• Korean Journal of Ecology and Environment
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• v.53 no.1
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• pp.1-10
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• 2020

The Stream/River Ecosystem Survey and Health Assessment has been carried out regarding the ecological health of the streams by the Ministry of Environment (MOE), South Korea. However, the sources of impairment of the stream ecosystem and the interactions between the sources, stressors, and the responses of impaired streams have not been taken into consideration. The purpose of this study is to propose the establishment of diagnosis systems for the impaired stream ecosystem because of the need to incorporate the same in the making of the policy to enable the recovery and improvement of the health of the impaired streams or river ecosystem. First, we define the concept of a diagnosis of the impaired stream or river ecosystem through a literature review. Second, through case studies [e.g., US CADDIS (Causal Analysis/Diagnosis Decision Information System), AUS. Eco Evidence, EU WFD (Water Framework Directive)], we try to develop the diagnosis system for the making of policy. In this study, the diagnosis system that is proposed consists of eight steps including the basic data collection, detecting or suspecting impairment, defining the impaired stream reach, identifying the biological impaired cases and listing the candidate causes, illustrating the interactive conceptual diagrams between stressors and responses, investigating the stressors-responses in the field, verifying causes and identifying the probable causes of the impaired cases, and summarizing and proposing the restoration of the streams. The results of this study will support and enable efficient decision-making for sustainable stream restoration and management based on the diagnosis of the probable causes for the impaired complex and the diverse stream ecosystem.

• Ecology and Resilient Infrastructure
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• v.6 no.4
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• pp.304-313
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• 2019

Biopolymer based on microbial β-glucan and xanthan gum is effective for vegetation and has a function of enhancing soil strength, which can be used as soil reinforcement and stabilization materials in river embankment. The purpose of this study is to verify the vegetation effect of the surface of levee by biopolymer with seed spraying method. Mixed soils with biopolymer were used to cover the surface of embankments. The strength is higher in biopolymer-treated soil and xanthan gum based biopolymer has advantage for quality control in field scale. In addition, the vegetation of F. arundinacea and L. perenne showed various reactions with types of biopolymers. Biopolymer has a positive effect on the vegetation of them. In contrast, root growth tended to decrease in biopolymer-treated soils. The results indicate that root growth is slow down due to increasing ability to retain water in biopolymer-treated soil. In order to apply biopolymer to river embankment, it is necessary to examine the effects of biopolymers on a wide range of plant species in river embankment.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.3
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• pp.201-208
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• 2011

When designing a river, it is important to select the appropriate bank revetment methods, but there are no specific guidelines until now. Accordingly, it is important to prevent over-budgeting by deciding the suitability of the adopted bank revetment methods when designing a river. In this study, an assessment method was developed to assess the suitability of the adopted bank revetment methods when designing a river. By adopting this method to eight rivers, its validity was examined. Analytic Hierarchy Process (AHP) was used for the assessment, along with suitability index (SI) of the adopted bank revetment methods when designing a river. In order to select the best bank revetment methods, all environmental variables of the selected location have to be considered. Accordingly, to assess the designed bank revetment methods, all variables of the selected location have to be considered. The assessing items include hydraulic stability, environmental-ecological feasibility, economy, and amenity of the bank revetment. Each item includes four to five sub-items, and each sub-items reflect survey results on the locations. The assessment method was adopted and assessed for eight rivers, and bank revetments was designed to determine the SI. The result of this study is considered to be appropriate when assessing an eco-friendly bank revetment methods, and inappropriate designed bank revetments will guide future planners for selecting the most appropriate construction method.

• Korean Journal of Ecology and Environment
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• v.56 no.3
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• pp.218-228
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• 2023

Invasive predators are one of the most damaging species groups to biodiversity. In the Nakdong River, the lake skygazer Chanodichthys erythropterus is a dominant species that is fiercely carnivorous and a concern for commercial fish. Although it is important to understand the ecological characteristics related to the feeding habit, studies on the diets of lake skygazer in Nakdong River have been limited to studies of gut contents. In this study, the trophic position (TP) and feeding habits of C. erythropterus were studied by calculating TPs using samples collected from 13 sites throughout the Nakdong River. Compound-specific isotopic analysis of amino acids provided reliable TPs from the muscle of Lake skygazer C. erythropterus without any isotope baseline. The results were approximately 3 to 3.6 and suggesting a carnivorous but size-dependent prey variation. In particular, the TP variability of C. erythropterus observed in the Nakdong River showed that it had a selective feeding habit compared to carnivorous fish species of relatively similar trophic levels.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.17 no.2
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• pp.1-14
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• 2014

The purpose of this study is to identify the efficiency of LID technologies for controlling non-point source pollution from urban areas. The recent technical responses to managing water resource and urban areas according to the influence of climate change is an important national policy, along with green growth. Through various reference studies reasonable ways to consider a wholistic plan on urban-eco-friendly river management, the Low Impact Development (LID) as the adequate river management method is being undertaken in foreign countries to technically apply to urban plans. However, the LID is at the initial stage in Korea, with no specific studies implemented. Thus, this study explored whether LID technologies can be efficient measures to control non-point source pollution on the cost side. Ulsan's Namgu and Bukgu have been chosen as case studies that illustrate the efficiency of the LID technologies. On investigation, if LID technologies are designed properly, the efficiency of them is expected to higher than that of sewage treatment plant.

• Korean Journal of Ichthyology
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• v.30 no.1
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• pp.46-54
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• 2018

The habitat characteristics and the age of endangered miho spine loach, Cobitis choii, were investigated in Ji Stream, Guem River, Korea in 2011 to provide baseline data for its restoration. The habitat of the C. choii was the downstream portion composed of sand, and the sand particle sizes was mostly 0.21~1.18 mm (88.7%). Juveniles (age 0+) preferred slower water velocity (0~25 cm/sec) and a lower water depth (5~20 cm) than did individuals who were more than 1 year old, as this group inhabited rapids with 10~25 cm/sec of water velocity and 20~50 cm of water depth. The C. choii rapidly grew during the active period from April to October and they stopped growing during the hibernating period from November to March. The estimated age of the C. choii (females) based on their total length distribution during the spawning period (June) indicated that 1-, 2-, 3- and more than 4-year-old were 40~61 mm, 64~79 mm, 80~91 mm and 92~106 mm, respectively.

• Journal of the Korean Geotechnical Society
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• v.31 no.10
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• pp.17-28
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• 2015

The strict regulations on eco-friendly construction and the significant reduction of natural aggregate resources have raised public concerns on the utilization of recycled aggregates for backfilling a power transmission pipeline trench. In this paper, the particle breakage of concrete-based recycled aggregates and river sand has been experimentally studied during the standard compaction test. The applied compaction energy does not significantly break the river sand particles down, and thus causes no change in the compaction curve, thermal resistivity, and particle gradation characteristics. On the other hand, considerable particle breakage was observed in case of the three recycled aggregates. Such particle breakage leads to enhancing compaction effort, reducing thermal resistivity, and changing particle gradation curve with finer particles that are broken during the first compaction. In addition, particle breakage is more dramatic in lower water contents because pore water may damp down the compaction energy.

• Journal of Korea Water Resources Association
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• v.34 no.4
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• pp.365-379
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• 2001

This paper presents an echo-hydraulic experimental approach to assessment of ascending capacity of migratory fish in a baffled fishway. Sweetfish, Plecoglossus altivelis, trout, Oncorhynchus mykiss, are used in these experiments. Ascending environment of the migratory fish in rivers is analyzed through the results of taco-hydraulic experiments. Important factors affecting the ascending capacity of migratory fish in baffled fishways are the discharge and slope of fishways and the fall height between the fishway entrance and the river bed. In these fishways the migratory capacity of sweetfish for a given fishway discharge is mainly affected by fishway slope, whereas the ascending capacity of trout for a given fishway slope was influenced by the change of fishway discharge. Loss of ascending properties of landlocked salmon, Oncorhynchus masou var ishikawai, was confirmed by these experiments. An ascending hydraulic criteria of the baffled fishway is defined by means of dimensionless factor F$_{f}$ and falling head H$_{f}$. Ascending capacity of migratory fish in existing baffled fishways in river of eastern coastal region is poor because the slope of fishways is verb steep.eep.

• Korean Journal of Ichthyology
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• v.30 no.2
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• pp.92-99
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• 2018

Feeding ecology of endangered Korean endemic miho spine loach, Cobitis choii, was investigated in Jicheon Stream, Geumgang River, Korea to provide ecological characteristics and baseline data for its restoration. C. choii is active during daylight hours above sand from March to October when the water temperature exceeded $13^{\circ}C$, but tended hibernate in the stream bottoms (sand) in the winter months (November~February) when the water temperature was lower than $13^{\circ}C$. They fed (index of relative importance, IRI) mainly Diptera (69.9%), Copepoda (23.2%), Arcellidae (2.3%), Branchiopoda (2.0%) and Ploima (2.0%). And their small juvenile (age 0+) fed mainly small size, Ploima and Branchiopoda, however, they ate mainly large size, Chilonomidae, while growing to adult fish (age 2+~3+).

• 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.