• 한국물환경학회지
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• 제33권1호
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• pp.40-50
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• 2017

We were interested in the long-term temporal and spatial variability trends of water quality. Trend tests such as the Seasonal and Regional Kendall tests and LOWESS (LOcally WEighted Scatter plot Smoother) have been recommended as outstanding tools for trend detection. In this study, we conducted four types of nonparametric trend tests (Seasonal and Regional Kendall tests, LOWESS, and flow-adjusted Seasonal Kendall). We aimed to identify water quality trends using the monthly data for five variables (BOD, COD, TN, TP, and flow) collected from 24 sites in the Nakdong River from August 2004 to December 2013. According to the Regional Kendall test, BOD, COD, and TN increased but TP decreased trend. The Seasonal Kendall test showed that BOD, TN, and TP remained constant at 62.5-83.3% of the sites. COD remained constant at 58.3% of the sites. LOWESS showed that TP gradually increased between 2007 and 2008, then decreased slowly at the Gumi, Geumhogang6, Daeam-1 and Milyanggang3 sites. BOD increased slightly between 2008 and 2009, and then decreased slowly at the Namgang4-1 site. Lastly, a flow-adjusted Seasonal Kendall test was conducted. There were different results between Seasonal Kendall and flow-adjusted Seasonal Kendall tests at 11 of the 24 sites. According to the results from six of the eleven sites, BOD increased at one site, showed no trends at three sited, and decreased at two sites. Each of COD, TN increased at two, one site. but TP decreased at two sites.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2004년도 학술발표회
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• pp.134-147
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• 2004

Theses days, there are 3 prerequisites for dam building in Korea: First one is how to build the dam safe and stable from the technical points of view. Second one is how to design and construct the dam environmentally sound with the minimum change of the surrounding area of the dam site. Third one is how to activate the local economy of the surrounding area of the dam site in order to make the dam construction sustainable from the social and economical points of view. As far as technical aspects far dam building, there are hardly any problems in dam design and construction in our country. However, there are a little difficulty according to the location of the dam site. In order to fulfill the second option it is believed that a lot of effort should be made to accomplish the second task not only because that fairly large area shall be inundated with water after impounding but also because that ecological environments shall be changed due to change of water environment. Therefore, thoughtful investigation and assessment of the environmental features of the local regions have to be preceded before starting of the dam building. In order to overcome these difficulties Hantan river dam has been declared as an Eco-dam with 3 strategies and 9 activities plan at the design stage after sufficient consideration of the local identities of these region and coupled national plans for surrounding areas. Finally, Eco-tourism with the several coupled network-wise touristic courses, namely PERTH model, has been proposed after thorough analysis of the local identities by the Jahari window to make local economy being activated. Detailed descriptions for 3 strategies and 9 activities plan for declaration of Eco-dam and proposal of Eco-tourism with the network-wise touristic courses will be mentioned in the main content.

• 한국물환경학회지
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• 제26권6호
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• pp.895-902
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• 2010

The effect of seasonality on water quality variation is very significant. Generally, it reduce the power of the trend extraction. A parametric time-series model was used for detecting trends in historic constituent concentration data. The effect of seasonality is able to remove from time series decomposition technique. According to such statistic methode, long-term water quality trend analysis system (NTrend 1.0) was developed by Nakdong River Water Environmental Research Center. The trend analysis of BOD variation was conducted with NTrend 1.0 at Goreong and Moolkum site in Nakdong river to show the effect of water quality management action plan. Power test of trend extraction was tried each case of 'deseasonalized and deannulized' data and 'deseasonalized' data. Analysis period was from 1989 to 2006, and it's period was divided again three times, 1989~1993, 1994~1999 and 2000~2006 according to action plan period. The BOD trend was downward in Goreong site during three times and it's trend slope was very steep, and upward in Moolkum during 1989~1993, but it was turned downward during 1994~1999 and 2000~2006. It was revealed that it's very effective to reduce the concentration of BOD by water quality management action plan in that watershed. The result of power test was shown that it is high for trend extraction power in case of 'deseasonalized' data.

• 한국수자원학회논문집
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• 제44권8호
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• pp.629-637
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• 2011

본 연구는 수질악화 등으로 사회적 논란이 되고 있는 영산강 하구를 대상으로 하구의 환경가치를 추정하였다. 본 연구는 (1) 동식물 산란지 및 서식지 기능, (2) 오염정화 기능, (3) 여가 및 심미적 기능, (4) 교육/과학/연구 기능 등 하구의 세부 기능별 가치를 평가하기 위하여 MAUT에 근거한 CVM을 적용하였다. 또한 하구 인근 지역만 대상으로 하거나 하구에서 떨어진 지역만 대상으로 해서는 결과의 일반화가 보장될 수 없으므로 하구 인근 지역과 인근 지역을 제외한 전국으로 표본을 분리하여 설문조사를 시행하였다. 분석결과 영산강 하구역인 전남 목포시, 나주시, 강진군, 해남군, 영암군, 무안군, 함평군에연간 약 10.6억원의 환경가치를 창출하고 있으며, 영산강 하구역을 제외한 전국에서연간 약 273.9억원의 환경가치를 창출하는 것으로 나타났다. 두 지역을 합칠 경우 연간 약 284.5억원에 해당한다. 본 연구의 결과는 하구 관리 정책을 위한 적정 투자수준 결정 및 하구관리정책과 관련하여 중요한 정량적 자료를 제공할 뿐만 아니라 후속 연구를 위한 방법론적 지침을 제시 할 것으로 기대된다.

• 물과 미래
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• 제52권8호
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• pp.43-55
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• 2019

• 농촌계획
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• 제2권1호
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• pp.69-78
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• 1996

Environmental impact assessment survey reflecting farmers` opinion on the residence and production space in rural settlement area by ORD showed that more than 86% of respondents thought their reservoirs and waterways (small rivers) were getting seriously contaminated primarily by garbage and livestock manure. A typical rural settlement unit was taken to assess the impact of improper management of livestock manure in the farms on the water quality of small river flowing down along the villages where swine and dairy farms were situated in Daejook 2, 3-ri, Seolseong-myun, Icheon-gun. Nitrogen compounds such as NO$_3$-N, NO$_2$-N, NH$_3$-N, and phosphorus compound H$_x$PO$_4$, DO, BOD$_5$, COD, and microbial density were analyzed to evaluate water quality at five test sites designated along the water stream. Tests showed. for example, BOD$_5$ at site 4 was average 9.2mg/l which was about 3~8 times higher than that of observation site 2 and 3, at which most livestock houses were situated. This is a clear evidence that the nutrients of livestock manure illegally discharged to small river can lead to an eutrophication of the river at downstream. A soil absorption system with aeration could be one of alternatives to treat the contaminated wastewater by livestock manure. The place at downstream, inbetween observation site 1 and 2, could be the best construction site for the treatment facility from the standpoint of the overall treatment efficiency, An enclosed composting system can also be regarded as a good alternative for treatment of the sludge which is the by-product of the soil absorption system operation.

• 상하수도학회지
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• 제34권4호
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• pp.277-288
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• 2020

In this study, we performed algorithms to predict algae of Chlorophyll-a (Chl-a). Water quality and quantity data of the middle Nakdong River area were used. At first, the correlation analysis between Chl-a and water quality and quantity data was studied. We extracted ten factors of high importance for water quality and quantity data about the two weirs. Algorithms predicted how ten factors affected Chl-a occurrence. We performed algorithms about decision tree, random forest, elastic net, gradient boosting with Python. The root mean square error (RMSE) value was used to evaluate excellent algorithms. The gradient boosting showed 10.55 of RMSE value for the Gangjeonggoryeong (GG) site and 11.43 of RMSE value for the Dalsung (DS) site. The gradient boosting algorithm showed excellent results for GG and DS sites. Prediction value for the four algorithms was also evaluated through the Receiver operating characteristic (ROC) curve and Area under curve (AUC). As a result of the evaluation, the AUC value was 0.877 at GG site and the AUC value was 0.951 at DS site. So the algorithm's ability to interpret seemed to be excellent.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.447-450
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• 2004

This study was conducted to characterize groundwater and river-water fluctuations at a riverbank filtration site in Daesan-myeon adjacent to the Nakdong River, using time series analysis. Water levels from six observation wells from January 2003 to October 2003 were measured. The autocorrelation analysis indicates that the wells are divided into three groups: group 1 represents strong linearity and memory, group 2 intermediate linearity and memory, and group 3 weak linearity and memory. The analysis indicates that groundwater levels in different monitoring wells vary in response to river-water levels, groundwater withdrawal and seasonal rainfall. Cross-correlation was also divided into three groups. Group 1 shows the highest cross-correlation function (0.49 - 0.54) for a lag time of 0 hours, group 2 intermediate cross-correlation function (0.34 - 0.45), and group 3 the lowest cross-correlation function (0.23 - 0.25). Different cross-correlation functions among the 3 groups are interpreted as an effect of tile distance from the river to the pumping wells.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.1188-1196
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• 2004

In this paper a determination of the optimal segment sealing material for a tunnel under the Han river between the Sungsoo-dong, Sungdong-Gu and the Chungdaw-dong, Kangnam-Gu in the Bundang railway. The geological investigation results show that some fractured zones exist loca]]y under the northern boundary of the Han river bed, but the other regions consist mostly of hard rocks of good Quality in the tunnel excavation level. Also, a hign water pressure of $5kgf/cm^2$ and a flash inflow of river water due to old boring holes are expected during tunnel excavation. A combined type sealing material of EPDM gasket with expansional rubber is selected as a optimal segment sealing material for the Han river tunnel considering the geological and site conditions.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(II)
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• pp.569-578
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• 2003

In this paper a determination of the optimal excavation method and machine type for a tunnel under the Han river between the Sungsoo-dong, Sungdong-Gu and the Chungdaw-dong, Kangnam-Gu in the Bundang railway. The geological investigation results show that some fractured zones exist locally under the northern boundary of the Han river bed, but the other regions consist mostly of hard rocks of good quality in the tunnel excavation level. Also, a hign water pressure of $5kgf/cm^2$ and a flash inflow of river water due to old boring holes are expected during tunnel excavation. A EPB shield TBM is selected as a optimal excavation machine for the Han river tunnel considering the geological and ,site conditions.