• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.2
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• pp.113-125
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• 2011

In this study, recent trends of the annual precipitation, the annual maximum precipitation of different durations and the rain days over several thresholds(i.e. 0, 10, 20, 40, 60 and 80 mm/day) according to the different local features were analyzed using daily precipitation data of 59 weather stations between 1973 and 2009. To analyze the variability according to the regional characteristics, 59 weather stations were classified by elevations, latitudes, longitudes, river basins, inland or shore(east sea, south sea, west sea) area and the level of urbanization. Results demonstrated that overall trend of variables increases except rain day. Results according to the regional characteristics showed that the increase trend becomes stronger with elevation increase. The increase trend of Han river basin is largest and that of Youngsan river basin is smallest. Also the increase trend becomes stronger with latitude increase and that of East coast is larger than that of South coast since it may be caused by the regional difference of elevation. The increase trend of urban area is larger than that of rural area. Overall trend showed that increase trend becomes stronger with elevation and latitude increase.

• Journal of the Korean GEO-environmental Society
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• v.14 no.9
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• pp.49-56
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• 2013

Looking at the changes in the earthquake of 33 years of South Korea, earthquake in the magnitude of 3.0 or stronger have been conducted about nine times a year on average, and the epicenter of the earthquake is moving towards the inland from the coast. As the possibility of earthquakes increase, it is time to require utilization of underground space integrated information for earthquake disaster prevention. But, now the data related to the characterization of the ground and geology in the areas weak against earthquakes is insufficient, so we need to collect new geology and the ground survey data on nationwide scale and have to establish earthquake disaster prevention plans through the joint use of the existing underground space information. In this study, we determined the scope of construction of underground space DB information that is needed for earthquake disaster prevention, presented the construction plan of DB static and dynamic information of underground space. It also suggested the utilization of underground space scheme information for built earthquake disaster prevention. The underground space information for earthquake disaster prevention that was built through determining the scope and constructing, planning the utilization of underground space information is supposed to used as DB of the integrated management system of underground space and steep slopes information for steep slopes and earthquake prevention by Emergency Management Agency.

• Journal of Navigation and Port Research
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• v.29 no.6 s.102
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• pp.537-545
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• 2005

Traditionally Jeju island has a mild oceanic climate throughout the year and famous as worldwide resort area bemuse of its pure natural environment and dramatic coastal scenery. But unpredicted coastal erosion problem, mused by variation of environmental conditions from construction of coastal structure and renovation of the existing ports, has raised its head above the water, and is becoming serious these days just like other coastal area in Korea. The phenomena happen here along the seaside of southern part of the island show that severe changes in coastal line from erosion and even witnessed the coastal cliff failure. In advanced countries, coastal engineers and researchers have studied deeply about this kind of problem for a long time. However, as it is not sot active in Korea and lack of research data, there exists difficulties on building protection methods and thoughtless constructions might make it more complicated and fatal to the coastal environment. In this study, we investigated some case studies of other countries and intended to induce and propose some integral protection methods for coastline erosion, considering environmentally sound and water friendly way of development such as artificial reef, floating breakwater, and double cellblock breakwater. Finally, we made analysis on the proposed methods with numerical model test and evaluation on the feasibility of each method.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.11-19
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• 2005

Traditionally Jeju island has a mild oceanic climate throughout the year and famous as worldwide resort area bacause of its pure natural environment and dramatic coastal scenery. But unpredicted coastal erosion problem, caused by variation of environmental conditions from construction of coastal structure and renovation of the existing ports, has raised its head above the water, and is becoming serious these days just like other coastal area in Korea. The phenomena happen here along the seaside of southern part of the island show that severe changes in coastal line from erosion and even witnessed the coastal cliff failure. In advanced countries, coastal engineers and researchers have studied deeply about this kind of problem for a long time. However, as it is not sot active in Korea and lack of research data, there exists difficulties on building protection methods and thoughtless constructions might make it more complicated and fatal to the coastal environment. In this study, we investigated some case studies of other countries and intended to induce and propose some integral protection methods for coastline erosion, considering environmentally sound and water friendly way of developement such as artificial reef, floating breakwater, and double cellblock breakwater. Finally, we made analysis on the proposed methods with numerical model test and evaluation on the feasibility of each method.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.343-343
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• 2022

강우의 유출은 하늘에서 발생한 강우가 다양한 유역을 거쳐 하천 및 해안 등으로 방류되는 일련의 과정을 의미한다. 강우의 유출과정에서 좀 더 효율적인 유량처리를 위하여 대부분의 도시 유역에는 우수관망이 설치되어 있다. 우수관망은 일정 빈도 이하의 강우량 방재를 목적으로 설계하며, 해당 강우량을 초과하는 경우 침수피해가 발생한다. 우수관망의 목표 강우를 초과하는 경우를 위하여 우수 저류지, 펌프장 및 LID(Low Impact Development) 시설물 설치 등 다양한 노력이 지속되어 왔으며, 이를 더욱 효율적으로 관리하기 위한 연구가 지속되고 있다. 본 연구에서는 강우 발생유역을 격자로 분할하여 우수의 흐름을 파악하여 효율적인 저류지 및 LID 시설물의 설치 위치를 지정하고자 한다. 분석지역은 경상남도 창원시 마산합포구 인근이며, ArcGIS 10.8을 이용하여 해당 지역의 지형을 3D로 구현하였으며 EPA-SWMM 5.1을 이용하여 침수분석을 진행하였다. 또한, 구성된 TIN(Triangulated Irregular Network)를 10m × 10m 크기의 격자로 분할하여 지표고에 따른 유량의 흐름 및 중첩을 판단하였다. 분할된 격자들 중 유량의 중첩 정도가 가장 높으며 침수피해 정도가 높은 지역을 대상으로 종류 및 크기를 고려한 최적의 비용과 효율을 갖는 저류지 및 LID 시설물 설치 위치를 결정하였다. 우수관망 시스템, LID 시설물, 우수 저류지 각각의 시선에서 접근한 기존의 연구와 달리 다양하고 포괄적인 방재시설물 설치를 통해 더욱 효율적이고 경제적인 우수 방재 시스템 구현에 도움이 될 것으로 기대된다. 우수관망 시스템, LID 시설물, 우수 저류지 각각의 시선에서 접근한 기존의 연구와 달리 다양하고 포괄적인 방재시설물 설치를 통해 더욱 효율적이고 경제적인 우수 방재 시스템 구현에 도움이 될 것으로 기대된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.264-268
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• 2011

급속한 도시화 및 이상강우의 발생은 우수 량을 증가시켜 하류부의 천변주변과 저지대에 대한 침수위험을 증대시키므로 풍수해 예방을 위해 각 시 도 지자체에서는 이러한 지역을 방재지역으로 지정하여 방재대책을 수립하고 있다. 본 연구는 침수피해 위험이 높은 광영동 하광마을을 연구대상지역으로 선정하여 상습침수구역을 토대로 현장조사를 실시하였다. 현장조사에서 과거 1988년 6월 택지 조성이 준공도면과 현 주택가 침수지역 침하량 분석결과 택지조성 당시보다 대략 0.4m이상 침하가 발생한 것을 확인할 수 있었다. 또한 우수관거에 대해 침하조사를 실시하였으며, 그 결과 1998년 우수관거 정비 사업을 실시하여 현재 관거침하 및 관거유실은 발생하지 않는 것으로 조사되었다. 그러나 현재 관가 실태는 우수발생시 약간의 토사유입으로 인해 부분적으로 퇴적된 구간이 조사되었으나, 일반적인 모래 질이며 퇴적깊이는 5~15cm정도이고 이는 강우발생시 우수 관거의 일반적인 토사 퇴적 침식 작용의 현상으로 판단되었다. 외수침수는 해안도로 지반침하와 조성당시의 조위에 의한 계획 고는 적용되었으나 하천 계획홍수위의 미적용으로 인해 강우발생시 조위 상승과 하천유출과의 관계에 있어 상습침수지역의 천변 해안도로로 외수유입이 발생 하는 것으로 분석되었다. 본 연구에서는 과거 침수실적을 바탕으로 기상조건 및 조위조건 등을 고려하여 HEC-HMS모형을 적용하여 9개의 소유역으로 분할된 유역에서 홍수유출량을 분석하였으며, 외수위 조건을 SWMM모형에 적용하여 우수관거 검토를 실시하였다. 그 결과 대상구역 조위 상승으로 우수관거의 내수배제가 되지 않는 것을 확인할 수 있었다. 이러한 분석들로 외수유입 방지대책으로 조위영향 및 하천 계획홍수위를 고려하여 20년, 100년 빈도별 외수위를 산정하고 방지대책으로 도로 숭상 및 파라펫 설치방안을 검토하였다. 내수침수 방지대책으로 저류조+배수펌프+게이트펌프 또는 관로신설+게이트펌프를 설치, 복합방식 (지하저류조+승수로(도로 또는 산지)+게이트펌프장)설치, 도수터널계획 방안을 제시하여 상류지역에 발생하는 유출량을 유출부로 직접 배출하거나 침수영향이 없는 타 지역으로 연계 방류하여 총 유출량을 저감시키는 방안을 제시하였다. 이와 같은 여러 방안을 제시함으로써 관련 지자체에서는 보다 효과적인 침수방지 대책계획에 활용될 수 있을 것으로 판단된다.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.759-762
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• 2008

A wastewater treatment plant located in coastal areas should be built considering the discharge of rainwater and treated water into the sea. The current Hagik Wastewater Treatment Plant in Incheon City was designed in the surface discharge method, which refers to discharging treated water directly into the sea. This method may cause hydrodynamic issues in a wastewater treatment plant because seawater enters an outfall riser when the level of discharged water is lower than the tidal level on a shore with high tidal range. In this study, a method for installing a weir in the discharge manhole was proposed in order to prevent seawater from entering the outfall riser of a wastewater treatment plant. Its feasibility was reviewed by calculating the hydrodynamic that had occurred due to the installation of the weir. As a result, seawater did not enter in the discharge manhole. Thus, even if the coast of Incheon City reaches the highest tidal level, treated water will be able to be properly discharged.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.33 no.3
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• pp.131-138
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• 2021

The armor blocks are used to protect the body of the structure and dissipate wave energies, so it is crucial to evaluate the stability of the armor unit. The stability of armor blocks has been mainly evaluated through empirical coefficients called the stability coefficient obtained from hydraulic model experiments. In this study, a new type of single-layered armor block called K-Block was proposed, and a new experimental method based on the pull-out force was proposed to evaluate the stability of the armor unit, including the interlocking effects. The pull-out force test proposed in this study directly measures the force required to separate the armor unit from the armored layer on the slope by applying a tensile force in the vertical and horizontal directions to the installed armor unit. The proposed experimental method confirmed that the interlocking effects of the armor block could be quantitatively evaluated, and the high stability of the K-Block was verified.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.6
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• pp.373-380
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• 2012

The sandy beach along the east coast of Korea offers beautiful scenery with high-quality sand for leisure, and is also famous for the white-sand and pine-tree which is an important scenic resource. Furthermore, the sandy beach helps to maintain natural environment of the costal area and functionates as a disaster prevention system against high waves. There are two major value evaluation methods, Travel Cost Method and Contingent Valuation Method, to assess the value of coastal sandy beach. Contingent Valuation Method is considered to be more appropriate for simultaneous evaluation on the usefulness and the uselessness of the beach. But in order to apply Contingent Valuation Method to coastal sandy beach evaluation, close examination and investigation on the potential bias, such as on questionnaires, surveys and replies, are required. In this study, the characteristic of primary amenity of sandy beach users is investigated, in prior to evaluating the usefulness and the uselessness of the beach measured by contingent valuation method. The characteristic of amenity on major sandy beaches on the east coast of Korea is studied and compared by diverse value evaluation methods.

• Journal of Korean Society of Forest Science
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• v.104 no.3
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• pp.411-420
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• 2015

This study examined methods for stand density control by using shape ratio (tree height/DBH) and its application for effective management of Pinus thunbergii coastal disaster prevention forests. We analyzed the present conditions (height, DBH, and density) of P. thunbergii coastal disaster prevention forests at 123 study sites on Jeju Island and west, south, and east coasts of South Korea and compared them with results from previous studies. The average shape ratio for P. thunbergii showed positive correlations with stand density and was significantly higher on the west coast (66.32) than on the south (49.57) and east (48.19) coasts and Jeju Island (48.29). Stands with shape ratio higher than 70 accounted for 50% of the total study sites on the west coast, indicating a decrease in their disaster prevention function compared to that of other previous studies. The stand density in most coastal areas, except the east coast, was significantly higher than the standards recommended by the Korea Forest Service and the Forestry and Forest Products Research Institute of Japan, indicating the need for stand density control. According to the growth estimation equation for P. thunbergii in the coastal area of South Korea, density control is required for young stands less than 14 years old, which show drastic increase in the shape ratio, to conserve their disaster prevention function. Particularly, the first thinning of P. thunbergii forests should be implemented before the stand age of 8 years that a shape ratio exceeds 70. For disaster-prone young stands (${\leq}20cm$ DBH) of P. thunbergii, the stand density was higher in the standard of Japan considering shape ratio than in that of Korea aiming timber production. Hence, the standard guidelines employed in Japan, which assign higher importance to disaster prevention function based on field surveys, can be applied effectively for controlling the stand density of P. thunbergii coastal forests in South Korea, to improve their disaster prevention function.