• Title/Summary/Keyword: Peak Runoff Volume

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Real-time Flood Forecasting Model for Irrigation Reservoir Using Simplex Method (최적화기법을 이용한 관개저수지의 실시간 홍수예측모형(수공))

  • 문종필;김태철
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2000.10a
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    • pp.390-396
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    • 2000
  • The basic concept of the model is minimizing the error range between forecasted flood inflow and actual flood inflow, and accurately forecasting the flood discharge some hours in advance depending on the concentration time(Tc) and soil moisture retention storage(Sa). Simplex method that is a multi-level optimization technique was used to search for the determination of the best parameters of RETFLO (REal-Time FLOod forecasting)model. The flood forecasting model developed was applied to several strom events of Yedang reservoir during past 10 years. Model perfomance was very good with relative errors of 10% for comparison of total runoff volume and with one hour delayed peak time.

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A Study on the Unit Hydrograph Derivation by the Triangular Form (삼각도형에 의한 단위도의 유도에 관한 연구)

  • Yun, Hak-Gi;Kim, Si-Won;Seo, Seung-Deok
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.19 no.2
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    • pp.4377-4384
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    • 1977
  • The curvilinear hydrograph can be replaced by an equivalent triangular hydrograph which is more easily constructed and, for routing through reservoirs or stream channels, gives results about as accurate as those obtained using the curvilinear hydrograph. A synthetic hydrograph is prepared using the data from a number of watersheds to develop a dimensionless unit hydrograph applicable to ungauged watersheds. The dimensionless unit hydrograph for the NakDong River Basin was prepared from the unit hydrographs of a variety of nine subwatersheds. The equation for the peak rate of flow (unit volume of runoff in 1.0mm) was derived as {{{{ { q}_{p } = { 0.21AR} over { {T }_{p } } }}}} The results summarized in this study are as follows: 1) It found that the watershed lag time (Lg, hrs) could be expressed by Lg=0.253(L.Lca)0.4171 The product L.Lca is a measure of the size and shape of the watershed. Correlation coefficient for Lg was 0.97 which defined with high significance. 2) The base length of the unitgraph, in hours, was adopted as Tb=17.51+2.073Lg with high significant correlation coefficient, 0.92. 3) Time in hour from start of rise to peak rate (TP) generally occured at the position of 0.289 Tb with some indication of higher values for larger watershed. 4) Triangular hydrograph is a dimensionless unitgraph prepared from the 40 unitgraphs. The equation is shown as {{{{ { q}_{p } = { K.A.R} over { { T}_{p } } }}}}. The constant K=0.21 is defined to NakDong River basin. 5) In the light of the results analyzed in this study, average errors in the peak discharge of the Trjangular unitgraph was estimated as 5.34 percent to the peak of observed average unitgraph. Each ordinate of the Triangular unitgraph was approached closely to the observed one.

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Analysis of Hydrologic Cycle and BOD Loads Using HSPF in the Anyancheon Watershed (HSPF 모형을 이용한 안양천 유역의 물순환 및 BOD 부하량 분석)

  • Lee, Kil-Seong;Chung, Eun-Sung;Lee, Joon-Seok;Hong, Won-Pyo
    • Journal of Korea Water Resources Association
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    • v.40 no.8
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    • pp.585-600
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    • 2007
  • The hydrologic cycle and BOD pollutant loads of all sub-watersheds were analyzed using HSPF (Hydrological Simulation Program-Fortran). At first, sensitivity analyses to water quantity (peak discharge and total volume) and quality (BOD peak concentrations and total loads) were conducted and some critical Parameters were selected. For more precise simulation, the study watershed was divided into four parts according to the landuse characteristics and used climate data and so calibrated and verified respectively. It was found that as the urban area ratio increases in the downstream direction, baseflow decreases (11.1 % $\rightarrow$ 5.0%) and the ratio of direct runoff volume(42.5 % $\rightarrow$ 56.9 %), BOD concentration (3.3 mg/L $\rightarrow$ 15.0 mg/L) and unit loads (55.4 kg/ha/year $\rightarrow$ 354.5 kg/ha/year) increase.

Yongdam Dam Watershed Flood Simulation Using GPM Satellite Data and KIMSTORM2 Distributed Storm Runoff Model (GPM위성 강우자료와 KIMSTORM2 분포형 유출모형을 이용한 용담댐 유역 홍수모의)

  • KIM, Se-Hoon;KIM, Jin-Uk;CHUNG, Jee-Hun;KIM, Seong-Joon
    • Journal of the Korean Association of Geographic Information Studies
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    • v.22 no.4
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    • pp.39-58
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    • 2019
  • This study performed the dam watershed storm runoff modeling using GPM(Global Precipitation Measurement) satellite rain and KIMSTORM2(KIneMatic wave STOrm Runoff Model 2) distributed model. For YongdamDam watershed(930㎢), three heavy rain events of 25th August 2014, 11th September 2017, and 26th June 2018 were selected and tested for 4 cases of spatial rainfalls such as (a) Kriging interpolated data using ground observed data at 7 stations, (b) original GPM data, (c) GPM corrected by CM(Conditional Merging), and GPM corrected by GDA(Geographical Differential Analysis). For the 4 kinds of data(Kriging, GPM, CM-GPM, and GDA-GPM), the KIMSTORM2 was calibrated respectively using the observed flood discharges at 3 water level gauge stations(Cheoncheon, Donghyang, and Yongdam) with parameters of initial soil moisture contents, stream Manning's roughness coefficient, and effective hydraulic conductivity. The total average Nash-Sutcliffe efficiency(NSE) for the 3 events and 3 stations was 0.94, 0.90, 0.94, and 0.94, determination coefficient(R2) was 0.96, 0.92, 0.97 and 0.96, the volume conservation index(VCI) was 1.03, 1.01, 1.03 and 1.02 for Kriging, GPM, CM-GPM, and GDA-GPM applications respectively. The CM-GPM and GDA-GPM showed better results than the original GPM application for peak runoff and runoff volume simulations, and they improved NSE, R2, and VCI results.

A Comparison and Analysis of Planning Models for the Design of Detention Pond in Urban Area (도시유역의 저류지 설계를 위한 계획모형 비교분석)

  • Lee, Jae-Joon;Kwak, Chang-Jae;Lee, Sang-Won
    • Journal of the Korean Society of Hazard Mitigation
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    • v.8 no.3
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    • pp.105-115
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    • 2008
  • Urbanization results in increased runoff volume and peak flowrate and shortening in time of concentration, which may cause frequent flooding downstream. There are various types of flow retardation methods including detention ponds, retention ponds, and infiltration ponds. In general, hydrologic models to design the detention pond are classified into planning model and design model. This study is comparing and analyzing of planning model to design the detention pond in urban area. Detention ponds data of Disaster Impact Assessment Report on 22 sites were analyzed to investigate proper planning models in this study. From this research, following conclusions are derived, 1) In case of on-line detention pond, Lee model(1991) is the best planning model and similar to real storage volume. 2) In case of off-line detention pond, Abt and Grigg model is much more proper model compared to other models.

Analysis of Infiltration Trench Facility for Runoff Reduction Effect (침투트렌치 시설의 유출저감 효과 분석)

  • Yeon, Jong Sang;Jang, Young Su;Shin, Hyun Suk;Kim, Eung Seok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.9
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    • pp.5813-5819
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    • 2014
  • LID planning and application has been actively developed to reduce the runoff volume at increased impervious areas due to rapid urbanization. In this study, a performance and applicability evaluation was performed in an infiltration trench using the SWMM model, based on the experimental conditions for infiltration trenches. The infiltration trench application area was applied to 5~15% of the drainage area. The SWMM results of discharge and the BOD reduction efficiency were analyzed at a peak discharge of 45.7~61.9%, total discharge of 47.2~62.3%, and BOD load of 52.3~55.3. The discharge and BOD was estimated to be 12~24% higher and 37~38% smaller than the experimental results. This study can help in the application and performance evaluation of infiltration trenches.

Pollutant Load Characteristics from a Small Mountainous Agricultural Watershed in the North Han River Basin (북한강 중류 산간농업 소하천에서의 오염부하특성분석)

  • Shin, Yong-Chul;Choi, Joong-Dae;Lim, Kyoung-Jae;Shim, Hyeok-Ho;Lyou, Chang-Won;Yang, Jae E.;Yoo, Kyung-Yoal
    • Journal of The Korean Society of Agricultural Engineers
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    • v.47 no.6
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    • pp.83-92
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    • 2005
  • Natural environment of the Wolgokri stream watershed, located in Chuncheon, Gangwon province, Korea, has been well preserved as a traditional agricultural watershed. To analyze characteristics of NPS pollution generated from an mountainous agricultural watershed, the flow and water qualities of the study watershed were monitored and were analyzed to estimate pollution loads. Annual runoff volume ratio was $70.4\%$. Concentrations of T-N, T-p, COD, and TOC were higher when monthly rainfall was between $0\~30mm$ than those when monthly rainfall was between $30\~70mm$. However, the concentrations varied considerably when monthly rainfall was higher than 100mm. The flow weighted mean concentrations(mg/L) of BOD, COD, TOC, $NO_3-N$, T-N, T-P and SS were 1.96, 2.72, 3.32, 1.41, 4.70, 0.187 and 13.36, respectively. The BOD, SS, T-N and T-P loads of July, 2004 were $48\%,\;17\%,\;51\%\;and\;32\%$ of annual load, respectively. The BOD, COD, TOC, $NO_3-N$, T-N, T-p, and SS loads (kg/ha) from Mar. 2004 to Apr. 2005 were 19.09, 26.55, 32.39, 13.85, 45.92, 1.887 and 130.18, respectively. The highest concentrations of BOD, NO3-N, T-N, T-p, SS, COD and TOC were found before the flow reached the peak runoff, possibly due to the first flushing effect. Generally, pollution loads of the Wolgokri watershed were not that significant. Phosphorus load, however, was higher enough to cause eutrophication in the receiving water body It was recommended that best management practices need to be implemented to reduce phosphorus sources.

Applicability Examination of the RUSLE Sediment Yield Prediction Equation in Korea (해외토사유출량 산정공식의 국내적용성 검토(II);MUSLE를 중심으로)

  • Son, Gwang-Ik
    • Journal of Korea Water Resources Association
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    • v.34 no.3
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    • pp.209-216
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    • 2001
  • Universal Soil Loss Equation(USLE) was developed for the estimation of the annual average soil loss from farm land. But, USLE has been applied in estimation of the sediment yield due to the construction activities in Korea without any calibration for last couple of years. Therefore, applicability and the limitation of the MUSLE(modified USLE), which was developed for the estimation of the sediment yield due to single rainfall event, is examined by application of MUSLE into several construction sites and comparing the estimated sediment yields with the actual ones. It is found that MUSLE could be applied in Korea as long as the concentration time, runoff volume and the peak flow rate are estimated with appropriate methods. Comparisons between the applicability of RUSLE and MUSLE are also carried out.

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A Study on First Flush Storage Tank Design for Combined Sewer Overflows (CSOs) Control (합류식하수도 월류수 관리를 위한 초기우수 저류조 설계방안 연구)

  • Son, Bongho;Oa, Seongwook
    • Journal of Korean Society on Water Environment
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    • v.27 no.5
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    • pp.654-660
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    • 2011
  • One of the best way to control Combined Sewer Overflow (CSO) is proposed to construct first flush storage tank. But there is little known parameters for optimum design of these facilities. This study was conducted to get optimum design parameters for a first flush storage tank construction. The optimization of the tank is generally based upon some measure of SS(Suspended Solid) mass holding efficiency. Water quality deterioration of receiving water body happened right after first time occurring rainfall in dry weather seasons. So, design rainfall intensity is used at 2 mm/hr for peak of monthly average intensities of dry seasons. The capacities for each evaluated catchment are designed from 14.4 min to 16.1 min HRT of CSOs flow at design rainfall intensity. Owing to all storage tanks are connected to interception sewer having a redundancy, the suggested volume could be cut down.

Evaluation of Flood Events Considering Correlation between Flood Event Attributes (홍수사상 요소의 상관성을 고려한 홍수사상의 평가)

  • Lee, Jeong Ho;Yoo, Ji Young;Kim, Tae-Woong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.3B
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    • pp.257-267
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    • 2010
  • A flood event can be characterized by three attributes such as peak discharge, total flood volume, and flood duration, which are correlated each other. However, the amount of peak discharge is only used to evaluate the flood events for the hydrological plan and design. The univariate analysis has a limitation in describing the complex probability behavior of flood events. Thus, the univariate analysis cannot derive satisfying results in flood frequency analysis. This study proposed bivariate flood frequency analysis methods for evaluating flood events considering correlations among attributes of flood events. Parametric distributions such as Gumbel mixed model and bivariate gamma distribution, and a non-parametric model using a bivariate kernel function were introduced in this study. A time series of annual flood events were extracted from observations of inflow to the Soyang River Dam and the Daechung Dam, respectively. The joint probability distributions and return periods were derived from the relationship between the amount of peak discharge and the total volume of flood runoff. Applicabilities of bivariate flood frequency analysis were examined by comparing the return period acquired from the proposed bivariate analyses and the conventional univariate analysis.