• Journal of Ecology and Environment
• /
• v.48 no.1
• /
• pp.85-95
• /
• 2024

Background: In Korea, riparian zones and some floodplains have been converted into agricultural fields and urban areas. However, there are essential for maintaining biodiversity, as they are important ecological spaces. There are also very important spaces for humanity, as they perform various ecosystem services in a changing environment including climate change. Due to the importance of rivers, river restoration projects have been promoted for a long time, but their achievement has been insignificant. Development should be pursued by thoroughly evaluating the success of the restoration project. Ecological restoration is to accelerate succession, a process that a disturbed ecosystem recovers itself, with human assistance. Ecological restoration can be a test bed for testing ecological theories in the field. In this respect, ecological restoration should go beyond a 'simple landscaping exercise' and apply ecological models and theories in restoration practice. Results: The cross-section of the restored stream is far from natural rivers due to its steep slope and artificial material. The vegetation profiles of the restored streams did not reflect the flooding regime of the river. The species composition of the vegetation in the restored stream showed a significant difference from that of the reference stream, and was also different from that of an unrestored urban stream. Although species richness was high and the proportion of exotic species was low in the restored stream, the effect was offset by the high proportion of gardening and landscaping plants or obligate terrestrial plants. Conclusions: Based on both the morphological and ecological characteristics of the river, the restoration effect in the restored stream was evaluated to be very low. In order to solve the problems, a systematic adaptive management plan is urgently required. Furthermore, it is necessary to institutionalize the evaluation of restoration effects for the development of river restoration projects in the future.

• Proceedings of the Korean Institute of Landscape Architecture Conference
• /
• 2023.04a
• /
• pp.118-120
• /
• 2023

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.7 no.5
• /
• pp.66-74
• /
• 2004

Since 1960s urban streams in Seoul have been dried and polluted because of urbanization. So, these devastated urban stream environment need to be restored for the better life of residents. Since 1995 stream restoration project which is called Natural-Style Stream Project have begun. However, some projects focused on the restoration of park-style open space rather than restoration of stream environment. As a result there are some stream landscapes to be improved. Therefore, this study aims to investigate the current status of urban stream landscape after Natural Style Stream Project and to propose the alternatives for the urban stream landscape improvement. The study site is Yangjae stream, Seoul.

• Environmental Engineering Research
• /
• v.21 no.2
• /
• pp.211-218
• /
• 2016

Cheonggye-cheon is a partly restored urban stream located in central Seoul. We monitored fecal contamination using three different fecal indicators, total coliforms (TC), fecal coliforms (FC) and E. coli, to assess differences in each indicator on days of varying weather conditions. Presumptive TC, FC and E. coli colonies were identified by their 16S rRNA sequences. The results showed that enumeration of E. coli provided a better reflection of fecal contamination of the stream than TC and FC. The main sources of contamination were the inflow of fecal-polluted groundwater from the vicinity of a subway line and two inflowing streams. The fecal contamination was worsened on days with heavy rain because untreated sewage from a collecting facility flowed into the stream. Moreover, growth potential of fecal indicator (E. coli) in situ induced by algal exudates was measured. Our results suggest that an appropriate standard based on E. coli rather than TC and FC should be established for improving water quality management strategies of Cheonggye-cheon in the future.

• Journal of Wetlands Research
• /
• v.10 no.3
• /
• pp.111-124
• /
• 2008

The changes in flora and distribution and structure of vegetation were monitored for seven years at a restored reach of an urban stream, the Yangjae Stream, southeast of Seoul, Korea. In the restored reach, diverse kinds of the close-to-nature stream restoration techniques were adapted and implemented in the winter of 1998-1999. The species numbers and diversity indices of riparian plants at the restored reach were higher than those at the unrestored reach seven years after the restoration implementation. But plant diversity was decreased from the early restoration stage of 1999 - 2001 to seven years after the implementation. The dominant species changed from a ruderal annual, Humulus japonicus, to a perennial, Phragmites australis. The floral structure was distinctly different between in the early stage and seven years later on the results of principal component analysis (PCA) because of decreasing in numbers of exotic or ruderal species and planted or introduced plants in newly disturbed habitats. The distribution areas of communities of Humulus japonicus and Erigeron annuus were decreased and those of communities Phragmites australis and Miscanthus sacchariflorus were increased after the restoration implementation. The results of detrended correspondence analysis (DCA) of plant communities revealed that the community structure were changed from the disturbed vegetations to the stable and natural vegetation after the restoration implementation. Total seven species of willows were found at the restored reach, of which two species were planted and the others were naturally introduced. The monitoring results showed that the stream ecosystem of the study reach were successfully recovered in flora and vegetation and could be used as a model site for the stream restoration in urban streams.

• Journal of the Korean housing association
• /
• v.25 no.6
• /
• pp.133-146
• /
• 2014

This study aims to analyze the changes of adjacent residential area after the restoration of covered urban streams in seoul. The changes of adjacent residential area after restoration were analyzed by changes of land using, urban structure, individual lot of land and architecture to investigate relationship of the urban stream and residential change. The result as follows: the first one is the change of land use and urban structure in adjacent residential area. This change of infrastructure through stream restoration has transformed land use and urban structure in adjacent residential area. Secondly, there is the changes of the individual lot of land. It seemed that new development by combined lots would be concentrated in stream-side blocks. But, the changes of lots such as combining or dividing lots tend to be concentrated in stream-side, main road and main streets. In stream-side, commercial function of land use has changed to residential one which has restored streams landscape by transformation of lots use without changes of ownership-lots. Finally, there is the change of architecture. It turned out new building in adjacent residential area is similar to general development. However, new building in streamside is related to direction of stream. In addition, remodeling and expansion tend to change in commercial buildings on stream-side bridges of corner lots intensively. As a result, it is related to expectation of architectural activation and improvement of sidewalk environment by stream restoration.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.27 no.4
• /
• pp.39-49
• /
• 1999

Urban streams have, recently, been straightened and widened to alleviate flooding problem. As a result, the stream have been modified inadvertently for ecological functions and microtopography. In this study, we investigated riparian vegetation and microtopography of the tributaries of Han River before and after the monsoon rain in summer. The purpose of this study was to relate the stream microtopography to the distribution of riparian vegetation. The stream microtopography was investigated for its scale and pattern. Vegetation was investigated from 131 plots by Braun-Blanquet method. The distribution of riparian vegetation was significantly correlated with the stream microtopography. Various herbaceous species occurred at stream bank slop, high terrace and channel side. However, at channel side and concave part of terrace where soils were in high moisture level, only a few wetland species were dominated. The complexity of the microtopography in the stream corridors led to heterogeneous riparian vegetation. The vegetation showed more stability against flooding at the stream corridors with natural and complex microtopography than at the urban-type stream corridors with simple topographical features. The results showed that the development of riparian vegetation was influenced by the changes in microtopography, which was primarily determined by the shape and characteristics of channel. It seemed that a close-to-nature river system would be restored more readily with an understanding of microtopographical features affecting the distribution of riparian vegetation.

• Journal of Environmental Science International
• /
• v.28 no.2
• /
• pp.235-248
• /
• 2019

The purpose of this study is to quantitatively analyze the effects of a restoration project on the decrease in the temperature in the surrounding areas. The thermal environment characteristics of the investigation area were analyzed using the meteorological data from the Busanjin Automatic Weather System which is closest to the target area. The terrain data of the modeling domain was constructed using a digital map and the urban spatial information data, and the numerical simulation of the meteorological changes before and after the restoration of the stream was performed using the Envi-met model. The average temperature of the target area in 2016 was $15.2^{\circ}C$ and was higher than that of the suburbs. The monthly mean temperature difference was the highest at $1.1^{\circ}C$ in November and the lowest in June, indicating that the temperatures in the urban areas were high in spring and winter. From the Envi-met modeling results, reductions in temperature due to stream restoration were up to $1.7^{\circ}C$ in winter, and decreased to $3.5^{\circ}C$ in summer. The effect of temperature reduction was seen in the entire region where streams are being restored.

• Journal of Environmental Science International
• /
• v.21 no.8
• /
• pp.939-951
• /
• 2012

This study is conducted to estimate the air temperature decreasing effects by restoring urban streams using WRF/CALMET coupled system. The types of land use on covered streams are constructed with the land cover map from Korea ministry of environment. Restoring covered streams changes the types of land use on covered areas to water. Two different types of land use(CASE 1 and CASE 2) are inputted to the WRF/CALMET coupled system in order to calculate the temperature difference. The results of the WRF/CALMET coupled system are similar to the observed values at automatic weather stations(AWS) in Busan area. Restoring covered streams causes temperature to be decreased by about $0.34{\sim}2^{\circ}C$ according to the locations of streams and the regions that temperature is reduced are widely distributed over the restored area. Reduction of temperature is increased rapidly from morning and maximus at 13LST. Natural restoration of streams will reduce the built-up area within urban. With this, temperature reductions which are the cause to weaken the urban heat island appear. Relief of urban heat island will help to improve the air quality such as accumulation of air pollutants in within urban area.

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