• Title/Summary/Keyword: Catchment

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A Comparative Analysis on Slope Stability Using Specific Catchment Area Calculation (비 집수면적 산정기법에 따른 사면 안정성 비교·분석)

  • Lee, Gi-Ha;Oh, Sung-Ryul;An, Hyun-Uk;Jung, Kwan-Sue
    • Journal of Korea Water Resources Association
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    • v.45 no.7
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    • pp.643-656
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    • 2012

  • There has been an increase for the landslide areas and restoration expenses due, in large part, to the increased locally heavy rains caused by recent climate change as well as the reckless development. This study carried out a slope stability analysis by the application of distributed wetness index, using the GIS-based infinite slope stability model, which took the root cohesion effect into consideration, for part of Mt. Umyeon in Seoul, where landslide occurred in July 2011, in order to compensate the defects of existing analysis method, and subsequently compared its result with the case on the exploitation of lumped wetness index. In addition, this study estimated the distributed wetness index by methodology, applying three methods of specific catchment area calculation: single flow direction (SFD), multiple flow direction (MFD), and infinity flow direction (IFD), for catchment area, one of the variables of distributed wetness indices, and finally implemented a series of comparative analysis for slope stability by methodology. The simulation results showed that most unstable areas within the study site were dominantly located in cutting-area surroundings along with the residential area and the mountaintop and unstable areas of IFD and lumped wetness index method were similar while SFD and MFD provided smaller unstable areas than the two former methods.

  • https://doi.org/10.3741/JKWRA.2012.45.7.643 인용 PDF KSCI

Discharge Estimation at Ungauged Catchment Using Distributed Rainfall-Runoff Model (분포형 강우-유출 모형을 이용한 미계측 중소유역의 유량 추정)

  • Choi, Yun-Seok;Kim, Kyung-Tak;Shim, Myung-Pil
    • Journal of Korea Water Resources Association
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    • v.43 no.4
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    • pp.353-365
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    • 2010

  • Generally, river discharge is measured at flood forecasting points, upstream dam points, large rivers, and important points over a basin, and it is hard to estimate discharge of medium or small stream and small catchment. Physically based rainfall-runoff model with geographical parameters can simulate discharge at all the points within a basin with optimized parameters for a point in the basin. In this study, GRM (Grid based Rainfall-runoff Model) calibrated at the outlet is applied. The discharge at upstream point is estimated and the possibility of model regionalisation is examined for ungauged catchment of small or medium stream within a river system. Wicheon and Boksu watershed in Nakdonggang (Riv.) and Yudeungcheon (Riv.) respectively are selected. The discharge at Miseong and Sindae station is simulated with the parameters estimated at Museong and Boksu station. The results of Miseong and Sindae station show good agreement with observed hydrographs in peak discharge and peak time and consistently linear relationships with high correlations in discharge volume, peak discharge, and peak time. And it shows GRM could be applied to estimate discharge at ungauged catchments along a river system.

  • https://doi.org/10.3741/JKWRA.2010.43.4.353 인용 PDF KSCI

Assessment of the Effect of Geographic Factors and Rainfall on Erosion and Deposition (지형학적 인자 및 강우량에 따른 침식 및 퇴적의 영향 평가)

  • Yu, Wan-Sik;Lee, Gi-Ha;Jung, Kwan-Sue
    • Journal of the Korean Society of Hazard Mitigation
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    • v.11 no.2
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    • pp.103-112
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    • 2011

  • This study aims to demonstrate the relationship between various factors and soil erosion or deposition, simulated from distributed rainfall-sediment-runoff model applications. We selected area, overland flow length, local slope as catchment representative characteristics among many important geographic factors and also used the grid-based accumulated rainfall as a representative hydro-climatic factor to assess the effect of these two different types of factors on erosion and deposition. The study catchment was divided based on the Strahler's stream order method for analysis of the relationship between area and erosion or deposition. Both erosion and deposition increased linearly as the catchment area became larger. Erosion occurred widely throughout the catchment, whereas deposition was observed at the grid-cells near the channel network with short overland flow lengths and mild slopes. In addition, the relationship results between grid-based accumulated rainfall and soil erosion or deposition showed that erosion increased gradually as rainfall amount increased, whereas deposition responded irregularly to variations in rainfall. Within the context of these results, it can be concluded that deposition is closely related with the geographic factors used in this study while erosion is significantly affected by rainfall.

  • https://doi.org/10.9798/KOSHAM.2011.11.2.103 인용 KSCI