• Journal of Korean Society on Water Environment
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• v.23 no.2
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• pp.260-265
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• 2007

This study was carried out to complement water quality standards and to establish new concept for water quality standards reflecting current state of water quality in small streams. By this purpose, discriminant analysis was performed and Water Quality Level Model (WQLM) was developed using the data such as EC, BOD, $COD_{Mn}$, SS, T-N, T-P, $NH_3-N$ in 224 agricultural streams. To give water quality level for water quality parameters, it divided into 20% respectively in the order of excellent water quality. On the basis of the lowest water quality level, water quality level of small streams is granted. As a result of it, number of stream corresponding to Level I was no, Level II was 2 streams, Level III was 22 streams, Level IV was 70 streams, and Level V was 130 streams. Average of water quality in each level was the highest in Level V. EC, SS, and T-N of 7 parameters were selected in variance concerned water quality level. By standardized canonical discriminant function coefficient, EC of three variances was the highest in 0.625 at the discriminant power. The next was T-N (0.509), SS (0.414). By discriminant function for water quality level, Level II was equal to $-2.973+19.376{\times}(EC)+0.647{\times}(T-N)+0.009{\times}(SS)$, Level III was equal to $-3.288+19.190{\times}(EC)+0.733{\times}(T-N)+0.041{\times}(SS)$, Level IV was equal to $-4.462+27.097{\times}(EC)+0.792{\times}(T-N)+0.053{\times}(SS)$, and Level V was equal to $-9.117+40.040{\times}(EC)+1.305{\times}(T-N)+0.111{\times}(SS)$. As a result of test at real agricultural watershed of Jeongan and Euidang in Gongju city, the fitness of WQLM was high to 88.78%. But, to get accomplished water quality assessment more exactly in agricultural streams, we had to concentrate and get vast data, and WQLM was modified and complemented continually.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.5
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• pp.75-86
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• 2005

Recently since urbanization has brought about a dried stream and a worse water quality, Anyang city discharged the third treated sewage into the upper stream of Anyancheon and Hakuicheon. As the result, Hakuicheon had the water level and velocity enough for a living thing in the water to live in but water quality was worse than it had been. Therefore in case of meeting the water level and velocity of the second grade water-quality which living things in the water can live in, the discharge and water quality to secure in-stream flow must be at least 0.350 $m^3/s$ and $BOD_5\;3.2 mg/{\iota}$ respectively. In Anyancheon the water level was increased a little higher than it had been but the velocity was almost unchanged in comparison with it before. On the other hand the water quality was a little better than it had been. Therefore in case of meeting the water level and velocity of the third grade water-quality that people can do water-friendly activity, the discharge and water quality to secure in-stream flow must be at least 0.688 $m^3/s$ and $BOD_5\;4.8 mg/{\iota}$ respectively. The water-quality prediction on the suggested eight scenarios was simulated in all satisfying the third grade water-quality.

• Journal of Environmental Health Sciences
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• v.32 no.5 s.92
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• pp.424-430
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• 2006

Since 1985, the Gangwon Institute of Health and Environment(GIHE) and Ministry of Environment have collected rivers and streams water quality data in an ambient surface water monitering program. This study was prepared to propose an achievement of water quality of rivers subject to management by area according to an created level while establishing a water quality level applicable to the Gangwon area. As a result of evaluating correlativity on the BOD-based water quality data, BOD versus TP, and TP versus SS demonstrated significance at a confidence level of 95%. Evaluating correlativity on $10{\sim}90$ percentile values of analyzed data, a coefficient of determination, $r^{2}$ of BOD versus TP, and TP versus SS were 0.625, 0.286 respectively. Grading the results by evaluation method, the representative values of TP were 0.030 mg/l for I level, 0.100 mg/l for II level, 0.200 mg/l for Ill level, 0.300 mg/l for IV level, and 0.350 mg/l for V level, and those of SS were indicated 4.0 mg/l for I level, 15.0 mg/l for II level, 30.0 mg/l for III level, 45.0 mg/l for IV level, and 60.0 mg/l for V level. As for the limiting factor allowing the water quality standard exceeded, BOD posted 61% as the factor was found in 11 places, TP 28%, and SS 33%.

• Journal of Environmental Impact Assessment
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• v.23 no.5
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• pp.393-405
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• 2014

In this study, the nonpoint sources were evaluated by calculating the Nadonggang basin regional water quality and nonpoint source pollution load discharged. And were selected the banks of first administration based on the results and the direction of the next administration. As a results of estimating the water quality about BOD concentration in the mid influence area in the Nakdonggang basin, it was founded that 10 sites for 'Ia' water quality level, 6 sites for 'lb' water quality level, 5 sites for 'II' water quality level, 1 sites for 'I' water quality level. The estimation of COD concentration in the mid influence area, It showed that 9 sites for 'Ib' water quality level, 6 sites for 'II' water quality level, 6 sites for 'III' water quality level, 1 site for 'IV' water quality level. The assessment of water quality made Mid influence area of Gumhogang, Nakdong Goryung, Nakdong Milyang and Namgang selected as the mid influence area of high pollution. And delivery loads of nonpoint sources were calculated for mid influence area in Nakdonggang basin(max delivery load : 17,706.7 kg/day for Gumhogang influence area). As the result of calculating NPS(nonpoint sources) delivery load and water quality at influence area in Nakdonggang basin, Gumhogang influence area was selected as an area for management priority among nonpoint sources.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.3
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• pp.187-196
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• 2021

When evaluating the extent of the impact of water pollutants on the surrounding area, we would like to present the target level (proposal) of the quality of the environment, which is the standard for evaluation. We propose the environmental quality target level for substances that need to be applied domestically by investigating overseas cases operating the integrated environmental management system and the implications of domestic environmental pollutant management. The appropriateness of the environmental quality target level reviewed in this study was determined using data from the water quality measuring network, and future improvement measures were proposed. We review the available methodologies for setting quality objectives for the environment. It proposed the environmental quality target level for 21 substances that have domestic water pollutant emission standards and do not have environmental standards, and proposed future improvement measures. If it is necessary to add quality target-level items of the environment in the future, it is believed that expansion will be possible based on the methodology presented in this study.

• Journal of Korean Society on Water Environment
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• v.36 no.5
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• pp.431-444
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• 2020

The relationship between dam construction and water quality has recently come to be considered an important issue. A dam is a physical factor which causes changes to the river system around it. Considering these points, this study was conducted to obtain basic data by analyzing the relationship between water level fluctuations and water quality parameters in the short-term. In terms of methodology, the new construction of the Yeongju Dam (M5) in 2016 was divided into Stage 1 as the lotic system and Stage 2 as the lentic system, with four years in each period, and the water level fluctuations and water quality were analyzed using official data. As a result of this study, M5, a stagnant area in which organic matter and nutrients accumulate, was found to be an important factor in water quality management. In addition, the water level changed rapidly (0.9±0.2 m → 10.9±7.1 m) as the river environment condition was converted from the lotic system to the lentic system. In addition, water quality parameters such as BOD, COD, TOC, and Chl-a significantly changed in the short-term. Further, since the transport of organic matter and nutrients occurred well in the lotic system, sedimentation was expected to be dominant in the lentic system. Therefore, it was determined that when the river flow is blocked, autochthonous organic matter is an important factor for long-term water quality management in the future. This process can increase the trophic state of the water body. As a result of this study, the TSI_KO value was converted from mesotrophic in Stage 1 to eutrophic in Stage 2. Eventually, short-term changes in the river environment will affect not only changes in water level but also changes in water quality. Thus, a comprehensive and strategic approach is needed for long-term water quality management in the future.

• Journal of Korean Society on Water Environment
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• v.30 no.6
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• pp.612-621
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• 2014

Physicochemical factors and the phytoplankton communities in the downstream area of Namhan-River were investigated from June 2012 to November 2013. We also assessed water quality using biological water quality indices. Total nitrogen was 2.4 mg/L, total phosphorus was 0.04 mg/L, and biological oxygen demand was 1.1 mg/L. This resulted in a level 2 (Ib, good) water quality rating. A total of 259 phytoplankton taxa were classified, consisting of 26 families, two subfamilies, 64 genera, 222 species, 32 varieties, and five formas. Bacillariophyceae dominated during a1l seasons and at all sites. The dominant species were Aulacoseira granulata, Cyclotella meneghiniana, C. stelligera, Melosira varians, Cocconeis placentula var. lineata, Nitzschia palea, N. amphibia, Cymbella minuta, and Achnanthes convergens. The diatom assemblage index for organic pollution values was level A-D, and TDI was level B-D. P-IBI at most sites was at the M (moderate) level, but TSI was at the E (eutrophic) level. Most indices dropped from upstream to downstream.

• Journal of Korean Society on Water Environment
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• v.23 no.6
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• pp.985-992
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• 2007

There are about 40,000 chemicals used in Korea and 300 new types of chemicals are added to the list every year, influencing quality of air, soil and water. Water quality standards that serve as the basis for water quality management have been proved inefficient and insufficient compared to those of advanced countries. This study aims to improve the existing water quality standards. Most importantly, the water quality standards need to take into account not only protection of human health but also aquatic resources. To that end, water quality criteria need to be set by monitoring each watershed every year and conducting risk assessment. Criteria for human health are set at $10^{-6}$ cancer risk level, and for aquatic life at conservative level, adopting the methodology of the U.S. and Australia, respectively. After carrying out technical and economic feasibility studies, more conservative criteria will be used to decide final water quality standards. The development of this system to establish integrated water quality standards for both human health and aquatic resources protection is urgently needed.

• Journal of Wetlands Research
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• v.17 no.4
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• pp.339-347
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• 2015

Differences in characteristics of flora and environmental factors of geomorphology, hydrology, water quality and soil were investigated in the shoreline of total 35 reservoirs according to their usages of waterpower generation, agricultural water supply, residential and industrial water supply and flood control in Korea. The number of plant species, floral structure and characteristics of species traits in the shoreline of reservoirs were different according to their usage. From the results of stepwise regression analysis, the total number of vascular plant species was increased at the environment of the higher flood frequency at the median water level and the longer exposure duration of the shoreline. The results of principal coordinates analysis and cluster analysis showed that the shoreline flora was classified as the 3 types of 1) flood control and residential and industrial water supply, 2) agricultural water supply and 3) waterpower generation reservoirs. The water level fluctuation, flood frequency at the median water level, lake water quality index and exposure duration of the shoreline were selected as important environmental factors affected on the characteristics of shoreline flora. The species richness of total flora and hydrophytes, especially submerged macrophytes, were much higher in the reservoirs for the purpose of the waterpower generation in which mesotrophic water quality and stable water levels were maintained. Annual or biennial ruderals were established on the ephemeral drawdown zone of flood control, residential and industrial water supply reservoirs which have oligotrophic or mesotrophic water quality and wide range of water level fluctuation. The floating hydrophytes were differentially dominated in the littoral zones of the agricultural water supply reservoirs with a mesotrophic or eutrophic water quality and a medium water level fluctuation. In conclusion environmental factors related to water level fluctuation and water quality were different and then the floral characteristics of shoreline were distinguishable according to usage of Korean reservoirs.

• Journal of Wetlands Research
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• v.7 no.1
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• pp.81-91
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• 2005

We construct the hydrology-water quality monitoring system which can watch the variations of river flow and water quality in real time. We also construct the river management system through the hydrology-water quality monitoring system that can observe water quality and its variations for preparing for the accident of river pollution. The Gyecheon basin which is located at the upstream of Heoengseong dam is selected as an experimental watershed for the system construction. The real time monitoring system for getting more correct hydrological and water quality data consists of 3-rainfall gauge station, 3-water level gauge station, and 1-water quality gauge station. We intend that the data such as rainfall, water level, velocity, flow, and water quality will be collected and we try that the data may be used for practical and other purposes.