• 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.

• Ecology and Resilient Infrastructure
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• v.6 no.2
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• pp.101-108
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• 2019

This study investigated the impact of abandoned channel restoration on fish habitat using the physical habitat simulation. The study area is a 1.2 km long reach of the Cheongmi-cheon stream. In the study area, the restoration of the abandoned channel was carried out from July 2012 to December 2105. Physical habitat simulations were carried out for both cases before and after the restoration. The River2D model and habitat suitability curve were used for hydraulic and habitat simulations, respectively. Zacco platypus, which is a dominant fish species in the study area, was selected as target fish for the physical habitat simulation. Hydraulic simulations were carried out before and after restoration for various discharges. Then, composite suitability index and weighted usable area were calculated before and after restoration and changes in the physical habitat of Zacco platypus were discussed. Simulation results indicated that the abandoned channel restoration is effective in creating fish habitat and mitigating the degradation of fish habitat from the high flow condition.

• Ecology and Resilient Infrastructure
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• v.2 no.1
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• pp.33-41
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• 2015

In this study, an optimal improvement method of stream channel structure is presented for the enhancement of fish habitat suitability by genetic algorithm. The correlation between fish habitat suitability and physical disturbance in stream is analyzed according to the changes of hydraulic characteristics by channel structure rehabilitation. Zacco koreanus which is an indicator fish of the soundness of aquatic ecosystem was selected as a restoration target species by investigating the community characteristics of fish fauna and river environments in Wonju stream. The habitat suitability is investigated by PHABSIM with the habitat suitability index of Zacco koreanus. Hydraulic analysis by HEC-RAS and physical disturbance evaluation in stream are carried out. The optimal channel width modified for the enhancement of fish habitat suitability is provided. The correlation analysis between habitat suitability and physical disturbance with the change of hydraulic characteristics by channel modification showed that the proper channel modification enhanced fish habitat suitability and mitigated physical disturbance in the stream. The improvement of physical disturbance score by the channel structure rehabilitation for the enhancement of fish habitat suitability was confirmed in this study.

• Ecology and Resilient Infrastructure
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• v.2 no.4
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• pp.317-323
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• 2015

This study investigated the impact of the morphological change on a physical fish habitat in the downstream reach of a dam using long-term mobile bed simulation. The quasi-steady model was used for hydraulic simulation and the habitat suitability index model was applied for physical habitat simulation. For simulating long-term morphological change of the stream bed, The Exner equation was used. Sorting of bed material was also considered. The results of simulation showed that erosion and armoring process occurred in a reach downstream of the dam and change of physical habitat for Zacco platypus followed. These results indicate that channel morphology and substrate conditions effected the physical habitat for considering long-term investigation.

• Journal of Korean Society on Water Environment
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• v.31 no.1
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• pp.35-41
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• 2015

This study focuses on whether a physical habitat model, River2D, is useful to assess and design stream restoration. To achieve the aim, the habitat suitability for Zacco Platypus was analyzed using River2D at midstream of the Anyang-Cheon through modifying the low flow channel and changing the flow discharge. The River2D simulation results show that the inhabited environment for Zacco Platypus is improved by increasing the sinuosity of the low flow channel, and vice versa. Also the inhabited environment for Zacco Platypus gets worse when there is no additional flow for maintenance water supply at the stream flowing through cities. In this respect, the physical habitat simulation study based on the River2D model is useful because it provides a practical guidance in designing stream restoration.

• Journal of Korea Water Resources Association
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• v.40 no.11
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• pp.909-920
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• 2007

River restoration and environmental improvement projects have been peformed by social needs, therefore methodology for evaluating such projects must be provided. The PHysical HABitat SIMulation system (PHABSIM) is proposed as a tool for the assessment of hydraulic habitat suitability for aquatic species related to flow regime in river. This study evaluates the change of physical habitat for Zacco platypus according to small dam removal and the model suitability by applying PHABSIM to the reach where small dam was removed. It is shown that the physical habitat is generally increased and improved where the small dam was removed. However, physical habitat in the spawning stage that has a weak swimming speed is decreased by increased flow velocity in the upstream area of small dam, so proper countermeasure for that condition should be needed. Consequently, PHABSIM can be effectively used to provide methodology for assessment and necessity of various river projects including a removal of out-aged hydraulic structures.

• Journal of Environmental Impact Assessment
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• v.21 no.5
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• pp.631-648
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• 2012

The integrative ecological approaches of chemical assessments, physical habitat modelling, and multi-metric biological health modelling were applied to Gwanpyeong Stream within Gap-Stream watersheds to evaluate environmental impacts on the constructions of residential and commercial complex. For the analysis, the surveys conducted from 45 sites of reference streams within the Gap-Stream watershed and 3 regular sites during 2009 - 2010. Physical habitat health, based on the habitat model of Qualitative Habitat Evaluation Index(QHEI) declined from the headwaters(good - fair condition) to the downstream(poor condition). Chemical water quality, based turbidity and electric conductivity(EC), was degraded toward to the downstream, and especially showed abrupt increases, compared to the values of control streams(CS). Also, concentrations of chlorophyll-a in the downstreams were greater compared to the control stream(CS), indicating an eutrophication. Biological health conditions, based on the Index of Biological Integrity(IBI) using fish assemblages, averaged 19.3 which is judged as a fair condition by the biological criteria of the Ministry of Environment, Korea. The comparisons of model metric values in sensitive species and riffle-benthic species on the Maximum Species Richness Line(MSRL) of 45 reference streams indicated a massive disturbances in all sampling locations. Also, tolerance guild and trophic guild analyses suggest that dominances of tolerant species and omnivores were evident, indicating a biological degradation by habitat disturbances and organic matter pollutions. There was no distinct longitudinal variations of IBI model values from the headwater to the downstream in spite of slight chemical and habitat health gradients among the sampling sites. Overall, integrative ecological health(IEH) scores, based on the chemical, physical, and biological parameters, were low compared to the 45 reference streams due to physical and chemical disturbances of massive constructions of the residential and commercial complex. This stream, thus showed a tendency of typical urban streams which are disturbed in the chemical water quality, habitat structures, and biological integrity. Effective stream management plans and restoration strategies are required in this urban stream for improving integrative stream health.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.805-812
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• 2014

This study investigates the impact of morphological change on the physical habitat simulation. For this, CCHE2D model is used for the hydraulic analysis including the morphological change, and the physical habitat suitability is assessed with habitat suitability curves. The model is applied to a 2.5km long reach downstream of the Goesan Dam, from Sujeon Bridge to Daesu Weir. Flow data of discharge and stage in July, 2006 are used in the computation. The numerical model is verified by means of comparison with the measured water surface elevation data, and the variation of the river bed is not verified in this study. Adult Zacco platypus is chosen for the dominant species. Physical habitat simulations result in composite habitat suitability and weighted usable area for drought, low, normal, and averaged-wet flows. The simulation results indicate that the composite suitability index increased at reaches right downstream of the Sujeon Bridge and around the bend. This also increased weighted usable area by 5.4-11.3%.

• The Korean Journal of Malacology
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• v.31 no.4
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• pp.307-314
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• 2015

This study sampled endangered species, Lamprotula coreana, and surveyed its habitat at the Guem River with three times from June to August 2013. To assess the habitat, this study conducted field survey considering diverse physical conditions of stream, such as pool, run and riffle, and measured transect, water depth, water velocity, substrate structure, and habitat type. When L. coreana collected, length, weight and age were measured. Water velocity, water depth and substrate structure were recorded to develop HSI (habitat suitability index) and performed PHABSIM (physical habitat simulation) to estimate the optimum flow discharge. Water level, flow discharge and transect data were used for habitat assessment, and PHABSIM was applied to calculate WUA (weighed usable area). Shell length was $73.1{\pm}18.4mm$ (28.5-102.0 mm), shell weight was $131.6{\pm}72.3g$ (28.0-281.0 g) and age was two to seven years from L. coreana collected at the upstream of the Guem River. Developed HSI indicated that the optimal habitat for L. coreana was 0.4-0.5 m for water depth, 0.3-0.5 m/s for water velocity and sand to boulder for substrate structure. The optimum ecological flow discharge for L. coreana was 2.1 cms and WUA was $3,730m^2$/1000 m by the result of PHABSIM. Recently, river construction work and habitat disturbance have caused negative impact on the distribution of L. coreana. The result of this study would provide fundamental data for habitat restoration and management of L. coreana.

• Ecology and Resilient Infrastructure
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• v.4 no.3
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• pp.169-179
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• 2017

This study analyzed the aspect of bed change according to the stable channel design on the Wonju River to quantitatively evaluate habitat suitability (HS). According to the result of evaluating stable channel of object section in the Wonju River, 17 sections among total 20 sections were stable and 3 sections were unstable. Physical disturbance improvement evaluation (PDIE) was the range average showed good disturbance condition with a range average of 112.17 points. Habitat suitability index of Zacco Koreanus, the most dominant species of the Wonju River, was used for analysis of physical habitat for fish. According to the physical habitat analysis result, HS was 0.16 and weighted usable area (WUA) was $347.68m^2$. The methods of improving/introducing/removing structures and dredging stream channel were used for stable channel design of unstable channel, and analyzed PDIE according to the aspect of bed change and changes in habitat suitability. Stable channel design was possible in 19 sections in times of structures improvement/introduction/removal, and PDIE was 117.53 points, HS was 0.14 points, and WUA was $313.37m^2$. Stable channel design was possible in all 20 sections when dredging the stream channel. PDIE was 116.50 points, HS was 0.16, and WUA was $332.14m^2$. Therefore, this study obtained channel design measures that can improve physical soundness and stability of the Wonju River, and it was analyzed that it will have no impact on changes of physical disturbance and physical habitat. Furthermore, this study analyzed velocity and depth of each section and appearance frequency of riffle and pool to analyze correlation between physical disturbance and physical habitat. According to the analysis result, it was identified that the analysis of riffle and pool showed similar result as the evaluation result of physical habitat.