• Journal of Wetlands Research
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• v.16 no.4
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• pp.477-486
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• 2014

Integrated sand control including sediment discharge from hinterland rivers is necessary to maintain coastal sand resources over a long term. In this regard, the following subjects should be considered; efficient ways to transfer discharged sand from a river to the neighboring coast, measures to improve storage efficiency of the discharged sand at the river delta and/or river terrace, measures to prevent the sand resources from being discharged into the deep sea during flooding. From the 1997 to January 2004, the jetty of 156 m length was constructed the Heoya-river mouth to protect the blockade of river mouth. Several tests were carried out to investigate the characteristics of sediment transport and morphological change due to the construction of the jetty at the Heoya-river mouth. Firstly, The sand discharge from Heoya river is quantified by one-dimensional numerical analysis assuming the mixed sand of three different particle diameters. Also the numerical mode system, which predicts the sea bed changes obtained from the Bailard's energy model(1981), was combined with the wave, wave-induced currents and sediment transport models. Then, to understand the changes to the blockade of the river mouth, several aerial photographs were compared, which showed that the changes were significant.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.1
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• pp.87-98
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• 2012

A river boundary is defined as the intersection between a main stream of a river and the land. Mapping of the river boundary is important for the protection of the properties in river areas, the prevention of flooding and the monitoring of the topographic changes in river areas. However, the utilization of the ground surveying technologies is not efficient for the mapping of the river boundary due to the irregular surfaces of river zones and the dynamic changes of water level of a river stream. Recently, the spatial information data sets such as the airborne LiDAR and aerial images are widely used for coastal mapping due to the acquisition of the topographic information without human accessibility. Due to these advantages, this research proposes a semi-automatic method for mapping of the river boundary using the spatial information data set such as the airborne LiDAR and the aerial photographs. Multiple image processing technologies such as the image segmentation algorithm and the edge detection algorithm are applied for the generation of the 3D river boundary using the aerial photographs and airborne topographic LiDAR data. Check points determined by the experienced expert are used for the measurement of the horizontal and vertical accuracy of the generated 3D river boundary. Statistical results show that the generated river boundary has a high accuracy in horizontal and vertical direction.

• Journal of Wetlands Research
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• v.25 no.2
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• pp.83-90
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• 2023

Due to climate change, the occurrence of abnormal rainfall is increasing, and the intensity and scale of damage caused by heavy rain are increasing every year. In addition, as the frequency of heavy rains becomes more frequent, heavy rains often occur continuously, resulting in large flooding damage that has never been seen before in urban area. When near rivers and coastal areas are impermeable areas, the maximum flow increases rapidly as the rainfall intensity increases, so a comprehensive flood risk evaluation is needed considering the characteristics of the basin. In this study, the flood inundation risk evaluation was analyzed by giving scores on evaluation factors as a measure to prevent inundation in subway stations. Through the flood inundation risk evaluation process considering the comprehensive evaluation index, the flood risk evaluation was conducted on five urban railway stations with a large amount of traffic and floating population that had been inundated in the past. It is judged that by comprehensively analyzing this and establishing a inundation risk grade (grade 1 to 4) to establish a flood measure suitable for the risk grade.

• Journal of The Geomorphological Association of Korea
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• v.18 no.4
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• pp.1-15
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• 2011

This work is to review the granite landforms studies by Korean geographers. It is verified that geomorphlogical characteristics of granite present landscapes characterized by 1) in case of mountains, are difficultly or irregularly weathered, so as to develop rocky forms such as domes, cliffs, and tors ; 2) in case of stream valley that is inter-massif lowland, low relief hills and flood plains with alluvium. All these facts owe to the difference of weathering mode granite properties. The granite hills and alluvial plains of southwestern coastal parts in Korean peninsula is low undulatory and large owing not only to the existence of highly weathered granitic regolith, but also to frequent flooding. Cultivated brownish field, orchard, meadow and forest are located at granite hills. On the other hand paddy rice field at granite alluvial plains. Korean peninsula have endured erodible geomorphlogical processes since Miocene when warping it up. Therefore many intermontane basins are located on the weathered granite areas which are surrounded by mountains composed of much less Precambrian gneiss complex. In fact, intermontane basin is mainly linear fault-line valley. The landforms of the intermontane basins are characterized by gentle piedmont slopes, alluvial fans, fluvial terraces and alluvial plains.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.5
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• pp.953-964
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• 2023

Climate change is undeniably the most urgent challenge that humanity faces today. Despite this, the level of public awareness and understanding of climate change remains insufficient, indicating a need for more proactive education and the development of supportive content. In particular, it is crucial to intensify climate change education during elementary and secondary schooling when values and ethical consciousness begin to form. However, there is a significant lack of age-appropriate, experiential educational content. To address this, our study has developed an innovative 3D simulator, enabling learners to indirectly experience the effects of climate change, specifically sea-level rise. This simulator considers not only sea-level rise caused by climate change but also storm surges, which is a design based on the analysis of long-term wave observation big data. To make the simulator accessible and engaging for students, we utilized the 'Unity' game engine. We further propose using this simulator as a part of a comprehensive educational program on climate change.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.4
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• pp.257-268
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• 2012

The EFDC model with find grid resolution system connecting the Gyeong-Gi bay and Han River estuary was constructed to study on spring-neap variability of net volume transport at each channel of the Han River estuary. The simulation time of numerical model is 124 days from May to August, 2009 with freshwater discharge at Han, Imjin and Yeseong River. The calibration and verification of model results was confirmed using harmonic components of water level and tidal current. The net volume transport was calculated during 30 days with normal freshwater conditions at Seokmo channel and Yeomha channel around Ganghwado. The ebbing net volume transport of 44% and 56% is drained into Gyeong-Gi bay through Yeomha and Seokmo channel, respectively. The ebbing net volume transport nearby Seodo at Yeomha channel convergence flooding net volume transport at Incheon harbor, and drain (westward direction) through channel of tidal flat between Ganghwado and Yeongjongdo to the Gyeong-Gi bay. The averaged net volume transport during 4 tidal cycles was compared to variation of spring-neap periods of the Yeomha channel. The convergence position is moved up- and down-ward according to spring-neap variability. The movement of the convergence zone is appeared because 1) increasing of discharged rate tidal flat channel between Ganghwado and Yeongjongdo at the spring period, 2) The growth of barotropic forcing with downward direction at the spring tide, and 3) The strength of the baroclinic pressure gradient is greater than spring with mixing processes.