• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.6
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• pp.30-36
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• 2002

A 0.19 hectare natural-type wetland for stream water treatment demonstration was constructed and planted with cattails from April 2001 to May 2001. Part of its bottom surfaces adjacent to levees have a variety of slope of 1 : 4~1 : 15. Two small open water areas were installed, in which emergent plants could not grow. Removal of nutrients from stream waters was a major objective of the wetland. Waters of Sinyang Stream flowing into Kohung Estuarine Lake were pumped and funneled into the wetland. The lake had been formed by a salt marsh reclamation project and was located southern coastal region of Korean Peninsula. Volumes and water quality of inflow and outflow were analyzed from July 2001 through December 2001. Inflow and outflow averaged $120.4m^3/day$ and $112.1m^3/day$, respectively. Hydraulic retention time was about 3.1 days. Average total phosphorous concentration of influent and effluent was $0.19mg/{\ell}$ and $0.075mg/{\ell}$, respectively. Total phosphorous loading rate of inflow and outflow averaged $12.05mg\;m^{-2}\;day^{-1}$ and $4.44mg\;m^{-2}\;day^{-1}$, respectively. Average total phosphorous removal rate in the wetland was $7.61mg\;m^{-2}\;day^{-1}$. Seasonal changes of phosphorous retention rates were observed. The wetland acted as effective phosphorous sinks in the initial stage of the constructed wetland.

• Journal of Environmental Impact Assessment
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• v.20 no.1
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• pp.1-11
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• 2011

This study was carried out to suggest the baseline data necessary for vegetation restoration at riverine wetland within stream corridor. We used the prevalence index for wetland assessment by applying the method of weighted averages with index values based on five hydrophyte indicator status as defined by estimated probability occurred in wetland. We selected near nature and urbanized reach of Gap and Yanghwa streams as experimental site. Although two sites have some different disturbance and characteristics of watershed, they showed that similarity of vegetation community including three dominant species - Salix koreensis, Phragmites communis, Miscanthus sacchariflorus - was very high. But in case of Yanghwa stream, various kinds of emergent plants along wetted condition were distinctly occurred, resulted from difference of hydrological regime and substrate, etc. Degree of naturalness of vegetation at the sampled areas indicated that near nature area of Gap stream and all area of Yanghwa stream were fitted as riverine wetland, while urbanized area of Gap stream has changed into upland condition. In conclusion assessment system using prevalence index would be considered an effective method for evaluating of natural states of riverine wetland, but further integrated consideration of physical, hydrological, and biological factors of stream process, and also with considering the difference between those qualitative data of vegetation community.

• Journal of Wetlands Research
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• v.10 no.3
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• pp.133-139
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• 2008

Urban streams are degrading functional role due to development and pollution. This study chose the representative stream of Do-rim and identified flora and fauna. The ecological survey aimed at identifying indicator of urban streams for measuring urban healthiness and we discussed the possibility of wetland conservation area. From the beginning of Dorim stream to An-yang mixture we were successfully identified 113 species of plants, 9 of mammals, 23 of birds, 4 of amphibians, 2 of reptiles and 2 of fish species. Terrestrial insects were 71 species. The wetland vegetation is quite various and we suggested 4 different vegetation zones (aquatic vegetation zone, emergent zone, riparian-meadow zone, riparian-woodland zone) depending on distance from the flowing water stream and vegetation characteristics for urban stream management.

• Korean Journal of Environment and Ecology
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• v.11 no.2
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• pp.210-213
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• 1997

This study for development of close-to nature revetment techniques is conducted to rehabilitate disturbed stream ecosystem. For this objective, the experimental reach as on-site dimonstrated research was set up in Hakyoul, the Yangjaech'on from Oct. 1995 to Nov. 1996. Special emphasis on the developing process of the design of revetments was given to geomorphic character of 3 types of low flow channel bank: point bar, attack point and shallow bay. Each revetment was developed with the consideration on revegetation of emergent plants. And designed techniques were applied to the experimental reach, and were evaluated with monitoring for 1 year. As a result of the process, the experiment suggested ecological alternatives to enhance technical feasibility and to replace the conventional river-work.

• Journal of the Korean Institute of Intelligent Systems
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• v.10 no.4
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• pp.315-323
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• 2000

In this paper, we propose a method of constructing neural networks using bio-inpired emergent and evolutionary concepts. This method is algorithm that is based on the characteristics of the biological DNA and growth of plants, Here is, we propose a constructing method to make a DNA coding method for production rule of L-system. L-system is based on so-called the parallel rewriting nechanism. The DNA coding method has no limitation in expressing the produlation the rule of L-system. Evolutionary algotithms motivated by Darwinaian natural selection are population based searching methods and the high performance of which is highly dependent on the representation of solution space. In order to verify the effectiveness of our scheme, we apply it one step ahead prediction of Mackey-Glass time series, Sunspot data and KOSPI data.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.557-562
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• 2005

The field scale experiment was performed to examine the effect of plant coverage on the constructed wetland performance and recommend the optimum development and management of macrophyte communities. Four sets(each set of 0.88ha) of wetland (0.8ha) and pond(0.08ha) systems were used. Water flowing into the Seokmoon estuarine reservoir from the Dangjin stream was pumped into wetland system. Water depth was maintained at $0.3{\sim}0.5m$ and hydraulic retention time was managed to about $2{\sim}5$ days; emergent plants were allowed to grow in the wetlands. After three growing seasons of the construction of wetlands, plant coverage was about 95%, even with no plantation, from bare soil surfaces at the initial stage. Dead vegetation affected nitrogen removal during winter because it is a source of organic carbon which is an essential parameter in denitrification. Biomass harvesting is not a realistic management option for most constructed wetland systems because it could only slightly increase the removal rate and provide a minor nitrogen removal pathway due to lack of organic carbon.

• Korean Journal of Environment and Ecology
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• v.34 no.6
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• pp.515-529
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• 2020

Constructed wetlands undergo biological and physical changes such as an increase in the proportion of arid plants due to the natural succession process after formation. It can adversely affect not only the purification function but also the habitat of species. As such, this study aims to identify environmental factors affecting biodiversity and propose management plans based on the monitoring results of physical environmental changes and the emergence of species in seven constructed wetlands selected based on the water depth and surrounding conditions among the lands purchased by the Nakdong River basin. We examined the environmental conditions and emergence of the Odonata, which is a wetland-dependent species, to predict the trend of changes in biodiversity and abundance. The results showed that the open water area decreased as the emergent plants spread to the deep water in 2015 compared to 2012 when they were initially restored to a depth of 0.2 to 1 m. While a total of 54 dragonfly species were observed, the habitat diversity, such as vegetation, water surface, and grassland, remained similar to the initial formation of the wetlands despite the expansion of the emergent plants. On the other hand, the number of Agrionidae species, which prefer areas with fewer aquatic plants, decreased between 2012 and 2015 due to the diminished water surface. The p-values of the differences in the number of species and population between wetlands by year were 2.568e-09 and 1.162e-08, respectively, indicating the statistically significant differences. The decrease in open water surface was found to have the greatest effect on the biodiversity and habitat density of dragonflies. The time-series survey of constructed wetlands confirmed that the spread of Phragmites communis, P. japonica, Typha orientalis, etc., caused a decrease in species diversity. It suggests that environmental management to maintain the open water surface area is necessary.

• Ecology and Resilient Infrastructure
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• v.2 no.3
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• pp.255-263
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• 2015

Biological invasion of alien plants is considered to be one of the most serious threats to biodiversity in riparian zones. The effects of two invasive alien plants, Sicyos angulatus and Paspalum distichum var. indutum, on the flora and community structure of the riparian vegetation were investigated at 22 sites at streams in Korea. Sicyos angulatus has invaded the central Korean Peninsula. This alien plant has caused problems to stream managers because of its aggressive vining growth. It had suppressed native vegetation such as trees, shrubs and tall grasses on bank slope and higher floodplains. Paspalum distichum var. indutum has become more widespread in the southern part of Korea. This invasive plant has shallow rhizomes and creeping, extensively branched stolons. It forms a dense mat over lotic or slowly-flowing water and threatens submerged and short emergent hydrophytes. In order to control the introduction and expansion of alien plants, limitation of artificial disturbances and appropriate alien plant management are needed in riparian areas.

• Korean Journal of Environmental Biology
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• v.17 no.4
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• pp.459-465
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• 1999

This work focused on the effects of the timing and the frequency of shoot cutting to maximize the productivity and the nutrient removal of three emergent macrophytes, Phragmites communis, Zizania latifolia and Typha angustifolia in natural wetlands. Shoot cutting significantly enhanced biomass production and resulted in more nitrogen and phosphorus removal from water in these three experimental species, compared to those of control. However, the frequency and the timing of shoot cutting, and the enhancement ratio were different among three species. For Phragmites stands, the highest productivity was 1.9 times of control in June treatment of the first year experiment, while 1.3 times in May treatment of the second year experiment. Zizania and Typha stands were both 1.2 times of control in August treatment and June and August treatment. Calculating the total annual removal rate of nitrogen and phosphorus based on the highest productivities among treatments, in Phragmites stands, 2.0 times of nitrogen and 1.8 times of phosphorus were removed in the first year, and both 1.4 times in the second year experiment. Likewise, for nitrogen and phosphorus; 2.4 and L.8 times in Zizania stands, and 1.8 and 1.9 times in Typha stands were removed. Overall, these results suggested that cutting treatment of shoots be effective. Thus, shoot cutting of two times during a growing season were recommended to maximize the effects: that is, in May or June, and October for Phragmites stands, and in August and October fur Zizania and Typha stands.

• Journal of Korea Water Resources Association
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• v.38 no.10 s.159
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• pp.871-883
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• 2005

This paper investigates the impacts of turbulent anisotropy on the mean flow and turbulence structures in vegetated open-channel flows. The Reynolds stress model, which is an anisotropic turbulence model, is used for the turbulence closure. Plain open-channel flows and vegetated flows with emergent and submerged plants are simulated. Computed profiles of the mean velocity and turbulence structures are compared with measured data available in the literature. Comparisons are also made with the predictions by the k-$\epsilon$ model and by the algebraic stress model. For plain open-channel flows and open-channel flows with emergent vegetation, the mean velocity and Reynolds stress profiles by isotropic and anisotropic turbulence models were hardly distinguished and they agreed well with measured data. This means that the mean flow and Reynolds stress is hardly affected by anisotropy of turbulence. However, anisotropy of turbulence due to the damping effect near the bottom and free surface is successfully simulated only by the Reynolds stress model. In open-channel flows with submerged vegetation, anisotropy of turbulence is strengthenednear the vegetation height. The Reynolds stress model predicts the mean velocity and turbulence intensity better than the algebraic stress model or the k-$\epsilon$ model. However, above the vegetation height, the k-$\epsilon$ model overestimates the mean velocity and underestimates turbulence intensity Sediment transport capacity of vegetated open-channel flows is also investigated by using the computed profiles. It is shown that the isotropic turbulence model underestimates seriously suspended load.