• 한국환경과학회지
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• 제11권4호
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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.

• 한국농공학회논문집
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• 제64권4호
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• pp.55-64
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• 2022

The objectives of this study were to assess physical habitat suitability of fish species for different life cycle stages and to suggest appropriate ecological stream flows in a Bokha downstream reach. A dominant species of Zacco platypus was selected as the study fish of which three stages of spawning, juvenile and adult in life cycle were considered into assessment. The stream hydraulic environment was calibrated with HEC-RAS before the PHABSIM simulation. The hydraulics of flow velocity and depth were used to estimate Weighted Usable Area (WUA) by multiplying respective habitat suitability indices with stream area. Overall the WUAs tend to be great in gentle slopes with relatively shallow water depth regions. Maximum WUAs, ie, candidate for ecological flow rates were 1 m³/s, 7 m³/s and 8 m³/s for the respective spawning, juvenile and adult stages of Zacco platypus. Since the ecological flow rates for juvenile and adult stages appeared to be is greater than the abundant flow rate (3.67 m³/s) for the study reach, additional water supply may be needed but should be cautious to avoid the spawning period of Apr through May from the stream water management perspective.

• 생태와환경
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• 제42권4호
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• pp.495-501
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• 2009

The study was conducted in 2007~2008 in order to understand preference of physical microhabitat on the $1^{st}$-class endangered species, Gobiobotia naktongensis inhabiting the Gam Stream, tributary of Nakdong River. The total number of fish caught from the study sites was 3,671 representing 7 families 24 species. There were 8 Korean endemic species including Odontobutis platycephala, and 2 introduced species (Carassius cuvieri, Micropterus salmoides) were found. According to investigation and analysis of physical microhabitat on Gobiobotia naktongensis caught in the Gam Stream, a total of 57 individuals were found at shallow depth (0.14~0.46 m) and run (0.239~0.585m $sec^{-1}$). As a result of sieve analysis, stream beds consisted of about 1% gravel and 99% sand (83.4% coarse sand, 15.6% find sand). Therefore, Gobiobotia naktongensis seemed to inhabit shallow-run with coarse sand bed than deep-pool microhabitat. The findings indicate preference of physical microhabitat on Gobiobotia naktongensis, and it is important to enhance efficiency of fish conservation and ecological restoration with understanding species-specific characteristics in microhabitat including protected species.

• 수산해양교육연구
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• 제27권3호
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• pp.841-852
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• 2015

The objectives of this study are to amend of the Small Stream Maintenance Act. In general, small streams have diverse ecological and social characteristics because they are extensively formed across watersheds over time. However, small streams in Korea have been significantly degraded primarily because of human disturbances including stream maintenance activities. Especially, covered streams are majority problem in the Small Stream Maintenance. In order to improve this problem, the Small Stream Maintenance Act be amended to the Small Stream Management Act.

• 한국환경복원기술학회지
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• 제21권3호
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• pp.67-81
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• 2018

We tried to analyze qualitatively a total of 110 the research papers which were related domestic ecological restoration technologies about 15 years through semantic network analysis in social network analysis. In order to understand the research trends of ecological restoration technologies, we analyzed the degree centrality and betweenness centrality of the Stream/Wetland, Slope, Soil/Others fields selected as Word Cloud. As a result, ecological restoration technologies have been changed. They were focused on the restoration of species or their habitats in the past. However, they have been evolved into the detailed systems to respond in unpredictable natural disasters and climate change, high-resolution image implementation technology to accurately grasp the practical environment and methods related to environmental restoration for human in urban ecosystem. In the future, investment and technology for the ecosystem restoration field will be continuously demanded for the symbiosis of human beings and species in the damaged ecosystem. Therefore, the research trend of ecological restoration technologies should be provided as reliable guidelines when decision makers establish the policy direction or when researchers select their subjects.

• 한국환경복원기술학회지
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• 제4권2호
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• pp.62-73
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• 2001

The riparian environments of urban streams in Korea have been disturbed through the channelization for flood control and artificial land use as well as water pollution and flow decrease due to industrialization and urbanization. The flora and vegetation structure were investigated and an implication of stream restoration was discussed for the conservation of biodiversity in the riparian area of the Seunggi stream in Incheon. Naturalized plants and ruderal plants were widely distributed in the riparian area which was disturbed from cultivating, trampling, dumping etc. Submerged and floating hydrophytes were not found in the stream due to channelization and water pollution. Some halophytes were remained in downstream and reservoir after reclamation and embankment. The communities of Humulus japonicus, Panicum dichotomiflorum, Digitaria sanguinalis, Artemisia montana, Amaranthus retroflexus, and Aster pilosus were distributed in the disturbed area of bank slope and floodplain in the stream. As a natural potential vegetation, Phragmites australis in the wet meadow, Typha latifolia, Typha angustifolia, Oenanthe javanica, Persicaria thunbergii, and Penthorum chinense in the marsh, and Salix babylonica and Salix matsudana for. tortuosa in the woodland appeared in the floodplain. The topography in the stream played an important role on the distribution of riparian vegetation in the Seunggi stream. Appropriate methods for conservation and restoration of the riparian ecosystems must be planned on the basis of the actual vegetation in the disturbed urban stream.

• 환경영향평가
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• 제21권5호
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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.

• 한국물환경학회지
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• 제26권6호
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• pp.1000-1007
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• 2010

In this study, toxicity monitoring of sediments collected from 25 stations in the Geum river basin was conducted using Daphnia magna and Moina macrocopa. According to the results of acute toxicity tests (immobilization and mortality) of organic extracts of semdiments, Miho stream showed much less toxicity than Gap and Nonsan streams. In particular, significant toxicity was observed in both species for St.15 and St.16 sediment samples that passed through Deajeon city as a branch of Gap stream. For Nonsan stream, St.23 sediment showed high toxicity toward M. macrocopa. This site seemed to be affected by upper agricultural industrial complex. Additionally, M. macrocopa showed a higher sensitivity than D. magna for organic extracts of sediments. In the case of toxicity tests using sediment pore water and aqueous extracts, only pore water of St.27 sediment was toxic against D. magna. Toxicity identification evaluation showed that hydrogen sulfide was likely a major toxicant in the pore water.

• 한국지리정보학회지
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• 제11권2호
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• pp.93-107
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• 2008

최근 한국에서는 하천의 환경적 생태적 기능을 되살리기 위해 하천복원과 관련된 여러 가지 사업이 진행되고 있다. 이러한 하천복원사업에 있어서 사업대상 하천의 생태성에 대해 평가하고, 이를 바탕으로 하천복원사업의 목표와 계획을 수립할 수 있도록 하는 일은 학술적이나 사업적으로나 모두 값진 일이 될 것이다. 한편, 하천의 생태성을 개략적으로 판단할 수 있는 방법의 하나는, 하천의 수문지형 물리적 구조(hydromorphological structure)를 평가하는 것이다. 본 연구에서는 LAWA(물관리 연구 독일 연방 법적공동체)의 하천 평가 기법을 이용하여 중 소규모 하천의 자연 생태성을 평가하기 위한 하천의 수문지형 물리적 구조를 평가하는 현장 조사 체계(field survey system)를 개발하고, 아울러 조사결과를 이용하여 도면자동화 체계(auto mapping system) 및 보고서로 작성하는 과정을 지원하는 GIS 기반의 하천 평가 체계를 개발하였다. 하천복원 및 관리 분야 종사자들이 하천복원 계획 수립과 관리의 단계에서 대상하천의 하천자연도 내지 생태성을 인지하고 분석하는데 도움을 주고, 대상하천의 '도달해야 하는 이상적인 하천모델상'을 결정하기 위한 기초 자료를 수집하는데 도움을 주고자 한다.

• 한국환경과학회지
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• 제16권7호
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• pp.831-838
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• 2007

In order to improve the water environment at urban streams in Korea, several river restoration projects have been initiated for past few years. This study evaluates the impact of diverting water application at the riverhead of Onchun stream through the monitoring program for several water quality and ecological parameters. Various water quality parameters and ecological item such as benthic macroinverterates has been investigated between 09/05 and 12/06. Analysis indicates that the application of diverting water from Nakdong river to Onchun stream distinctly improved several water quality parameters such as, PH, BOD, TN, TP and concentrations of heavy metals. Low flow augmentation also improve ecological indicies such as the diversity index of benthic macroinvertebrates. Generally speaking, releasing addition water from head water of Onchun stream improves various water environmental characteristics.