• 한국습지학회지
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• 제20권3호
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• pp.201-209
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• 2018

본 연구에서는 낙동강 주요 지류지천의 수질 모니터링 자료를 이용하여 수질지수를 산정하고 우선 관리가 필요한 지류지천을 파악하기 위해 장기 경향성 분석을 수행하였다. 환경부에서 시행하고 있는 실시간수질지수 방법을 적용하여 수질지수를 산정하고 모수 통계기법인 선형회귀와 비모수 통계기법인 Mann-Kendall Test와 Sen Slope Test를 적용하여 경향성을 분석하였다. 미전천2, 서교천2 지점을 제외한 주요 지류지천의 수질지수는 Fair 등급 이하의 범위에 있으며 북안천, 천내천, 호계천, 용덕천을 제외한 나머지 지점에 대해서는 유의성을 가진 경향이 나타나지 않았다. 따라서 본류에 대한 수질개선을 위해서는 지류에 대한 관리가 선행되어야 할 것으로 검토되었다.

• 한국물환경학회지
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• 제26권2호
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• pp.243-251
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• 2010

Evapotranspiration and rainfall-runoff are the major components of hydrological cycle and thereby the changes of them can directly affect the wetness/dryness or runoff characteristics of basins. In this study the wetness/dryness in Geum river basin are classified by dint of cumulative probability density function of monthly moisture index and the long term changes of them are analyzed based on climatic water balance concept. The drought events in Geum river basin are selected through evaluation of monthly moisture index and the various hydrological properties of them are investigated in detail. Also the trends of time-series of climatic water balance components are examined by Seasonal Kendall test and the variability of hydrological cycle in Geum river basin during the recent decade is inquired. It is judged that the results of this study can be contributed to establishment of the counter plan against the future drought events as the fundamental information.

• 산업기술연구
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• 제35권
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• pp.23-30
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• 2015

In recent, the various methods to predict the hydrological impacts due to climate change have been developed and applied. Especially, the variability of the meteorological factors such as rainfall, temperature, and evaporation can impact on the ecosystem in a basin. The variability caused by climate change on the meteorological factors can be divided by a gradual and abrupt change. Therefore, in this study, the gradual change is detected by simple linear regression and Mann-Kendall trend test. Also, the abrupt change is detected by Bayesian change point analysis. Finally, the result using these methods can identify the meteorological threats in the Cheongmicheon basin.

• 한국물환경학회지
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• 제24권4호
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• pp.480-487
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• 2008

Spatial and temporal analyses of water qualities were performed for 11 monitoring stations located in Mangyung watershed in order to analyze the trends of monthly water quality data of Biochemical Oxygen Demand (BOD), Total Nitrogen (TN) and Total Phosphorus (TP) measured from 1995 to 2004. The long-term trends were analyzed utilizing Seasonal Mann-Kendall test, LOWESS and three-dimensional graphs were constructed with respect to distance and time. The graph can visualize spatial and temporal trend of the long-term water quality in a large river system. The results of trend analysis indicated that water quality of BOD and TN showed the downward trend. This quantitive and quantitative analysis is the useful tool to analyze and display the long-term trend of water quality in a large river system.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2010년도 학술발표회
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• pp.1640-1644
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• 2010

In this study the wetness/dryness in Geum river basin are classified by dint of cumulative probability density function of monthly moisture index and the long term changes of them are analyzed based on climatic water balance concept. The drought events in Geum river basin are selected through evaluation of monthly moisture index and the various hydrological properties of them are investigated in detail. Also the trends of time-series of climatic water balance components are examined by Seasonal Kendall test and the variability of hydrological cycle in Geum river basin during the recent decade is inquired. It is judged that the results of this study can be contributed to establishment of the counter plan against the future drought events as the fundamental information.

• 대한토목학회논문집
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• 제34권1호
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• pp.117-133
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• 2014

본 연구에서는 전국의 8개 주요 도시지점 강우관측 자료를 대상으로 다양한 분류 기준을 적용하여 Quantile Regression (QR)에 의한 기준강수량 초과 강우의 선형추세분석과 Mann-Kendall, Sen 검정을 실시하였다. 분석결과 봄철과 여름철 강수의 뚜렷한 증가경향이 있으며, 가을철과 겨울철 강수는 감소하는 경향이 있음을 확인하였고, 폭우 사상은 최근 30년 평균 3.1~15% 증가 하였다. 또한, 연도별 발생강우의 Ranking에 따른 Top $10^{th}$ 백분위 강수의 3IQR (inter quartile range)의 최근증가경향을 분석한 결과, 대부분 지점에서 강수의 증가경향을 확인하였으며, Quantile 90%의 평균 백분위 강수량은 43.5mm, 증가경향은 0.1412mm/yr, Quantile 99%의 평균 백분위 강수량은 68.0mm, 증가경향은 0.1314mm/yr로 분석되었다. 본 연구의 결과는 매년 발생한 연최대치계열에 대한 분석뿐만 아니라 기준값 이상의 수문 사상정보에 대한 반영과 최근 변화하는 기후의 증가경향을 반영한 수공구조물 설계의 기초자료로 활용이 가능할 것으로 사료된다.

• 한국수자원학회논문집
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• 제47권3호
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• pp.269-283
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• 2014

본 연구에서는 기상청에서 제공하는 RCP 기후변화시나리오를 이용하여 기후변화와 유역유출특성에 따른 환경영향을 평가하였다. SWAT모형을 이용한 미래 댐 유입량 평가, HEC-ResSim 모형을 이용한 댐 안전성 평가 및 하류 유황분석을 수행하였다. 또한, 기존 수질관측자료를 이용하여 Seasonal-Kendall Test를 통해 수질변화 추세에 대해 분석하였고, SWAT과 HEC-ResSim 모형으로 도출된 방류량 및 지류유출량을 Qual2E모형에 적용하여 미래 수질변화 추세에 대해 분석하였다. 다음과 같은 유역 통합환경검토 기법은 하천환경에 대한 과학적 물환경 관리 체계를 확보하고, 기후변화 등 새로운 환경문제에 선제적으로 대응하기 위한 지침을 마련할 수 있을 것이다.

• 한국물환경학회지
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• 제30권2호
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• pp.148-158
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• 2014

In order to assess the effect of TMDLs management and improve that in the future, it is necessary to analyze long-term changes in water quality during management period. Therefore, long term trend analysis of BOD was performed on thirty monitoring stations in Geum River TMDL unit watersheds. Nonparametric trend analysis method was used for analysis as the water quality data are generally not in normal distribution. The monthly median values of BOD during 2004~2010 were analyzed by Seasonal Mann-Kendall test and LOWESS(LOcally WEighted Scatter plot Smoother). And the effect of Total Maximum Daily Loads(TMDLs) management on water quality changes at each unit watershed was analyzed with the result of trend analysis. The Seasonal Mann-Kendall test results showed that BOD concentrations had the downward trend at 10 unit watersheds, upward trend at 4 unit watersheds and no significant trend at 16 unit watersheds. And the LOWESS analysis showed that BOD concentration began to decrease after mid-2009 at almost all of unit watersheds having no trend in implementation plan watershed. It was estimated that TMDLs improved water quality in Geum River water system and the improvement of water quality was made mainly in implementation plan unit watershed and tributaries.

• Membrane and Water Treatment
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• 제10권5호
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• pp.339-352
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• 2019

Long term water quality change was analyzed to evaluate the effect of the Total Maximum Daily Load (TMDL) policy. A trend analysis was performed for biochemical oxygen demand (BOD) and total phosphorus (TP) concentrations data monitored at the outlets of the total 41 TMDL unit watersheds of the Nakdong River in the Republic of Korea. Because water quality data do not usually follow a normal distribution, a nonparametric statistical trend analysis method was used. The monthly mean values of BOD and TP for the period between 2004 and 2015 were analyzed by the seasonal Mann-Kendall test and the locally weighted scatterplot smoother (LOWESS). The TMDL policy effect on the water quality change of each unit watershed was analyzed together with the results of the trend analysis. From the seasonal Mann-Kendall test results, it was found that for BOD, 7.8 % of the 41 points showed downward trends, 26.8 % and the rest 65.9% showed upward and no trends. For TP, 51.2% showed no trends and the rest 48.8% showed downward trends. From the LOWESS analysis results, TP began to decrease in most of the unit watersheds from mid-2010s when intensive chemical treatment processes were introduced to existing wastewater treatment plants. Overall, for BOD, relatively more points were improved in the main stream compared to the points of the tributaries although overall trends were mostly no trend or upward. For TP, about half of the points were improved and the rest showed no trends.

• 한국물환경학회지
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• 제39권5호
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• pp.377-389
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• 2023

Chungcheongnam-do has been measuring the flow rate and water quality of streams in the province once a month since 2011 in order to water environment policies. Based on the results, after evaluating the coefficient of variation and the tendency of the water quality trend by using the Mann-Kendall test and Sen's Slope for each stream, the streams subject to priority introduction of Total Pollution Load Management at Tributaries were selected through the Stream Grouping Method. The water quality trend analysis results for 125 streams using the Mann-Kendall test and Sen's Slope were evaluated as streams showing a tendency of deteriorating water quality Biochemical oxygen demand (BOD): 13 streams, Total Phosphorus (T-P): 16 streams). Streams with deteriorating water quality were classified into A-D groups using the Stream Grouping Method. Group A, which has a high flow rate and high water quality, is a stream that requires priority management, and was selected as a stream for introduction of Total Pollution Load Management at Tributaries. There are 7 streams that need to be introduced into the BOD category, and there are 7 streams that need to be introduced into the T-P category. In this study, based on flow and water quality monitoring data accumulated over a long period of time (2011-2022), statistical techniques are used to select watersheds in which water quality is deteriorating. Accordingly, it is expected that it will be useful in establishing a water quality improvement plan in the future.