• Progress in Superconductivity and Cryogenics
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• v.20 no.2
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• pp.16-19
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• 2018

Comprehensive utilization of zinc smelting iron slag not only solves environmental problems but also creates huge economic benefits. This study was conducted on the enrichment and recovery of ${\alpha}-Fe_2O_3$ from zinc smelting iron slag by superconducting HGMS technology. Several variables such as slurry flow velocity, slag concentration, magnetic field intensity and the amount of dispersing agent were tested in magnetic separation. In the experiments, obtained optimal magnetic separation parameters were 1.60 T of magnetic flux intensity, 600 mL/min of slurry flow velocity of, 15 g/L of slag concentration of, 0.10 g/L of dispersing agent. Under this condition, the content of ${\alpha}-Fe_2O_3$ was increased from 86.22% to 94.39% that can approach the Chinese national standard requirements (A level) of iron oxide red. It was concluded that using superconducting HGMS technology was an effective method for the purification of ${\alpha}-Fe_2O_3$ from zinc smelting iron slag.

• Ecology and Resilient Infrastructure
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• v.6 no.1
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• pp.1-11
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• 2019

This study performed the impact of ecological waterway on fish community in a reach of the Dal River, Korea. Fish monitoring revealed that 9 fish species are dominant, namely Zacco platypus, Coreoleuciscus splendidus, Zacco koreanus, Pungtungia herzi, Acheilognathus yamatsutae, Rhinogobius brunneus, Tanakia signifer, Gobiobotia macrocephala, and Pseudopungtungia tenuicorpus, and account for 95% of the total fish community. The River2D model was used for the computation of the flow and the HSI model for the habitat simulation. The restoration of the waterway performed through the small dam removal, the formation of the pool-riffle structure, and the change of the bed elevation and width. Simulation results indicated that the restoration of the ecological waterway effects significantly increased by about 16% for the WUA (Weighted Usable Area) of the total fish community in optimal ecological flow conditions ($Q=7.0m^3/s$). The restoration of the ecological waterway is more advantageous to fish community.

• Journal of Ecology and Environment
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• v.39 no.1
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• pp.43-49
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• 2016

Fishways are constructed to provide longitudinal connectivity of streams or rivers where their flow has been altered by in-stream structures such as dams or weirs. Nature-like fishways have an additional function of providing fish habitats. In the study, we estimated the role of a nature-like fishway (length: 700 m, slope: 1/100) for fish habitat by using two dominant species in the Sangju Weir, Nakdong River, to calculate the optimal ecological flow rate using Physical HABitat SIMulation (PHABSIM). To identify the dominant species that used the fishway, we conducted trap monitoring from August to November 2012 at the fishway exit. The dominant species were Zacco platypus and Opsariichthys uncirostric amurensis with a relative abundance of 62.1% and 35.9%, respectively. Optimal habitat suitability indices (HSIs) for Z. platypus and O. u. amurensis were calculated as 0.6-0.8 m/s (water velocity) and 0.2-0.4 m (water depth), and 0.5-0.7 m/s (water velocity) and 0.1-0.3 m (water depth), respectively. The optimal ecological flow rates (OEFs) for Z. platypus and O. u. amurensis were 1.6 and 1.7 cubic meter per second (CMS), respectively. The results of the study can be used in a management plan to increase the habitat function of nature-like fishways in the Sangju Weir. This methodology can be utilized as an appropriate tool that can determine the habitat function of all nature-like fishways.

• Journal of Environmental Science International
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• v.11 no.4
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• pp.309-317
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• 2002

In this study, water protection reservoir is selected as the target which is located at the estuary of Taehwa river to analyze and examine the effects of hydraulic structure on river environment. This study examined the water quality variation characteristics among many effects of hydraulic structure on river environment before and after removal of the sediment protection reservoir when low flow is yielded. This study aims at the definition of factors which cause the change of ecological environment of river due to the effects of the sediment protection reservoir, and the proposal of the direction of environmental friendly river space development through the comparison of stream variation conditions(depth, velocity, and etc.) and riverbed variation characteristics with ecological depth condition of Taehwa-river's channel for each representative species of fish and examination those. Firstly, from the examination result of water quality when low flow is yielded before and after removal of the sediment protection reservoir for problems about water quality of river due to flow amount decrease in river, it is found that DO decreases about 0.78~0.86ppm at the lower stream of Myeongchon-gyo, and BOD decreases about 0.06~0.24ppm from right upper stream to the direction of estuary when the sediment protection reservoir is removed. It is known from the above that there is some improvement of water quality from the lower stream of Taehwa-gyo to the estuary in case of removal the sediment protection reservoir. Nextly, it is thought that the effects on ecosystem due to water depth and draw down in channel is not serious on the basis of the examination of water quality analysis result according to removal of sediment protection reservoir and hydraulic depths for reservation of ecosystem, these are 10~40cm for breeding season, 10~50cm for fry period, and 10~100cm for adult period of the representative species of fish in Korea.

• Korean Journal of Environmental Biology
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• v.26 no.3
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• pp.203-213
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• 2008

Benthic macro invertebrate communities were collected at six different sampling sites in the Musucheon stream in Korea from July 2006 to July 2007, and ecological exergy values were calculated based on five different functional feeding groups (collector-gatherer, collector-filterer, predator, scrapper, and shredder) of benthic macro invertebrates. Each sampling site was categorized to three stream types (perennial, intermittent and drought) based on the water flow condition. Exergy values were low at all study sites right after a heavy rain and relatively higher in the perennial stream type than in the intermittent or the drought stream type. Self-Organizing Map (SOM), unsupervised artificial neural network, was implemented to pattern spatial and temporal dynamics of ecological exergy of the study sites. SOM classified samples into four clusters. The classification reflected the effects of floods and droughts on benthic macroinvertebrate communities, and was mainly related with the stream types of the sampling sites. Exergy values of each functional feeding group also responded differently according to the different stream types. Finally, the results showed that exergy is an effective ecological indicator, and patterning changes of exergy using SOM is an effective way to evaluate target ecosystems.

• Journal of the Korean Society for Marine Environment & Energy
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• v.20 no.1
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• pp.12-17
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• 2017

This study established ecological goals and success criteria by using results of the coastal ecosystem restoration demand survey. The ecological goals are set for species diversity, regulation of seawater flow, improvement of purification, erosion prevention and habitat provision by ecosystem types. The indicators of success criteria are chosen the number of emergence species and community characteristics of target organism and pertinent items of hydrologic, water quality and sediment environment by ecological goals among the investigation items of tidal flat investigation guideline.

• Journal of the Korean Institute of Landscape Architecture
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• v.32 no.2
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• pp.102-119
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• 2004

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 Bokha stream. Stream habitat is classified into nine types for the aquatic insects and fish. For vegetation and birds, habitat is classified into five types of medium-scale streams, including both physical and chemical streams are analyzed accordingly. The major results of this study are as follows: 1) A pool connected to the main stream has a certain water depth (about 80 cm) and is disturbed at least 5 to 6 times a year. Although the pool has a somewhat bad water quality, it provides a habitat for various types of young fish. 2) A meander riffle is about 15 cm deep, the flow velocity in the region is about 75 cm/s. This region does not have large structures to which aquatic insects can attach, so it cannot be used as a spawning ground. 3) A rock type pool is about 60 cm deep, the flow velocity in the meander riffle is about 25 cm/s. In this region, many aquatic insects attached to large structures appear. Due to various riparian vegetation, the rock type pool is used as a habitat for aquatic insects. 4) A pool which is only connected to the main stream during floods has a bad water quality. Despite of its relatively small size, it has a high population density of aquatic insects. faculty.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.1
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• pp.33-44
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• 2019

Due to the recent climate change realization (timing, rainfall pattern changes), the flow regime is changing according to the watershed. The long-term change of flow regime is causing a significant change in structure and function of aquatic ecosystems. However, there is no analysis from the viewpoint of the aquatic ecosystem including flow rate alteration and ecological characteristics as well as the climate change connection in Korea yet. Therefore, We quantitatively assessed the impact of present-future flow regime alteration due to climate change on the Pseudopungtungia nigra habitat in the Mankyung river and floodplain area. As a result, it was confirmed that extreme hydrological conditions such as flood and drought are intensified in the future than the present. Especially, the changes of flow regime characteristics were clarified by comparing and analyzing the magnitude, frequency, duration, rate of change, and by linking flow regime characteristics with physical habitat analysis, it could be suggested that climate change would significantly increase the risk of future ecological changes.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.106-106
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• 2015

The information of flow regimes continues to be norm in water resource and watershed management, in that stream flow regime is a crucial factor influencing water quality, geomorphology, and the community structure of stream biota. The objectives of this study were to estimate Korean stream flows from landscape variables, classify stream flow gages using hydraulic characteristics, and then apply these methods to ungaged biological monitoring sites for effective ecological assessment. Here I used a linear modeling approach (MLR, PCA, and PCR) to describe and predict seasonal flow statistics from landscape variables. MLR models were successfully built for a range of exceedance discharges and time frames (annual, January, May, July, and October), and these models explained a high degree of the observed variation with r squares ranging from 0.555 (Q95 in January) to 0.899 (Q05 in July). In validation testing, predicted and observed exceedance discharges were all significantly correlated (p<0.01) and for most models no significant difference was found between predicted and observed values (Paired samples T-test; p>0.05). I classified Korean stream flow regimes with respect to hydraulic and hydrologic regime into four categories: flashier and higher-powered (F-HP), flashier and lower-powered (F-LP), more stable and higher-powered (S-HP), and more stable and lower-powered (S-LP). These four categories of Korean streams were related to with the characteristics of environmental variables, such as catchment size, site slope, stream order, and land use patterns. I then applied the models at 684 ungaged biological sampling sites used in the National Aquatic Ecological Monitoring Program in order to classify them with respect to basic hydrologic characteristics and similarity to the government's array of hydrologic gauging stations. Flashier-lower powered sites appeared to be relatively over-represented and more stable-higher powered sites under-represented in the bioassessment data sets.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.2B
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• pp.153-160
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• 2006

To recommend ecological flow for major tributaries in Han River basin, the Instream Flow Incremental Methodology (IFIM) have been applied. In particular physical habitat simulation using PHABSIM have been selected for microhabitat variables and QUAL2E model have been used to implement macrohabitat simulation. Habitat Suitability Criteria (HSC) for different life stages in accordance with different hydraulic variables (depth and velocity) have been presented by the field surveying data. We review IFIM procedures and discuss limitations of habitat simulation with specific reference to Han River basin. The results of this research can be used as reference flow for estimation of instream flow in Han River.