오염총량지원도구인 EFDC 모델을 적용하였다. 저수지내 퇴사량 조사시 측정된 실측치와의 지형 재현성 검토, 실측수위와 모의결과의 비교를 그래프와 통계지표를 활용하여 실시하였고 염료 추적 모의를 통해 도달시간 등을 산정하였다.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.4
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• pp.24-32
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• 2005

Budget distribution system suporting dam area was changed largely in 2005, and thus, population survey and area calculation for dam and needed to be performed based upon the new criteria. According to the former regulations, dam area was confined to inside of 5km from the H.W.L-line. However, new regulations divide it into two categories : inside and outside of catchment area within 2km from the H. W. L-line and those belong to 2~5km from the same line. In this study, topography, DEM, TIN and Hydrological Unit Map were build for the analysis of the Namgang Dam area. It shows that analysis of dam area using GIS methods produces a good results to be used for rational distribution of budget.

• Journal of Korea Water Resources Association
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• v.55 no.9
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• pp.687-700
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• 2022

For comprehensively assessment the water resources performance of multi-purpose dams and water supply dams in South Korea, a methodology was proposed to utilize the durational reliability along with the integrated auxiliary indicators including resiliency, dimensionless vulnerability, water resource efficiency, specific inflow, and specific water supply. In addition, for the purpose of sustainable dam operation in the future, a plan to grade the water resources performance was presented to periodically evaluate the performance and determine the priority of each dam's structural or non-structural planning according to the evaluation results. As major results, in the case of Sumjingang Dam, the durational reliability was 99.0%, but the integrated auxiliary index was the lowest of 44 points, which was 5th grade. This means that despite the current high reliability, hydrological changes due to future climate change or regional change of water demand-supply balance can have significant impacts on the water resources performances. In contrast, the Chungju Dam with a durational reliability of 93.0%, which is below the average among all multi-purpose dams, shows the 76 points of the integrated auxiliary index, which is 3^rd highest following the Soyanggang Dam and the Namgang Dam. Nevertheless, due to the size of the basin, the specific inflow is sufficiently high as 185%, so the actual performance could be evaluated relatively high. The water supply dams designed for a single purpose tend to be evaluated relatively high because they have a high proportion of industrial and municipal water supply and have enough room for the supply capacity.

• Journal of Korea Water Resources Association
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• v.42 no.3
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• pp.259-270
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• 2009

The applicability of the developed distributed rainfall runoff model using a multi-directional flow allocation algorithm and a real-time updating algorithm was evaluated. The rainfall runoff processes were simulated for the events of the Andong dam basin and the Namgang dam basin using raingauge network data and weather radar rainfall data, respectively. Model parameters of the basins were estimated using previous storm event then those parameters were applied to a current storm event. The physical propriety of the multi-directional flow allocation algorithm for flow routing was validated by presenting the result of flow grouping for the Andong dam basin. Results demonstrated that the developed model has efficiency of simulation time with maintaining accuracy by applying the multi-directional flow allocation algorithm and it can obtain more accurate results by applying the real-time updating algorithm. In this study, we demonstrated the applicability of a distributed rainfall runoff model for the advanced basin-wide flood management.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5D
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• pp.749-757
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• 2008

Recently, flood damages have increased with heavy rainfall and typhoon influences, and it requires that visualization information to the flood inundation area of downstream in dam discharge. This study developed 3D GIS system that can visualize flood inundation area for Namgang Dam downstream. First, DEMs extracted from NGIS digital maps and IKONOS satellite images were optimized to mount in iWorld engine using TextureMaker and HeightMaker modules. And flood inundation area of downstream could be efficiently extracted with real-time flooding water level using Coordinate Operation System for Flood control In Multi-reservoir (COSFIM) and Flood Wave routing model (FLDWAV) in river cross section. This visualization information of flood inundation area can be used to examine flood weakness district needed in real time Dam operation and be applied to establish the rapid flood disaster countermeasures efficiently.

• Journal of Korean Society for Geospatial Information Science
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• v.18 no.4
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• pp.21-30
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• 2010

In this paper, the parallel distributed rainfall runoff model(K-DRUM) using MPI(Message Passing Interface) technique was developed to solve the problem of calculation time as it is one of the demerits of the distributed model for performing physical and complicated numerical calculations for large scale watersheds. The K-DRUM model which is based on GIS can simulate temporal and spatial distribution of surface flow and sub-surface flow during flood period, and input parameters of ASCII format as pre-process can be extracted using ArcView. The comparison studies were performed with various domain divisions in Namgang Dam watershed in case of typoon 'Ewiniar' at 2006. The numerical simulation using the cluster system was performed to check a parallelization effectiveness increasing the domain divisions from 1 to 25. As a result, the computer memory size reduced and the calculation time was decreased with increase of divided domains. And also, the tool was suggested in order to decreasing the discharge error on each domain connections. The result shows that the calculation and communication times in each domain have to repeats three times at each time steps in order to minimization of discharge error.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.5
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• pp.1039-1049
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• 2015

The inflow estimation at large multipurpose dam reservoir is carried out by considering the water balance among the discharge, the storage change during unit time interval obtained from the observed water level near dam structure and area-volume curve. This method can be ideal for level pool reservoir but include potential errors when the inflow is influenced by the water level slope due to backwater effects from upstream flood inflows and strong wind induced by typhoon. In addition, the other uncertainties arisen from the storage reduction due to sedimentation after the dam construction and water level noise due to mechanical vibration transmitted from the electric power generator. These uncertainties impedes the accurate hydraulic inflow measurement requiring exquisite hydrometric data arrangement for reservoir waterbody. In this study, the distributed hydrologic model using UBC-3P boundary setting was applied and its feasibility was evaluated. Finally, the modeling performance has been verified since the calculated determination coefficient has been in between 0.96 to 0.99 after comparing with observed peak inflow and total inflow at Namgang dam reservoir.