• 한국환경과학회지
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• 제24권11호
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• pp.1473-1483
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• 2015

In this study, a digital terrain analysis had been performed for a mountainous watershed having wetlands. In order to consider the impact for wetland in the flow determination algorithm, the Laplace equation is implemented into the upslope accounting algorithm of wetness computation scheme. The computational algorithm of wetland to spatial contribution of downslope area and wetness was also developed to evaluate spatially distributed runoff due to the presence of wetland. Developed schemes were applied to Wangpichun watershed located Chuncuk mountain at Ulzingun, South Korea. Both spatial distribution of wetness and its histogram indicate that the developed scheme provides feasible consideration of wetland impact in spatial hydrologic analysis. The impact of wetland to downslope propagation pattern is also useful to evaluate spatially distributed runoff distribution.

• 한국농공학회논문집
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• 제48권4호
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• pp.3-12
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• 2006

Watershed is the land area that contributes runoff to an outlet point. To delineate an watershed, watershed delineation using GIS that contains grid data structure is the most general method. Some researchers have studied to implement algorithms that revise the TIN topography since it is difficult to delineate watershed boundary more accurately. In this study kruskal's greedy algorithm and triangulated irregular network (TIN) were used to delineate a watershed. This method does not require a conversion from to DEM in grid and automatically obtain(generates) the oulet points. Delineation algorithm was tested in Geosan-gun, Chung-cheongbuk-do and get small watershed areas. Finally, kruskal's algorithm could operate more precisely with revision algorithm.

• 한국물환경학회지
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• 제26권4호
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• pp.654-663
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• 2010

Attention has increasingly focused on the pollutant load discharged from rural area since the enforcement of total maximum daily loads (TMDLs) in korea. As one of the methods to control the inflow of pollutant load during wet weather events, local governments are attempting to apply non-point source control facility. To design those facilities appropriately, it is essential to understand the runoff characteristics of pollutants such as TSS, $BOD_5$, $COD_{Cr}$, TP and TN. In the paper, the quantitative analyses for pollutant runoff characteristics were examined in a small rural watershed with the area of about 53 hectares. For a dry weather day and wet weather events, variation patterns of dry weather flow and runoff characteristics of wet weather flows were monitored and investigated. The runoff model using XP-SWMM reflecting the landuse types of the watershed in detail was simulated to perform the sensitivity analyses for several factors influencing on their hydrograph and pollutographs. As a result, for the case of medium and small rainfall events (i. e. total rainfall of 35.8 and 17.5 mm), the impervious area including green house, roof and road which covers relatively low portion of total area (i. e. 16%) caused substantial first flush and the majority of total runoff load. Therefore, it has been concluded that the runoff characteristics of each pollutant and distribution of impervious area should be considered for the establishment of the control strategy of non-point pollutant runoff at a rural area.

• 한국농공학회지
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• 제27권4호
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• pp.42-52
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• 1985

This study was attempted to derivate empirical formulas for the runoff: ratio during ilood. season at three watersheds of Dan Yang, Chung Ju, and Yeo Ju are located at upper, middle, and lower portion of Nam Han river basin, respectively. Obtained formulas for flood runoff ratio can be applied as an element for the estimation, peak discharge for the design of various hydraulics structures which can be concidented with meteorological and topographical condition. The obtained through this study were analyzed as follows. 1.It was found that the magnitude of runoff ratio depends on the amount of rainfall for all studying basins. 2.Empirical formulas 'for the runoff' ratio were derivated as 1- 2,707 Rt0.345, 1-1.691 Rt0.242 and 1-1.807 Rt0.227 at Dan Yang, Chung Ju and Yeo Ju watershed, respectively. 3.The magnitude of runoff ratio was appeared in the order of Dan Yang, Chung Ju, and Yeo Ju are located at upper, middle and lower portion of Nam Han rivet basin, respectively. 4.It was assumed that in general the more it rains, the lesser becomes the ratio of loss rainfall. Especially, the ratio of loss rainfall for Dan Yang, upper portion of river basin was shown as the lowest among three watersheds. Besides, the magnitude of that was appeared in the order of Chung Ju and Yeo Ju watershed located at middle, and lower part of river basin, respectively. 5.Relative and standard errors of runoff ratio calculated by empirical formulas were shown to be within ten percent to the observed runoff ratio in all watersheds. 6.It is urgently essential that the effect of antecedent rainfall have an influence on the next coming flood should be studied in near future.

• 한국수자원학회논문집
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• 제54권11호
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• pp.955-968
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• 2021

수자원 계획 수립시 인위적인 하천수의 사용 및 조절 과정을 거치지 않는 자연유량 상태를 기반으로 이루어지며, 관측자료를 이용하거나 장기유출모형을 이용한 방법 등을 통해 산정할 수 있다. 그러나, 자연적인 유출 상태를 보이는 유역은 매우 제한적이며, 미계측유역은 수문모형을 구축한 후 이를 전이시켜 산정하는 등 신뢰성 있는 수문자료는 여전히 부족한 실정이다. 본 연구에서는 GR4J 강우-유출모형을 활용하여 14개 댐 상류 유역에 대한 매개변수 최적화를 수행하여 자연유량의 재현성을 평가하였다. 매개변수의 불확실성을 정량적으로 고려하기 위해 Bayesian 이론을 도입하였으며, 매개변수의 사후분포로부터 추출되는 다수의 매개변수를 지역화에 활용하였다. 최종적으로 최적 매개변수와 유역의 특성을 갖는 인자에 대한 상관관계를 파악해 유역특성인자를 선별하였으며, 인자 사이의 상관성을 효과적으로 고려하기 위하여 Copula 함수를 활용해 매개변수 지역화 모델로 확장하였다. 결과적으로 지역 매개변수를 활용해 산정된 유량과 14개 댐 관측 유입량이 약 0.8 이상의 높은 상관성을 확인하였다. 본 연구에서 제안한 방법론은 미계측유역의 강우-유출모형 매개변수 추정시 유역특성을 고려한 지역 매개변수의 추정이 가능하다는 측면에서 유리한 장점을 확인할 수 있으며, 동시에 불확실성 정보를 제공함으로써 미계측유역의 자연유량 예측 모형으로 활용 가능할 것으로 판단된다.

• 한국농공학회논문집
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• 제47권3호
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• pp.77-86
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• 2005

A monitoring study has been conducted to identify hydrologic conditions, water quality and nutrient loading characteristics of small watershed in Juam Lake. Climate data of the watershed were collected; flow rate was measured and water quality sampling was conducted at the watershed outlet for this study. Water quality data revealed that T-P concentrations meet I grade of lake water quality standard during non-storm period, but degraded up to II-III grade of lake water quality standard during storm period. The observed T-N concentrations always exceeded lake water quality standard. Therefore, T-P was identified as limiting chemical constituent for eutrophication of Juam Lake. T-P concentration of non-storm period also revealed that point source pollution is not serious in the watershed. Three year monitoring results showed that the observed T-N losses were $10.85\~18.88$ kg/ha and T-P losses were $0.028\~0.323$ kg/ha during six month (Mar. - Oct.), respectively. Major portion of runoff amount discharged by a few storm events a year and nutrient load showed apparent seasonal variation. Huge runoff amounts were generated by intense storms, which make application of water treatment or detention facilities ineffective. Monitoring results confirmed that water quality improvement by abating nonpoint source pollution in rural watershed of monsoon climate should be focused on source control. T-P losses from paddy field seemed to consist of significant amount of total load from study watershed. Therefore, management of drainage from paddy field is considered to be important for preventing algal blooming problem in Juam Lake.

• 한국수자원학회논문집
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• 제47권12호
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• pp.1121-1134
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• 2014

유사발생 잠재성 및 토양침식으로 인한 유사발생 위험성이 높은 것으로 평가된 내성천유역을 대상으로 강우-유출-토양침식-유사이송으로 이어지는 유역단위의 분포형 모형을 구축하였으며 유출과 유사농도 모의 결과에 주요한 영향을 미치는 조도계수 및 투수계수의 민감도 분석을 실시하였다. 모의결과, 내성천유역의 토지 피복이 숲인 지역의 조도계수를 0.4에서 0.45로 변경하여 지표수 유출 유속을 감소시킴으로써 향석 지점에서의 유출곡선에 미치는 영향을 분석하였으나 유출수문곡선의 변화에 영향을 미치지 않는 것으로 나타났으며 평균 유사농도 값과 유사농도의 범위에 있어서도 모의 결과가 근소하게 증가하나 유의한 변화는 없는 것으로 나타났다. 투수계수에 대한 민감도 분석 결과, 투수계수 값을 저감 시킬수록 총 유출량 및 첨두 유출량은 점차 증가하는 것으로 나타났다. 유사농도 모의의 경우에도 투수계수를 저감시킬수록 모든 지점에서 평균 유사농도 및 유량에 따른 유사농도 범위가 증가하였으며, 향석 지점의 경우 투수계수를 50% 저감하였을 때 유사 농도 모의 값이 유량-유사량 관계식에 의해 계산된 값과 가장 근사한 것으로 나타났다.

• 한국수자원학회논문집
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• 제52권1호
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• pp.21-33
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• 2019

본 연구에서는 비슬산 이중편파 Radar 자료와, GPM 위성자료 및 21개 (Korea Meteorological Administration, KMA) 지상강우자료를 활용하여 분포형 강우-유출 모형(KIneMatic wave STOrm Runoff Model2, KIMSTORM2)을 이용해 남강댐 유역($2,293km^2$)을 대상으로 유출해석을 수행하였다. 모형의 유출 해석은 2016년 10월 5일 02:00~09:00 총 8시간 동안 최대강우강도 33 mm/hr, 유역평균 총 강우량 82 mm이 발생한 태풍 차바(CHABA)를 대상으로 하였으며, Radar 및 GPM 자료와 조건부합성(Conditional Merging, CM) 기법을 적용한 Radar (CM-corrected Radar) 및 GPM (CM-corrected GPM) 자료를 각각 활용하여 결과를 비교하였다. 이 때, 공간 강우자료에 유출 검보정은 남강댐 유역 내 3개의 수위관측 지점(산청, 창촌, 남강댐)을 대상으로 실시하였으며, 모형의 매개변수 초기토양수분함량, 지표와 하천의 Manning 조도계수를 이용하여 검보정하였다. 유출 결과는 결정계수(Determination coefficient, $R^2$), Nash-Sutcliffe의 모형효율계수(NSE) 및 유출용적지수(Volume Conservation Index, VCI)를 산정하였다. 그 결과 CM-corrected Radar, GPM 자료가 평균 $R^2$는 0.96, NSE의 경우 0.96, 유출용적지수(VCI)는 1.03으로 가장 우수한 결과를 나타내었다. 최종적으로 CM 기법을 이용한 보정된 공간분포자료는 기존의 자료에 비해 시공간적으로 정확한 홍수 예측에 사용 될 것으로 판단된다.

• 한국환경과학회지
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• 제22권4호
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• pp.493-505
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• 2013

This study was to investigate the runoff characteristics of non-point pollutants source at the urban area in Suwon city. The highest T-N and T-P concentration of rainfall runoff observed in agricultural area. In residential area, the highest $BOD_5$ and SS concentration of rainfall runoff was investigated. During rainfall events, the peak concentrations of SS and $BOD_5$ were observed after 1~2 hours of rainfall in urban area. Whereas, the peak concentrations occurred within 1~2 hours after rainfall and then the highest concentrations of SS and $BOD_5$ sharply decreased, showing strong first flush effect in urban area. The EMC results indicated that the highest value of T-N and T-P in agricultural area was observed. While residential area was shown the lowest EMC value as T-N and T-P. Non-point pollutant loads on the land use types in urban area were investigated in the order of residential>industrial>agricultural>highway. $BOD_5$ and SS loads on urban watershed were investigated in the order of Suwon>Hwangguji>Seoho>Wonchunri. Whereas, T-N and T-P loads on urban watershed were investigated in the order of Hwangguji>Suwon>Wonchunri>Seho.

• 한국수자원학회논문집
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• 제32권5호
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• pp.515-524
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• 1999

본 연구는 토양수분의 공간적 분포를 고려하는 과정에서 TOPMODEL이 가지고 있는 구조상의 문제를 해결하는 방안을 제시한다. 포화초과유출을 모의하는 기존 TOPMODEL은 유출모의시 유역내 포화부분의 공간적인 정보를 반영하는 과정에 있어 포화면적의 연결성을 고려한 유출 알고리즘의 개발로 발전되었다. 개발된 알고리즘은 TOPMODEL의 매개변수를 증기시키지 않고 개선된 유출경로 추적의 근거를 제시함으로써 모형의 합리성과 적용성을 제고시켰다. 본 연구에서 개발된 포화면적 연결모형과 기본적인 통계적 입력모형형태의 TOPMODEL을 국제수문개발계획 대상유역인 위천유역내의 동곡소유역에 적용한 결과 본 연구에서 개발된 포화면적 연결모형이 다른 두 모형에서 발생하는 모의시 과도첨두유량계산의 문제를 해결할 수 있었다.