• Korean Journal of Ecology and Environment
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• v.53 no.2
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• pp.138-147
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• 2020

The Singil Stream, flowing into an artificial lake, Lake Shihwa (South Korea), experiences a strong anthropogenic pressure with continuous organic matter (OM) inputs from rural, urban, and industrial areas. In this study, we investigated suspended particulate matter (SPM) and streambed sediments collected along the Singil Stream in 2014 and 2016, by applying a dual element approach (δ¹³C and δ¹⁵N) to identify OM sources. The SPM and streambed sediment samples from the indusrial area showed higher organic carbon and nitrogen concentrations (or contents) than those from the other areas, with distinctively lower δ¹⁵N values. Accordingly, our dual element approach indicates that the industrial area was the predominant OM source influencing OM quality and thus water quality of the Singil Stream flowing into Lake Shihwa during the study periods. However, further studies are necessary to better constrain OM sources in the Singil Stream since OM sources from the industrial area appear to be complex.

• Journal of the Korean Geophysical Society
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• v.9 no.4
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• pp.321-331
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• 2006

Recently, runoff characteristics of urban area are changing because of the increase of impervious area by rapidly increasing of population and industrialization, urbanization. It needs to extract the accurate topologic and hydrologic parameters of watershed in order to manage water resource efficiently. Thus, this study developed more precise input data and more improved parameter estimating procedures using GIS(Geographic Information System) and GA(Genetic Algorithm). For these purposes, XP-SWMM (EXPert-Storm Water Management Model) was used to simulate the urban runoff. The model was applied to An-Yang stream basin that is a typical Korean urban stream basin with several tributaries. The rules for parameter estimation were composed and applied based on quantity parameters that are investigated through the sensitivity analysis. GA algorithm is composed of these rules and facts. The conditions of urban flows are simulated using the rainfall-runoff data of the study area. The data of area, slope, width of each subcatchment and length, slope of each stream reach were acquired from topographic maps, and imperviousness rate, land use types, infiltration capacities of each subcatchment from land use maps, soil maps using GIS. Also we gave the management scheme of urbanization runoff using XP-SWMM. The parameters are estimated by GA from sensitivity analysis which is performed to analyze the runoff parameters.

• Korean Journal of Agricultural Science
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• v.38 no.1
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• pp.163-172
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• 2011

To provide the operation rule curve for suppling instream flow to urban stream from reservoir, the Soho reservoir with watershed area of 7.4 $km^2$ and total water storage of 2.58 $Mm^3$ was planned at the headwaters of the Daejeoncheon. Daily streamflow was simulated and using the simulated streamflow and desired instream flow, the operation rule curve by Senga method was drawn and evaluated through reservoir operation. Senga method is derived by accumulating the differences between streamflow and desired instream flow adversely. Water storages were simulated on a daily basis to supply urban instream flow from Soho reservoir, but the amount of supplying instream flow to urban stream was not nearly increased comparing with that of normal operation that does not used the rule curve. Thereafter the new simulation-based operation rule curve was derived and applied to supply instream flow from Soho reservoir. In normal operation, the amount of instream flow was shown to 15,000 $m^3$/d, but it was increased to 27,700 $m^3$/d in withdrawal limited operation using the new derived rule curve, in which the applicability of this rule curve was proved. Also comparing with the flow duration curves at station just before urban Daejeoncheon stream without and with upstream Soho reservoir, the 95th flow was decreased from 1.64 mm/d to 1.51 mm/d, and the 355th flow was increased from 0.17 mm/d to 0.30 mm/d. Monthly streamflows during October to March were increased from 10.6~24.1 mm to 24.1~34.0 mm with the increasing rate of 141~227%.

• Journal of Wetlands Research
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• v.10 no.2
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• pp.129-141
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• 2008

This study analyzed and assessed the water quality of a small urban stream in the apartment complex of Yewol-Dong, Buchun-Si at Korea. The flows in the stream due to the interceptions of sewage and normal flow are usually low and the water quality and offensive odor problems by inflows of the sewage and other pollutants are occurred in the study area. Therefore we intended to monitor and identify the water quality conditions. Based on this, we simulated water quality using QUAL2E model and investigated water quality characteristics for the future. As the results, we found that the water quality depended on the inflows of point and non-point sources and so it is important to maintain instream flow for improvement of water quality problem and to intercept point and non-point sources in this study area.

• Journal of Environmental Health Sciences
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• v.11 no.1
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• pp.1-8
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• 1985

Urban sewage and stream water in Wonju city were examined and the results were as follows: The average water quality of Wonju stream was flow 52.8m$^3$/min, BOD 21.14ppm, COD 7.06 ppm, SS 212.4ppm, Cl$^-$ 23.14ppm, O-Phosphate 1.08ppm, NH$_3$-N 1.08ppm, NO$_2$-N 2.63ppm and pH 7.48 respectively. The average water quality of urban sewage was flow 2.76m$^3$/min, BOD 112.7ppm, COD 33.6ppm, SS 374.4ppm, Cl$^-$ 46.2ppm, O-Phosphate 1.56ppm, NH$_3$-N 5.96ppm and NO$_2$-N 3.28 ppm respectively. The quality of stream water showed was 4th grade area according to environmental water quality standard. The survey showed k$_1$ 0.11day$^{-1}$, k$_2$ 0.29day$^{-1}$ and the self- purification coefficient 2.5 in average.. In calculating oxygen variation in water by Streeter-Phelp's equation the zero station exhibited in down stream.

• Korean Journal of Ecology and Environment
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• v.43 no.1
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• pp.11-18
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• 2010

The contamination of a suite of heavy metals were evaluated in water and sediments of urban stream, Tancheon down the stream. Tancheon is a urban stream which goes all the way across the urban area where various pollution sources are present. The sixteen study sites from seven different areas were designated down the stream. The heavy metal levels of the streams were detected in the order of Zn>Cu>Ni>Pb>Cd>Cr>Sb. There was a difference in the relative order of the concentration ranking in lake sediments. There is a trend that the heavy metal levels are higher at the sites where the construction causes inflow of soil particles to stream. Toxicity tests using pore-water in sediments were conducted for samples collected in some study sites, and pore-water in one site was proven to be toxic to Japanes medaka (Oryzias latipes). The reason may be the fecal pollution rather than heavy metal effect. Strong odor was detected in the sediment whose pore-water samples showed ecotoxicity. We did not observed the increasing concentration of heavy metals down to stream since the soil texture varied in the stream area of our study. Further study is needed to find quantitative relations between the level of contamination and its eco-effect.

• Korean Journal of Ecology and Environment
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• v.43 no.2
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• pp.232-241
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• 2010

Epilithic diatom communities and water quality were monitored to evaluate the ecological impact of the inflow of Wonju-stream passing through the urban area in the Seom River Watershed. We selected the 14 sampling stations (5 main stream sites and 9 tributary sites), and collected diatom and water samples between October 2007 and September 2008, on the seasonal basis. The results indicate that most water quality parameters showed the site-specific patterns over the study, except for water temperature and dissolved oxygen. The levels of water quality parameters were highest at the site of Wonju stream, whereas the lowest in the upstream sites, and intermediate or gradually decreased in the downstream sites of the Seom river. One species, Achnanthes convergens, showed the highest biomass and frequency over the sites, while three saprophilous species-Navicula goeppertiana, Navicula subminuscula, Nitzschia palea were appeared only in Wonju Stream and other polluted sites. According to trophic diatom index (TDI) values, which were highly correlated with nutrients and EC, the study sites were classified into three classes: upstream and tributary (Class A and B), Wonju Stream (Class D), and mixed zone and downstream (Class C). A cluster analysis supported the result of TDI classification. Therefore, Wonju-stream located in populated urban area exerted the adverse ecological effects on the epilithic diatom community and water quality of the lower Seom River System, although its severity gradually decreased downstream.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.397-397
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• 2015

The frequency of urban floods is recently increased as a consequence of climate change and haphazard development in urban area. To mitigate and prevent the flood damage, we generally utilized a numerical model to investigate the causes and risk of urban flood. Contrary to general flood inundation model simulating only the surface flow, the model needs to consider flow of the sewer network system like SWMM and ILLUDAS. However, this kind of model can not consider the interaction between the surface flow and drainage network. Therefore, we tried to evaluate the impact of bidirectional interaction between sewer and surface flow in urban flooding analysis based on simulations using the quasi-interacted model and the interacted model. As a general quasi-interacted model, SWMM5 and FLUMEN are utilized to analyze the flow of drainage network and simulate the inundation area, respectively. Then, FLO-2D is introduced to consider the interaction between the surface flow and sewer system. The two method applied to the biggest flood event occurred in July 2011 in Sadang area, South Korea. Based on the comparison with observation data, we confirmed that the model considering the interaction the sewer network and surface flow, showed a good agreement than the quasi-interacted model.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.23 no.3
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• pp.23-43
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• 2020

The purpose of this paper is to create ecological values for urban rivers. For this, the paper looks into river bed structures and how nearby lands are used. This study was performed to set the specific sections for analysis through a field investigation of the infrastructure conditions, surrounding land use, and the inter habitat structure of Seongnaecheon(Stream). A total of 780 individuals from 31 species of wild birds appeared in Seongnaecheon(Stream). According to foraging guild's habitat, there were 9 species of water, 8 types of water edges, 5 types of crowns, 5 types of shrubs, 2 types of tree trunks, 2 types of birds of raptors, and 355 individuals of water, 243 shrubs, 90 crowns, 84 water edges and 5 raptors. Many water birds were observed at the site where the Seongnaecheon(Stream) sandy plains and wetland herbaceous area were developed and the open water was secured. Most of the forest birds appeared on levee slope connected with forest around and riverside with fewer facilities for use. The species diversity index of Shannon, the entire section of Seongnaecheon(Stream), was 2.2697 and the downstream ecological landscape conservation area of Seongnaecheon(Stream) was found to be useful as a habitat for wild birds in the city compared to other sections. Some sections of Seongnaecheon (Stream) had low species diversity index due to lack of green space and surrounding urbanization areas. In choosing target species, I researched the special features of the habitats and the habitation structure of wild birds in each zone. Regarding detailed plans, by classifying the breeding place & roosting site and the roosting site & shelter that took account of the inhabitation characteristics of the target species in different sections, this paper suggested the major plant species and multilayer planting structures. Moreover, this study proposed the development of habitats for water birds and forest birds along with the connection of the green network for improving the Eco-corridor linkage and inhabitation features in Seongnaecheon(Stream).

• Journal of Environmental Impact Assessment
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• v.19 no.4
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• pp.397-407
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• 2010

The increase of the solar reradiation from urban areas relative to suburban due to urbanization heats up the air temperature in urban areas and this is called the urban heat island (UHI) effect. This UHI effect has a positive relationship with the degree of urbanization. Through the studies on UHI using the satellite imagery, the effect of the surface heat radiation was observed by verifying the relationship between the air temperature and the land cover types (surface materials such as urban, vegetation, etc.). In this study, however, the surface temperature distribution was studied in terms of land use types for Seoul. Using land use types, the surface temperature in urban areas such as residential, industrial, and commercial areas in Yeongdeungpo, highly packed with industrial and residential buildings, was maximum $6^{\circ}C$ higher than in the bare ground, which indicated that the surface temperature reflected the pattern of the human-consumed energy on the areas and showed that one of the important causes influencing the air temperature except the surface heat reradiation by the sun is the anthropogenic heat. Also, the effect due to the restoration of the Chunggae stream on UHI was investigated. The average surface temperature for the Chunggae stream was reduced about $0.4^{\circ}C$ after restoration. Considering that each satellite image pixel includes mixture of several materials such as concrete and asphalt, the average surface temperature might be much lower locally reducing UHI near the stream.