• 상하수도학회지
• /
• 제26권1호
• /
• pp.1-12
• /
• 2012

The purpose of water distribution system is supplying water to users by maintaining appropriate pressure and water quality. For efficient monitoring of the water distribution system, determination of optimal locations for pressure monitoring is essential. In this study, entropy theory was applied to determine the optimal locations for pressure monitoring. The entropy which is defined as the amount of information was calculated from the pressure change due to the variation of demand reflected the abnormal conditions at nodes, and the emitter function (fire hydrant) was used to reproduce actual pressure change pattern in EPANET. The optimal combination of monitoring points for pressure detection was determined by selecting the nodes receiving maximum information from other nodes using genetic algorithm. The Ozger's and a real network were evaluated using the proposed model. From the results, it was found that the entropy theory can provide general guideline to select the locations of pressure sensors installation for optimal design and monitoring of the water distribution systems. During decision-making phase, optimal combination of monitoring points can be selected by comparing total amount of information at each point especially when there are some constraints of installation such as limitation of available budget.

• 한국물환경학회지
• /
• 제31권4호
• /
• pp.377-386
• /
• 2015

The purpose of this research was to suggest the water quality improvement in streams by evaluating the distribution characteristics of organics and ammonia nitrogen discharged by pollution sources from human living. The public sewage treatment plants'(PSTPs) effluents and the waters from streams in Gyeonggi-do were sampled and analyzed. Nitrogenous oxygen demand (NOD) was measured for the stream waters as well as the PSTPs effluents, and the correlations of NOD and $NH_3$-N, $NH_3$-N and water temperature in the PSTPs effluents were confirmed. In the case of the stream waters, the ratios of NOD to BOD and $NH_3$-N increased in the downstream sites after discharging the PSTPs effluents. As a result of statistical analysis of $NH_3$-N concentrations for the national water quality monitoring streams in Gyeonggi-do, $NH_3$-N showed the non-normal distribution which were biased to the left, but showed the considerable level because of higher coefficient of variation. Therefore, it is required to establish the water quality standard for the $NH_3$-N as a new parameter for judging the quality of the streams. In addition, inducing complete nitrification and introducing a logical standard setting system are needed to improve the water quality of streams by identifying distribution of the nitrogen components from PSTPs effluents.

• 한국물환경학회지
• /
• 제30권3호
• /
• pp.283-291
• /
• 2014

To study the distribution characteristics of diatom communities in relation to the gradient of water quality and land-use, water samples and epilithic diatoms were collected from 90 sites including mainstream and tributaries, in the Geum River System (GRS) during no rainfall, May 2011. Of 239 taxa identified, Achnanthes convergens and Cymbella minuta were dominated over all the sites. Cluster analysis on the GRS divided into three groups. Group 1 (G1) is the mountainous upstream, a relatively good water quality, and mainly consisted of saproxenous species. Group 2 (G2) is the urban sites, polluted (high in electric conductivity, total phosphate and soluble reactive phosphorus), and saproxenous and common species. Group 3 (G3) is the agriculture sites, and polluted (turbidity, total nitrogen, nitrate), and saprophilous species. There were some discrepancies between abiotic and biotic variables in GRS; biologically similar between G1 and G2, but abiotically similar between G2 and G3. These differences may attribute to not only physiological characteristics of diatom cells, but complicate relationships between microhabitat and water quality. Thus, an urgent development of generalized or standardized methods to diminish the differences between epilithic diatom community and environments is advent.

• 한국환경농학회지
• /
• 제41권3호
• /
• pp.177-184
• /
• 2022

BACKGROUND: Recently, the inflow of nonpoint pollutants into rivers caused by rapid urban and industrialization promotes the proliferation of algae, which causes eutrophication of rivers. This study was conducted to evaluate the seasonal variation of water quality characteristics and cryptomonads growth in the Oncheon River. METHODS AND RESULTS: The water quality and distribution characteristics of cryptomonads in the Oncheon River were investigated monthly for 12 months from January 2021. The cell number of cryptomonads was intensively developed in January-April, and it decreased sharply in the summer with heavy rainfall. In particular, cryptomonads moved to the downstream side of the river depending on the time, and as a result, significant differences were shown for each investigation point. The Korean trophic state index (Tsi_KO) in Oncheon River was classified as eutrophy all year round, indicating that cryptomonads can grow year-round. Distribution characteristics of cryptomonads in Oncheon River showed high correlations with DO (r=0.678), BOD (r=0.826) and chlorophyll-a (r=0.613) in water. CONCLUSION(S): In order to reduce cryptomonads in the Oncheon River, it is judged that a complex countermeasure considering the residence time, insolation and precipitation along with water quality factors is required.

• Current Research on Agriculture and Life Sciences
• /
• 제32권4호
• /
• pp.203-209
• /
• 2014

This study investigated characteristics of rainfall and water quality in Saemangeum area with attention to temporal and spatial distributions. A high variability in rainfall was noted during July and August. The temporal analysis of water quality data indicated that DO and TN as well as BOD, COD and SS were within national standards except for increased concentrations during spring and summer, unlike TP values that indicated poor water quality. Standard deviation showed a high variability in SS among the seasons most especially during summer. The high dispersion indicated variability in the chemical composition of pollutants where the temporal and spatial variations caused by polluting sources and/or seasonal changes were most evident for BOD and COD during winter and spring. The box plots and bar charts showed steadily low concentrations of BOD, COD, TN and TP except within Iksan and notable significant variations in SS concentrations among the monitoring stations. Thus, high pollution levels requiring intervention were identified in Mangyeong river basin with particular concern for areas represented by Iksan station. It was noted that Iksan received a considerable amount of rainfall which meant high runoff which could explain the significant pollution levels revealed in the water quality spatial distribution. Major pollution contributing pollutants within Saemangeum area were identified as SS, BOD, COD and TN. Therefore the present results could be used as a guideline for the temporal and spatial distributions analysis of both rainfall and water quality in Saemangeum watershed.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 1999년도 Proceedings of International Symposium on Remote Sensing
• /
• pp.363-370
• /
• 1999

Remotely sensed data is regarded as a potentially effective data source for the measurement of water quality and for the environmental change of water bodies. In this study, we measured the spectral reflectance by using multi-spectral image of low resolution camera(LRC) which will be loaded in the OSMI multi-purpose satellite(KOMPSAT) scheduled to be launched on 1999 to use the data in analyzing water pollution. We also investigated the possibility of extraction of water quality factors in water bodies by using remotely sensed low resolution data such as NOAA/AVHRR. In this study, Shiwha-District and Sang-Sam Lake was set up as the subject areas for the study. In this part of the study, we measured the spectral reflectance of the water surface to analyze the radiance of the water bodies in low resolution spectral band and tried to analyze the water quality factors in water bodies by using radiance feature from another remotely sensed data such as NOAA/AVHRR. As the method of this study, first, we measured the spectral reflectance of the water surface by using SFOV( Single Field of View) to measure the reflectance of water quality analysis from every channel in LRC spectral band(0.4~O.9${\mu}{\textrm}{m}$). Second, we investigated the usefulness of ground truth data and the LRC data by measuring every spectral reflectance of water quality factors. Third, we analyzed water quality factors by using the radiance feature from another remotely sensed data such as NOAA/AVHRR. We carried out ratio process of what we selected Chlorophyll-a and suspended sediments as the first factors of the water quality. The results of the analysis are below. First, the amount of pollutants of Shiwha-Lake has been increasing every you since 1987 by factors of eutrophication. Second, as a result of the reflectance, Chlorophyll-a represented high spectral reflectance mainly around 0.52${\mu}{\textrm}{m}$ of green spectral band, and turbidity represented high spectral reflectance at 0.57${\mu}{\textrm}{m}$. But suspended sediments absorbed high at 0.8${\mu}{\textrm}{m}$. Third, Chlorophyll-a and suspended sediments could have a distribution chart as a result of the water quality analysis by using NOAA/AVHRR data.

• 한국수자원학회논문집
• /
• 제55권spc1호
• /
• pp.1235-1249
• /
• 2022

본 연구에서는 웹 크롤링 방법을 이용한 자료수집, 텍스트 마이닝을 활용한 데이터 분석과 같은 빅데이터 분석기법을 이용하여 국내 상수도 수질사고에 대한 전개양상 분석을 수행하였다. 상수도 시스템의 수질사고 빅데이터 뉴스의 추출을 위한 웹크롤링 기법을 적용하고 정확한 수질사고 뉴스를 획득하고자 알고리즘을 절차화하여 제시하였다. 또한 대규모 수질사고의 경우 사고발생에 따른 사고인지, 사고확산, 사고대응, 사고해결 등과 같은 전개양상이 나타나므로, 각 단계에 따른 적절한 뉴스기사를 추출하고, 이에 따른 정보분석을 실시하였다. 즉, 각 단계 별 주요 키워드, 감성분석을 통한 수질사고 전개양상분석을 사례기반으로 상세히 실시하고 그 의미를 분석, 도출하였다. 제안된 방법론을 2020년 발생한 인천광역시 유충사고기간에 적용하여 분석하였다. 그 결과, 수질사고와 같은 소비자에게 직접적인 영향을 미치는 정보의 공개가 제한된 상황에서 사고발생시 장기간의 피해 지속성이 있는 수질사고에 대한 뉴스 기사 언론보도의 논조 및 소비자의 긍부정도가 시간에 따라 명확히 변화됨을 확인할 수 있었다. 이것은 공급자 입장에서의 수질사고의 전개양상은 시설물의 빠른 복구도 매우 중요하지만 소비자의 긍정도를 높이기 위한 소비자 중심의 정책마련의 필요성을 제시하고 있다.

• 한국환경과학회지
• /
• 제22권12호
• /
• pp.1615-1624
• /
• 2013

The aims of this study were to investigate and confirm the occurrence and distribution patterns of blood lipid lower agents (BLLAs) in Nakdong river basin (mainstream and its tributaries). 4 (atorvastatin, lovastatin, mevastatin and simvastatin) out of 5 statins and 2 (clofibric acid and zemfibrozil) out of 3 fibrates were detected in 29 sampling sites and simvastatin (>50%) was predominant compound followed by atorvastatin, lovastatin and clofibric acid. The total concentration levels of BLLAs on April, August and November 2009 in surface water samples ranged from ND~25.7 ng/L, ND~18.8 and ND to 38.8 ng/L, respectively. The highest concentration level of BLLAs in the mainstream and tributaries in Nakdong river were Goryeong and Jincheon-cheon, respectively. The sewage treatment plants (STPs) along the river affect the BLLAs levels in river and the BLLAs levels decreased with downstream because of dilution effects.

• 한국물환경학회지
• /
• 제32권2호
• /
• pp.163-172
• /
• 2016

This study aimed to develop a plan for effective performance of a watershed through correct identification of a river watershed by using the flowrate of the river and water quality data, which is the basis for the establishment of the water environment policy. The target river for water quality improvement was selected based on the monitoring result for 4 water systems in Chungcheongnamdo province in the recent 3 years. The result of analysis for the distribution of discharge capacity by a pollution source group for the water quality improvement target river showed that most of the target river has a high discharge capacity in the water system for living and livestock. Analysis for the density of the total discharge capacity of the whole watershed of Chungcheongnamdo indicated that the river that needs water quality improvement has high BOD concentration and high discharge load density at the point that this river is located. Thus, for efficient watershed management through selection and concentration, Chungcheongnamdo needs to improve the target river in priority. Stepwise planning is also required to establish and execute the water quality improvement in order to satisfy said target water quality, and establish the index for the water improvement rate for its evaluation.

• 한국물환경학회지
• /
• 제26권2호
• /
• pp.297-302
• /
• 2010

It is very important to know mean and confidence interval of water-quality constituents such as BOD for water-quality control and management of rivers and reservoirs effectively. The mean and confidence interval of BOD at Anseong2 and Hwangguji3 sampling stations which are located at the border of local governments in Anseong Stream were estimated and analyzed in this paper using Bootstrap technique which is one of non-parametric statistics. The results of Bootstrap were compared with arithmetic mean, geometric mean, Biweight method mean as a point estimator and distribution mean came from the appropriate probability distribution of Log-normal. In Bootstrap technique 12 data set was randomly selected in each year and 1000 samples was produced to get parameter of population. Visual Basic for Applications (VBA) of Microsoft Excel was utilized in Bootstrap. It was revealed that the Bootstrap technique can be used to explain more rigorously and robustly the achievement or violation of BOD target concentration in Total Maximum Daily Load (TMDL).