• Journal of Environmental Science International
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• v.29 no.6
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• pp.579-603
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• 2020

In order to provide fundamental information about the floristic composition of the area along with an assessment of the environmental impact, a floristic study of the vascular plants in the Tamjin River estuary in Gangjin-gun was conducted for a total of nine days, in the period from June 2014 to September 2014. We found that the vascular plants in this region comprised 424 taxa belong to 102 families, 281 genera, 390 species, 5 subspecies, 26 varieties, and 3 forma. Five taxa of Korean endemic plants including Weigela subsessilis (Nakai) L.H.Bailey, Lespedeza maximowiczii var. tricolor (Nakai) Nakai, and Clematis trichotoma Nakai were collected. Two least concern (LC) taxa of rare plants (as designated by the Korea Forest Service) were collected: Hydrocharis dubia (Blume) Backer and Platycladus orientalis (L.) Franco. Ten the floristic regional indicator taxa from the third to the fifth grade were identified: two taxa belonged to grade IV, and eight taxa belonged to grade III. Twenty-four taxa of salt-tolerant plants, including Artemisia fukudo Makino, Carex rugulosa Kuk., and Suaeda glauca (Bunge) Bunge, as well as 44 taxa of aquatic plants, including Najas marina L., Nuphar oguraensis Miki, and Nymphoides indica (L.) Kuntze, were investigated in this region. Fifty-nine taxa of naturalized plants were recorded, among which the following six taxa were plants that caused ecosystem disturbance: Ambrosia artemisiifolia L., Humulus scandens (Lour.) Merr., Lactuca scariola L., Rumex acetosella L., Solidago altissima L., and Symphyotrichum pilosum (Willd.) G.L.Nesom.

• Journal of Wetlands Research
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• v.11 no.2
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• pp.17-28
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• 2009

The investigated Varcular plants in Youngsan River Streams of Downtown in Gwangju Metropolitan City consist of total 437 taxa: 2 forms, 49 varieties, 386 species, 265 genera, 91 families. Among 53 taxa of hydrophytes, emerged plants were 16taxa, floating-leaved plants were 10taxa, suvmerged plants were 10taxa, and free-floating plants were 3taxa and swamp plants were 14taxa. Based on the list of Rare and Endangered plants, 5taxa were recorded such as Hydrocharis dubia, Euryale Ferox, Penthorum chinense, Prunus yedoensis, Nymphoides coreana. And Korean endemic Plants were appeared as 5taxa: Poa annua, Forsythia koreana, Paulownia coreana, Galium koreanum, Aster koraiensis. From the specific plant species sorted by classes, class I has 10taxa, class II has 2taxa, class III has 2taxa, class IV has 3taxa, class V has 5taxa. Naturalized plant were listed as 62taxa: 15families, 44genera, 59species, 3varieties, and naturalization index was 14.19%. The ecosystem disturbance plants assigned by the Ministry of Environment, 3taxa were recorded: Paspalum distichum, Ambrosia artemisiifolia var. elatior, Solanum carilinense.

• Journal of Korean Society on Water Environment
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• v.32 no.2
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• pp.205-215
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• 2016

In order to improve water quality in the Paldang Lake, a riparian vegetation belt, treatment wetland, and artificial floating island were designed for introduction in the upland field, the estuary of tributaries, and the section of water facing mountainous land, respectively. We synthesized vegetation information collected from a reference river and found that herbaceous, shrubby, and tree vegetation zones tended to be dominated by Phragmites japonica, Phalaris arundinacea, etc.; Salix gracilistyla, S. integra, etc.; and S. koreensis, S. subfragilis, and Morus alba, respectively. In our plan, the herbaceous vegetation zone, which is established on floodplains with a high frequency of disturbance, will be left in its natural state. A shrubby vegetation zone will be created by imitating the species composition of the reference river in the ecotone between floodplain and embankment. A tree vegetation zone will be created by imitating species composition on the embankment slope. In the treatment wetland, we plan to create emerged and softwood plant zones by imitating the species composition of the Zizania latifolia community, the Typha orientalis community, the P. communis community, the S. integra community, and the S. koreensis community. The floating island will be created by restoring Z. latifolia and T. orientalis for water purification purposes.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.518-518
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• 2017

Since Korea lunched the 4 Major River Restoration Project, the hydrological regime which is one of the major determinants for riverine condition have actually changed. It also important to connect hydrological characteristics and vegetation. The objective of this study is to investigate the influence of hydrological regime on riverine vegetations and its successions. Iunundated exceedance probability concept are suggested to estimate rehabilitated and succession on the Binae island in the Han River. The result shows that the P=0.08 or lower IEPs should have the disturbance for vegetations, or should be changed to a hydrophilic ones. Therefore, agency which is mainly responsible for river and flow may have to be changed and considered flow regulation standard to conserve riverine zone.

• Journal of Ecology and Environment
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• v.43 no.3
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• pp.314-319
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• 2019

Background: The dramatic worldwide decline in the butterfly species Leptalina unicolor (Bremer & Grey) is largely the result of continuous habitat decline and disturbance by humans. The discovery of a narrow habitat in riverside wetlands utilized by L. unicolor raises the hope that such restricted key areas could be rather easily protected. Results: Here, we explain the environmental variables and habitat characteristics that primarily influence the distribution of L. unicolor discovered at the riverside areas along the Geum River. L. unicolor larvae were found at 9 of 13 study sites, and their abundance was strongly positively correlated with plant biomass. Our investigation showed that among four plant species (Miscanthus sinensis, Spodiopogon cotulifer, Setaria viridis, and Imperata cylindrica), L. unicolor larvae were the most abundant on the leaves of M. sinensis. They were not abundant on the leaves of S. cotulifer, S. viridis, or I. cylindrica. Interestingly, the number of L. unicolor larvae was positively correlated with the coverage area ($m^2$) of M. sinensis (F = 41.7, $r^2=0.74$, P < 0.0001). Conclusions: It appears that water (e.g., wetlands, ponds, and watersides) located along the riverside areas along the Geum River is important for the constant maintenance and conservation of L. unicolor. This is based on the habitat characteristics (water preference) of M. sinensis, which is used as a habitat by L. unicolor larvae. However, the waterside is dry and terrestrialization is in progress owing to the decreased water levels and water supply caused by an opened weir. Hereafter, this area will likely require management to secure a stable habitat for L. unicolor.

• Korean Journal of Environment and Ecology
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• v.37 no.1
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• pp.13-34
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• 2023

Many ecologists try to understand plant communities and societies' changing processes by interacting with environmental factors. Plant communities formed in the sidings of streams, which are more dynamic than forest vegetation, are closely related to the disturbance regime of streams. U. pumila, which forms communities at the edges of streams, is distributed over the central and northern regions of the Korean Peninsula. In this study, we intended to explain the regeneration of U. pumila communities in the upstream region of the Namhangang River. Heights from the stream surface to the mid-high points of communities increased when the age class of U. pumila communities increased. On the other hand, the height of U. pumila tended to increase and decrease as the age class increased. The richness (S), evenness (J'), diversity (H'), and maximum diversity (H'max) also showed a tendency to increase and then decrease as the age class increased. On the other hand, the number of stems per individual and density (D) decreased as the age class increased. Seedlings of U. pumila failed to regenerate in the communities at the intermediate or higher stage of the age class. Regeneration of seedlings occurred in the spaces formed by the flooding, which occurred periodically in streams. After regeneration, U. pumila communities grew like a single organism. On the other hand, the plant species consisting of U. pumila communities exhibited a process in which the S and H' increased and then decreased as they developed. In other words, we determined that the changes in the species compositions were associated with changes in each species' environment and community. A space where seeds can regenerate seedlings should be provided for the regeneration of U. pumila communities. In the mid/upstream region of the Namhangang River, where the present study focused, newly formed communities were rare because the space required to regenerate U. pumila ceased to exist. Accordingly, we suggest securing an appropriate space for the regeneration of seedlings to maintain the U. pumila communities in the upstream region of the Namhangang River.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.2127-2131
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• 2009

본 연구에서는 하천복원 및 적응관리 기술개발의 일환으로 하천의 물리적 구조를 평가하고 향후 하천복원사업 시행시 복원의 방향을 결정하는데 적용할 수 있는 기법 개발에 앞서 기준이 될 수 있는 대조하천으로서 남강 2개 구간, 섬진강 2개 구간, 내성천 2개 구간을 선정하고 현장조사 및 평가를 수행하여 비교, 분석하였다. 분석결과 하상경사의 변화가 다양하고 하상재료의 입경변화가 많은 하천이 하상경사가 완만하고 하상재료 입경변화가 작은 하천보다 하도의 물리적 구조가 다양하여 생태환경이 좋은 것으로 평가되었다.

• Proceedings of the Korean Geotechical Society Conference
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• 2007.09a
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• pp.383-395
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• 2007

As a state-of-the-art paper related to consolidation settlement, the 31th Terzaghi lecture was briefly described. Case histories that are compared between predicted and measured settlements in the Nakdong River deltaic plane were introduced to show the true picture of our technology. Structures and other features of clays in this country were needed to understand, which are closely related to sample disturbance and also consolidation properties. In order to improve the settlement-related technology, some problems that we have faced and their alternatives were considered.

• Journal of Electrical Engineering and Technology
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• v.6 no.5
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• pp.585-594
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• 2011

This paper presents the use of sequential outage checkers to identify the potential cascading processes that might lead to large blackouts. In order to analyze cascading outages caused by a combination of thermal overloads, low voltages, and under-frequencies following an initial disturbance, sequential outage checkers are proposed. The proposed sequential outage checkers are verified using the AEP 9-bus system, New England 39-bus system, and IEEE 118-bus system.

• Ecology and Resilient Infrastructure
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• v.3 no.3
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• pp.207-211
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• 2016

This study focuses on the categorization of the phenomenon of vegetative recruitment on riparian channels, so called, the phenomenon from "white river" to "green river", and proposes for the corresponding research direction. According to the literature review and research outputs obtained from the authors' previous research performed in Korea within a limited scope, the necessary and sufficient conditions for the recruitment and retrogression of riparian vegetation may be the mechanical disturbance (riverbed tractive stress), soil moisture (groundwater level, topography, composition of riverbed material, precipitation etc.), period of submergence, extreme weather, and nutrient inflow. In this study, two categories, one for the reduction in spring flood due to the change in spring precipitation pattern in unregulated rivers and the other for the increase in nutrient inflow into streams, both of which were partially proved, have been added in the categorization of the vegetative recruitment and retrogression on the riparian channels. In order to scientifically investigate further the phenomenon of the riparian vegetative recruitment and retrogression and develop the working riparian vegetative models, it is necessary to conduct a systematic nationwide survey on the "white to green" rivers, establishment of the categorization of the vegetation recruitment and retrogression based on the proof of those hypotheses and detailed categorization, development of the working mathematical models for the dynamic riparian vegetative recruitment and retrogression, and adaptive management for the river changes.