• The Journal of the Korea Contents Association
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• v.9 no.10
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• pp.417-426
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• 2009

The eco-friendly river restoration issue has been increased and the importance of the vegetation along the river banks has been understood with its scenery and significant role. However vegetation reduces the stream flow cross section and brings negative effects such as increase of water flow resistance and decreases of river flow velocity. In this study, the method to choose roughness coefficient is studied in the sudden changed hydraulic characteristics by river restoration. Using the HEC-RAS model and the two-dimensional vertical analysis method, Yangjae stream was calculated that the roughness coefficient of the main channel is 0.011~0.159 after river restoration, 0.031 without vegetation on the flood plain, and 0.034~0.506 with vegetation on the flood plain. The level of water in the river is predicted to rise 0.13~0.34m at 30% of vegetation density increase.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.185-185
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• 2011

Mapping of artificial levee lines, one of major tasks in river zone mapping, is critical to prevention of river flood, protection of environments and eco systems in river zones. Thus, mapping of artificial levee lines is essential for management and development of river zones. Coastal mapping including river zone mapping has been historically carried out using surveying technologies. Photogrammetry, one of the surveying technologies, is recently used technology for national river zone mapping in Korea. Airborne laser scanning has been used in most advanced countries for coastal mapping due to its ability to penetrate shallow water and its high vertical accuracy. Due to these advantages, use of LiDAR data in coastal mapping is efficient for monitoring and predicting significant topographic change in river zones. This paper introduces a method for construction of a 3D artificial levee line using a set of LiDAR points that uses normal vectors. Multiple steps are involved in this method. First, a 2.5-dimensional Delaunay triangle mesh is generated based on three nearest-neighbor points in the LiDAR data. Second, a median filtering is applied to minimize noise. Third, edge selection algorithms are applied to extract break edges from a Delaunay triangle mesh using two normal vectors. In this research, two methods for edge selection algorithms using hypothesis testing are used to extract break edges. Fourth, intersection edges which are extracted using both methods at the same range are selected as the intersection edge group. Fifth, among intersection edge group, some linear feature edges which are not suitable to compose a levee line are removed as much as possible considering vertical distance, slope and connectivity of an edge. Sixth, with all line segments which are suitable to constitute a levee line, one river levee line segment is connected to another river levee line segment with the end points of both river levee line segments located nearest horizontally and vertically to each other. After linkage of all the river levee line segments, the initial river levee line is generated. Since the initial river levee line consists of the LiDAR points, the pattern of the initial river levee line is being zigzag along the river levee. Thus, for the last step, a algorithm for smoothing the initial river levee line is applied to fit the initial river levee line into the reference line, and the final 3D river levee line is constructed. After the algorithm is completed, the proposed algorithm is applied to construct the 3D river levee line in Zng-San levee nearby Ham-Ahn Bo in Nak-Dong river. Statistical results show that the constructed river levee line generated using a proposed method has high accuracy in comparison to the ground truth. This paper shows that use of LiDAR data for construction of the 3D river levee line for river zone mapping is useful and efficient; and, as a result, it can be replaced with ground surveying method for construction of the 3D river levee line.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.2
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• pp.699-710
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• 2014

Government enacted "The special Law on the waterfront-space" to conduct four-river refurbishment project and to construct systematically regions around national rivers from 2009. This law allows public apartments and recreational facilities etc. to be located around four-river, then the law may give rise to serious space change and landscape damage. So we draw some problems of the established development project about the riverside area, and expected a space and landscape change of waterfront-space with a 3D simulation. The result, it is important to adjust the development density of site and apply various contents with take the regional characteristics into consideration for sustainable development.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.4
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• pp.15-28
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• 2017

A protected area means a space designated and protected by law from development pressure and environmental pressure. It is mainly designated to protect specific ecosystems, natural landscapes, and cultural resources from irrational development (or damage), and involves policies of the public sector such as central and local governments. The United Nations Educational, Scientific and Cultural Organization (UNESCO) has conducted conservation and restoration projects for preserving natural ecosystems and genetic resources. In order to conserve the ecosystem in the protected area, national and public organizations purchase private land and use it ecologically; in addition, ecological restoration project is carried out for the purpose of creating waterside ecological belt or preserving ecosystem. Land acquisition refers to the land where highly influenced by the water quality and need to restore, and purchased by negotiating with the landlord. Although the nation and public institution carried out ecosystem restoration project for partial purchase land in order to conserve ecosystem, it is below the expected effect due to lack of comprehensive management system and have some problems in restoration project and unification of management institutions. Land acquisition in Donggang River Basin Ecological Conservation area is initiated in 2005 for creating income of local residents and ecological restoration. However, the lack of overall management and awareness resulted in poor vegetation growth and poor response by local residents due to terrain exposure. As such, there is insufficient research on the current situation and systematic integrated management although the number of land acquisition is increasing year after year. Futhermore, overall recognition and follow-up monitoring of eco-restoration are still inadequate. Therefore, the survey on the awareness of the purchase land ecosystem restoration project is necessary for the efficient restoration project and establishment of the management strategy for land acquisition in the future. Therefore, in this study, we provide fundamental materials on further research projects by carrying out research on the awareness of ecological restoration projects in the Donggang River basin ecological preservation area.

• Korean Journal of Ichthyology
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• v.34 no.4
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• pp.270-276
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• 2022

In 2020 and 2022, the habitat of brown trout (Salmo trutta) was investigated in the Soyanggang River in Chuncheon, Gangwon province. As a result of the fish survey, A total of 43 individuals brown trout were identified. The total length of brown trout was widely confirmed from 60 cm or more to less than 10 cm. In January 2020, sperm release and spawn were observed in male and female confirmed at the St. 1. Brown trout were identified stably settled in the Soyanggang River and continues to live. In addition, benthic macroinvertebrates that can act as food sources of brown trout and abundantly inhabited. The riverbed structure is evenly composed of fine gravel and gravel, which constitutes the conditions necessary for habitat and spawning. However, the spawning grounds, spawned eggs and hatched fry have not yet been clearly identified, so continuous research is needed.

• 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 Korean Society on Water Environment
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• v.35 no.1
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• pp.55-63
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• 2019

The Four Major Rivers Restoration Project started in 2009 and completed in early 2013 is a large-scale inter-ministry SOC project investing ₩22.2 $10^{12}$ and one of the Project's objectives was to enhance the water-quality grade through recovering the river eco-system and environment. The average concentration and probability distribution of water-quality constituents at given and selected sampling sites are very significant elements for analyzing and controlling the water-quality of rivers or reservoirs effectively. Average concentration can be estimated by point estimator, distribution function of water-quality constituents or Bootstrap method, in which the distribution function estimated with more data in case of insufficient dataset, is applied. Ipo and Gangcheon water-quality monitoring stations in South Han River were selected to compare and analyze the variation of concentration before and after Ipo and Gangcheon Weirs construction, using the whole 4-year's data, from 2005 to 2008 and from 2014 to 2017. Water-quality constituents such as BOD and COD relating to oxygen demanding wastes and TP and Chlorophyll-a relating to the process of nutrient enrichment called eutrophication were also selected. The guidelines for water-quality control and management after weir construction including evaluation of water-quality constituents' variations can be presented by this paper.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.2 no.4
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• pp.293-297
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• 2021

The oriental stork (Ciconia boyciana) is listed as an endangered species internationally. Its resident population has been extirpated in South Korea since 1971. Its predicted historical habitat included forests (54%), rice paddy fields (28%), grasslands (17%), river-streams (less than 1%), and villages (less than 1%) based on pre-extirpation records in a previous study. However, habitat attributes of recently reintroduced oriental storks since 2015 remain unknown. To examine habitat use patterns and home ranges of recently reintroduced oriental storks, 2015-2017 tracking data of 17 individuals were used to analyze their spatial attributes with a Kernel Density Estimate method and breeding status. Their habitat use patterns from peripheral to core areas were highly associated with increasing rice paddy fields (26%) and decreasing forested areas (55%). Scale-dependent home ranges were 51% smaller for breeders than for non-breeders on average. Our study results highlight that the habitat use pattern of reintroduced oriental storks seems to be comparable to the historical pattern where the used area is likely to be more centralized for breeders than for non-breeders in South Korea. Furthermore, the direction of habitat management for oriental storks should focus on biodiversity improvement of rice paddy fields with chemical free cultivation and irrigation.

• Animal Systematics, Evolution and Diversity
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• v.34 no.4
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• pp.194-198
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• 2018

The genus Prionchulus Cobb, 1916 represents a group of predaceous nematodes belonging to the family Mononchidae Chitwood, 1937, and is found worldwide. However, only five species have been reported thus far from Korea. Prionchulus oleksandri Winiszewska and Susulovsky, 2003 is reported for the first time from Korea, from sediments collected from the Nakdong River. This species is distinguished from other Prionchulus species by its truncated lip region with small cephalic papillae and refringens vaginae. In this study, morphological characters(detailed morphometrics) of P. oleksandri are described and illustrated using optical microscopy. DNA barcode sequence information (the D2-D3 region of 28S rDNA, 18S rDNA, and internal transcribed spacer rDNA) is also provided for the molecular identification of the species.

• Journal of the Korean association of regional geographers
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• v.14 no.1
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• pp.1-18
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• 2008

If there is no choice but to be urbanized, we should examine how human interference has had influences on the area to keep the river environment safe and stable. This study is aimed at finding improvement by examining the effect of human interference in Gapcheon river in Daejeon, which is developing fast. Distinctive features of human interference in Gapcheon river are followings. First, middle and upper reaches of Gapcheon river are being maintained and restored focusing on flood control but are scheduled to develop city and channel. Second, the rear area of middle and lower reaches of Gapcheon river is already developed into an urban district and solidified into artificial stream for leisure activities installing the artificial structure for fun. Third, lower reaches of Gapcheon river are in an unstable condition because of straightening waterway and developing rear area of river. Up to now, geographical features and bio-diversity of Gapcheon river has been ruined by the artificial management of river centered for technical engineering. From now on, followings should be considered for management of urban river. First, it is focused on maintaining eco system by itself than usage for human. Second, natural features of rear area of river should be taken into consideration and should be preserved before developing urban city and hills, back marsh, channel deposit and swamp to directly have an influence on river.