• Korean Journal of Environment and Ecology
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• v.36 no.5
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• pp.468-480
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• 2022

Although the construction of the Nakdong River Estuary Barrage (NEB) improved the water supply in the region, it cut off the longitudinal connectivity of the estuary aquatic ecosystem. Thus, the social demands for opening the NEB have been continuously raised, and the efforts to restore the aquatic ecosystem of the Nakdong River estuary began in 2017. Many fish species have inhabited the Nakdong River estuary. Since their habitat and migration characteristics vary widely, the sluice gate operation considering them is essential for the restoration of the aquatic ecosystem. Therefore, in this study, we monitored the fish species living and migrating in the Nakdong River estuary and analyzed the possibility of smooth movement of for each fish species by calculating the average flow velocity according to the type and the height of the gate opening. Moreover, we selected the target fish species for each month and suggested the sluice gate operation according to the depth of the main habitat to present the measures that are ideal for optimal restoration of the aquatic ecosystem in the Nakdong River estuary area.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.16 no.4
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• pp.99-114
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• 2013

In this study, constructability of ecologocal stream restoration process was evaluated and improved approaches for habitat were suggested. The study site is Gucheon River in Geoje city where conducted ecologocal restoration work within maintaining its flood control function. Application of ecological design factors and constructability in the process from planning to construction was analyzed and its results are as follows: In the process of planning and designing, it was focused more on the naturality of Gucheon River rather than the human convinience and ecological design factors were applied within the ecological capacity of the site. First, the indexes for constructability evaluation is selected. It was classified into three major categories as construction quality, design quality and construction administration system. Each index has details, so there are twenty sub indexes for contractibility evaluation. Second, the evaluation results shows that the index most in need of improvement was plumbing construction, followed by Stone construction and pavement construction. design concept was evaluated as appropriate in entire categories. Finally it is suggested that it can be improved in both process of design to enhance the technology and process of construction to enhance the quality management. The constructability of ecological stream needs adaptive management and it must be discussed with its designing which is at the stage before construction. Also it needs discussion with its designer constantly and feed-back process.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.16 no.1
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• pp.207-225
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• 2013

Current ecological stream restoration is focusing on recovery of physical characteristic and ecological functions of individual stream. For effective stream restoration, the relationship between stream environment and riparian flora should be investigated. The purpose of this study is to analyze the relationship between disturbance of hydromorphological structures and naturalized plants ratio in small to mid-sized streams. For the study sites, Gwanpyeong stream, Dongdal stream, and Yongchoo streams were chosen as 'reference stream' while, Gunnam stream, Anchang stream, and Hwa stream were chosen as 'damaged stream'. The hydromorphological structures of streams were evaluated with LAWA and flora of the streams were completely enumerated to calculate naturalized plants ratio. The result showed that there was a significant correlation between the outcome of LAWA and naturalized plants ratio(r=0.675, p<0.01). The result of factor analysis of LAWA identified three factors, 'River front and land use', 'River bed materials and structures', and 'Crossing structure and bar'. Among the factors of hydromorphological structures given by the result of factor analysis, 'river front and land use' and 'bed materials and structures' have statistically significant relationship with naturalized plants ratio($R^2$=0.470, p<0.01). Given this results, quantitative analysis on the relationship between disturbance of hydromorphological structures of streams and naturalized plants ratio could provide some essential information for stream restoration. Also, as this study figured out major factors of hydromorphological structures that affect naturalized plants ratio, it might help monitor ecological states and current problems of small and mid-sized streams.

• Journal of Korea Water Resources Association
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• v.51 no.5
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• pp.461-470
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• 2018

Beyond river restoration focused on the inside region of main streams up to now, the river restoration including the outside region of streams has been started recently. As a part of this attempt, the restoration of abandoned rivers has been tried, but the development of a suitable model to quantitatively assess the improvement of hydraulic and ecological connectivity is not still satisfying. In this study, a grid - based hydraulic analysis model to evaluate the recovery of ecological connectivity through the restoration of abandoned rivers has been developed. In order to examine the applicability of this model, the ecohydaulic connectivity of the Cheongmi River Project area in Notap region was evaluated. This model can promptly and simply analyze the temporal and spatial distribution of the hydraulic and ecological characteristics, and it can be used as a appropriate tool to assess the hydraulic and ecological connectivity in the future.

• Journal of Environmental Impact Assessment
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• v.19 no.2
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• pp.127-140
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• 2010

This study investigates the relation between the location of a habitat and the ecological connections according to the habitat type in the riparian zone at the Nonsan Stream and Yanghwa Stream. Stream habitat is classified into nine types for the aquatic insects and fish. For vegetation and birds, habitat is classified into two types of medium-scale streams, including both physical and chemical streams are analyzed accordingly. Nowadays, The fundamental goal of the river environment restoration enterprise is the rehabilitation or the restoration of the characteristic the river scenic or environment. For instance, The Channel habitats which has physical nature environment such as flat, speedy rapids, or closed-channel wetland, pool are constructed by artificial, Consequently, make them autogenesis smoothy eco-environment. However, the river environment are controlled not only physical environment, but it also need reasonable the quality of the water to compose smoothly. Finally, understanding what influence are effecting on physical habitat environment which are made by natural factors to water quality are very important factor for the river environment restoration enterprise Therefore, In this research, we are targeting to a basin to investigate the environment of the physical channel habitat and evaluate the changing of the water quality. This results will be a important characteristic that can judge the physical habitat and reciprocality connected to the water quality or adequacy of restoration technology. Therefore in this study, as a step to quantify functions and values of habitats and definite factors to perform habitat, we selected a representative stream of sand-stream, gravel-stream to classify habitat characteristics and quantified the physical, chemical, biological characteristics.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.5
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• pp.19-29
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• 2012

The purpose of this study is to suggest improvements of Eco-Natural map preparation guideline by presenting assessment methods that can be applied to the result of river ecosystem health survey and assessment, using the Geographic Information System. The area for studying is the main stream of the Hwang River where is easy to collect data and available to compare before and after of river assessment. It was reevaluated by reflecting the result of river ecosystem health assessment of the Ministry of Environment. As the result, Eco-Natural map of the study area reflecting the river assessment, the changes in the area ratio by grade have been increased from 1.14% to 14.03% in the first-grade and from 24.64% to 43.91% in the second-grade. It is considered to present more realistic grade due to the assessment of the rivers that have not been reflected in the meantime. Consequently, the result of this study will be useful for establishing the development projects on the rivers, providing the foundation for more realistic and active protection.

• Journal of Environmental Science International
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• v.18 no.1
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• pp.113-127
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• 2009

This study was designed to present a river model with an aim at restoring the ecosystem and improving the landscape along the urban rivers on the basin of the Namhan river, a core life channel for the National Capital region. The revelation of botanical status, transition trend and correlation of plants might lead to providing the urban river restoration projects and ecological river formation projects with basic data for a model of ideal aquatic ecology and landscape. The outcomes of this study could be summed up as follows: 1. Communities of Juglans mandshurica, Cornus controversa and Fraxinus mandshurica constitute the main portion of flora at or around uppermost branch streams of the River Namhanis harbored mainly in and around small brooks 2. Typical terrestrial forest communities formed around the River Namhan are composed mainly of Larix leptolepis, Pinus rigida, planned forestation of Pinus koraiensis, Quercus acutissima, Quercus variabilis and Pinus densiflora. 3. The analysis into terrestrial environment of plant communities showed a high content of $P_2O_5$, typical communities found in the artificially disturbed land Finally, it seems also desirable to continue to make every exertion to explore the relationship between fluvial and terrestrial ecologies with a purport of building up a model of natural streams in urban area based on the surveyed factors for plant life, forest communities, soil and landscape and, moreover, on the forecasting for overall influences derived from the relation upon the ecosystem.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.5
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• pp.77-91
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• 2009

The purpose of this study is to define the species composition of the soil seed banks at major wetlands in Nakdong river basin and central korea and to investigate how soil seed banks relate to aboveground vegetation and soil texture. In 2005, we sampled seed banks at Baksil reservoir, Jillal marsh, Deapyeng marsh, Hwapo marsh, Upo marsh and Junam reservoir in Nakdong river basin and Osan stream and Amsa-dong in Seoul. The soil seeds were estimated with the emergence method from April to October. Total numbers of species at the seed banks were 33 at Baksil, 18 at Daepyeong, 35 at Jillal, 56 at Upo, 32 at Hwapo, 47 at Osan stream, 54 at Amsa waterside, 31 at Amsa meadow. The species diversity in the soil seed banks of Upo marsh was the highest as 0.95. The community overlap index that compares aboveground with underground vegetation is high in the Upo marsh (0.34), Jilla marsh (0.36), and Osan stream (0.27). Soil texture affected distribution of 8 species, Lindernia procumbens, L. attenuata, Arenaria serpyllifolia, Juncus effusus, Persicaria thunbergii, Eragrostis multicaulis, Cyperus nipponicus, Scirpus fluviatilis. Considering the social and cultural values, soils at Amsa meadow, Hwapo marsh and Osan stream have worth to use for wetland restoration.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.4
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• pp.1-12
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• 2006

The usages of urban riverine areas for the Gapchoen and Yudungcheon in Daejoen City were evaluated by analyzing riverbed characteristics and water quality and by surveying the status of the floodplain usage including questionnaires of people visiting the rivers. Both rivers appear to be stable with insignificant bed changes as the riverbeds are dominated by gravels. Water qualities of both rivers have been improved significantly over the past decade although there are quite large seasonal fluctuations, which is common in most rivers in Korea. The results of floodplain usage analyses show that Gapcheon is dominated with static uses (>70%) such as promenades and resting facilities, while Yudungcheon by dynamic uses (>44%) such as sports facilities. Overall, both rivers require better plans for riverine area usage management considering a balance between the dynamic uses and the static uses such as natural observation places for education and habitats for birds and fish in the rivers. The questionnaire survey results indicate that overall the present status of both rivers are satisfactory and that water quality improvement is one of the key factors to enhance the value of the riverine areas. Future river restoration should be conducted by taking into account the characteristics of urban rivers in harmony with surrounding natural sceneries.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.2
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• pp.40-54
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• 2008

Small and large dams are installed in the course of a stream for maintaining the water level of the stream or obtaining agricultural water. Currently about 18,000 of them are installed in Korea to supply water. However, the environmental problems of small dams are well known : the interruption of stream eco-corridors, deterioration of water quality in the upper reaches of the small dam, changes in the habitats of riparian organisms, damages to the stream scenery. In a very few of these small dams artificial eco-corridors like fishways are installed, but the number is very minimal.Accordingly, to efficiently restore stream eco-corridors by removing these small dams, it will be necessary to closely examine physical impacts, such as changes in the riverbed and changes in the shape of the stream caused by the removal, chemical impacts, such as changes in water quality, and transport and accumulation of contaminated sediments and biological impacts, such as changes in the habitats of organisms, and develop related technologies in advance, and have these technologies verified through demonstration application in the sites. In this study, we analyzed the physical, chemical and ecological impacts of the removal of the above-mentioned small dams, and conducted a research on the demonstration small dam removal project for a spot investigation. As a result, the small dam removal will restore the eco-corridor, there by improving the habitat of fishes and crustaceans. The number of major underwater organisms inhabiting the Gokreungcheon, such as Korean spotted sleepers, Chinese minnows, Microphysogobio yaluensis, Abbottina rivularis, stone morokos, striped shinners, long-nosed barbels, and Chinese mitten crabs, is expected to increase, and the food chain in the ecosystem will improve so that species diversity will improve as well.