• Journal of Environmental Impact Assessment
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• v.13 no.4
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• pp.153-164
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• 2004

An integration study of time-variable small watershed and stream models (USEPA's SWMM and WASP5) was performed for impact assessment of urbanization on water environment. The study area, the Kyoungan Stream, the tributary of Paldang Lake, was divided into 111 subbasins, based on the topographic condition, land use, and drainage system. RUNOFF block of SWMM was applied to estimate runoff flow and quality. EXTRAN block computed daily and hourly flow according to simulated runoff flow, water supply, and drainage data. SWMM was connected to WASP5 by transforming output file of SWMM into input file of WASP5. The nonpoint source loads and flow data of SWMM were imported to WASP5. The stream was divided into 45 segments based on the watershed delineation. The study included three water quality parameters, BOD, TN, and TP. The validate models were used to examine the impact of urbanization on stream flow and water quality.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.2
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• pp.15-21
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• 2005

This study is to trace the change of stream shape using the past series of aerial photographs, and to compare the land use changes of riparian area along the stream. For the Gyeongan national stream, aerial photographs of 1966, 1981 and 2000 were selected and ortho-photographs were made with interior orientation and exterior orientation, respectively. Apparent changes of the stream were found that the consolidated reaches of stream by levee construction became straight together with widening of their stream widths. Especially the stream width of inlet part of Paldang lake widened almost twice because of the rise of water level by dam construction in 1974. The land use of riparian areas of three selected years were classified into six categories (water, forest, agricultural land, urban area, road, sandbar) by digitizing method. The forest and agricultural lands decreased and urban area increased as the stream maintenance had been performed.

• Journal of Environmental Science International
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• v.17 no.3
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• pp.297-303
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• 2008

For last couple of years many apartments, roads and bridges are constructed along the Kok-kyo stream which is penetrating Asan city, Chung-Nam Province. The effect of construction on stream environment was investigated in this study. Various kinds of water qualities of the Kok-kyo stream were monitored for 5 months. As it passed through the construction sites, $COD_{cr}$ concentration increased abruptly whereas the increment of the $BOD_5$ was not so great, indicating that non-biodegradable organics were flowed from the construction sites to the stream. Particularly, 0.2 mg/L of N-hexane was measured, which is believed to be mainly responsible for the organic pollution from construction sites. In spite of short periods of water quality monitoring, it could be concluded that there was a good correlation between construction sites and stream pollution. Therefore, legislative activity or enforced management by local government to the construction sites are needed for keeping the small stream environment better.

• Journal of Environmental Science International
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• v.16 no.5
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• pp.649-655
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• 2007

This study was focused on estimating instream flow, and its optimal alternative for securing the required total amount of instream flow was also researched in order to restore ecosystems and riverine aesthetics of the Mugeo Stream. the first tributary of the Taewha River flowing through the center of Ulsan. In this study the hydraulic and hydrologic conditions and water quality were investigated at specific channel reaches and representative stations of the Mugeo Stream to determine a proper estimate of instream flow. And riverine functions, such as the minimum flow, water duality conservation, fish habitat, and recreation, were considered to restore the environmental functions of the stream, As a result, the total amount of $11,500m^3/day$ was set as the target instream flow for the Mugeo Stream. It was chosen as the optimal alternative for securing the total external supply of $10,000m^3/day$ which have to be transfered from the riverbed flow diverted through the Taewha Main river at upstream of Samho bridge. The water duality throughout the Mugeo Stream channels will be improved considerably to 3-4 mg/l of BOD standard if the target instream flow is supplied and sewage is intercepted by the sanitary sewage system.

• Journal of the Korean earth science society
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• v.26 no.8
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• pp.821-827
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• 2005

The Yocheon is an upper stream of Sumjin river, passing through Namwon city. The water temperature of the stream increases from upper stream to downstream. The amount of COD, T-P, T-N, EC, TDS abruptly increases at measuring site 8. Whereas, the pH and DO level abruptly decreases at this site. At this point, the Yocheon river joins another small stream passing through the central part of Namwon city. At a further downstream pass site 8, the amount of COD on April and June (a dry season) is on third grade of water quality for lacustrine. This contamination suggests that sewage from the Namwon city provide COD, T-N, T-P into the stream. At point 2, the high amount of T-N indicates that the upper stream is contaminated by agricultural activity.

• Korean Journal of Environmental Agriculture
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• v.21 no.3
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• pp.165-171
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• 2002

A study was conducted to investigate the seasonal changes in water quality of watershed in the Agricultural Environment Promotion Zone. Samples collected were 12 GW (ground water), 2 IW (irrigation water), 2 SW (stream water) in An-Dong City, 4 GW, 6 IW, 11 SW in Young-Yang Gun, and sampling was conducted separately during dry and rainy season. In the ground water, EC and ionic species, except pH, were higher than those in stream water, and especially $NO_3-N$ concentration exceeded the limitation of drinking water. Concentration of ions decreased as the sampling depth was far from the soil surface. During a rainy season, the concentrations of $NO_3-N$ and K in the stream water were slightly higher than those during season. COD was lower during dry season in Yong-Yang, while the trend was contrasted to An-Dong. These results suggest that ground water was polluted by fertilization and compost while streamwater was polluted by loss of soil and organic during the rainy season. Principal chemical components related with changing water quality were EC, $NO_3^-$, Ca, Mg, Na, $Cl^-$, $Cl^-$, $SO_4^-$ in ground water, whereas $NH_4-N$, K, Mg, $Cl^-$, $SO_4^-$ in stream water.

• Journal of Korean Society on Water Environment
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• v.27 no.2
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• pp.218-227
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• 2011

The objective approach for assessment of stream naturalness is an essential part of the stream restoration project. This study proposes the methodology for the assessment of stream naturalness considering physical, biological and chemical factors. Physical factors consists of riffle and pool, river bed material, bank protection, floodplain vegetation and levee materials; biological factors are benthic macroinvertebrate, KSI (Korean Saprobic Index), and IBI (Index of Biological Integrity) and chemical factors are pH, DO (dissolved oxygen), and TP (total phosphorus). This procedure is applied to the Mokgamcheon. As a result, the downstream of Mokgamcheon (zone I) needs the prompt improvement of stream naturalness, compared to the others (zone II and III). This evaluation technique will be an effective tool to quantify the stream naturalness and can be used to set the target of stream restoration project.

• Journal of Environmental Health Sciences
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• v.26 no.4
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• pp.105-109
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• 2000

The purpose of this study is to investigate on the water quality of the upper region of Wonchun stream located in Suwon city by chemical analysis and EROD-microbioassay methods using rat hepatoma cell line H4IIE. The water samples were collected at 6 sampling sites from sept. to Nov. 1999 and determined the quantitative toxic effects. Higher levels of BO $D_{5}$, CO $D_{Cr}$ and CO $D_{Mn}$ were determined at M6 site where the influent contains domestic and industrial wastewater. EROD activity of water samples was ranged from 3.43$\pm$0.08 to 9.05$\pm$0.10 pmol/mg protein/min. High correlation with EROD activities and COD values was observed. From the results, the upper region of Wonchun stream water area was presumed to be highly polluted with various persistent organic chemicals.s.

• Journal of Korean Society of Rural Planning
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• v.2 no.2
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• pp.91-102
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• 1996

Monitoring techniques for afro-ecological environments were studied, Hydrologic and ecological components in conjunction with water quality were monitored in the Balkan watershed. The hydrologic monitoring program consists of four water level gauging stations along creeks and stream at the watershed having 26.5 km2. Stage - storage relationship of reservoir, rainfall amount of the watershed, and rating curve of the stream gauging stations were established. Soil type, land use, hydrologic soil group, population and economic activities within the watershed were surveyed. Water quality data from the streams were sampled weekly and chemical analysis was conducted. Temporal variations of water quality were investigated and water quality map of each reach of stream was made to identify spatial variations. Seasonal and spatial variations of vegetation densities along stream in the watershed were investigated using grid, Density variations of insect species such as arthropod, flying insect, spider spices, rice insects were also monitored to determine seansonal surveying density. These monitored data will be used to develop monitoring techi%ues and afro - ecological environment models.

• Journal of Korean Society on Water Environment
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• v.22 no.3
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• pp.456-461
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• 2006

The facility of constructed wet land combined with filter media was examined in order to improve the water quality of a polluted stream, which has been performed as a part of national projects. Throughout 2 years of operation for a stream, it can provide the design and operating parameters for the purpose of future construction. The influent flow rate was about 50% against the design capacity. The removal efficiencies of BOD, $COD_{Mn}$, SS, T-N and T-P were 62.9%, 47.1%, 74.8%, 22.4% and 33.5%, respectively. In order to keep this facility stable, the removal of surface filter media and supplement should be periodically conducted. In addition, the proper selection of sites is recommended not to be flooded.