• Journal of Korean Society of Water and Wastewater
• /
• v.20 no.4
• /
• pp.585-594
• /
• 2006

This study focused on the causes of fish kills and its prevention methods in Yudeung Stream, Daejeon, Korea. Intense field data, continuous water quality monitoring system and water quality modeling were applied to analyze the causes. Pollutant can be delivered to urban streams by surface runoff and combined sewer overflows in rainfall events. However, water quality analysis and water quality modeling results indicate that the abrupt fish kills in the Yudeung stream seems to be caused by combined effect of DO depletion, increase in turbidity and other toxic material. Excessive fish population in the study area may harm the aesthetic value of the stream and also has greater potential for massive fish kills. It is suggested to implement methods to reduce delivery of pollutants to the stream not only to prevent fish kills but also to keep balance of ecosystem including human uses. Frequent clean up of the urban surface and CSO, installation of detention basin will be helpful. In the long run, it seems combined sewer system has be replaced with separate sewer system for more effective pollutant removal in the urban area.

• Korean Journal of Environment and Ecology
• /
• v.27 no.1
• /
• pp.30-51
• /
• 2013

This study was conducted to identify the impact of river improvement efforts by studying terrestrial insects inhabiting at streamside locations at the Daejeon and Yudeung streams. Seven surveys were conducted from April to October on 2008 and the results were analyzed. Totally 428 species of 110 families belonging to 11 orders of insects were investigated during the course of the present study. The insects identified at the Daejeon stream belonged to 335 species, 99 families and 11 orders, while those at the Yudeung stream were of 350 species, with 98 families and 11 orders. At the Daejeon stream, D-1 and D-2 points were the sites where the most species(178 species) were identified, while at the Yudeung stream, the Y-1 point was the site where the most species(179 species) emerged. In a cluster analysis based on a similarity index, Group A(without river improvement works) and Group B(downtown passing area with river improvement works) were created. Within Group A, survey points were classified as the Daejeon stream group(the A-1 Group) and the Yudeung stream group(the A-2 Group). It was found that the emergence patterns of insects were related to regional characteristics of the streams.

• Proceedings of the National Institute of Ecology of the Republic of Korea
• /
• v.2 no.1
• /
• pp.53-61
• /
• 2021

Distribution of fish community depends largely on environmental disturbance such as habitat change. In this study, we evaluated the impact of environmental variables and microhabitat patch types on fish distribution in Yudeung Stream at 15 sites between early May and late June 2019. We used non-metric multidimensional scaling to examine the distribution patterns of fish in each site. Gnathopogon strigatus, Squalidus gracilis majimae, Zacco koreanus, and Zacco platypus were associated with riffle and boulder areas, whereas Iksookimia koreensis, Acheilognathus koreensis, Coreoleuciscus splendidus, Sarcocheilichthys nigripinnis morii, and Odontobutis interrupta were associated with large shallow areas. In contrast, Cyprinus carpio, Carassius auratus, Lepomis macrochirus, and Micropterus salmoides were found at downstream sites associated with large pool areas, sandy/clay-bottomed areas, and vegetated areas. On the basis of these results, we suggest that microhabitat patch types are important in determining the diversity and abundance of fish communities, since a mosaic of different microhabitats supports diverse fish species. As such, microhabitat patches are key components of freshwater stream ecosystem heterogeneity, and a suitable patch composition in stream construction or restoration schemes will support ecologically healthy food webs.

• Journal of Korean Society of Water and Wastewater
• /
• v.20 no.4
• /
• pp.573-584
• /
• 2006

This study was carried out to investigate the causes of fish kills in the Yudeung Stream in Daejeon, Korea using literature reviews, governmental and our water quality monitoring data of the study site, rainfall data, intensive water quality monitoring during rainfall events, sediment pollutant contents and laboratory bioassay tests. Fish kill in urban streams can be caused by combined effect of reduction in dissolved oxygen concentration, increase in toxic material or increase in turbidity in waterbody due to introduction of surface runoff or effluent of combined sewer overflows after rainfall from the watershed areas. Despite of extensive and intensive field surveys and laboratory tests, it was found that those conventional methods have limitations to identify causes of fish kills in urban streams. It would be necessary to use dynamic water quality modeling to predetermine the range and level of water pollution in the stream and automatic water quality monitoring system that can collect water samples and detect water quality continuously.

• Journal of the Mineralogical Society of Korea
• /
• v.19 no.4 s.50
• /
• pp.259-264
• /
• 2006

This work carried out to analyze the physicochemical properties and investigate the assessment of heavy metal contamination of stream sediments of the Yudeung and the Gab streams in the Daejeon area. The pH of stream sediments of the Yudeung stream shows the range of weak acid and weak alkaline. Most of stream sediments contain about 80% sand grain and have low water and cation retention capacity. Hence the stream sediments are not suitable fur various plans to grow up. The analysis of heavy metals in the stream sediments shows that the concentration of Pb, Cr and Cd increases from upstream to down stream. It is likely that the trend has a relationship with the water. Contamination of stream water. The authors recommend that clay materials be replenished in the stream sediments to increase the self-purification capacity and to make the suitable condition for growing up of various plants, and that water quality of the stream which can Influence into the contamination of stream sediments be monitored.

• Korean Journal of Environment and Ecology
• /
• v.24 no.2
• /
• pp.147-156
• /
• 2010

This study was conducted from April, 2002 to March 2006, using three urban streams(Gap Stream, Yudeung Stream and Daejeon Stream) in Daejeon Metropolitan City. 12,027 individual birds summed by the peak count in 126 species, 34 families, and 13 orders were observed from three stream sites. Dominant species were of Anas poecilorhyncha, Anas crecca, Columba livia, Passer montanus, and Egretta garzetta(in that order). The groups of birds were classified into six types. The most frequent group were the arbor birds(54 species), while the smallest group was the diving ducks(7 species). As for the number of individuals, the shrub bird group had 721 individuals while the dabbling ducks observed had 4,974 individuals. Regarding the distribution of birds appeareing in each stream, 14,885 individual numbers in 114 species were observed at Gap Stream, 6,642 individuals in 90 species at Yudeung Stream and 4,202 individuals in 69 species at Daejeon Stream. Various indices of the birds were analyzed with respects to the similarities between streams. Gap Stream had similar characteristics to Yudeung Stream, and the latter was similar to Daejeon Stream. However, Gap Stream and Daejeon Stream showed different characteristics. The dominance index of each section was calculated using ten dominant bird species top-down. Subsequently, the birds and their preferred environment were analyzed. The results showed that shrub birds and arbor birds preferred the upper stream of every stream, while herons and dabbling ducks inhabited the midstream. Dabbling ducks and some diving ducks appeared downstream.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2008.05a
• /
• pp.2136-2140
• /
• 2008

Recently environmental and ecological river management have been held in high repute, therefore it needs to river restoration and management works considering topographical shape of river. This study estimated the change of topographical shape in Gab- and Yudeung-River using time-series aerial photos. Especially, we selected location points of river facilities as weir and bridge that were built and removed and the confluence of Gab- and Yudeung-River. And we investigated the change of time-series flux and flow-direction. Also, through the estimation of sediment by river flow together, it is possible to supply decision making data that is very important to instream flow and environmental and ecological river restoration in urban stream.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.48 no.6
• /
• pp.89-100
• /
• 2006

In order to estimate delivered nutrients load from non-point sources in the Gap stream watershed in Daejeon, a distributed watershed model SWAT2000 was used so that it could predict the impact of land management practices on water, sediments and chemicals yields in large complex watersheds with varing soils, land uses and management condition over long period of time. The SWAT2000 was applied to the Daejeon (Indong), Yudeung (Boksu) and Gap (Hoeduck) streams for TMDL (Total Maximum Daily Load) of nutrients. The observed water quality and streamflow data of the year of 2002 and 2003 were used for calibration, and those of the year 2004 and 2005 were used for validation. Simulated results were evaluated by Estimation Efficiency Analysis (COE), Regression Analysis $(R^2)$ and Relative Error (R.E.) for the nutrients amounts on the monthly and yearly basis by comparing observed load with estimated load obtained by using SWAT2000 simulations. The COE value fur T-N was ranged from 0.59 to 0.78, $R^2$ values for T-N ranged from 0.65 to 0.84, and R.E values fur T-N load ranged from 4% to 20%. COE value far T-N was ranged from 0.59 to 0.73, $R^2$ values for T-P ranged from 0.67 to 0.82, and R.E values for T-P load ranged from 3% to 25%. Estimated results of SWAT2000 simulation for 3 sites (Indong, Boksu, Hoedeok) were reasonably satisfactory. This study indicated that SWAT2000 model could be applicable to estimate the nutrients load from the Gap stream watershed in Korea.

• Economic and Environmental Geology
• /
• v.42 no.4
• /
• pp.315-333
• /
• 2009

In this study, the hydrochemical and the isotopic characteristics of major streams in the Daejeon area were investigated during rainy and dry seasons. The stream water shows the electrical conductivity of the range of $37{\sim}527{\mu}s$/cm, and pH $6.21{\sim}9.83$. The chemical composition of stream waters can be grouped as three types: the upper streams of Ca(Mg)-$HCO_3$ type, Ca(Mg)-$SO_4(Cl)$ type of middle streams flowing through urban area, and Na(Ca)-$HCO_3$(Cl, $SO_4$) type of the down streams. Based on in-situ investigation, the high pH of stream waters flowing through urban area is likely to be caused by the inflow of a synthetic detergent discharging from the apartment complex. The electrical conductivity of stream waters at a dry season is higher than those of at a rainy season. We suggest that the hydro-chemical composition of stream waters in the Daejeon area was affected by the discharging water from the sewage treatment facilities and anthropogenic contaminants as well as the interaction with soil and rocks. ${\delta}D$ and ${\delta}^{18}O$ values of the stream waters show the relationship of ${\delta}D=6.45{\delta}^{18}O-7.4$, which is plotted at a lower area than global meteoric water line(GMWL) of Craig(1961). It is likely that this isotopic range results from the evaporation effect of stram waters and the change of an air mass. The isotope value shows an increasing trend from upper stream to lower stream, that reflects the isotopic altitude effect. The relationship between ${\delta}^{13}C$ and $EpCO_2$ indicates that the carbon as bicarbonate in stream water is mainly originated from $CO_2$ in the air and organic materials. The increasing trend of ${\delta}^{13}C$ value from upper stream waters to lower stream waters can be attributed to the following reasons: (1) an increasing dissolution of $CO_2$ gas from a contaminated air in downtown area of the Daejeon, and (2) the increment of an inorganic carbon of groundwater inflowed into stream by base flow. Based on the relationship between ${\delta}^{34}S$ and $SO_4$ of stream waters, the stream waters can be divided into four groups. $SO_4$ content increases as a following order: upper and middle Gab stream${\delta}^{34}S$ value decreases as above order. ${\delta}^{34}S$ value indicates that sulfur of stream waters is mainly originated from atmosphere, and is additionally supplied by pyrite source according to the increase of sulfate content. The sulfur isotope analysis of a synthetic detergent and sewage water as a potential source of the sulfur in stream waters is furtherly needed.

• Korean Journal of Agricultural Science
• /
• v.37 no.2
• /
• pp.285-293
• /
• 2010

To secure instream flow at the Yudeung urban stream reach of Daejeon city in South Korea, Yudeung upstream diversion was designed with total water storage of $59{\times}10^4m^3$, and the upstream Seongol reservoir was planned to raise the bank with various sizes. Downstream streamflows were simulated by considering outflows from upstream diversion and reservoir, and after then flow durations were analyzed and compared with flows of no reservoir condition. In case of no diversion or reservoir upstream, flow durations were $1^{st}$ flow of $84.72m^3/s$, $95^{th}$ flow of $2.10m^3/s$, $185^{th}$ flow of $0.92m^3/s$, $275^{th}$ flow of $0.42m^3/s$, and $355^{th}$ flow of $0.31m^3/s$. In case of upstream diversion, flow durations were $1^{st}$ flow of $94.38m^3/s$, $95^{th}$ flow of $2.96m^3/s$, $185^{th}$ flow of $1.22m^3/s$, $275^{th}$ flow of $0.50m^3/s$, and $355^{th}$ flow of $0.35m^3/s$. The increase flow rates were $0.04m^3/s$ in $355^{th}$ flow, $0.08m^3/s$ in $275^{th}$, and $0.30m^3/s$ in 185th. In case of Seongol reservoir with effective storage capacities of $365{\times}10^4m^3$, $544{\times}10^4m^3$, $750{\times}10^4m^3$, and $992{\times}10^4m^3$, flow durations were $85.5{\sim}83.9m^3/s$ on $1^{st}$ flow, $2.85{\sim}2.57m^3/s$ on $95^{th}$ flow, $1.16{\sim}1.27m^3/s$ on $185^{th}$ flow, $0.64{\sim}0.99m^3/s$ on $275^{th}$ flow, and $0.56{\sim}0.94m^3/s$ on $355^{th}$ flow. The increase flow rates were $0.25{\sim}0.63m^3/s$ in $355^{th}$ flow, $0.22{\sim}0.57m^3/s$ in $275^{th}$, and $0.24{\sim}0.35m^3/s$ in $185^{th}$. The more the sizes of upstream reservoirs increased, the $1^{st}$ and $95^{th}$ flows decreased in which coefficients of determination were 0.92, 0.99, respectively and the $185^{th}$, $275^{th}$, and $355^{th}$ flows increased in which coefficients of determination were 0.93 to 0.99.