• Korean Journal of Environmental Agriculture
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• v.19 no.5
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• pp.382-393
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• 2000

The principal indicators contributing to water qualities was screened by factor analyses, based on the monitored chemical parameters of water quality for various water resources from 1995 to 1999 in the small agricultural catchments of the Han River Basin. Water samples of streams, groundwaters, and reservoirs were taken four times a year from upper (Daegwanryong), middle (Dunnae and Chunchon) and lower (Guri) reaches of Han River Basin. In these areas, the respective type of farming practiced was alpine agriculture and livestocks raising, typical upland and paddy cultivation, and intensive cropping in the plastic film house. Water quality was monitored for twenty-one water quality parameters, including pH, EC, SS, T-N, T-P, COD, cations, anions, and heavy metals. pH, EC and COD of the stream waters were suitable for the Korea irrigation water quality guidelines. However, T-N and T-P concentrations of water samples in four catchments far exceeded the irrigation water guideline. Concentrations of canons and heavy metals in Wangsuk stream in Guri area were higher than those in streams in other areas. Factor analysis revealed that significant correlation was observed for 81 pairs out of 231 water quality indicators of stream water among the $21\;{\times}\;21$ cross correlation matrix of stream water quality indicators. The first factor accounted for 27.01% of the total variation in stream water quality indicators, and high positive factor loadings were shown on EC, K, Na, $NH_4\;^+-N$, $PO_4\;^{3-}$, $SO_4\;^{2-}$, and COD. Fifty-three water quality indicator pairs were significant out of 190 ground water quality parameters. The first factor accounted for 28.54% of the total variation in ground water quality indicators, and high loadings were revealed on EC, Ca, Mg, K, Na, $NH_4\;^+-N$, and $SO_4$. Twenty-nine pairs of reservoir water quality indicators were significant out of 66 pairs. The first factor accounted for 37.06% of the total variation in reservoir water quality indicators, and high loadings were shown on EC, Mg, K, Na, SS, T-P, Cl, and COD. These results demonstrate that EC was the first factor contributing to water quality.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.379-383
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• 2015

Indicators of environmental conditions describe the state of the environment and the quantity and quality of natural resources. This study deduced the evaluation items to assess each sub-indicator for agricultural water quality and conducted the surveying using the Delphi method based on agricultural water quality experts. Considering its importance, environmental, state, and management indicators showed that state indicator such as COD concentration for surface water and $NO_3-N$ concentration for groundwater was ranked as first and followed by amount of fertilizer. Its indicators were correlated with state and environmental indicators in surface water and groundwater. The best management indicators were calculated to assess the agricultural surface water and ground water quality. The indicator could be used in established policies for management and conservation of water resources.

• Journal of Korean Society on Water Environment
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• v.21 no.2
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• pp.109-117
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• 2005

Understanding the condition of our nation's water resources, identifying what caused problems, and determining how to solve these problems are essential but difficult undertakings. The natural water cycle is itself intricate, and the addition of human activities increased this complexity. Consequently, answering the basic question "How clean and safe is our water?" is not easy. One way to present the condition of our water resources and the impacts of related human activities is to develop understandable measures, or indicators, that singly or in combination provide information on water quality. Managers and scientists can then use this information to develop effective solutions and make sound decisions to protect our water resources. It is important to note that environmental indicators can be used to measure a variety of phenomena. Indicators can present information on status or trends in the state of the environment, can measure pressures or stressors that degrade environmental quality, and can evaluate society's responses aimed at improving environmental conditions.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.509-514
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• 2015

Indicators of environmental conditions qualitatively and quantitatively describe the state of the environment and natural resources, and the OECD (Organization for Economic Cooperation and Development) has initiated and suggested AEIs (Agri-Environmental Indicators) to assess trends over time of the effects of agriculture on the environment and the effectiveness and efficiency of agricultural and environmental policy measures since 1990's. This study aims to develop the state indicators of water quality for agricultural water, surface and groundwater, to evaluate the environmental impacts of agricultural activities and policies by qualifying the environmental levels of a nation. Status indicators were calculated according to the agricultural water quality standards of OECD and Korea, and their trends were analyzed over time. Particularly, nitrate ($NO_3{^-}$) status indicators of ground water in 2013 were significantly lower than the ones in 2000. Overall, the water quality indicators of surface water in 2013 were higher than the ones in 2012, except for pH and DO. The groundwater quality indicators in 2013 were lower than those of previous years. The optimal management indicators were calculated to assess agricultural surface water and groundwater quality. The findings of this study indicated that the state indicators could play a significant role to establish policies and procedures for managing and conserving water resources. This study also discussed water pollution caused by agricultural and industrial effluents.

• Journal of Korean Society on Water Environment
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• v.29 no.5
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• pp.630-640
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• 2013

It is one of the most critical steps identifying impaired waterbodies exactly in the selection of target water quality indicators for the management of Total Maximum Daily Loads (TMDLs). Excess ratio and excess level were applied and analyzed by the stream zone basis in order to evaluate water impairment for Nakdong, Geum, Youngsan and Seomjin rivers. Each river basin was divided into stream zones in the light of its watershed and waterbody characteristics. Selected water quality parameters discussed in this study were pH, DO, BOD, COD, SS, T-P, T-Coli and F-Coli. The excess ratios of the water quality parameters were used to discriminate water bodies that did not meet water quality standards. The excess levels were used to classify the degradation of water quality. The excess ratios and the excess levels to the water quality criteria of the medium influence areas were used for each stream zone. The results indicate that the excess ratios and the excess levels are varied on the stream zone in each river basin. Three parameters, pH, DO and SS, met water quality standards in all stream zones. The other five parameters indicated very high excess ratios in most waterbodies, and especially T-P and T-Coli revealed to be very high excess levels in some waterbodies. These parameters could be considered as major target indicators for the management of TMDLs.

• Journal of Korean Society on Water Environment
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• v.22 no.6
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• pp.1004-1013
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• 2006

To effective a watershed management, it is necessary to have one or more quantitative measures that can be used to evaluate the relationship between pollutant sources and their impact on water quality. Such measurable quantities are termed indicators. Once an indicator has been selected, a target value for that indicator must be established that seek to distinguish between the impaired and unimpaired state of the waterbody. Various factors will be considered for the selection of an appropriate watershed management indicator. For example, available data, application, management conditions, cost, etc. This paper lists various factors that should be addressed in choosing a watershed management indicators and investigates applicable indicators during watershed management period.

• Journal of Korean Society on Water Environment
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• v.29 no.4
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• pp.531-539
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• 2013

In order to apply a water quality indicator as a certain target pollutant, the indicator should have the representability of an index for the management of Total Maximum Daily Loads (TMDLs). Scientific groundwork and treatment technologies also should be provided for the application of the indicator. This study analyzed the applicability of major water quality indicators for target pollutants. The results showed that four water quality indicators of TOC, T-N, SS & T-Coli can be considered as target pollutants besides existing BOD and T-P. These indicators can be applied with the preparations such as essential basic data, pollution load estimation framework as well as legal criteria setting when the need is raised. As the importance of TOC, which is considered as a replacement of BOD, is emphasized, technical and institutional terms are being prepared in order to determine TOC as another target pollutant in the near future. It could be considered to combine TOC with BOD for the time being during the $3^{rd}$ stage of TMDLs in view of the present conditions for the management of TOC. TOC can be the most effective index for the organic matter and help to be managed more systematically in the waterbodies where rivers and lakes are mutually connected.

• Journal of Korean Society on Water Environment
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• v.25 no.4
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• pp.606-614
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• 2009

To evaluate the biological water quality, diatom-based biological indices (DAIpo and TDI) were examined in the Sum-River and the Dal-stream. Having BOD concentrations below $2mg{\cdot}L^{-1}$ in most sites, water quality of both rivers was good. The DAIpo and TDI values ranged from 29.8 to 91.4 and from 38.7 to 93.0 respectively. From the biological water quality assessment, DAIpo and TDI for both rivers displayed fair to fairly poor water quality levels. However, the two indices showed more polluted conditions than expected from the BOD vlaues. In addition, DAIpo, having wider range of differences, appears to be more sensitive to the change in water quality when compared to TDI values. Statistical analysis using principal component analysis showed that Nitzschia palea and Diatoma vulgare might not be the appropriate indicators due to their low correlations with other indicators.

• Journal of Environmental Impact Assessment
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• v.20 no.3
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• pp.281-297
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• 2011

The specie composition, stranding crops and the dominant species of phytoplankton were studied in three streams, Namdae-stream, Yeongok-stream and Sacheon-stream from May 2008 to February 2009. The water qualities of the three streams which run into estuary were also examined using phytoplankton indicators. As the result, the phytoplankton appeared 94 taxa in Namdae-stream, 79 taxa in Yeongok-stream and 73 taxa in Sacheon-stream, diatoms appeared the most in phytoplankton. Genus Navicula and Cymbella in diatoms appeared to be over 10 taxa in each stream, N. cryptocephala, N. cryptotenella and N. gregaria, the pollution tolerance taxa, appeared more frequent in the downstream. Due to the separation of each substrate by the rapid water velocity in the upstream, Achnanthes minutissima, a known periphyton, was dominant in upstream site at Namdae and Yeongok-stream. Some construction areas and sites of downstream of Namdae-stream, Yeongok-stream and Sacheon-stream were shown to be polluted because pollution tolerance taxa, such as Cyclotella meneghiniana, Nitzschia palea and Oscillatoria limnetica, were dominant. The total of 20 taxa phytoplankton indicators were found, composed of 16 taxa of Water pollution algae including Oscillatoria limosa, 2 taxa of Clean water algae Meridion circulare and Staurastrum puntulatum, 1 taxa of Toxic algae Microcystis aeruginosa and 1 taxa of Taste and odor algae Fragilaria construens. Water pollution indicators were appeared frequently in polluted sites of biological water quality(DAIpo, TDI) and of sites containing high trophic state index(TSI). Therefore, using the phytoplankton indicators can assess water quality through relation of biological water quality and trophic state index.

• Journal of Korean Society of Water and Wastewater
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• v.34 no.6
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• pp.495-502
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• 2020

The 37 indicators for performance evaluation of public sewage management agencies are divided into four major categories (agency manpower management ability, wastewater treatment plant operation and management, sludge and water reuse, service quality) in the first stage, and the necessity and score acquisition for the detailed indicators by each major category in the second stages. Priority was investigated through the Analytic Hierarchy Process (AHP) analysis technique for ease and relevance of company efforts. Also, based on the results of this analysis, integrated type weighting and relative importance were analyzed. As a result of the analysis, the weight and relative importance of the first stage classification were in the order of wastewater treatment plant operation and maintenance, operation agency manpower management ability, sludge and water reuse, and service quality. As a result of analyzing the weights and priorities of the detailed performance indicators in the second stage, it was found that operator's career years, the percentage of certification holding rate in operators, compliance with the effluent water quality standards, training times for operators, and efforts to manage hazardous chemicals were important. Some of the indicators of operation agency performance evaluation may include indicators in which the performance of the company's efforts is underestimated or overestimated. In order to improve this, it is necessary to give weights in consideration of the necessity of the indicator, the relevance of the company's efforts, and the ease of obtaining scores.