• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.169-169
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• 2020

According to the IPCC analysis, severe climate changes are projected to occur in Korea as the temperature is expected to rise by 3.2 ℃, the precipitation by 15.6% and the sea level by 27cm by 2050. It is predicted that the occurrence of abnormal climate phenomena - especially those such as increase of concentrated precipitation and extreme heat in the summer season and severe drought in the winter season - that have happened in Korea in the past 30 years (1981-2010) will continuously be intensified and accelerated. As a result, the impact on and vulnerability of the water management sector is expected to be exacerbated. This research aims to predict the climate change impacts on streamflow of Daecheong Lake area of Geum River in South Korea during the summer and winter seasons, which show extreme meteorological events, and ultimately develop an integrated policy model in response. We projected and compared the streamflow changes of Daecheong Lake area of Geum River in South Korea in the near future period (2020-2040) and the far future period (2041-2060) with the reference period (1991-2010) using the HEC-HMS model. The data from a global climate model HadGEM2-AO, which is the fully-coupled atmosphere-ocean version of the Hadley Centre Global Environment Model 2, and RCP scenarios (RCP4.5 and RCP8.5) were used as inputs for the HEC-HMS model to identify the river basins where cases of extreme flooding or drought are likely to occur in the near and far future. The projections were made for the summer season (July-September) and the winter season(November-January) in order to reflect the summer monsoon and the dry winter. The results are anticipated to be used by policy makers for preparation of adaptation plans to secure water resources in the nation.

• Journal of Ecology and Environment
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• v.36 no.1
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• pp.89-94
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• 2013

Diatoms have become an integral part of the UK's freshwater monitoring strategy over the past two decades, mostly in response to increasingly stringent European Union (EU) legislation. The use of diatoms is based on strong correlations between diatom assemblages and environmental variables, and from knowledge of the "expected" (= "reference") state of each river. The nationwide overview of the ecological health of rivers this gives allows those stretches of rivers which fail to meet EU criteria to be identified. This, in turn, allows appropriate remediation measures to be planned. Because diatom assemblages vary in space and time, even within a single water body, effective use of diatoms requires a consistent approach in order to minimise uncertainty. This includes the use of methods which comply with European Standards, a training and accreditation scheme for analysts, and a suite of quality assurance methods. Those aspects of uncertainty that cannot be readily controlled have been quantified and all estimates of ecological status are accompanied by the appropriate "confidence of class" and "risk of misclassification". This, in turn, helps planners prioritise those locations which are most likely to benefit from remediation.

• International Journal of Contents
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• v.7 no.1
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• pp.45-51
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• 2011

To protect water pollution and scarcity in lake and river, water quality monitoring applications have become important tools to understand the change of aquatic ecosystem. KLEON (Korean Lake Ecological Observatory Network) is designed to manage and share the ecological observations. The various kinds of water quality and phytoplankton observations are collected from the selected observatories such as seven lakes/rivers/wetlands. To deeply understand the collected observations with weather, KLEON also manages the observatory information such as lake, dam, floodgate, and weather. The accumulated observation and analyzed results are used to improve the water quality index of the observatories and encourage the ecologists' cooperation.

• Korean Journal of Ecology and Environment
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• v.38 no.2 s.112
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• pp.237-248
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• 2005

To determine the content of hazard microcystin (MC) in Han River system and Ecological Ponds in Seoul City and Kyunggi district, a most toxic derivative, microcystin-LR (MCLR) of 15 samples of 7 ponds, 4 rivers and 4 reservoirs during low precipitation and cold season in 2003 were analyzed by ELISA method. With the change of water temperature ($0.4\;{\sim}\;21.9^{\circ}C$), cyanobacteria including Microcystis aeruginosa dominated the cold phytoplankton community in small ecological ponds such as Kyungbokgung Kyunghyaeru (KBP), Seokchon reservoir (SCR), Yangsoori Ryukgakji (YSS), having the long residence time. Contents of MCLR (the detection limit; $0.05\;{\mu}g\;L^{-1}$) were high in cyanobacteria-rich sites, especially, Microcystis aeruginosa. Total MCLR, cell extracted type plus dissolved type, were $1.39\;{\mu}g\;L^{-1}$ in KBP, $0.55\;{\mu}g\;L^{-1}$ in SCR and $0.59\;{\mu}g\;L^{-1}$ in YSS, in the first sampling having a high temperature (>$20^{\circ}C$), while some detected only in YSS during the cold season. As expected, the MCLR content was correlated with Microcystis aeruginosa (r = 0.526 for cell extracted type, r = 0.433 for dissolved type). Therefore, low concentration of MCLR detected in small ponds and Han river system in Seoul metropolitan city and Kyunggi district, maybe hardly affect human recreation activity, especially the drinking water supply.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09b
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• pp.985-986
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• 2005

• Korean Journal of Ecology and Environment
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• v.38 no.spc
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• pp.54-57
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• 2005

It is important to assess the change of water environment in the present and past. In this study, present-day water quality standards are applied to the expressions in literary works to reconstruct the historical water environment including the quality. As the result, the historical reconstruction of water quality has been made distribution of water quality from 1905 to 1935 for the Sumida River in Tokyo.

• Journal of Ecology and Environment
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• v.33 no.3
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• pp.237-244
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• 2010

In this study, we evaluated the distribution, habitat characteristics, and diet of two Korean freshwater turtle species (Chinemys reevesii, Pelodiscus sinensis) and an invasive turtle species (Trachemys scripta elegans) in the area surrounding the Seomjin River and the Nam River. We surveyed basking turtles in multiple locations along a 48-km stretch of the Seomjin River and in 99 reservoirs distributed along the Seomjin and Nam rivers from June to September, 2009. We observed 8 and 6 red-eared turtles in 3 reservoirs and at 3 sites in the Seomjin River, respectively, and 33 Reeve's turtles in 9 reservoirs. There were also 28 and 16 mud turtles detected at 15 sites along the Seomjin River and in 8 reservoirs, respectively. Among the 14 biotic and abiotic habitat characteristics that might influence the abundance of freshwater turtles in reservoirs, only the distance between a reservoir and the nearest residential areas was correlated negatively with abundance. With regard to the diet, all Reeve's and red-eared turtles investigated were determined to forage on water snails. Some turtles also foraged on vegetation and aquatic invertebrates. Additionally, we found fish in the stomach of one of the Reeve's turtles, and dragonflies in the stomachs of two red-eared turtles.

• The Korean Journal of Ecology
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• v.23 no.4
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• pp.299-307
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• 2000

To understand the mechanism of phytoplankton succession in the Nakdong River, the resource availability (silica) and grazing effect on the phytoplankton community were investigated in an enclosure experiment at Mulgum in March 1995. In all enclosures, Stephanodiscus hantzchii was dominant during the first week. Two weeks later, the diatom community in the A (river water only) and B (filtered river water) enclosures was shifted to colonial green algae (Actinastrum sp., Pediastrum spp. and Scenedesmus spp.) and nanoplankton (2~3 ${\mu}$m of diameter) due to the silica depletion. In the C (silica addition in river water, 3 mg 1$^{-1}$ week$^{-1}$) and D (silica addition in filtered water) enclosures, Fragilaria crotonensis and Synedra acus increased as the silica addition was continued. The percentage of small phytoplankton (size, 10~13 ${\mu}$m) in the filtered enclosures (B and D) was much higher than that of A and C enclosures. A laboratory bottle experiment conducted in the fall of 1994 also showed similar results. Therefore, it is concluded that silica and zooplankton are important regulators in phytoplankton succession during the diatom blooming season in the Nakdong River.

• Journal of Korean Society on Water Environment
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• v.23 no.4
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• pp.535-542
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• 2007

The Geumho river watershed located in the middle of the Nakdong river has been threatened by high population growth and urbanization. Of concern specifically is the potential impact of future developments in the watershed on the reduction of base flow and the consequent risk of degradation of ecological habitats in Geumho river. Anticipated increase in imperviousness, on the other hand, is expected to elevate flood risk and the associated environmental damage. A watershed hydrology based modeling study is initiated in this study to assist in planning for sustainable future development in the Geumho river watershed. The Soil and Water Assessment Tool (SWAT) is selected to model the impact of urbanization in the Geumho river watershed on the hydrologic response thereof. The modeling results show that in general the likelihood that the watershed will experience high and low stream flows will increase in view of the urbanization so far achieved.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.446-446
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• 2018

The urban rivers have unique hydraulic characteristics between natural rivers and artificial canals. These hydraulic characteristics determine the characteristics of urban rivers with small environmental capacity and fragile ecosystems. With the development and utilization of natural resources, the pollutants that have been produced enter the river through different channels, which seriously damages the urban river ecosystem. Therefore, how to restore contaminated water to a normal state and reproduce a natural, self-regulating ecosystem is one of the most concerned issues in recently. Eco-hydraulics is a cross-disciplinary subject of hydraulics biology and ecology. It is closely related to the protection of rivers, wetlands, and ecological self-repair. In this study, The basic principle of eco-hydraulics is concisely described and its approaches to protection and rehabilitation of river are introduced. The conception of establishing gardenesque eco-pond for urban use is suggested. The strategies including changing the hydrodynamic features of rivers, adjusting the breeds and species and constructing the gardenesque eco-pond for improving the exist ing urban rivers are proposed. It provides scientific information and guidance for the restoration of rivers and wetlands by studying the close relationship between river hydraulic characteristics, currents, and rivers and ecosystems.