• Title/Summary/Keyword: Horton 비

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Revisiting Horton Index Using a Conceptual Soil Water Balance Model (개념적인 토양수분수지 모형을 이용한 Horton 지수의 재논의)

  • Choi, Daegyu;Kim, Sangdan
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.5B
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    • pp.471-477
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    • 2010
  • In this study, the variability of the Horton index which is ratio of vaporization and wetting water is investigated using a conceptual soil water balance model. From the proposed model, the steady-state soil water probabilistic density function is derived through meteorological and watershed characteristics and then the sensitivity of Horton index to the precipitation occurrence rate and the mean of wet day precipitation is examined. As a result, the inter-annual variability of the Horton index is lower than that of precipitation and they showed the strong negative correlation. It is also shown that although precipitation is not varied, the Horton index can be varied due to the fluctuation of the precipitation occurrence rate and the mean of wet day precipitation. In addition, it is presented that there is a non-linear relationship which has a critical point switching proportional or inverse relationship between the Horton index and two main characteristics of precipitation process.

Development of a GIUH Model Based on River Fractal Characteristics (하천의 프랙탈 특성을 고려한 지형학적 순간단위도 개발(I))

  • Hong, Il-Pyo;Go, Jae-Ung
    • Journal of Korea Water Resources Association
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    • v.32 no.5
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    • pp.565-577
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    • 1999
  • The geometric patterns of a stream network in a drainage basin can be viewed as a "fractal" with fractal dimensions. Fractals provide a mathematical framework for treatment of irregular, ostensively complex shapes that show similar patterns or geometric characteristics over a range of scale. GIUH (Geomorphological Instantaneous Unit Hydrograph) is based on the hydrologic response of surface runoff in a catchment basin. This model incorporates geomorphologic parameters of a basin using Horton's order ratios. For an ordered drainage system, the fractal dimensions can be derived from Horton's laws of stream numbers, stream lengths and stream areas. In this paper, a fractal approach, which is leading to representation of a 2-parameter Gamma distribution type GIUH, has been carried out to incorporate the self similarity of the channel networks based on the high correlations between the Horton's order ratios. The shape and scale parameter of the GIUH-Nash model of IUH in terms of Horton's order ratios of a catchment proposed by Rosso(l984J are simplified by applying the fractal dimension of main stream length and channel network of a river basin. basin.

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Analysis of Variance for Horton Index Using a Stochastic Soil Water Balance Model (추계학적 토양수분수지 모형을 이용한 Horton 지수 변동성 분석)

  • Park, Myung Woo;Kim, Sang Dan
    • Proceedings of the Korea Water Resources Association Conference
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    • 2015.05a
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    • pp.474-474
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    • 2015
  • Horton 지수는 유역에 대한 수문순환의 특성을 정량화하는 지수로서 유역의 습윤량과 기화량의 비로 산출된다. 습윤량과 기화량은 토양 수분과 밀접한 관계를 가지므로 추계학적 거동에 따른 토양수분의 동역학모형을 파악하여 Horton 지수를 산출할 수 있다. 본 연구에서는 추계학적인 토양수분수지 모형을 이용하여 서울, 부산, 대구, 제주 지역을 대상으로 30년간 일 기상자료(강우량, 일 평균기온, 풍속, 상대습도, 일조시간)을 이용하여 Horton 지수를 각각 산출하였으며 Horton 지수에 대한 변동성 분석을 실시하였다. 분석 결과, 모든 대상 유역에서 기후의 계절성에 의하여 Horton 지수가 작아짐을 확인할 수 있었다. 하지만 습윤한 기후를 가진 서울과 건조한 기후를 가진 대구에서는 각각 연 강우량이 많거나 연 강우량이 적은 해에 Horton 지수에 미치는 기후의 계절성의 영향력이 줄어듦을 살펴볼 수 있었다.

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Variability of Hydrologic Partitioning revisiting Horton Index (Horton 지수의 재논의를 통한 수문분할의 변동성)

  • Choi, Dae-Gyu;Choi, Min-Ha;Ahn, Jae-Hyeon;Park, Moo-Jong;Kim, Sang-Dan
    • Journal of Wetlands Research
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    • v.13 no.1
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    • pp.35-44
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    • 2011
  • In order to explore vegetation adaptation to climate variability and the impacts on water balance dynamics, the inter-regional and the inter-annual variability of both water availability and vegetation productivity are investigated. The Horton index, which is the ratio between actual evapotranspiration and catchment wetting as a measure of vegetation water use at catchment-scale, is revisited to quantify the effects of growing-season water availability on hydrologic partitioning at catchment scale. It is shown that the estimated Horton index is relatively constant irrespective of inter-annual climate variability. In addition, the Horton index is compared with catchment-scale vegetation rain use efficiency. The results show that there is an interesting pattern in the response of vegetation water use to water availability. When water becomes the limiting factor for vegetation productivity, the catchment-scale vegetation rain use efficiency converges to a common maximum value in agreement with earlier findings at the ecosystem level.

An analysis of the correlation for runoff characteristics with the geomorphological characteristics in the Han River basin (한강 유역의 지형학적 특성과 유출의 상관분석)

  • Lee, Ji Haeng;Lee, Woong Hee;Choi, Heung Sik
    • Proceedings of the Korea Water Resources Association Conference
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    • 2017.05a
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    • pp.36-36
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    • 2017
  • 일반적으로 유역의 지형학적 특성을 나타내는 인자들은 유역면적, 유로연장, 유로경사 등 여러가지가 있다. Horton (1945)은 수계의 발달 형태에 기초한 하천의 차수를 이용하여 분기비, 길이비, 면적비, 하천 밀도 등 지형학적인 매개변수로 제시하였다. 유역 지형학적 매개변수는 Horton이 제시한 유역내 하도망의 지형학적인 구성에 대한 특성을 반영하는 것으로 유출에 지배적인 영향을 미친다. 한강 유역 19개 하천의 27개 지점을 대상으로 유출 특성과 지형학적 특성의 상관 분석을 위하여 유역과 하천의 지형학적 특성을 Arc-Map을 이용하여 구하였다. 하천차수법칙에 의한 지형학적인 매개변수로 분기비, 길이비, 함몰도, 면적비를 산정하였고, 유역의 지형학적 인자는 유역면적, 유로연장, 유로경사, 형상계수, 단일형상계수, 세장률, 수계밀도, 수계빈도를 산정하였다. 수계의 연간 유출률은 실측 유출량과 강수량 자료를 이용하여 산정하였다. 각각의 지형학적 특성인자에 대한 상관 매트릭스를 분석하고 그 상관특성을 분석하였다. 특히 지형학적 매개변수와 지형학적 요소와 연간 유출률과의 상관관계식을 제시하였다.

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Analysis of the Direct Runoff by Using the Geomorpologic Parameters of Watersheds (유역(流域)의 지상인자(地上因子)를 이용(利用)한 홍수량(洪水量) 해석(解析))

  • Suh, Seung Duk;Lee, Seung Yook
    • Current Research on Agriculture and Life Sciences
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    • v.7
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    • pp.55-66
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    • 1989
  • The purpose of this study is to estimate the flood discharge and peak time by the SCS method and the probability method using the geomorpologic parameters obtained from the topographic maps following the law of stream classifying and, ordering by Horton and Strahler. The SCS method and the probability method are used in estimating the times to peak and the flood discharges at An-dong, Im-ha, and Sun-san basins in the Nakdong River system. The results obtained are as follows : 1. The range of the values of the area ratio, the bifurcation ratio and the length ratio agree with those of natural streams presented by Horton and Strahler. 2. Comparisons of the probability method and observed values show that small relative errors of 0-7% of flood discharge, and 0-2hr, difference in time to peak respectivly. But the SCS method shows that large relative errors of 10-40% of flood discharge, and 0-4hr, difference in time to peak. 3. When the rainfall intensity is large, the error of flood discharge estimated by using the probability method is relativly small.

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Estimation of Continuous Infiltration Process by Unsaturated Permeability (불포화투수계수를 이용한 지반의 연속 침투능 산정)

  • Han, Heui-Soo;Lee, Jung-Sik;Jang, Jin-Uk;Yang, Nam-Young
    • The Journal of Engineering Geology
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    • v.20 no.2
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    • pp.137-146
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    • 2010
  • To estimate the accumulated infiltration, Horton's and Green-Ampt's equations are usually applied. Because the real infiltration is penetrated into the soil continuously, to cover the problems of the conventional equations derived from the discontinuous infiltration system, new infiltration equation is derived from the concepts of continuous infiltration system. Furthermore, infiltration tests were done to compare the results from the conventional Horton's and Green-Ampt's equations and newly derived equation. Unsaturated permeability is the function of water content ratio or saturation degree, which affects directly to the infiltration capacity and accumulated infiltration. Therefore, the variation term of unsaturated permeability is inserted into the new equation to estimate the proper infiltration capacity and accumulated infiltration. It will make the more accurate analysis for the safety of structure and the behavior of groundwater.

A Study on a Runoff Coefficient of Block Paved Area with Considering Regional Rainfall Distribution (지역별 강우분포를 고려한 블록포장지역의 유출계수 산정에 관한 연구)

  • Kang, Shin-Kweon;Kim, Tae-Gyun
    • Journal of the Korean Institute of Landscape Architecture
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    • v.36 no.4
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    • pp.111-119
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    • 2008
  • The runoff coefficient for a block paved area is determined with regional rainfall distribution. The Rational Method is a basic equation of a drainage system design and is a function of runoff coefficient, rainfall intensity and area. A runoff coefficient is the ratio of rainfall intensity and runoff. The rainfall intensity which is a function of the return period and rainfall duration differs by region. Therefore the runoff coefficient varies regionally even though there is the same return period and rainfall duration. The ratio of rainfall intensity and rainfall duration is decided by the loss of rainfall. The constant infiltration capacity of Horton's equation is adopted to determine the loss of rainfall. As time passed, the joint of the block paved area through which the infiltration occurs is covered by pollution material, sandy dust, pollen and is hardened by foot pressure, so the constant infiltration capacity may decrease. Six different sites were selected to verify the assumption of the constant infiltration capacity decrease and 10 year return period. 10, 20, and 30 minute rainfall duration were applied to calculate rainfall intensity. The results indicate that the Horton's constant infiltration capacity decreases over time and the minimum constant infiltration capacity is selected to compute runoff coefficients. The runoff coefficients varied by region ranging from $0.94{\sim}0.84$ for 10 minute of rainfall duration.

The Yield-Line Analysis of Reinforced Concrete Slabs Subjected to Loads of Hydrostatical Type (정수압(靜水壓) 형태(形態)의 하중(荷重)을 받는 철근(鐵筋)콘크리트 슬래브의 강복선해석(降伏線解析))

  • Oh, Jue Won;Lee, Kyu Wan
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.4 no.4
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    • pp.37-48
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    • 1984
  • The yield-line analysis is used for earring out the limit analysis of reinforced concrete slabs which are for example like those of vertical walls of tanks subjected to the loads of hydrostatical type. It is considered both isotropic and orthotropic reinforcement using the coefficient of orthotropy with different edge conditions. The yield-line analysis is carried out by using the vertical work method and four collapse mechanisms including the fan mechanisms which is more realistic than over diagonal mechanisms is considered. It is found that the fan mechanisms are more complicated than ever simple diagonal mechanisms which have used for the orthotropically reinforced concrete slabs subjected to hydrostatic pressures. Especially Horton's study is extended in this study, and they are formulated to the constrained multi-variables nonlinear optimization problems, which are solved by the Rosen-Brock Hillclimb Procedure Program and are more critical.

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Fractal Dimension of Stream Networks and Main Stream Length with Map Scale (지형도(地形圖) 축척(縮尺)에 따르는 하천 수로망(水路網)과 본류(本流) 하천길이에 관한 Fractal Dimension)

  • Jeon, Min Woo;Cho, Won Cheol
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.12 no.4_1
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    • pp.97-106
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    • 1992
  • Total length of stream networks and main stream length vary with topographic map scales, and the stream length of drainage basin on topographic map can be viewed as a fractal. Total length of stream network and main stream length are represented as only stream area ratio($R_a$) based on Horton's laws, thereafter the fractal dimensions of stream network and main stream length are derived as a simple function of stream length($R_L$) and stream area ratios($R_a$) respectively. The derived equations of fractal dimension are applied to Sansung basin in Kum River and compared with the equations already existed. The stream network appeared as space filling with fractal dimension near 2 as map scale increases, while main stream length shows near 1. The results of this study are expected to be helpful in the quantitative analysis of drainage network composition with map scale.

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