• Economic and Environmental Geology
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• v.14 no.1
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• pp.35-49
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• 1981

The studied area is largely occupied by thick piles of the late Cretaceous volcanic rocks of the Yucheon group, which is northeastern border part of the vast volcanic region in the Yucheon basin. The Yucheon group overlies the Geoncheonri Formation and is intruded by granitic and dioritic stocks and dykes. The group can be devided into two parts; the lower is Jusasan andesitic rocks which was called as Jusasan Porphyrite Formation by Tadeiwa in 1929, and the upper is Unmunsa rhyolitic rocks. The volcanic pile consists mainly of various tuffs such as tuff breccia, lapilli tuff, coarse to fine tuff and tuffaceous sediments, and interlayered flows, which range from basaltic andesite to rhyolite in their lithology. The results of petrochemical and volcanostratigraphic studies on the Jusasan andesitic socks suggest that the volcanic rocks were derived from two cyclic evolutions of magmatic fractionation. Systematic study of 5226 joints from the area reveals two sets of steep joints striking $N20^{\circ}-40^{\circ}E$ and $N40^{\circ}-70^{\circ}W$, are dominant and coincide with the fault pattern developed in the area. Three defferent maximum principal stress axes were recognized from conjugate shear joints, which are trending east-west, north-northwest, and north-northeast.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.1
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• pp.23-32
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• 2018

This study starts from the architectural and urban interest to integrate the daily life and behavior of residents in the city of Seongnam and to sustain the community. A fixed abode is something that can not be separated from the place and should be approached from a comprehensive perspective reflecting the physical and social conditions of the region. Although residential neighborhoods have a residential walking range, which has a steep slope, it has been formed in the suburbs of the residential area where commercial facilities are activated organically. The humanities and social organizations of the residents are integrated with the physical space and act as constituent factors of major cities. This is an attempt to suggest improvement and activation of existing cities based on their daily lives, rather than destroying cities and creating new ones. Also, it is proposed to 'Neighborhood Street' as an indicator of a uniform urban renewal plan for existing urban regeneration projects. Based on the definition of the city of living in the city, the center of the city will be located in the center of the city, and it will be the center of the city's bustling streets.

• Journal of Forest and Environmental Science
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• v.39 no.2
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• pp.65-72
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• 2023

The endangered species of Cyathea spinulosa (tree ferns) are among the least concerned ferns of Nepal that bring threats to them and their habitat. A way to reduce such threats is by maintaining a database of species' whereabouts and generating a scientific understanding the habitat preferences. This will eventually help in the formulation of conservation plans for the species. This research aimed to characterize the suitable habitat of C. spinulosa by enumerating the location of species in the Panchase Forests of central Nepal. The statistical index method was applied to relate the occurrence locations of species with various environmental factors for the development of indices. The suitable habitat of C. spinulosa (more and most suitable categories) covered 119 km² and accounted for 43% of the total area studied. 74.4% of occurrence locations of C. spinulosa were recorded from these habitats. The habitat characteristics suitable for C. spinulosa were: proximity to streams (high moisture), land covered by forested area (shady area), mid-elevations of hills about 1,000 m to 2,000 m (sub-tropical climate), slope gradient of 20° to 40° (steep slopes), and northern to eastern aspects. These habitat characteristics could be considered for in-situ protection of tree ferns and designating the conservation plots.

• Journal of the Korean association of regional geographers
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• v.16 no.2
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• pp.100-109
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• 2010

The study examines two different sites to analyze the difference of stream channel profile between two different landuse areas on Neponset River, Boston, MA. Landuse represents the current status of land in terms of human, agricultural or forest, industry and environmental activity types. According to the previous research, forest and urban area are significantly distinguished in chemical characteristic, shape and bed load of the stream. On the chosen sites, I look at the cross-section profile, the slope, velocity, and roughness of the channels. With the data collected at the site I determined the value for the channel bed material using Manning's equation, and compared with the result of HEC-RAS model with the cross-section profile data I measured. In the forest area, water surface elevation and bed material obtained through Manning's equation are very close to HEC-RAS model result. However, in the resident area the Manning's 'n' value calculated much higher than assumption which was considered as cobble whose 'n' value is 0.03-0.06. The difference could be caused by unusual steep elevation on the site and the dam present down further. With the steep elevation upside of dam, there is critical-depth condition occurs. The difference of Manning's 'n' value reflects the difference of depth. HEC-RAS model was run to analyze the difference and the result shows that depth is 0.36 much less than 0.688 what I computed when the Manning's n value is 0.03(cobble) instead of the result of the study (0.13292). Beside, dam is a major source of fragmentation and degradation of stream, and it's possibly inferred upstream water levels are increased and stream velocity is decreased. This study is meaningful for introduction of HEC-RAS in geography field to analyze different sites with channel bed material, and it is going to be used more actively to manage river and river side.

• Journal of the Korean Geographical Society
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• v.42 no.1 s.118
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• pp.27-40
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• 2007

The streams evolve to diverse forms influenced by various factors such as rock resistance tectonic process, sediments and discharge. This study focuses on erosion resistance of rocks among these factors. The morphology of plane and longitudinal profile has been analysed in upper and lower reach of 6 streams using GIS; Yeoryong-cheon, Heungjeong-cheon, Duhak-cheon, Daehwa-cheon, Namcheon-cheon, Guryong-cheon, having distinct bedrock types between upper and lower reach. While the basins of granite have gentle slope, low concavity and wide valley area, those of gneiss form steep slope, high concavity and narrow valley area. However, the basins of sedimentary rock make steep slope and high relief in main channel, the other features show some differences in each stream. Among the various morphological features, the indices on slope and concavity of main channel, drainage density, ratio of valley area, average slope and average relief of the basin which have clear differences between rocks in upper and lower reach are calculated to interpret the erosion resistance of rocks in upper and lower reach. As a result, the upper reaches composed of gneiss have the highest erosion resistance, sedimentary rocks in upper and lower reaches show moderate resistance, and granite reaches generally have the lowest resistance except the upper reaches bordered by sedimentary rock.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.23 no.5
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• pp.59-71
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• 2020

Using high-resolution stereoscopic aerial images (in 2008, 2012 and 2016), we conducted to analyze the spatial characteristics affecting evergreen coniferous die-off in the northwestern ridge (major distribution area such as Abies nephrolepis), Seoraksan National Park. The detected number of dead trees at evergreen coniferous forest (5.24㎢) was 1,223 in 2008, was 2,585 in 2012 and was 3,239 in 2016. The number of cumulated dead trees was 7,047 in 2016. In recent years, the number of dead trees increased relatively in the northwest ridge, Seoraksan National Park. Among the analysed spatial factor (altitude, aspect, slope, solar radiation and topographic wetness index), the number of dead trees was increased in the conditions with high altitude, steep slope and dry soil moisture. A spatial distribution of dead tree was divided into 2 groups largely (high altitude with high solar radiation, low altitude with steep slope). In conclusion, the dead trees of evergreen coniferous were concentrated at spatial distribution characteristics causing dryness in the northwestern ridge, Seoraksan National Park.

• Journal of Korea Water Resources Association
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• v.36 no.3 s.134
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• pp.455-464
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• 2003

In this paper, the experiments with installing a rainfall storage tank in the sub-surface were conducted and the reduction rates of the total runoff volume were investigated. The analysis were conducted based upon the variations of the rainfall intensity, surface coverage and surface slope. The reduction rate of the runoff volume was varied from 42.3% to 52.9% with the soil in the bank of the Seung Gi stream. In the experiments, the rainfall intensities were varied from 40mm/hr to 100mm/hr and the results indicate that the direct runoff reduction can be obtained with the installation of the rainfall storage tank in the sub-surface. The variation of the stored volume in the tank is very large in the mild slope but very small in the steep slope with over 3% slope. With this results, the reduction of the direct runoff volume for the longtime flood is expected with the installation of the rainfall storage tank in the region haying the steep slope such as the mountain area.

• Korean Journal of Plant Resources
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• v.25 no.1
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• pp.89-95
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• 2012

This study was conducted to provide basic information for conservation and restoration through investigation of vegetation structure on the Euchresta japonica Hook. f. ex Regel (Korean endangered species) in Mt. Halla in Jeju Island. Very few individuals were discontinuously distributed and restricted at 220 m above sea level, very steep slope ($40-50^{\circ}$), rocky area of north face of Donneko Valley. For investigation of environmental condition, we established $10{\times}20\;m$ quadrat and one control $20{\times}20\;m$ quadrat in the habitats. Thirty three species were found at habitat under 10-16 m Castanopsis sieboldii tree layer (70-80%). The principal causes of threat which were investigated in this study are competition among companies, very steep slopes, artificial management of valley. For restoration and conservation of habitats, it is needed to suitable plans.

• Journal of Korea Water Resources Association
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• v.56 no.10
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• pp.691-695
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• 2023

In this study, two sections with different topographic gradients were in the Hyogyo-ri area, the hydraulic gradients were calculated for each section, and the hydraulic gradient fluctuations according to the topographic gradient and rainfall were analyzed. The variations of the hydraulic gradient within the research site was large in the section with steep topographic gradient and small in the section with gradual topographic gradient. The influence of the variation in hydraulic gradient due to rainfall was high in the section with steep topographic gradient, and low in the section with gradual topographic gradient. Through this study, it was found that the hydraulic gradient fluctuations in unconfined aquifer showed as a complex effect of topographic gradient and rainfall.

• Journal of Environmental Health Sciences
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• v.28 no.5
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• pp.13-21
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• 2002

This study analyzed the characteristic of basic river structure, a flood level, the tree planting recommendation and syn thetic design, in order to establish a basic plan for preparing a natural practical area of environmental ecosystem at Bukchun and its surroundings. It was also investigated based on the opinion of citizens, geographical condition and the equipment/utilization examination of Bukchun which were included ecological circumstances, and thus provided a composite item for managing the natural river. This study also considered the development of the river in terms of culture, environment and ecology concept. The results were summarized as followed. Bukchun showed that the speed of a funning fluid is very fast on a period of flood. but very slow in a period of water shortage about 0.02 m/s. To prevent the speed change of a running fluid by a steep slope in a riverbed, there established Dongchun sluice gates under a bridge, including three sluice gates under a bridge, but there occurred extremely a riverbed erosion and corrosion section. The result of comparison between real flood degree and prediction flood data, there should perform a countermeasure the riverbed structure regulation of this area. Also, it was needed an exhaustive flood management in summer. According to the Bukchun and Hyungsangang riverbed investigation, there were needed preparation for natural/practical area and ecology Park development in the future. This study was investigated tree Planting/flower/blossom around the Bukchun and its surroundings. It was recommended willow, Italian poplar, bamboos and cherry blossoms in the Hyungsangang and Bukchun. There exist together historical space, environment space iud have enough possibility both natural learning space and civil rest space. And, it is possible to compose ecology natural learning and experimental area.