• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.2
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• pp.157-166
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• 2012

Most of the roads are paved with impermeable materials such as asphalt concrete and cement concrete, and in the event of heavy rainfall, rainwater directly flows into river through a drainage hole on the pavement surface. This large quantity of rainwater directly spilled into the river frequently leads to the flooding of urban streams, damaging lowlands and the lower reaches of a river. In recent years there has been a great deal of ongoing research concerning water permeability and drainage in pavements. Accordingly, in this research, a porous polymer concrete was developed for permeable pavement by using unsaturated polyester resin as a binder, recycled aggregate as coarse aggregate, fly ash and blast furnace slag as filler, and its physical and mechanical properties were investigated. Also, 3 types of permeable polymer block by optimum mix design were developed and rainfall runoff reduction effects by permeability pavement using permeable polymer block were analyzed based on hydraulic experimental model. The infiltration volume, infiltration ratio, runoff initial time and runoff volume in permeability pavement with permeable polymer block of $300{\times}300{\times}80$ mm were evaluated for 50, 100 and 200mm/hr rainfall intensity.

• Journal of Ecology and Environment
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• v.31 no.4
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• pp.277-290
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• 2008

In the past two decades Mikania micrantha Kunth, a climbing plant species originating from tropical America, has spread across Taiwan. It can now be found frequently in the lowlands and lower mountain areas up to 1,000 m a.s.l. in the centre and south of the island. Mikania micrantha is considered a problematic invasive alien plant species which is said to cause economical as well as environmental damage. This study investigated the ecological site characteristics of M. micrantha in Taiwan. 112 vegetation surveys were carried out in habitats where the alien plant was present. A comparison between sites with a high and a low abundance was carried out in order to assess which factors especially influence the extensive spread of the plant. Furthermore, the influence of disturbances was examined. Results showed that Mikania micrantha grows very dense in habitats which are characterized by good light conditions combined with vertical structures, such as trees. Results revealed that this invader occurs most frequently in agricultural fallows and wastelands, but it could hardly be found in the intensively managed plantations in the investigation area. Results provide great evidence that the plant is strongly influenced by disturbances, but only if impacts occur rarely.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.995-998
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• 2007

It is essential to establish some systematic counterplans to diminish such damages of large-scale tidal invasion on coastal lowlands considering the recent weather conditions of growing scale of typhoons. Therefore, the purpose of this research is to make the counterplans for prevention against disasters fulfilled effectively based on the data conducted by comparing and analyzing the accuracy between observation values and the results of estimating the greatest overflow area according to abnormal tidal levels centered on Masan area where there was the severest damage from tidal wave at that time.

• Journal of Environmental Science International
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• v.28 no.12
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• pp.1157-1169
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• 2019

We used numerical models to reliably analyze the groundwater flow and hydraulic conductivity on Jeju Island. To increase reliability, improvements were made to model application factors such as hydraulic watershed classification, groundwater recharge calculation by precipitation, hydraulic conduction calculation using the pilot point method, and expansion of the observed groundwater level. Analysis of groundwater flow showed that the model-calculated water level was similar to the observed value. However, the Seogwi and West Jeju watersheds showed large differences in groundwater level. These areas need to be analyzed by segmenting the distribution of the hydraulic conductivity. Analyzing the groundwater flow in a sub watershed showed that groundwater flow was similar to values from equipotential lines; therefore, the reliability of the analysis results could be improved. Estimation of hydraulic conductivity distribution according to the results of the groundwater flow simulation for all areas of Jeju Island showed hydraulic conductivity > 100 m/d in the coastal area and 1 - 45 m/d in the upstream area. Notably, hydraulic conductivity was 500 m/d or above in the lowlands of the eastern area, and it was relatively high in some northern and southern areas. Such characteristics were found to be related to distribution of the equipotential lines and type of groundwater occurrence.

• The Plant Pathology Journal
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• v.17 no.3
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• pp.154-158
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• 2001

A severe root rot of kiwifruit caused by a species of Phytophthora occurred in 1-to 5-year-old vines at the south coast region of Korea in 1997. Infected vines exhibited leaf chlorosis, scorch and defoliation, root and stem rot, and eventual death. The disease was relatively severe in poorly drained lowlands, of which 19 out of 23 fields were damaged by the disease. Meanwhile, only one among 58 upland fields was infected by the disease. Incidence of infected vines reached over 80% in heavily damaged fields and a species of Phytophthora was isolated from inner tissues of roots, stems, and rhizosphere soils of the plants. The causal pathogen was identified as P. drechsleri based on its mycological characteristics. Pathogenicity of the fungus was confirmed by artificial inoculation to seedlings of kiwifruit 'Hayward'. The pathogen was re-isolated from the inoculated plants showing symptoms similar to those observed in the fields. Root rot of kiwifruit caused by P. drechsleri has not been reported previously in Korea.

• Journal of Ecology and Environment
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• v.29 no.5
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• pp.445-452
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• 2006

The number of species and forest area has decreased as urbanization is progressed. The landscape degradation was examined by analyzing vegetation map, satellite image and characteristics of actual vegetation. The study was conducted in Mt. Baekja and its surroundings located on Gyeongsan city, southeastern Korea. As the result of landscape analysis, agricultural field was a characteristic attribute of the study area. Lowlands of this study area were occupied by agricultural field and various plantations. For 15 years from 1987 to 2002, forest area decreased from 2,072.9 ha to 1,853.2 ha, and shape index and fractal dimension of vegetation patches increased from 1.32 to 1.65 and from 1.05 to 1.09, respectively. Pinus densiflora Siebold & Zucco. community showed the highest species diversity, whereas Larix kaempferi (Lamb.) Carriere community showed the lowest species abundance. As forest management implications, monitoring of endangered plant species (Jeffersonia dubia (Maxim.) Benth. & Hook.f. ex Baker & S.Moore), and restoration of lowland forest from plantation to natural forest were discussed. Further, establishment of greenways utilizing existing streams, roadside, and public facilities were recommended.

• Korean Journal of Plant Taxonomy
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• v.40 no.3
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• pp.169-173
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• 2010

Sparganium fallax Graebn. (Sparganiaceae), a species previously unrecorded for the Korean flora, was collected in a broad-leaved, evergreen swamp in the lowlands of eastern Jeju Island. This species was known to be distributed south of Jeju Island including Japan, South China, Taiwan, India, Indonesia (Sumatra), Myanmar, and New Guinea. S. fallax differ from others of Sparganiaceae in Korea by having keeled leaves, 4-7 staminate heads, relatively wide separation between each pistillate head and usually sessile or lowest pedunculated pistillate heads. The somatic chromosome number was 2n = 2x = 30 and the size of chromosomes was very small (0.69 to $2.19{\mu}m$).

• Korean Journal of Plant Taxonomy
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• v.39 no.3
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• pp.233-236
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• 2009

The genus Triodanis Raf. ex Greene (Campanulaceae), which is native to America, is newly reported for Korea based on the discovery of T. perfoliata (L.) Nieuwl in the lowlands of Donneko, Seogwipo-si, Jeju-do. The common name 'Bi-neo-seu-geo-ul-sok' is given for the genus and 'Bi-neo-seu-do-ra-ji' for the species. The morphological characters of the genus and species, and illustrations of the species are provided along with photographs of its habitat.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.95-95
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• 2020

Urban flooding occurs in the form of internal-water inundation on roads and lowlands due to heavy rainfall. Unlike in the case of rivers, inundation in urban areas there is lacking in research on predicting and warning through measurement data. In order to analyze urban flood patterns and prevent damage, it is necessary to analyze flooding measurement data for various rainfalls. In this study, the pattern of urban flooding caused by rainfall was analyzed by utilizing the urban flooding measuring sensor, which is being test-run in the flood prone zone for urban flooding management. For analysis, 2019 rainfall data, surface water depth data, and water level data of a street inlet (storm water pipeline) were used. The analysis showed that the amount of rainfall that causes flooding in the target area was identified, and the timing of inundation varies depending on the rainfall pattern. The results of the analysis can be used as verification data for the urban inundation limit rainfall under development. In addition, by using rainfall intensity and rainfall patterns that affect the flooding, it can be used as data for establishing rainfall criteria of urban flooding and predicting that may occur in the future.

• Journal of Forest and Environmental Science
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• v.40 no.1
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• pp.53-63
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• 2024

Alnus japonica is indigenous to korea and usually grows in wet lowlands and damp regions in the mountains. Oregonin, is known as a representative compound of the diarylheptanoid mainly found in Alnus species and has been reported to have anti-inflammatory and antioxidant effects. In this experiment, we conducted a study on the presence of orogonin in the native Alnus japonica from the Baekdudaegan mountain range in Korea. We collected a total of 30 samples from Chuncheon, Yangyang, and Jeongseon and conducted experiments. In the HPLC analysis, we confirmed that oregonin was detected in all samples. After the quantitative analysis, samples with the highest content from each region were selected and LC-MS/MS experiments were performed. As a result, the same molecular weight as oregonin, 477.2 m/z, was confirmed in all samples.