• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.459-459
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• 2021

오래 전부터 농업용수 취수 등의 목적을 위해 설치된 하천 내 횡단구조물이 약 34,000개에 달하고, 홍수피해 방지를 위해 하천변을 따라 많은 제방이 설치되어 있다. 특히 보, 낙차공, 교각 보호공 등의 횡단구조물은 흐름의 단차를 발생시킴으로써 어류의 이동 등 하천의 종적 연속성을 훼손 또는 단절하고 있어 하천 수생태계 연속성 확보 측면에서 매우 중요한 요인으로 볼 수 있다. 하천 종적 연속성과 관련된 연구는 북미, 호주, 유럽, 일본 등에서 수생 종 특히, 어류를 중심으로 장벽의 영향을 분석하는 데 중점을 두고 진행되어 왔다. 하천 네트워크 규모에서 다수의 장벽 설치에 대한 누적 효과를 분석한 사례는 거의 없으며, 서식지 및 수생태계 연결과 관련하여, 하천 시스템의 네트워크 규모에서 속성을 설명하고 정량화하는 도구 역시 찾아보기 어렵다. 본 연구에서는 하천 네트워크 내의 종적 방향의 연결성을 정량화하기 위한 방법으로 Cote 등(2009)이 제시한 DCI(Dendritic Connectivity Index) 지표를 이용하였다. 수계 연속성 지표(DCI)는 하천 수계 내의 종적 연속성 평가를 목적으로 횡단구조물의 개소수와 위치, 어류의 이동률을 누적하여 정량화한 방법으로써, 구조물 단위 평가가 아닌 하천 단위 평가 방법이다. 곡성천과 삼척오십천을 대상으로 국가어도정보시스템 및 항공사진을 통해 구축한 구조물의 개소수와 위치정보를 이용하여 시계열 DCI를 산정하였다. 그리고 2차 조사에 걸쳐 횡단구조물 현황 및 수리 특성, 어류현황 및 이동특성 조사 및 분석결과를 DCI에 반영하여 DCIm을 산정하였다. 곡성천의 경우 현재(2018년) DCI 결과는 5.63%이며, 어류 이동률 적용 결과 DCIm은 6.29%로 산정되었고, 약 11.7% 증가하는 것으로 나타났다. 삼척오십천의 현재(2018년) DCI 결과는 9.78%이며, 어류 이동률 적용결과 DCIm은 10.34%로 산정되었고, 약 5.7% 증가하는 것으로 나타났다. 향후 하천 내 수생태계의 연속성을 확보하기 위해서는 우선적으로 하천 수생태계 훼손, 단절, 연속을 효과적으로 비교·평가할 수 있으며, 이를 통해 개선사업의 우순순위 등 의사결정을 위한 방법론의 개발이 필요하다.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.49-49
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• 2023

지구온난화의 영향으로 가뭄의 발생 빈도가 전 세계 곳곳으로 증가하고 있는 추세이다. 가뭄이란 강수량 혹은 가용 수자원 등이 평균적인 수준에 비해 지속해서 적게 유지되는 현상으로 다양한 분야(기상, 농업, 사회, 경제 등)에 피해를 발생시킨다. 가뭄이 지속되면 인간 사회 뿐만 아니라 동·식물이 서식하고 있는 생태계에도 영향을 미치게 된다. 우리나라에서도 2000년대 이후 주기적으로 발생한 가뭄으로 인해 가뭄 현상을 모니터링하고 예측, 전망하기 위한 다양한 연구가 진행되고 있으나 아직까지 환경생태가뭄에 대한 연구는 미흡한 실정이다. 본 연구에서는 가뭄으로 인해 환경생태계에 미치는 영향 중 수생태계에 초점을 맞춰 진행하였으며, 수생태계에 서식하는 동·식물 중 어류만을 대상으로 하였다. 생태가뭄을 빠르고 쉽게 예측하기 위해 Ecological Nomograph를 개발하여 가뭄에 따른 수생태계에 미치는 영향을 분석하고자 하였다. 본 연구에서 나온 결과를 바탕으로 환경가뭄을 감시하고 대응하기 위한 분석 방법으로 활용할 수 있을 것으로 판단된다.

• 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.

• Journal of Wetlands Research
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• v.25 no.1
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• pp.64-73
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• 2023

Before 2022, there was a lot of confusion in the process of planning and implementing the projects for ecological restoration of the stream due to dualization the principal agent of stream management. Because the Ministry of Environment took charge of the project in 2022, securing the health of aquatic ecosystem of stream became an essential factor in the project. Therefore, in this study, the streams that require the project for ecological restoration was selected in Han River estuary, where it is essential to secure the health of the stream aquatic ecosystem as blackish water zone and Ramsar wetland are located. Physical, chemical, spatial/humanistic, health of aquatic ecosystems evaluation indexes were calculated based on the detailed facts and figures of the project for ecological restoration of the stream in the beginning. Ranking, re-scaling, z-score, and t-score normalization methods were applied to the calculated evaluation index, and the values were compared and analyzed. After that, the entropy weight method was applied to each evaluation index. Through this process, the streams(Mokgamcheon, Anyangcheon etc.) that require the project for ecological restoration were selected for the purpose of securing the health of the aquatic ecosystem in Han River estuary. The result of this study can be used as basic research data in the process of selecting the priority determination of the projects for ecological restoration of the stream.

• River and Culture
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• v.5 no.4
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• pp.97-106
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• 2009

• Korean Journal of Environmental Biology
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• v.35 no.4
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• pp.533-544
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• 2017

In this study, the fauna of freshwater fish were investigated from March until October of 2016 in 24 independent streams in the Jeonnam and Jeonbuk provinces, which were flowing into the Yellow Sea. The health of the aquatic ecosystem in those streams was assessed through the biological and abiological character index (BAc index). During the surveyed period, a total of 4,127 individuals were collected; they belonged to 59 species of 44 genera in 18 families. The most dominant species identified was Zacco platypus, and 12 species were endemic species of Korea, including Rhodeus uyekii. The BAc index indicated a statistically significant correlation (p<0.01 or 0.05). The stage distribution of the aquatic ecosystem health assessment showed the highest rating of 41.7% at the "Fair" stage. The "Good" and "Poor" stages accounted for 20.8% while the "Excellent" stage took up 16.7%. It has been confirmed that the aquatic ecosystem health of independent streams is influenced more by the abiological character index as a consequence of geographical characteristics and artificial/natural limiting factors, than by the biological character index.

• Journal of Environmental Impact Assessment
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• v.30 no.6
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• pp.355-360
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• 2021

As the domestic water management policy shifted from concentration-oriented water management to load management-centered Total Maximum Daily Load (TMDL), water quality and aquatic ecosystems brought changed. However, it was difficult to determine whether the water quality and the health of the aquatic ecosystem improved after the implementation of the TMDL due to changes in pollutant sources and discharge fluctuations ect, so the effect was analyzed using a log-linear model and biological indicators (Benthic Macroinvertebrates). As a result, BOD and T-P concentrations in the Jinwi River Watershed were reduced by 30% and 35%, showed the effect of improving water quality, however the benthic macroinvertebrates index (BMI) downgraded from grade D to grade E. Therefore, efforts to cultivate ecologicalrivers are necessary to upgrade the health of the aquatic ecosystem in the river watershed.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.467-467
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• 2022

1990년대 후반부터 시작된 자연형 하천정비 사업은 기존의 수질보전정책 외에도 하천생태계에 대한 관심이 부각되는 계기로 작용하고 있다. 이 중 환경생태유량은 기존의 하천유지유량보다 확대된 개념으로 수생태계 건강성 회복을 위한 중요한 요소이다. 본 연구에서는 도시하천 수생태계 건강성 회복방안 마련을 위한 기초자료 마련을 위해 부산의 대표적인 도시하천인 온천천과 학장천을 대상으로 환경생태유량을 산정하였다. 환경생태유량은 하천의 물리적 특성 및 어류·유량을 조사하는 하천현장조사, 서식지적합도지수 산정의 과정을 통해 산정된다. 온천천과 학장천에서 각각 3개의 대표지점을 선정하고 각 지점별로 2회의 현장조사를 통해 각 지점에서의 수심, 유속, 하상재료, 어류 조성을 조사하였다. 조사결과를 바탕으로 붕어와 참갈겨니를 대표어종으로 선정하고 Instream Flow and Aquatic Systems Group(IFASG, 1986)에서 제시한 방법을 이용하여 서식지적합도지수를 산정한 후, 미국지질조사국의 물리적서식지모의시스템(PHABSIM)을 이용하여 하천별, 어종별 환경생태유량을 산정하였다. 온천천의 경우, 붕어와 참갈겨니 모두 약 0.7~0.8m³/s에서 가용서식지면적이 가장 크게 산정되어 일 60,000~70,000m³ 가량의 환경생태유량 공급이 필요한 것으로 나타났다. 학장천의 경우, 붕어는 약 0.6~0.7m³/s, 참갈겨니는 약 0.3~0.4m³/s에서 가용서식지면적이 가장 크게 산정되어, 각각 일 50,000~60,000m³, 25,000~35,000m³ 가량의 환경생태유량이 필요한 것으로 나타났다. 본 연구로부터 산정된 환경생태유량을 금번 관측유량 및 현재의 하천유지용수 공급계획량과 비교해보면 온천천에서는 일 15,000m³ 이상, 학장천에서는 어종에 따라 일 7,000m³ 이상의 추가유량 확보가 필요한 것을 알 수 있었다. 특히 학장천의 경우, 어종에 따른 환경생태유량의 차이가 크게 나타나 하천 구간별 유량조사를 통해 어종별 주요 서식지 구간 설정 및 관리가 필요할 것으로 판단된다.

• Korean Journal of Ecology and Environment
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• v.55 no.1
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• pp.60-75
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• 2022

The Bayesian algorithm model is a model algorithm that calculates probabilities based on input data and is mainly used for complex disasters, water quality management, the ecological structure between living things or living-non-living factors. In this study, we analyzed the main factors affected Korean Estuary Trophic Diatom Index (KETDI) change based on the Bayesian network analysis using the diatom community and physicochemical factors in the domestic estuarine aquatic ecosystem. For Bayesian analysis, estuarine diatom habitat data and estuarine aquatic diatom health (2008~2019) data were used. Data were classified into habitat, physical, chemical, and biological factors. Each data was input to the Bayesian network model (GeNIE model) and performed estuary aquatic network analysis along with the nationwide and each coast. From 2008 to 2019, a total of 625 taxa of diatoms were identified, consisting of 2 orders, 5 suborders, 18 families, 141 genera, 595 species, 29 varieties, and 1 species. Nitzschia inconspicua had the highest cumulative cell density, followed by Nitzschia palea, Pseudostaurosira elliptica and Achnanthidium minutissimum. As a result of analyzing the ecological network of diatom health assessment in the estuary ecosystem using the Bayesian network model, the biological factor was the most sensitive factor influencing the health assessment score was. In contrast, the habitat and physicochemical factors had relatively low sensitivity. The most sensitive taxa of diatoms to the assessment of estuarine aquatic health were Nitzschia inconspicua, N. fonticola, Achnanthes convergens, and Pseudostaurosira elliptica. In addition, the ratio of industrial area and cattle shed near the habitat was sensitively linked to the health assessment. The major taxa sensitive to diatom health evaluation differed according to coast. Bayesian network analysis was useful to identify major variables including diatom taxa affecting aquatic health even in complex ecological structures such as estuary ecosystems. In addition, it is possible to identify the restoration target accurately when restoring the consequently damaged estuary aquatic ecosystem.

• Journal of the Korean Association of Geographic Information Studies
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• v.18 no.2
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• pp.174-189
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• 2015

The objective of this study was to reconstruct spatial information using the results of the investigation and evaluation of the health of the living organisms, habitat, and water quality at the investigation points for the aquatic ecosystem health of the Nakdong River basin, to support the rational decision making of the aquatic ecosystem preservation and restoration policies of the Nakdong River basin using spatial analysis techniques, and to present efficient management methods. To analyze the aquatic ecosystem health of the Nakdong River basin, punctiform data were constructed based on the position information of each point with the aquatic ecosystem health investigation and evaluation results of 250 investigation sections. To apply the spatial analysis technique, the data need to be reconstructed into areal data. For this purpose, spatial influence and trends were analyzed using the Kriging interpolation(ArcGIS 10.1, Geostatistical Analysis), and were reconstructed into areal data. To analyze the spatial distribution characteristics of the Nakdong River basin health based on these analytical results, hotspot(Getis-Ord Gi, $G^*_i$), LISA(Local Indicator of Spatial Association), and standard deviational ellipse analyses were used. The hotspot analysis results showed that the hotspot basins of the biotic indices(TDI, BMI, FAI) were the Andong Dam upstream, Wangpicheon, and the Imha Dam basin, and that the health grades of their biotic indices were good. The coldspot basins were Nakdong River Namhae, the Nakdong River mouth, and the Suyeong River basin. The LISA analysis results showed that the exceptional areas were Gahwacheon, the Hapcheon Dam, and the Yeong River upstream basin. These areas had high bio-health indices, but their surrounding basins were low and required management for aquatic ecosystem health. The hotspot basins of the physicochemical factor(BOD) were the Nakdong River downstream basin, Suyeong River, Hoeya River, and the Nakdong River Namhae basin, whereas the coldspot basins were the upstream basins of the Nakdong River tributaries, including Andong Dam, Imha Dam, and Yeong River. The hotspots of the habitat and riverside environment factor(HRI) were different from the hotspots and coldspots of each factor in the LISA analysis results. In general, the habitat and riverside environment of the Nakdong River mainstream and tributaries, including the Nakdong river upstream, Andong Dam, Imha Dam, and the Hapcheon Dam basin, had good health. The coldspot basins of the habitat and riverside environment also showed low health indices of the biotic indices and physicochemical factors, thus requiring management of the habitat and riverside environment. As a result of the time-series analysis with a standard deviation ellipsoid, the areas with good aquatic ecosystem health of the organisms, habitat, and riverside environment showed a tendency to move northward, and the BOD results showed different directions and concentrations by the year of investigation. These aquatic ecosystem health analysis results can provide not only the health management information for each investigation spot but also information for managing the aquatic ecosystem in the catchment unit for the working research staff as well as for the water environment researchers in the future, based on spatial information.