• Journal of Environmental Health Sciences
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• v.38 no.5
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• pp.438-447
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• 2012

Objective: The objective of this study was to suggest a method through which load duration curve was used to assess the achievement of water quality targets in accordance with the criteria for pollutant load depending on flow rate variation. Methods: The stage-discharge curve and flow duration curve of Jungnang Stream were deduced. Using water quality targets and measurement of the stream, the flow duration curve was also drawn. Based on these, the feasibility of achievement of water quality targets in respect to flow rate was assessed. Results: In terms of the load duration curve of the stream, it was observed that excess of criteria for concentrations of $BOD_5$, $COD_{Mn}$ and SS frequently occurred. On the other hand, when the flow rate was low, the concentrations of T-N and T-P exceeded the criteria. Conclusions: Through the load duration curve, the overall water quality of Jungnang Stream was understood. When the flow rate is high, management of point source of $BOD_5$, $COD_{Mn}$ and SS is needed to achieve water quality targets for Jungnang Stream. On the other hand, when the flow rate is low, the management of non-point source T-N and T-P is necessary to attain the water quality goal.

• Korean Journal of Ecology and Environment
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• v.46 no.4
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• pp.507-512
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• 2013

Aquatic oligochaetes were investigated from a small amount of sediment sampled from the Jungnang Stream, an urban stream in Seoul, Korea, in November 2012. Sorted oligochaetes were observed under a light microscope in a drop of carbonated water, and then preserved in 70% ethanol. Some specimens were slide mounted using glycerin and Eupharal. As a result, the following 12 species were identified including 8 new Korean records, Bothrioneurum vejdoskyanum Stolc, Branchiodrilus hortensis (Stephenson), Chaetogaster cristalinus Vejdosky, Nais communis Piguet, Nais pardalis Piguet, Dero obtusa d'Udekem, Piguetiella denticulata Liang, and Haemonais waldvogeli Brescher and 4 additional known species, Limnodrilus hoffmeisteri Cleparede, Branchiura sowerbyi Beddard, Chaetogaster diastrophus (Gruithuisen), and Stylaria fossularis Leidy. This study shows how freshwater oligochaetes are diverse even in urban streams in Korea, if a proper sampling and examining method is employed.

• Journal of the Korea Furniture Society
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• v.20 no.1
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• pp.71-81
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• 2009

This study aimed at creation of bench design to be placed in the public spaces for the citizen who live in Jungnang-Gu. In Jungnang-Gu surrounded by the excellent natural environment like Jungnang-stream, Mangwoo Mt., Bongwha Mt. and Youngma Mt., there are many public places where a citizen can take a rest. Among the public facilities being in such public places however, the benches especially were installed so unplanned and disordered, even that they look unbalanced with the natural environment, though they need to play a meaningful role in park and walking paths. Hereupon this study intends to investigate the geographical environment in Jungnang-Gu and furthermore to develop the bench-design on the basis of the investigation. The concept of design lies in modern style of a bench matched up with the nature well and also taking the functional aspect for rest, in consideration of the public places utilized by the abundant natural greens. The environment-friendly timber, marble and metal were used here and the design with and without the back of a bench & the dimension for Korean people's figure were considered.

• Korean Journal of Ecology and Environment
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• v.40 no.2
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• pp.234-243
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• 2007

Algal growth potential (AGP) test was performed to evaluate the water quality and changes in phytoplankton communities before and after a heavy rain event at six sampling sites in Cheonggye Stream (St. 1 and 2), Jungnang Stream (St. 3 and 4), and Lower part of Han River System (St. 5 and 6) after rehabilitation of Cheonggye Stream, October 2005. To test AGP on each sampling site, cyanobacterium Microcystis aeruginosa was applied as a standard alga. Total nitrogen (TN) showed high values at Jungnang Stream, while St. 4 recorded highest values in this study. However, TN values of Cheonggye Stream and Lower Part of Han River showed similar levels. Total phosphate (TP) also showed high values at Jungnang Stream, while St. 4 recorded highest. However, TP in Cheonggye Stream were extremely low levels. Although chlorophyll-${\alpha}$ (chi-${\alpha}$) contents before the rain event were similar through the sampling sites, chl-${\alpha}$ after the rain increased dramatically at Jungnang Stream and Lower part of Ban River. In particular, after the rain, TP was the highest at St. 4, where Cyclotella sp. dominated the phytoplankton community. When compared with control, AGP values before the rain were comparatively low in all sites, while those after the rain highly increased with the dose-dependently of field water added, due perhaps to the increased nutrients by rainfall. Similar results were observed in Cheonggye Stream. Therefore, for the aesthetic fostering for the citizens, although Cheonggye Stream was Presently being sustained by treated water supply, they have a potential of outbreak of phytoplankton by the increased nutrients supply when a heavy rain comes.

• Journal of Korea Water Resources Association
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• v.43 no.1
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• pp.51-65
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• 2010

We suggest a simple and practical flood forecasting and warning system, which can predict change in the water level of a river in a small to medium-size watershed where flash flooding occurs in a short time. We first choose the flood defense target points, through evaluation of the flood risk of dike overflow and lowland inundation. Using data on rainfall, and on the water levels at the observed and prediction points, we investigate the interrelations and derive a regression formula from which we can predict the flood level at the target points. We calculate flood water levels through a calibrated flood simulation model for various rainfall scenarios, to overcome the shortage of real water stage data, and these results as basic population data are used to derive a regression formula. The values calculated from the regression formula are modified by the weather condition factor, and the system can finally predict the flood stages at the target points for every leading time. We also investigate the applicability of the prediction procedure for real flood events of the Jungnang Stream basin, and find the forecasting values to have close agreement with the surveyed data. We therefore expect that this suggested warning scheme could contribute usefully to the setting up of a flood forecasting and warning system for a small to medium-size river basin.

• Journal of Ecology and Environment
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• v.34 no.2
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• pp.175-191
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• 2011

Colonization patterns and community changes in benthic macroinvertebrates in the Cheonggye Stream, a functionally restored stream in downtown Seoul, Korea, were studied from November 2005 to November 2007. Benthic macroinvertebrates were quantitatively sampled 15 times from five sites in the stream section. Taxa richness (59 species in total) increased gradually over the first year, whereas the density revealed seasonal differences with significantly lower values in the winter season and after flood events. The benthic macroinvertebrate fauna may have drifted from the upstream reaches during floods and from the Han River, arrived aerially, or hitchhiked on artificially planted aquatic plants. Oligochaeta, Chironommidae, Psychodidae, and Hydropsychidae were identified as major community structure contributors in the stream. Swimmers and clingers colonized relatively earlier in the upper and middle reaches, whereas burrowers dominated particularly in the lower reaches. Collector-gatherers colonized at a relatively early period throughout the stream reaches, and collector-filterers, such as the net-spinning caddisfly (Cheumatopyche brevilineata), predominated in the upper and middle reaches after a 1-year time period. Cluster analyses and multi-response permutation procedures demonstrated that the Cheonggye Stream shares more similarities with the Jungnang Stream than with the Gapyeong Stream. Detrended correspondence analysis and nonmetric multidimensional scaling demonstrated that physical environmental factors (depth, current velocity, dissolved oxygen, and pH) as well as nutrients (total nitrogen and total phosphorous), water temperature, and conductivity could affect the distribution of benthic macroinvertebrates in the study streams.

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

• Korean Journal of Environment and Ecology
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• v.37 no.2
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• pp.140-150
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• 2023

The Eurasian otter (Lutra lutra) is an apex predator of the riparian ecosystem. It is a keystone and an indicator species; consequently, its presence suggests a sustainable water environment. Otter is a keystone species as a predator at the top of the food web in the aquatic environment and an indicator species representing the health of the aquatic environment. Although Eurasian otters disappeared from the Han River urban water system because of anthropogenic activities like habitat destruction, poaching, and environmental pollution in the 1980s, the species were sighted in the Cheonggye Stream, Jungrang Stream, and Seongnae Stream, which are urban sections of the Han River, in 2016 and 2021. Therefore, it is pertinent to assess the habitat potential in the area for conservation and management measures to ensure its permanent presence. However, existing studies on otter habitats focused on natural rivers and reservoirs, and there is a limit to applying them to habitats artificially confined habitats in narrow spaces such as tributaries in urban areas of the Han River. This study selected the Cheonggye Stream, an artificially restored urban stream, to evaluate its potential as a habitat for Eurasian otters in urban water environments using the habitat suitability index (HSI). The HSI was calculated with selected environment attributes, such as the cover, food, and threat, that best describe the L. lutra habitat. According to the results, the confluence area of Seongbuk Stream and Cheonggye Stream and the confluence area of Cheonggye Stream and Jungnang Stream were suitable otter habitats, requiring appropriate conservation efforts. The HSI model suggests a valuable method to assess the habitat quality of Eurasian otters in urban water environments. The study is crucial as it can help rehabilitate the species' populations by identifying and managing potential Eurasian otter habitats in highly urbanized areas of the Han River basin and its tributaries.

• Korean Journal of Environment and Ecology
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• v.37 no.4
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• pp.251-258
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• 2023

Invasive species are introduced for various purposes, such as pets and food, and the trade of reptiles among them has continuously increased due to their unusual or rare external character traits. As their imports increase, the number of exotic reptiles in the wild is also increasing, and most of the recently discovered exotic turtles have been found near urban areas. Therefore, this study aims to report the current status of exotic turtles inhabiting the Jungnang Stream in downtown Seoul, Republic of Korea. As a result of the survey, seven species of exotic turtles were identified: Chrysemys picta picta, Pseudemys concinna, P. nelsoni, Trachemys scripta elegans, T. s. scripta, T. s. troostii, and Mauremys sinensis. One native turtle species was found: Pelodiscus maackii. Six species are designated as "ecosystem disturbance species" in the Republic of Korea. The dominant species was P. concinna, and C. p. picta, which is still traded in pet shops, was also found. The results have confirmed the current status of exotic turtles in urban rivers, and it was determined that the results show that they are continuously entering the wild.

• Land and Housing Review
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• v.8 no.2
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• pp.73-82
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• 2017

Although Changdong Sanggye area has been developed during 1980s as a new city for the supply of low-income housing, currently it was degraded to a bed town located outside Seoul. However, Changdong Sanggye area is designated as the center of a metropolitan area in '2030 Seoul City Basic Plan' due to a variety of potential factors such as a traffic center for linking metropolitan areas, location of 15 universities, and neighboring natural environment like Jungnang stream and Buckhan mountain. The purpose of urban regeneration plan is to create a new CBD of Changdong Sanggye which is the center of vocational and cultural lives of 3.2 million people in the northeastern metropolitan area. To achieve the purpose, 12 unit projects and 24 sub-unit projects are set up based on the three major goals and core strategies. An enterprise project team of northeastern area was newly founded and then a dedicated organization was established by the Seoul government in 2015 in order to integrate separated urban regeneration related functions. In the Seoul government an administrative council and a project promotion council are operated for consultation and coordination between the administrative divisions and government projects for urban regeneration. Through the success in Changdong Sanggye regeneration project, they are expected to have economic effects such as job creation and increase in tax revenue and to re-vitalize the area as a new economic center in northeastern Seoul having amenities and cultural facilities and waterfront parks.