• Journal of the korean society of oceanography
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• 제36권3호
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• pp.59-71
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• 2001

In order to investigate the temporal variability of dissolved and particulate trace metals in the Han River, water samples were collected intermittently at two sites for 3 years (August 91 to December 94). Surface seawaters covering the range of salinity were also collected at the estuarine region to evaluate the role of estuary for the riverine fluxes of trace metals within the estuary during October 95 and 96. During the study period, dissolved metal concentrations in riverwaters varied by a factor of 5-10 for Fe, Ni, Co and Cu and 50-100 for Mn, Cd and Pb depending upon the water level; high concentration during the low water and low concentration in high water period except for Fe. The concentration of dissolved Fe increased with increasing water discharge. These concentration-discharge relationships of the studied trace metals are explained by the successive dilution of waters from two different origins, which can be presumably identified as anthropogenic discharges and watershed flushing. Although estuarine waters at early mixing region were not collected due to the difficulty of sampling, mixing behaviors of metals were inferred from the concentration-salinity relationships through the laboratory mixing experiment and field sampling, and distribution coefficients between dissolved and labile particulate phases. It is suggested that the Han River estuary plays a role of accumulating Fe, Mn, Co and Pb from riverine sources due to high turbidity caused by strong tidal current, whereas this system serves as a source of dissolved Cd due to release caused by extended residence time of riverine particles.

• 한국수자원학회논문집
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• 제43권1호
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• pp.67-79
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• 2010

한국수자원공사는 낙동강 및 금강수계에 대해 실시간 물관리 시스템을 개발하여 수계 내 다목적 댐의 효율적인 운영을 도모하였다. 본 연구에서는 이를 확장하여 최적화 기법인 표본 추계학적 동적계획법을 사용하여 한강수계 다목적댐의 효율적인 월말 목표저수량을 산정하고 이를 통해 실시간 물관리시스템의 효율을 극대화하고자 수행되었다. 수계 내 댐중 저수용량과 용수공급 측면에서 중요도가 높은 소양강댐, 충주댐, 화천댐 등 3개 댐만을 대상으로 모형을 개발하였으며 저수량 상태변수의 민감도 분석 결과를 통해 저수량 상태변수 개수를 설정하였다. 본 연구를 통해 제시된 최적화모형을 통한 운영률과 한국수자원공사의 운영목표수위에 의한 저수지 운영방식과 비교를 실시한 결과 연평균 37.22 MCM의 수계 내 요구용수 부족량 감소효과와 더불어 발전량 측면에서도 연간 171 GWh가 증가하는 것을 확인하였다. 또한 이수기 저수지 운영계획 시스템을 실제 적용한 결과 2007년~2008년 이수기 동안 전력생산, 수질개선 등을 위한 추가적인 용수공급이 가능하다는 것을 확인하였다. 이러한 실제 적용사례를 통해 SSDP 모형과 이수기 저수지운영 시스템의 그 유용성을 타진할 수 있었으며 다른 수계로 확장을 실시한다면 보다 합리적인 저수지 운영계획이 가능할 것으로 기대한다.

• 환경영향평가
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• 제12권2호
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• pp.73-86
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• 2003

In this study, we performed 8 times of water quality sampling and continuous measurement of flow to identify wastewater flow characteristics for wastewater treatment basins of Namyangju city. The field survey has been conducted 6 times in dry weather period and 2 times in wet weather period. Each survey conducted 24-hr water quality sampling in the interval of 2-hr. From the analysis of flow data and water quality data, the following conclusions can be drawn. For Namyangju-1 station, which represents residential and commercial mixed area, flow rises early in the morning before office-going hour and moves up and down within narrow range, and lasted after office-leaving hour, resulting from continuous commercial activity. In case of Namyangju-5 station representing community and Namyangju- 6 station representing residential area, the flow immediately falls down after rising early in the morning and later rises again at the office-leaving hour, and arrives at peak flows around late evening. In the analysis of wastewater characteristics for weekdays and weekends, without landuse types the flow rate of weekends is higher than that of weekdays because it reflects population, being not contributed to generate wastewater during the working hours of weekdays, stay home and produce wastewater for weekends period.

• 한국지하수토양환경학회지:지하수토양환경
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• 제21권6호
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• pp.179-191
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• 2016

In addition to the measurement of the concentration of soil contaminants, the new idea of indicative parameters was proposed to validate the remedial works through the monitoring for the changes of soil characteristics after applying the clean up technologies. The parameters like CFU (colony forming unit), pH and soil texture were recommended as indicative parameters for land farming. In case of soil washing, water content and the particle size distribution of the sludge were recommended as indicative parameters. The sludge is produced through the particle separation process in soil washing and it is usually treated as a waste. The parameters like water content, organic matter content, CEC (cation exchange capacity) and CFU were recommended as indicative parameters for the low temperature thermal desorption method. Besides the indicative parameter, sampling methods in stock pile and the optimal minimum amount of composite soil sample were proposed. The rates of sampling error in regular grid, zigzag, four bearing, random grid methods were 17.3%, 17.6%, 17.2% and 16.5% respectively. The random grid method showed the minimum sampling error among the 4 kinds of sampling methods although the differences in sampling errors were very little. Therefore the random grid method was recommended as an appropriate sampling method in stock pile. It was not possible to propose a value of optimal minimum amount of composite soil sample based on the real analytical data due to the dynamic variation of $CV_{fund{\cdot}error}$. Instead of this, 355 g of soil was recommended for the optimal minimum amount of composite soil sample under the assumption of ISO 10381-8.

• 한국물환경학회지
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• 제20권1호
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• pp.1-11
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• 2004

Water quality is monitored at 1,837 points which are streams and sources for water supply in Karea. The monitoring carry out the measurement of 16 parameters of pH, BOD, SS, DO and so on with once a month, and of other parameters such like heavy metal with once a quarter. But most of the monitoring is carried out uncontinuously, so it is very difficult to understand exactly the changes of water quality compared with continuous monitoring. Therefore, real time monitoring system was equipped with basic parameters such as pH, temperature, DO, turbidity and electric conductivity at 25 major sources of water supply after installation of Noryangjin and Dukdo in 1974. But the systems have some problems which cannot be considered the sampling sites to represent for water quality of stream of lake, and can be caused a change of water quality by long distance from analyzer to intake pipe. Therefore, it has carefully to evaluate selection of sample sites for real time monitoring system. Also, problems on the area has been to identify which parameters are best suited to monitoring stream of lake water and the differences, of analyzing results compared with manual analyzing. This paper presents some approaches to handle such problems, namely selection of sampling site and measurable parameters, to connect with bio-monitoring system solving a Limitation of measurable parameters, The bio-monitoring system of an early alarm that is desirable to perceive a toxic material inflow into stream can be applied to continuos water quality monitoring system effectively. Also, this paper presents to build a on line system transmitting immediately from a mobile analyzer house or container to main monitoring center the results of analyzer by a telemeter.

• 상하수도학회지
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• 제31권1호
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• pp.29-37
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• 2017

To estimate pollution sources in the watershed with various industries, the simulation of contamination route and distribution of 2-methyl-4,6-dinitriophenol(DNOC) were performed with a numerical model Hydro Geo Sphere. This study was performed calculations of the load using the measured concentration and simulated flow rate. And, the river was divided by the sampling sites at the mainstream, and the contribution rate at downstream sampling sites was calculated for each section. The results showed the concentration of the downstream sampling sites were decided by the concentration of upstream sites, and the contribution rates of the tributaries were calculated below 10%. The results also showed that the impact of the potential sources in Section 1(Geumho1 ~ Geumho2) and Section 5(Geumho5 ~ Geumho6) was larger than in the other area. In Section1 and Section5, It seemed to require detailed investigation.

• 한국물환경학회지
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• 제29권5호
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• pp.691-702
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• 2013

This review paper summarizes the theory, application, and potential drawbacks of diffusive gradient in thin film (DGT) probe which is a widely used in-situ passive sampling technique for monitoring inorganic contaminants in aquatic environments. The DGT probe employs a series of layers including a filter membrane, a diffusive hydrogel, and an ionic exchange resin gel in a plastic unit. The filter side is exposed to an aquatic environment after which dissolved inorganic contaminants, such as heavy metals and nuclides, diffuse through the hydrogel and are accumulated in the resin gel. After retrieval, the contaminants in the resin gel are extracted by strong acid or base and the concentrations are determined by analytical instruments. Then aqueous concentrations of the inorganic contaminants can be estimated from a mathematical equation. The DGT has also been used to monitor nutrients, such as ${PO_4}^{3-}$, in lakes, streams, and estuaries, which might be helpful in assessing eutrophic potential in aquatic environments. DGT is a robust in-situ passive sampling techniques for investigating bioavailability, toxicity, and speciation of inorganic contaminants in aquatic environments, and can be an effective monitoring tool for risk assessment.

• 물과 미래
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• 제25권2호
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• pp.89-97
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• 1992

본 연구는 한강유역내 수위표지점 중에서 댐에 의한 인위적 유량 조작을 받지 않는 자연하천유역에서의 지점들을 대상으로 홍수빈도예측을 위한 통계학적 모형의 적용성을 비교 검토하였고 그 결과 적용 가능한 것으로 입증하였다. 또한 홍수빈도모형에 의한 홍수추정량으로 부터모형의 통계학적 효용성을 검토한 결과, 단 기간 기록년수의 자료에서 유용한 부분기간치계열 방법에 의한 POT모형이 연최대치계열 방법에 의한 ANNMAX형보다 효과적임이 판명되었다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2012년도 학술발표회
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• pp.366-366
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• 2012

확률강우량은 하천설계, 수자원설계 및 계획을 위한 기초자료로 활용되며 최근 이상기후 및 기후변화로 인한 극치강우의 빈도 및 양적 증가로 인한 확률강우량 산정의 불확실성 분석에 대한 관심이 크게 증가하고 있다. 수문빈도 해석에 있어서 대부분 지역이 50년 이하의 수문자료가 이용되고 있으며 수문설계에서 요구되는 50년 이상의 확률강수량 추정시에는 상당한 불확실성을 내포하고 있다. 이러한 점에서 본 연구에서는 자료연수에 따른 Sampling Error와 분포형의 매개변수의 불확실성을 고려한 해석모형을 구축하고자 한다. 빈도해석에서 매개변수를 추정하기 위해서는 일반적으로 모멘트법, 최우도법, 확률가중모멘트법이 이용되고 있으나 사용되는 분포형에 따라서 통계학적으로 불확실성 구간을 정량화하는 과정이 난해할 뿐만 아니라 극치 수문자료가 Thick-Tailed분포의 특성을 가짐에도 불구하고 신뢰구간 산정시 정규분포로 가정하는 등 기존 해석 방법에는 많은 문제점을 내포하고 있다. 본 연구에서는 이러한 매개변수의 불확실성 평가에 있어서 우수한 해석능력을 발휘하는 Bayesian기법을 도입하여 분포형의 매개변수를 추정하고 매개변수 추정과 관련된 불확실성을 평가하고자 한다. 이와 별개로 자료연한에 따른 Sampling Error를 추정하기 위해서 Bootstrapping 기반의 해석모형을 구축하고자 하며 최종적으로 빈도해석시에 나타나는 불확실성을 종합적으로 검토하였다. 빈도해석을 위한 확률분포형으로 GEV(generalized extreme value)분포를 이용하였으며 Gibbs 샘플러를 활용한 Bayesian Markov Chain Monte Carlo 모의를 기본 해석모형으로 활용하였다.

• 한국관개배수논문집
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• 제11권2호
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• pp.82-94
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• 2004

This study was carried out to investigate the change of stream water quality in the downstream of the Mangyeong river. Water samples were taken at 6 sampling sites for 11 months from November,2003 to September,2004. Water quality was analyzed with respect