• 한국환경복원기술학회지
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• 제23권6호
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• pp.137-149
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• 2020

This study was carried out to analyze the monthly runoff concentration on non rainfall days in order to prepare basic data to compare the runoff concentration on rainfall days in 7 forest watersheds in the Republic of Korea. Forest stream water has been collected through 15 times of sampling in each watershed and analyzed based on the changes in concentration of Biochemical Oxygen Demand(BOD), Chemical Oxygen Demand(COD), Total Organic Carbon(TOC), Total Nitrogen(TN), and Total Phosphorus(TP). The average concentration was 0.8 mg/L for BOD, 1.4 mg/L for COD, 0.8 mg/L for TOC, 1.85 mg/L for TN and 0.002 mg/L for TP during non rainfall days. Coniferous forested watersheds showed higher value of TN and TP concentration. Concentrations of BOD and TP in early March (p<0.01) were affected by melt water flow input in spring season. Significant differences (p<0.01) in concentrations were observed in BOD and TOC, indicating seasonal rainfall and vegetation growth impacts on forest stream quality. Concentration of TN and TP showed significant positive correlation, and weak negative correlation was found in the concentration of BOD and TOC. It is expected that result of forest stream water on non rainfall days could be basic information in managing non-point source from forest watersheds.

• 물과 미래
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• 제28권5호
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• pp.219-233
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• 1995

강우의 평균과 분산이 시 공간적으로 변하는 비정상 다변량 모형을 강우모형으로 선정하였다. 그리고 강우모형의 상태 및 매개변수의 추정을 위해 비정상 대변량 모형의 잔차항에 Kalman Filter 순환추정 알고리즘을 적용하여 강우예측모형 시스템을 구성하였다. 그후 반응시간이 짧은 도시지역에 설치된 T/M 강우관측소에 입력되는 매 시간(10분간격) 강우자료를 사용하여 호우개수방법에 의한 비정상(Non-stationary) 평균과 분산의 추정 그리고 호우속도 추정을 통한 정규잔차 공분산을 추정하여 다수의 지점들 및 선행시간들의 실시간 다변량 단기 강우예측 (On-line, Real-time, Multivariate Short-term, Rainfall Prediction)을 하였다. 강우예측시스템 모형에 의한 결과와 비정상 변량 모형에 의한 강우모의 결과가 잘 일치하였다. 그리고 예측정도를 측정하는 방법인 제곱 평균 제곱근 오차(RMSE)와 모형 효율성 계수(ME)를 분석한 결과, 강우 예측시간 즉 선행시간이 갈수록 제곱 평균 제곱근 오차가 커지고 모형 효율성 계수가 1로부터 점차 작아지는 것으로 보아 강우예측 정도가 떨어지는 것을 알 수 있었다. 또한 호우개수방법으로 구한 평균이 호우구조의 많은 부분을 차지하고 있음을 알 수 있었다.

• 한국물환경학회지
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• 제34권5호
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• pp.487-493
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• 2018

Urban stormwater runoff is the one of the most extensive causes of deterioration of water quality in streams in urban areas. Especially, in the Suyeong River watershed, non-point sources from urban-residential areas are the most common cause of water pollution. Also, it has been ascertained that BOD and COD as indexes of organic matter, have limitation on management of Suyeong River's water quality. In this study, changes of organic matter properties of Suyeong River from inflow of non-point source during rainfall were investigated. Fractions of organic matters were analyzed using water samples collected at two sites (Suyeong River and Oncheon Stream) during a rain event. Variations of dissolved organic carbon (DOC) concentration by rainfall were similar to flow rate change in the river. Distribution of organic matter fraction according to change of rain duration revealed that while hydrophilic component increased at initial rainfall, the hydrophobic component was similar to change in dissolved organic carbon (DOC) concentration. Also, the relative proportion of hydrophilic components in organic matter in river water increased, due to rainfall. Results of biodegradation of organic matters revealed that decomposition rate of organic matters during rainfall was higher than that of during a non-rainfall event.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.1798-1802
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• 2007

The practice of business estimate flood discharge by rainfall-flow relation that is easy collection of observation data. The important factor is rainfall, coefficient of runoff, and drainage area for analysis of runoff-flow relation.The practice of business usually use probability rainfall that use a weighted average value after each observation post estimate probability of non-same time. It has more error than same time probability rainfall, and it can excess of estimation because it can't consider space distribution of rainfall.The study of result showed similar aspect with existing ARF but width of coefficient become smaller. And the comparison of peak flow did not different what used by ARF and same time probability rainfall(A group). But non-same time probability rainfall is bigger 25% more than another(B group). Between A group and B group of the difference increased with the lapse of time.

• 산업기술연구
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• 제27권A호
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• pp.95-102
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• 2007

The practice of business estimate flood discharge by rainfall-flow relation that is easy collection of observation data. The important factor is rainfall, coefficient of runoff, and drainage area for analysis of runoff-flow relation. The practice of business usually use probability rainfall that use a weighted average value after each observation post estimate probability of non-same time. It has more error than same time probability rainfall, and it can excess of estimation because it can't consider space distribution of rainfall. The study of result showed similar aspect with existing ARF but width of coefficient become smaller. And the comparison of peak flow did not different what used by ARF and same time probability rainfall(A group). But non-same time probability rainfall is bigger 25% more than another(B group). Between A group and B group of the difference increased with the lapse of time.

• 한국환경보건학회지
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• 제31권1호
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• pp.1-6
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• 2005

This study was conducted to identify the runoff characteristics of non-point source according to rainfall in Nam watershed. Land-uses of the Nam watershed were surveyed paddy field 4.5%, crop field 6.8%, mountainous 78.7%, urban 2.4%, and etc. 7.7%. Mean runoff coefficients in each area were observed Ⅰ area 0.08, Ⅱ area 0.08, and Ⅲ area 0.05. In the relationship between the rainfall and peak-flow, correlation coefficients(r) were investigated Ⅰ area -0.8609, Ⅱ area 0.6035, and Ⅲ area -0.4913. In the relationship between the antecedent dry period and first flow runoff, correlation coefficients(r) were investigated Ⅰ area -0.9093, Ⅱ area -0.1039, and Ⅲ area -0.7317. The discharge of pollutant concentrations relates to the flow rate of storm-water. In the relationship between the rainfall and watershed loading, exponent values of BOD, COD, SS, and T-N were estimated to 1.2751, 1.2003, 1.3744, and 1.1262, respectively.

• 대한환경공학회지
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• 제33권8호
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• pp.572-577
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• 2011

비점오염부하량 산정을 위해 사용되는 원단위는 쉽게 이용 가능하지만, 지역의 토지이용 특성과 강우강도의 시간적인 변이를 고려하지 못하는 단점이 있다. 본 연구에서는 간편하면서도 강우량에 따른 부하량 변화를 고려한 보다 정확한 비점부하량 산정방법을 개발 및 적용하였다. 경기도 경안천 유역에 위치한 두 개의 비점오염저감시설을 대상으로 2010년 6월부터 11월까지 모니터링을 수행하여 강우강도, 유출 특성, 오염부하 등에 관한 분석을 진행하였다. 비점오염원 유출수의 특성을 나타내는 유량가중평균농도(Event Mean Concentration; EMC)의 경우에는 도시 지역인 경기도 광주시 경안동이 산과 밭으로 이루어진 용인시 모현면에 비해 높거나 비슷한 값을 보였으나, TP (Total Phosphorus)의 경우 유역 내 농경지에 사용된 퇴비나 비료에 포함된 인의 영향으로 모현면이 경안동보다 더 높게 나타났다. 강우량과 오염물질 배출부하량과의 관계는 3차원 다항식에 의해 가장 잘 설명되었으며, 0.33~0.81 범위의 결정계수를 나타내고 있다. 산정된 유출율 및 부하량 함수의 기울기가 EMC 결과와 반대되는 경향을 보이는 것으로부터, 비점오염원은 토지이용 이외에도 지형, 토성, 수리 수문현상 등에 따라 배출특성이 달라짐을 알 수 있다. 따라서 비점오염물질의 유출 특성을 정확히 파악하기 위해서는 장기모니터링을 통한자료의 수집을 바탕으로 강우량에 따른 부하량 변화를 고려한 비점부하량 산정함수를 구하는 것이 필요하다.

• 한국수자원학회논문집
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• 제43권2호
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• pp.187-199
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• 2010

본 연구는 최근에 개발된 비정상성 강우빈도해석법을 적용하여 추정한 확률강우량에 대한 적용성 및 신뢰성을 평가하였다. 이를 위하여 기상청 관할 강우관측소 중 자료의 증가 경향성이 유의한 4개 지점에 대하여 3가지 형태의 확률강우량을 산정하였다. 첫 번째 확률강우량은 1973-1997년의 관측자료를 가지고 일반적인 강우빈도해석을 적용하여 추정한 확률강우량(SPR1997)이고, 두 번째 확률강우량은 1973-2006년의 관측자료를 가지고 일반적인 강우빈도 해석을 적용하여 추정한 확률강우량(SPR2006), 그리고 세 번째 확률강우량은 1973-1997년의 강우량 자료를 가지고 1997년을 현재시점이라 가정하여 2006년의 확률강우량을 비정상성 강우빈도해석법을 적용하여 추정한 확률강우량(NSPR2006)이다. 2006년을 목표연도라 가정하고, 확률강우량을 비교분석한 결과, 비정상성 강우빈도해석법에 의한 확률강우량(NSPR2006)이 정상성 확률강우량(SPR1997)에 비해 목표연도의 확률강우량에 대하여 적절한 값을 추정하는 것으로 나타났다. 본 연구는 또한 Bootstrap 기법을 이용한 신뢰구간을 비교하여 비정상성 확률강우량 추정에 적용되는 매개변수 추정법에 대한 평가를 수행하였다. 최우도법에 의한 신뢰구간 길이가 확률가중모멘트법에 의한 신뢰구간 길이보다 좁게 나타났으며, 이는 최우도법이 비정상성 강우빈도해석법에 적용되어 신뢰성 높은 확률강우량을 추정하는 것으로 판단된다.

• 상하수도학회지
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• 제25권2호
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• pp.265-274
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• 2011

Nowadays, the importance of non-point source pollution treatment is being emphasized. Especially, the easy runoff characteristic of highly concentrated pollutants in the roads makes the circumstance more complicated due to impermeability of roads. When the pollutants flow into steam it could make water quality in stream worse and it also causes a bad influence in the aquatic ecosystem because the effluents of rainfall-runoff may contain indecomposable materials like oil and heavy metals. Therefore, we tried to figure out the property of non-point source pollution when it is raining and carried out an assessment for the property of runoff for non-point source pollution and EMC (Event Mean Concentrations) of the essential pollutants during this study. As the result of the study, the EMC was BOD 5.2~21.7 mg/L, COD 7.5~35.4 mg/L, TSS 71.5~466.1 mg/L, T-N 0.682~1.789 mg/L and T-P 0.174~0.378 mg/L, respectively. The decreasing rate of non-point pollutant in Chungyang-Hongsung road indicates the maximum decrease of 80% until 5 mm of rainfall based on SS concentration; by the rainy time within 20~30 minutes, the decreasing rate of SS concentration was shown as 88.0~97.6%. Therefore it was concluded that it seems to be possibly control non-point pollutants if we install equipments to treat non-point pollutants with holding capacity of 30 min. It is supposed that the result of this study could be used for non-point pollutants treatment of roads in Chungyang-Hongsung area. We also want to systematically study and consistently prepare the efficient management of runoff from non-point source pollution and pollutant loading because the characteristics of non-point source pollution runoff changes depending on different characteristics and situations of roads and rainfall.

• 상하수도학회지
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• 제30권1호
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• pp.51-58
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• 2016

On account of the increase in water demand and climate change, droughts are in great concern for water resources planning and management. In this study, rainfall characteristics with stationary and non-stationary perspectives were analyzed using Weibull distribution model with 40-year records of annual minimum rainfall depth collected in major cities of Korea. As a result, the non-stationary minimum probable rainfall was expected to decrease, compared with the stationary probable rainfall. The reliability of ${\xi}_1$, a variable reflecting the decrease of the minimum rainfall depth due to climate change, in Wonju, Daegu, and Busan was over 90%, indicating the probability that the minimal rainfall depths in those city decrease is high.