• Journal of Korea Water Resources Association
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• v.41 no.9
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• pp.919-927
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• 2008

Flow exchanges between stream and groundwater are assessed on urban streams in Daegu, Korea. Two rivers and 25 streams with the total length of 240 km run through the study area. The interaction between surface water and groundwater was estimated using Darcy's method. The study was conducted by dividing the basin into 16 smaller watersheds, and for comparison purposes. Groundwater level, surface water level, hydraulic conductivity, thickness of aquifer, and the distance between the well and the nearest stream were used for quantifying the interaction. To investigations the groundwater interaction in the watersheds, the amount of effluent seepage from groundwater to the stream, the amount of influent seepage from the stream to groundwater, and the amount of annual interaction between surface water and groundwater were computed. The total amount of effluent seepage from the groundwater to stream in the basin was approximately $72{\times}10^6m^3/year$. The total amount of influent seepage from the stream to groundwater was approximately $35{\times}10^6m^3/year$. It appeared that the total amount of annual interaction between surface water and groundwater was approximately $108{\times}10^6m^3/year$ and the total groundwater flow balance was approximately $37{\times}10^6m^3/year$. The annual amount of interaction between the surface water and groundwater was the largest in the Goryung Bridge Basin($29{\times}10^6m^3/year$) and the least in the Dalchang Dam Basin($0.2{\times}10^6m^3/year$). The results show that flow exchanges between stream and groundwater are very active and that there are significant difference among the smaller watersheds. Finally, the results indicate that it is necessary to further investigate to more precisely understand the interaction characteristics between surface water and groundwater in urban areas.

• Journal of Korea Water Resources Association
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• v.39 no.2 s.163
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• pp.109-120
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• 2006

Permeable pavement and release of treated wastewater into streams can increase streamflow of urban streams for a dry weather period. A SWMM code was modified to have a permeable pavement option. The modified SWMM was applied to continuous simulations of urban runoff from Hakuicheon watershed and it was used to analyse the effect of a permeable pavement installation and the reuse of treated wastewater. A critical error in the pan coefficient multiplication was also corrected in the modification. The analysis results of the reuse of treated wastewater is as follows: The low flow ($Q_{275}$) increases by 1.63 times as much as the current one and the drought flow ($Q_{355}$) increases by 3.57 times as much as the current one. If the impervious area in the Hakuicheon watershed is replaced with the permeable pavement area by 10 percent, the low flow and the drought flow increases by 3 percent and 17 percent, respectively. The results shows the effectiveness of the release of treated wastewater into stream to increase urban streamflow. The permeable pavement installation also play a minor role in the drought flow increase.

• Journal of Environmental Impact Assessment
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• v.13 no.3
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• pp.137-151
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• 2004

Many of today's environmental problems are regional in scope and their effects overlap and interact. The purpose of this paper is to developed a simple method for an integrated assessment of environmental conditions across the Mid-Nakdong River Region, by combining data on land use, impervious cover, roads, streams, riparian areas, forest patches, population, pollutant loadings, soil erosion and topography. A cluster analysis was used to identify groups of sub-watersheds with similar environmental characteristics. The mean value for each group was used to find watershed that may be more vulnerable to future environmental degradation. Watersheds in cluster I and II had high amount of forest, but the amount of riparian vegetation was low. Watersheds in cluster III, which located in the middle Geumho River and the main course of Nakdong River, had a greater proportion of their agriculture, a greater proportion of agriculture on steep slopes, and less forest adjacent to streams. Watersheds in cluster IV and V were in the most urbanized areas of the region. The principal adverse impacts for watersheds in this group were high scores for urban area, impervious cover, pollutant loadings, population density, forest fragmentation, and low amounts of forest and riparian forest cover. Notwithstanding the exploratory nature of cluster analysis, it appears to be a useful tool for grouping watersheds with similar environmental characteristics.

• Korean Journal of Environment and Ecology
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• v.29 no.2
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• pp.228-235
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• 2015

Stream ecosystems are closely related to many human activities. Therefore, streams are affected by anthropogenic disturbances such as riverine development and gravel-mining as well as deterioration of water quality. The goal of this study was to elucidate the recolonization process of the macroinvertebrate community after a small-scale anthropogenic disturbance. Field studies were conducted at three sites in a natural stream. The number of recolonizing species tended to increase slightly over time, exceeding the total species number of the control. Ephemeroptera contributed the most to shaping the recolonizing pattern of the entire community. From the result of changes in dominant species, the early recolonizers of each site were the species that showed more frequent occurrence particulary at each sites. But the late recolonizers are Chironomidae at all the sites commonly. This result implies that the actual differences exist among the recolonizing trends of each benthic macroinvertebrate taxon. Collector-gatherers and scrapers comprised about 70% of the recolonizing species. These results indicate that the recolonizing process of an aquatic community after an artificial disturbance depends on the environmental conditions(particularly substratum composition or organic pollution) of the habitat.

• Journal of Korean Society on Water Environment
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• v.27 no.6
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• pp.760-768
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• 2011

Jinwi Stream is considerably polluted. The urban development in a Jinwi Stream basin can make state of aquatic ecosystem worse. However, researches for aquatic ecosystems in Jinwi Stream are insufficient. In this study, biotic indices of periphytic diatoms (DAIpo and TDI), benthic macroinvertebrates (EPT, KSI and ESB) and fish (IBI) were compared with the annual water quality data. Benthic macroinvertebrates indices showed highly significant correlations with concentrations of organic materials and nutrients, while DAIpo, TDI and IBI showed low correlations with them. In particular, ESB can be considered as an useful indicator that reflects the degree of diversity and abundance of biotic community as well as water quality. In polluted and disturbed streams as Jinwi Stream, DAIpo, TDI and IBI appeared to be not available for evaluating and discriminating the water quality, although they have been known as good indices in general streams.

• Korean Journal of Ecology and Environment
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• v.52 no.4
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• pp.385-393
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• 2019

Chironomid communities are indicators of water pollution because of their ability to thrive under freshwater conditions. However, it is difficult to distinguish between chironomid larvae based on morphology. DNA barcoding, based on nucleotide sequences of marker genes, can be used to identify chironomid larvae. Samples of chironomid larvae were collected from Gwangju Stream and Pungyeongjeong Stream, tributaries of the Yeongsan River in South Korea. We identified 3 subfamilies, 13 genera, 16 species, and 1 cryptic species. There were 7 genera and 10 species from the subfamily Chironominae, 5 genera and 5 species from subfamily Orthocladiinae, 1 genus and 1 species from subfamily Tanipodinae, and the cryptic chironomid species of the family Chironomidae. There were 21 individuals from, 7 species and 1 cryptic species from the Gwangju Stream and 24 individuals, belonging to 10 species from the Pungyeongjeong Stream. The only species detected in both streams was Cricotopus bicinctus. The relationship between water quality and the species detected was difficult to explain, but the number of species showed a tendency to increase at sites where water quality was poor. Additional investigations and studies are needed to understand the relationship between water quality and the chironomid species occurring in these two streams.

• Journal of Ecology and Environment
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• v.38 no.3
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• pp.307-318
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• 2015

The objectives of this study were to identify multi-level stressors from blood biomarkers to community-level bioindicators and diagnose the stream ecosystem health in polluted streams. Blood chemistry such as total protein ($T_{Pro}$), blood urea nitrogen ($B_{UN}$), total cholesterol ($T_{Cho}$) and $A_{lb}$umin ($A_{lb}$) were analyzed from sentinel fish tissues; the functions of kidney, gill and liver were significantly decreased in the impacted zone ($I_z$), compared to the control zone ($C_z$). Histopathological analysis showed that fish liver tissues were normal in the $C_z$. Fish liver tissues in the $I_z$, however, showed large cell necrosis and degeneration and also had moderate lobular inflammation and inflammatory cell infiltration of lymphocytic histocytes. Species biotic index (SBI) at species level and stream health assessment (SHA) at community level indicated that chemical impacts were evident in the $I_z$ (ecological health; poor - very poor), and this was matched with the blood tissue analysis and histopathological analysis. The impairments of the streams were supported by water chemistry analysis (nitrogen, phosphorus). Tolerance guild analysis and trophic guild analysis of fish were showed significant differences (P < 0.01) between $C_z$ and $I_z$. Overall, multiple parameter analysis from biomarker level (blood tissues) to bioindicator level (community health) showed significantly greater impacts in the $I_z$ than $C_z$. This approach may be effective as a monitoring tool in identifying the multilateral and forthcoming problems related to chemical pollution and habitat degradation of stream ecosystems.

• Land and Housing Review
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• v.2 no.3
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• pp.299-305
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• 2011

Streams and rivers are among the most fascinating and complex ecosystems on Earth. Recently, many plans of ecological streams are developed and performed in several regions. In spite of obtaining of instream water is most important problem to composite an ecological stream, assessment methods for instream water are too various to estimate an optimal result. In this study, we developed decision support system so that decision-maker may can be supported decision making for composite an ecological stream with connecting the satisfaction of residents in stream. Decision support system is composed of hydraulic, water quality, eco-river simulation model and can show optimal instream flow assessment and water quality improvement.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.14 no.4
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• pp.11-23
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• 2011

Mountain streams, which are major components of an entire river network, play an important role as the source of water, sediment, coarse and fine organic matter, and nutrients for lowland rivers. Therefore, dynamics and downstream linkages of each compartment of the mountain stream can be essential for watershed management in catchment scale. The dynamics and downstream linkages are understood as a development of step-pool sequences along a river course. Recently, stream restoration after flooding event often employ the development of step-pool sequences in the world. In this paper, we 1) examined the geomorphic characteristics and the role of step-pool sequences in steep mountain streams by reviewing the results of past studies, and 2) introduced the case studies of stream restoration using step-pool sequences, and finally 3) addressed design methods considering geometry and stability of artificial step-pool sequences for stream restoration. Step-pool sequences play an important role not only as roughness with energy dissipation but also as heterogeneity of stream feature for aquatic habitat. Step-pool sequences, even if they are constructed artificially along a stream, may be effective for small stream restoration considering eco-friendly torrent controls. So far the artificial step-pool sequences were employed for mountainous streams, but those would be applied to urban stream.

• Journal of Korean Society on Water Environment
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• v.22 no.5
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• pp.943-951
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• 2006

Spatial distribution of water pollution in the Gap Stream was investigated from October to November, 2005. Sampling was conducted three times including effluents discharged from a wastewater treatment plant (WWTP) and a dam reservoir during the low-flow period. As a typical urban stream, total nitrogen and inorganic nitrogen concentrations increased toward downstream. Ammonia concentration was the highest in the treated water of the wastewater treatment plant and the lowest nitrate concentration was found in the effluent of the dam reservoir. A part of soluble reactive phosphorous (SRP) in total phosphorous was 22~54% in the upstream reach of WWTP in the Gap Stream whereas 68~73% in the downstream reach. Mean chlorophyll-a concentration ranged from 1.6 to $11.0{\mu}g/L$ and it tends to increase toward downstream except for WWTP effluent. As expected, untreated wastewater and WWTP effluent were suggested as the major sources of water pollution in the Gap Stream. In this study, the water pollution of the Gap Stream is a significant undergoing typical eutrophication, caused by excessive phosphorus and nitrogen nutrients from WWTP located in the watershed. As a result, the critical factor for the water pollution was evaluated to dissolved inorganic nitrogen and phosphorus nutrients. Particularly, SRP is a most important for the eutrophication. It suggest that may occur in the most urban streams of Korean peninsula. Therefore, because the necessity of water pollution management in the urban stream, inorganic N and P nutrients should be included as an essential component of water quality criteria in the advanced water quality project of Korean Government by enforcing of water quality assessment and total maximum daily loads (TMDLs).