• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2005년도 학술발표회 논문집
• /
• pp.1533-1537
• /
• 2005

The recent rainfall has happened to exceed the design rainfall after 1990 often, due to the characteristic of the rain to be changed. So, it is failing the ability safety of flood defense equipments to exist. This study analyzed the rainfall of Busan in 2003 since 1961 through the FARD2002(Frequency Analysis of Rainfall Duration). The result is equal to the thing which the design rainfall increased a little since 1991. The change of design rainfall created the result to be a flood discharge increase. This study investigated about the impact to influence on the river bank according to the change of flood discharge, the rainfall pattern change as well. This study used the program of HEC-RAS with HEC-HMS and calculated flood discharge with flood level of river. The result is equal to the thing which the computation became a flood level which exceed 50year(River design criteria-Korea water resources association 2002) criteria with 30year(River establishment criteria-Ministry of construction & transportation 1993), because of an area of impermeability increased of model basin.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2006년도 학술발표회 논문집
• /
• pp.1191-1195
• /
• 2006

Now days, heavy storm occur to be continue. It is hard to use before frequency based on flood discharge for decision that design water pocket structure. We need to estimation of frequency based on flood discharge on the important basin likely city or basin that damage caused by flood recurrence. In this paper flood discharge calculated by Clark watershed method and SCS synthetic unit hydrograph method about upside during each minute of among time distribution method of rainfall, Huff method choosing Bocheong Stream basin that is representative basin of International Hydrologic Project (IHP) about time distribution of rainfall that exert big effect at flood discharge estimate to research target basin because of and the result is as following. Relation between probability flood discharge that is calculated through frequency analysis about flood discharge data and rainfall - runoff that is calculated through outward flow model was assumed about $48.1{\sim}95.9%$ in the case of $55.8{\sim}104.0%$, SCS synthetic unit hydrograph method in case of Clark watershed method, and Clark watershed method has big value overly in case of than SCS synthetic unit hydrograph method in case of basin that see, but branch of except appeared little more similarly with frequency flood discharge that calculate using survey data. In the case of Critical duration, could know that change is big area of basin is decrescent. When decide time distribution type of rainfall, apply upside during most Huff 1-ST because heavy rain phenomenon of upsides appears by the most things during result 1-ST about observation recording of target area about Huff method to be method to use most in business, but maximum value of peak flood discharge appeared on Huff 3-RD too in the case of upside, SCS synthetic unit hydrograph method during Huff 3-RD incidental of this research and case of Clark watershed method. That is, in the case of Huff method, latitude is decide that it is decision method of reasonable design floods that calculate applying during all $1-ST{\sim}4-TH$.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2015년도 학술발표회
• /
• pp.173-173
• /
• 2015

The flood water level in tidal river is determined by the joint effects of flood discharge and tidal water levels at downstream boundary. Due to the variable tidal boundary conditions, the evaluated design water levels associated with a certain flood event can be significantly different. To avoid determining of design water levels just by a certain tidal boundary condition and remove the influence of variability in boundary condition from the evaluation of design water levels, a probabilistic approach is considered in this study. This study focuses on the development of a method to evaluate the realistic design water levels in tidal river with taking into account the combined effects of river discharge and tidal level. The flood water levels are described by the joint probability of two driving forces, river discharge and tidal water levels. The developed method is applied to determine design water levels for the tidal reach of the Han River. An unsteady flow model is used to simulate the flow in the reach. To determine design water levels associated with a certain flood event, first, possible boundary conditions are obtained by sampling starting times of tidal level time series; then for each tidal boundary condition, corresponding peak water levels along the channel are computed; and finally, design water levels are determined by computing the expectations of the peak water levels. Two types of tides which are composed by different constituents are assumed (one is composed by $M_2$, and the other one is composed by $M_2$ and $M_2$) at downstream boundary, and two flood events with different maximum flood discharges are considered in this study. It is found that (a) the computed design water levels with two assumed tides have no significant difference for a certain flood event, though variability of peak water levels due to the tidal effect is considerably different; (b) tidal effect can reach to the Jamsil submerged weir and the effect is obvious in the downstream reach of the Singok submerged weir; (c) in the tidally affected reach, the variability of peak water levels due to the tidal effect is greater if the maximum flood discharge is smaller.

• 한국농공학회:학술대회논문집
• /
• 한국농공학회 2001년도 학술발표회 발표논문집
• /
• pp.340-343
• /
• 2001

The main objective of this study is to simulate design flood discharge of the Sungjoo basin. GIS and HEC-HMS were used in this study. GIS technique can extract various hydrological factors from D.E.M(Digital Elevation Model) and the parameters extracted from each watershed were applied to the HEC-HMS. As a result of this study, GIS technique is useful to tile extraction of watershed characteristics factors and HEC-HMS is successful in tile simulation of design flood discharge.

• 한국습지학회지
• /
• 제19권3호
• /
• pp.335-344
• /
• 2017

본 연구에서는 미계측유역의 설계홍수량을 산정하는 방안으로 유역의 면적비를 적용하는 방안을 제안하였다. 이를 위해 유역출구에서의 실측자료를 활용하여 유출매개변수를 결정하고 면적비를 적용하여 첨두홍수량을 산정하였다. 위 방법론을 검증하기 위해 소하천 유역의 관측유량 및 하천정비종합계획의 설계홍수량과의 비교를 통해 면적비 전이 방법론의 타당성을 검토하였다. 그 결과를 정리하면 다음과 같다. 면적비를 적용한 유출량과 관측유량자료를 비교한 결과 14~25% 정도의 차이를 보였다. 제안된 방법론의 타당성을 재확인하기 위해 하천정비종합계획에서 산정된 첨두유량과 소유역과의 면적비로 계산한 첨두유량을 비교하였다. 이를 위해 31개소의 소하천을 대상으로 설계홍수량을 비교한 결과, 20% 정도의 홍수량의 차이가 발생하였다. 따라서 면적비를 적용한 미계측지역에서의 첨두유량 산정방법론이 타당하다고 판단된다.

• 한국환경과학회지
• /
• 제26권12호
• /
• pp.1321-1331
• /
• 2017

This study reviewed the applicability of the existing flood discharge calculation method on Jeju Island Han Stream and compared this method with observation results by improving the mediating variables for the Han Stream. The results were as follows. First, when the rain-discharge status of the Han Stream was analyzed using the flood discharge calculation method of the existing design (2012), the result was smaller than the observed flood discharge and the flood hydrograph differed. The result of the flood discharge calculation corrected for the curve number based on the terrain gradient showed an improvement of 1.47 - 6.47% from the existing flood discharge, and flood discharge was improved by 4.39 - 16.67% after applying the new reached time. In addition, the sub-basin was set separately to calculate the flood discharge, which yielded an improvement of 9.92 - 32.96% from the existing method. In particular, the steepness and rainfall-discharge characteristics of Han Stream were considered in the reaching time, and the sub-basin was separated to calculate the flood discharge, which resulted in an error rate of -8.77 to 8.71%, showing a large improvement of 7.31 - 28.79% from the existing method. The flood hydrograph also showed a similar tendency.

• 한국수자원학회논문집
• /
• 제44권12호
• /
• pp.941-954
• /
• 2011

본 연구에서는 국내의 다목적 댐을 대상으로 강우-유출 모형에 의한 과거의 홍수량 산정방식과 최근의 홍수량 산정방식을 유역 면적 규모별로 분류하여 비교 분석하였다. 홍수량에 영향을 미치는 기본인자로 강우량, 강우의 시간분포, 유효우량 산정방법, 강우-유출 모형, 매개변수 추정 및 기저유량 등을 선정하여 각 인자별 민감도 분석을 수행함으로써 홍수량에 미치는 영향을 정량적으로 분석하였다. 분석결과 최근의 방법으로 산정한 홍수량과 과거의 방법으로 산정한 홍수량이 유역면적 규모에 따라 다양한 변동폭으로 증가하거나 감소하였는데, 강우의 시간분포 변경이 홍수량을 감소시키는 원인으로 분석되었고, 최근 기상이변에 의한 강우량의 증가와 단위도의 매개변수 추정방법의 변경이 홍수량을 증가시키는 가장 큰 원인으로 분석되었다.

• 한국수자원학회논문집
• /
• 제55권5호
• /
• pp.333-343
• /
• 2022

수자원의 계획 및 설계에 활용되는 홍수량 산정 방법은 홍수량 빈도해석 방법과 강우-유출모형에 의한 방법이 사용된다. 홍수량 빈도해석 방법은 홍수량 자료를 직접 빈도해석 하여 확률홍수량을 산정하며 이론적으로 가장 정확한 방법으로 평가된다. 기존의 홍수량 해석은 자료의 제약으로 인하여 실측유량의 직접 빈도해석은 한계가 있었으나 과거부터 국가적으로 수문조사를 수행하여 10년 이상의 실측유량 자료를 확보할 수 있는 수준에 도달하였다. 본 연구는 수위-유량 관계곡선식을 통하여 안정적으로 확보된 실측유량 자료를 활용하여 홍수량 빈도해석을 수행하였다. 홍수량 빈도해석을 위하여 Bayesian 기법을 적용하여 매개변수를 산정하고 빈도별 홍수량의 불확실성을 정량화하였다. 확률홍수량 산정 결과는 장기간의 강우량 자료를 적용하여 강우-유출모형으로 산정된 홍수량과 근접한 것을 확인하였다. 수문조사를 통하여 장기간의 실측유량 자료를 활용하여 다각적인 관점으로 수문해석이 가능할 것으로 판단된다.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2011년도 학술발표회
• /
• pp.277-281
• /
• 2011

본 연구에서는 국내의 다목적 댐 전체를 대상으로 강우-유출 모형에 의한 과거의 홍수량 산정방식과 최근의 홍수량 산정방식을 유역 면적 규모별로 분류하여 비교 분석하였다. 홍수량에 영향을 미치는 기본인자로 강우량, 강우의 시간분포, 유효우량 산정방법(손실분석), 강우-유출 모형, 매개 변수 추정 및 기저유량 등을 선정하여 각 인자별 민감도 분석을 수행함으로써 홍수량에 미치는 영향을 정량적으로 분석하였다. 분석결과 최근의 방법으로 산정한 홍수량과 과거의 방법으로 산정한 홍수량이 유역면적 규모에 따라 다양한 변동폭으로 증가하거나 감소하였는데, 강우의 시간분포 변경이 홍수량을 감소시키는 원인으로 분석되었고, 최근 기상이변에 의한 강우량의 증가와 단위도의 매개변수 추정방법의 변경이 홍수량을 증가시키는 가장 큰 원인으로 분석되었다.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2005년도 학술발표회 논문집
• /
• pp.937-942
• /
• 2005

It is necessary to estimate the runoff hydrograph and peak flood discharge using law of probability for synthetic flood control policy and design of hydraulic structures. Rainfall analysis is needed in the process of peak flood discharge estimation and the time distribution of a design rainfall is a very important process in the analysis. In this study, we estimate design flood for a small urban basin and a rural basin of medium scale which have different travel times. The Huff method is widely used in Korea for the time distribution of design rainfall to estimate design flood. So, we use Huff method and a conceptual method which is suggested in this study for the comparative purpose. The 100-year frequency rainfall is used to estimate design flood for each basin and the design flood is compared with the existing design flood. As the result, the design flood is overestimated $14.6m^3/sec$ by Huff method and is underestimated $70.9m^3/sec$ by a conceptual method for the rural basin. For the small urban basin, the design flood is excessively overestimated $294.65m^3/sec$ by Huff method and is overestimated $173m^3/sec$ by a conceptual method. The reason of excessive overestimation by Huff method in the small urban basin is that the increased rate of rainfall intensity according to the decrease of duration is large and the duration exceeds the time of concentration when the increased rainfall intensity is concentrated in a quartile. Therefore, we suggested a conceptual method for the time distribution of design rainfall by considering the rainless period and duration. Especially, the conceptual method might be useful for the small urban basin with short concentration time which the design flood is overestimated by Huff method.