• Water Engineering Research
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• 제5권1호
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• pp.17-36
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• 2004

This paper evaluated the water resources aspect of the operating results of the Daecheong Multipurpose Dam for the last 21 years. The elements that were evaluated included the amount of water supply from the dam. volume of outflow from the regulating dam, changes in the runoff volume at the dam site and downstream, and variations in the water supply capacity of the Daecheong Multipurpose Dam and the Geum River Barrage Dam situated in the estuary. The rainfall-runoff model was used to evaluate the changes in the runoff volume, and the water balance analysis system was used to evaluate the variations in the dams'water supply capacities. The volume of domestic and industrial water supply from the Daecheong Multipurpose Dam increased to 6.1 times for the last 21 years from 61${\times}$$10^6$$m^3$ in 1981 to 375${\times}$$10^6$$m^3$in 2001. The rate of outflow to inflow of the Daecheong Dam was analyzed 1.30 times in dry season, 1.12 times in semi-dry season, and 0.90 times in rainy season. The volume of inflow to the Geum River Barrage Dam down- stream after the dam's construction increased to 1.25 times in dry season and 1.02 times in semi-dry season and decreased to 0.94 times in rainy season. The water supply capacity of the estuary barrage dam almost did not change in cases with or without the Daecheong Multipurpose Dam, but storages were largely affected by the outflows of the Daecheong Multipurpose Dam.

• 환경영향평가
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• 제14권2호
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• pp.63-73
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• 2005

This study was performed to characterize stormwater runoff of pollution material from nonpoint sources during rainfall in drainage basins of Hongjechun watershed, and to suggest management methods to control the first flush of nonpoint sources. We conducted 4 times of field surveys including 3 times of wet period and 1 times of dry period for 5 stations, which consist of 3 stations in main stream of Hongjechun and 1 station in tributaries of Sinyoungchun and Gukichun, respectively. The variation of pollutant concentrations in terms of BOD, COD, SS and TP was large depending on the flow rate of stormwater, while a little change of TN concentration was investigated. Depending on the rainfall event, the difference of flowrates, and runoff loadings was large, while the difference of those for dry wether period was not noticeable for various sub-basins. In the results of unit load calculation, the range of 153-277 kg/ha/yr for BOD, 222-422 kg/ha/yr for COD, 264-432 kg/ha/yr for SS, 40-70kg/ha/yr for TN, and 13-25 kg/ha/yr for TP was obtained for Hongjechun, Sinyoungchun, and Gukichun sub-basins. Compared with the previous studies, the result of this study was founded to be acceptable.

• 물과 미래
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• 제27권3호
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• pp.145-158
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• 1994

소유역 강우-유출모형으로서 유출함수법을 대폭 개선한 선형저수지 강우-유출 체계를 수립하였다. 매개변수의 수는 6개이고 수문학적 손실은 일정량의 초기손실과 일정비의 후기손실로 계산하며 추적식은 해석적으로 유도하였다. 변수추정은 Hooke and Jeees 방법에 의한 자동추정법을 사용하였다. 이를 서면과 문막 수위표의 '84∼'89년 홍수에 적용하여 모형을 검증하였다. 매개변수중 초기손실은 선행강우의 영향을 받으나 이를 고려하지 않았으므로 이에 대한 연구가 필요하고 실시간 예측시 주요 매개변수를 선택하는 방법도 보완되어야 한다.

• 물과 미래
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• 제19권4호
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• pp.347-354
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• 1986

강우와 유역특성으로부터 홍수유출을 예측하기 위해서 Nash 모델의 매개변수 N, K가 결정될 필요가 있다. 또한 순간단위도의 매개변수 N,K가 적율법에 의해서 유도되어야 한다. 강우특성으로부터 유도되는 Nash 모델의 매개변수는 낙동강에 위치한 위천유역에 적용하였다. 선형이론에 의한 순간단위도의 유도에 있어서 강우특성으로서 저장상수 K는 매우 높은 상관계수 0.97을 가진 K=1.327 $·$·$·$·$·$을 채택하였다. 이와 같은 강우특성으로서 Gamma 함수 N는 매우 높은 상관계수인 0.97로서 N=0.032$·$·$·$·$·$으로 나타났다. 검정결과 Nash 모델의 순간단위도와 이로 인한 홍수유출은 강우특성으로부터 예측될 수 있음이 입증되었다.

• 한국물환경학회지
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• 제34권6호
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• pp.650-660
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• 2018

The objective of this study was to compare the rainfall-runoff characteristics in streams of classified urban and rural watershed using land use and population density. EMC (event mean concentration) of BOD, COD, TP and SS increased significantly in urban and rural watershed, but that of TN remained unchanged. Although there were no significant differences in EMC of BOD, COD, TN, TP depending on the watershed characteristics, EMC of BOD and COD significantly increased in the urban watershed, while EMC of TP increased in the rural watershed. In the urban watershed, the first flush time was faster and the first flush effect was stronger in BOD, COD, and TP. However, the difference between cumulative mass and cumulative volume was found to be less than 0.2 in the rural watershed, indicating a weak first flush effect. The discharged masses of BOD (70 %), COD (64 %), and TP (66 %) in the first flush of runoff were higher in urban watershed, while TN (67 %) was higher in rural watershed. The reproducibility of first flush time and the strength of first flush using CV (coefficient of variation) was found to be more reproducible for first flush time in both watersheds. In rural watershed, the CV value of first flush time for TP out of water quality parameters was lower. Whereas the CV values of first flush time for BOD, COD and TP in urban watersheds were similar.

• 한국수자원학회논문집
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• 제48권11호
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• pp.925-936
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• 2015

본 연구의 목적은 이중편파 레이더 강우자료와 격자기반 분포형 강우-유출 모형인 KIMSTORM(KIneMatic wave STOrm Runoff Model)을 이용하여 유출해석을 수행하고, 침수실적자료와의 비교를 통해 레이더 강우자료의 효용성을 검토하는데 있다. 남강댐유역($2,293km^2$)을 대상으로, 2012년 4개의 강우 이벤트(집중호우, 카눈, 볼라벤, 산바)에 대하여 비슬산 레이더 강우자료를 사용하였다. 분포형 모형은 28개 지점 강우와 레이더 강우를 이용하여 보정되었으며, $R^2$(coefficient of determination), ME(model efficiency), VCI(volume conservation index)를 이용하여 적용성을 평가하였다. 모형의 보정결과, $R^2$, ME, VCI의 평균이 지점강우를 이용한 경우 각각 0.85, 0.78, 1.09, 레이더 강우를 이용한 경우 각각 0.85, 0.78, 0.96의 결과를 보였다. 태풍 산바에 의한 하천범람 침수실적자료의 두 침수지역(신연지구와 문대/신기지구)과 레이더와 지상강우에 의한 유출분석 결과를 비교하였다. 신연지구와 문대/신기지구 두 침수지역에서 레이더강우가 지상강우보다 더 많은 지역강우를 발생시켜 지표유출량을 더 크게 모의하는 것을 확인할 수 있었다. 특히 수위관측소가 존재하는 문대/신기지구의 경우, 지점강우보다 레이더 강우가 침수지역내 수위관측소의 실제 첨두유량에 가깝게 모의하였으며, 하천수위도 0.72m 높게 모의하였다.

• 한국환경과학회지
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• 제17권6호
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• pp.601-609
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• 2008

In this study for the development of area due to the increasing of industry, population and spreading of urbanization is rapidly increasing but about seventy percent of our nation's areas consists of the mountainous districts. In such case, when those areas have the heavy rains break, they are washed away by a fast-flowing stream of a valley and overflowed. Thus it could result on human life and property damage and also the widespread of flood damage in the downstream area. To decrease those damage, the construction of flood control reservoir is necessary. This research was aim to construct the flood runoff models of a mountainous small district and to determine the probability rainfall by analyzing precipitation. The study also examined the effects of location and size of flood control reservoir on flood reduction. The result showed that the construction of detention basin was an effective way to ensure the safety of flood control and multiple detention basin had superior result for reducing amount of runoff in the down stream area than the single detention basin.

• 한국환경과학회지
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• 제18권9호
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• pp.1017-1026
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• 2009

In Jeju island, the surface runoff characteristics are quite different from those of inland. Most of streams show dried characteristics by means of large portion of recharge which goes to the deep aquifer. For this reason, the accurate estimation of hydrologic components by using watershed model like SWAT is very difficult. On the other hand, the integrated SWAT-MODFLOW model is able to simulate the complex runoff structure including stream-aquifer interaction, spatial-temporal groundwater recharge and so on. The comprehensive results of Pyoseon region in Jeju island show that the amount of groundwater discharge to stream is very small, but it might be added to the discharge into the sea. Statistical analysis shows that SWAT-MODFLOW's results represent better than SWAT's. Also, SWAT-MODFLOW produces a reasonable water budget which shows a quite similar pattern of observed one. This result proves that the integrated SWAT-MODFLOW can be used as a proper tool for hydrologic analysis of entire Jeju island.

• 한국안전학회지
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• 제24권1호
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• pp.89-94
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• 2009

The purpose of this study is to estimate the critical flood discharge and flash flood trigger rainfall for alarm system providing for a flash flood in mountainous area. The flash flood need non-linear approaching method, because rainfall-runoff is nonlinear and it is difficult to explain the existing linear rainfall-runoff. Hydrological characteristics would be utilized to apply such as hydrologic modelling or basin management. This study was effectively estimated a topographic characteristic factor of basin using the GIS. Especially, decided stream order using GIS at stream order decision that is important for input variable of GCIUH. A flash floods defined as a flood which follows shortly after a heavy or excessive rainfall event, with a few hours. In this study, we gave a definition that a critical flood for alarm is the flood when valley depth judging dangerous depth is over 0.5m depth from the bottom of channel. Result that calculate threshold discharge to use GCIUH, at the Mureung valley basin, flash flood trigger rainfall was 16.34mm in the first 20minutes when the threshold discharge was $14.54m^3/sec$.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2021년도 학술발표회
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• pp.138-138
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• 2021

Flash floods are one of the types of natural hazards which has severe consequences. Flash floods cause high mortality, about 5,000 deaths a year worldwide. Flash floods usually occur in mountainous areas in conditions where the soil is highly saturated and also when heavy rainfall happens in a short period of time. The magnitude of a flash flood depends on several natural and human factors, including: rainfall duration and intensity, antecedent soil moisture conditions, land cover, soil type, watershed characteristics, land use. Among these rainfall intensity and antecedent soil moisture, play the most important roles, respectively. Flash Flood Guidance is the amount of rainfall of a given duration over a small stream basin needed to create minor flooding (bank-full) conditions at the outlet of the stream basin. In this study, the Sejong University Rainfall-Runoff model (SURR model) was used to calculate soil moisture along with FFG in order to identify flash flood events for the Geum basin. The division of Geum river basin led to 177 head-water catchments, with an average of 38 km². the soil moisture of head-water catchments is considered the same as sub-basin. The study has measured the threshold of flash flood generation by GIUH method. Finally, the flash flood events were used for verification of FFG. The results of the validation of seven past independent events of flash flood events are very satisfying.