• Korean Journal of Environmental Agriculture
• /
• v.31 no.4
• /
• pp.328-343
• /
• 2012

BACKGROUND: For effective subwatershed management, it is very important to select the tributaries for improving water quality and understand the characteristics of tributaries. Until now, however, the case study of main streams has been managed. 17 tributaries in Geum river subwatershed were monitored to regulate the source of water contaminations and identify their current situations in this study. METHODS AND RESULTS: As pollution indicators, such as biological oxygen demand($BOD_5$), chemical oxygen demand($COD_{Mn}$), suspended solid(SS), total nitrogen (T-N), total phosphate(T-P) and total organic carbon(TOC) in Geum river were examined from January to December in 2011. The results were as follows : The annual average concentration of nutrients in Yongdam reservoir upsteam was 0.7 mg/L for BOD, 3.0 mg/L for COD, 8.4 mg/L for SS, 2.905 mg/L for T-N, 0.035 mg/L for T-P and 1.6 mg/L for TOC. Water quality of Daechung reservoir upstream was mostly similar tendency in comparison to Yongdam reservoir upstream. Among the 22 tributaries, water quality in Daechung reservoir downstream was more polluted. T-N contents were significantly high in Miho B4 located Daechung reservoir downstream(annual average concentration: 13.53 mg/L). In cases of Miho A1, A2 and C1, pollution degree was worsened during rainy season expecially. CONCLUSION(S): For improving water quality of Geum river subwatershed, the tributaries in the Mihocheon area should be preferentially considered. Mihocheon tributary is the highest in pollution site, and thus a study on long-term effects should be research.

• Korean Journal of Ecology and Environment
• /
• v.48 no.1
• /
• pp.12-25
• /
• 2015

The tributaries of Daechung Lake play an important role in controlling eutrophication in the lake, which is used for agricultural purposes and as potable water. However, water quality properties were not extensively studied in the tributaries of Daechung Lake. The objectives of this study are to investigate spatial and temporal properties of water quality and to characterize streams which could threaten water quality of Daechung Lake. For this study, water samples were weekly or monthly collected from February 2014 to October 2014 in 9 streams. Water quality parameters analyzed in this study include biochemical oxygen demand (BOD), chemical oxygen demand (COD), total organic carbon (TOC), total nitrogen and phosphorus (TN and TP), suspended solids (SS), and chlorophyll a. Based on temporal distribution and principal component analysis, BOD, COD, TOC, SS, and TP were controlled by not only river discharge that increased during summer due to heavy rain fall, but also due to anthropogenic input (e.g., bridge construction and/or agricultural activity). Dilution is also one of the factors explaining TN and conductivity, both of which decreased with increased discharge. Generally, concentrations of contaminants (BOD, COD, TOC, TN and TP) in the tributaries were higher than those of Daechung Lake. However, pollution load indicated that only the main channel of Geum River and Sook Stream may largely influence lake waters, attributed mostly to their large volumes. This implies that the main channel and Sook Stream are the major influences on the water quality of Daechung Lake.

• Journal of Wetlands Research
• /
• v.20 no.3
• /
• pp.201-209
• /
• 2018

In this study, the water quality index was calculated using the water quality monitoring data of the major tributaries of the Nakdong River and long-term trend analysis was performed to identify the tributaries requiring priority management. We used a Real-Time Water Quality Index method implemented by the Ministry of Environment. Linear regression as a parametric method and Mann-Kendall Test and Sen Slope Test as a nonparametric method were applied for the trend analysis. The water quality index of major tributaries except for Migeon2 and Seokyo2 was in the range below Fair grade and there were no significant trends for the rest of the sites except Bukan, Chennae, Hogye, Yongdeok. Therefore, in order to improve the water quality of the main stream, management of the tributaries should be preceded.

• Journal of Environmental Science International
• /
• v.28 no.3
• /
• pp.357-369
• /
• 2019

In this study, the water quality components (pH, BOD, COD, TOC, SS, DO, TP) and the water quality, observed for 10 years (2008~2017) in the five tributaries of the Nakdong River with the highest flow rates, were analyzed. Monthly levels of the water quality components were estimated and regression functions were used to quantitatively explain the changes in the BOD and COD components, with respect to the TOC components. The results of analyzing the water quality levels in terms of the living environmental standards show that the lowest water quality was observed midstream (ST-3) and the highest water quality was observed upstream (ST-1 and ST-2). The regression function was estimated to be a linear function in all five tributaries, and the goodness of fit of the function was high upstream (ST-2), midstream (ST-3), and downstream (ST-4). According to the regression analysis using the observation data from 2008~2017, we found that the consumption of dissolved oxygen increased with an increase in organic matter in the major tributaries of the Nakdong River.

• Journal of Korean Society on Water Environment
• /
• v.27 no.5
• /
• pp.670-679
• /
• 2011

Chlorophyll-a is a major water quality indicator for an algal bloom in streams and lakes. The purpose of the study is to estimate chlorophyll-a concentration in tributaries of the Seonakdonggang by an artificial neural network (ANN). As the tributaries are ungauged streams, a watershed runoff and quality model was used to simulate water quality parameters. The tributary watersheds include urban area and thus Storm Water Management Model (SWMM) was used to simulate TN, TP, BOD, COD, and SS. SWMM, however, can not simulate chlorophyll-a. The chlorophyll-a series data from the tributaries were estimated by the ANN and the simulation results of water quality parameters using SWMM. An assumption used is as follows: the relation between water quality parameters and chlorophyll-a in the tributaries of the Seonakdonggang would be similar to that in the mainstream of the Seonakdonggang. On the assumption, the measurement data of water quality and chlorophyll-a in the mainstream of the Seonakdonggang were used as the learning data of the ANN. Through the sensitivity analysis, the learning data combination of water quality parameters was determined. Finally, chlorophyll-a series were estimated for tributaries of the Seonakdonggang by the ANN and TN, TP, BOD, COD, and temperature data from those streams. The relative errors between the estimated and measured chlorophyll-a were approximately 40 ~ 50%. Though the errors are somewhat large, the estimation process for chlorophyll-a may be useful in ungauged streams.

• Journal of environmental and Sanitary engineering
• /
• v.14 no.3
• /
• pp.71-79
• /
• 1999

The Hg, Cd, Cu, Mn, and Zn in bottom sediments of han river and their tributaries were analyzed to evaluate the seasonal variations of heavy metals. Leaching tests were also performed for estimation of availability of heavy metal retention in sediments. Sediments of Anyang stream showed the highest concentration of heavy metal in the sediment samples. Heavy metal concentration was heavily depended upon the heavy metal source of tributaries of han river and particle distribution. Clay and silt had higher concentration of heavy metals than very fine san and fine sand due to difference of retention capability of heavy metal. The highest concentration of heavy metal was observed in bottom sediments irrespective of sites investigated. Heavy metals and ignition loss showed positive relations, and higher relationships with p-value <0.01 were observed between copper and lead. copper and zinc, and depended on the pH condition of leaching test, and leachated fraction increased with decrease of the pH.

• Microbiology and Biotechnology Letters
• /
• v.24 no.3
• /
• pp.364-370
• /
• 1996

Sediments collected from the Jungnang-cheon and its tributaries were used to enumerate anaerobic bacteria by most probable number (MPN) methods. A simple method was developed to detect ferrous ion in the culture fluid in order to count the number of iron ion reducers, and sulfate-reducing bacteria (SRB) and methanogens were detected by the presence of FeS precipitate in the culture or methane in the head space, respectively. The numbers of iron reducer was in the range of 10$^{7}$ - 10$^{8}$ /g in the sediment of the stream containing higher organic content than the tributaries. The sediments of tributaries were analyzed to contain iron reducers less than 10$^{7}$ cells/g. With one exception the numbers of SRB and methanogens were less than 10$^{3}$ cells/g in the sediment. From these results it is concluded that organics in the sediment support the growth of iron reducers, which out-compete SRB and methanogens.

• Membrane and Water Treatment
• /
• v.11 no.1
• /
• pp.49-57
• /
• 2020

The effect of Combined Sewer Overflow on the river system was investigated throughout three preliminary field tests and three main ones. As a result of the study, Combined Sewer Overflow did not affect water qualities on the main stream since the concentration of the main stream did not significantly changed during rainfall events although the water quality of tributaries has rapidly deteriorated due to the influence of the Combined Sewer Overflow during rainfall events. The main cause of the result is that the flow rate of the tributaries is considerably lower than that of the main stream, so that the tributaries with deteriorated water quality during rainfall events did not significantly affect the quality of the actual main stream. Therefore, the water quality of the Kumho River is more affected by the wastewater treatment facilities that discharges water continuously to the main stream than pollutants from non-point pollution sources during rainfall events. As a result, managements for discharges from wastewater treatment facilities should be strengthened in order to improve the water quality of the river.

• Journal of Korean Society on Water Environment
• /
• v.20 no.4
• /
• pp.352-356
• /
• 2004

Variations of water quality parameters were investigated for last 13 years in Han river. Deviation from 3 month moving average was suggested for the variation analysis. Many parameters of mainstream and tributaries showed similar monthly fluctuations. Suspended solid of mainstream showed higher fluctuation than that of tributaries due to summer flood. Contrarily, the organic parameters such as BOD, COD, and TN showed lower fluctuations in the mainstreams. The magnitude of deviation was in the order of pH < DO, COD, temp. < BOD, TN < TP, SS. Strong correlation was found in BOD data of adjacent sites. Main sites showed low deviation in comparison to adjacent common sites of mainstream (1:2.4). Mainstream showed low deviation in comparison to tributaries (1:1.7). Seasonal tendency of monthly BOD was confirmed using autocorrelation function. The deviation was in inverse proportion to the magnitude of BOD.

• Journal of Environmental Science International
• /
• v.16 no.5
• /
• pp.657-664
• /
• 2007

The content and distribution of some heavy metals (Fe, Mn, Cr, Co, Cu, Ni, Zn and Pb) were investigated in the <$63{\mu}m$ bed sediments of the Mangyeong river to recognize the extent of contamination. Results showed that a wide range of concentrations was apparent for every metal. These variations were particularly significant at the confluence of tributaries. High levels of metals occur mainly in the confluence of tributaries. Geoaccumulation indexes have been calculated to assess whether the concentration observed represent background or contaminated levels. It is proved that the Mangyeong River is moderately to strongly polluted for Mn, Cr, Cu, Zn and Pb. The spatial extent of pollution was examined, and it was found that the most polluted area is located in the confluence of Iksan and Jeonju tributaries.