• 한국지형학회지
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• 제25권3호
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• pp.71-87
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• 2018

As part of further study on Gwangseungri coastal deposits which occurred at 10 ~ 15m above sea level and was analyzed as palaeo-coastal flood-type sediments, six burial ages of six additional samples from the two cross sections (KST1 and, KST2) near to the points of the past study were estimated and the geochemical analysis was performed. Further investigation on the cross section KST1 revealed a reversal of the burial age at the bottom of the section which was identified as palaeo-flooding sediments and supposed to have been buried about 350 years ago. At the lower part of the KST1, the burial age of the sediment layer was estimated to be 3,800 years. The lower part of KST2 sediments was identified as sediments that was formed about 6,600 years ago and about 20,000 years ago. Considering the inclination of the sediment layers, the coastal flooding sedimentsreported to have formed 700 years ago in the previousstudy are located at the top and the KST1 section analyzed in thisstudy seemed to be connected to the lower part. The chemical analysis showed that the relationship between these layers was not continuous but had a discontinuous characteristic influenced by a specific event, and the chemical composition also showed a rapid change. If we judge these together, the lowest part of Gwangseungrisediment layerseemed to have formed during the last glacial period but it was hard to find its origins clearly. On top of this layer, a fine sediment layer containing gravels was also formed.Itseemed thatsedimentation did not occur continuously, but was affected by temporary events in such a way that after a sediment layer was formed, it stopped. Since then, a coastal flooding event occurred about 700 years ago, and part of flooded sediments accumulated in the rear slope. After that, when a flood layer including additional granular materials about 350 years ago was formed, sedimentation along the slope seemed to have occurred.

• 한국해안·해양공학회논문집
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• 제29권6호
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• pp.279-285
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• 2017

일반적으로 멱법칙과 대수함수 프로파일은 유속 연직 프로파일 모델로 많이 사용된다. 그러나 해역특성에 따라 모델별 매개변수의 값들이 상이하므로 실제 관측치를 통해 이들 값을 추정할 필요가 있다. 본 연구에서는 울돌목 해역에서 관측한 30분 평균 유속자료를 이용하여 창 낙조 시 멱법칙의 고도분포지수(n) 값과 대수함수 프로파일의 마찰속도($u^*$)와 조도길이($z_0$)를 추정하였다. 또한, 수심평균유속과 매개변수간의 상관관계를 분석하였으며, 관측치와의 오차분석을 수행하였다. 그 결과, power law의 고도분포지수(n)는 창조 시에는 평균 10.75, 낙조 시에는 평균 9.3의 고도분포지수 값을 가지는 것으로 나타났다. 한편, 대수함수 프로파일의 $u^*$는 창 낙조 시, 0.084 m/s와 0.105 m/s로 각각 추정되었으며, $z_0$는 0.004 m, 0.006 m로 각각 추정되었다.

• 환경정책연구
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• 제11권4호
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• pp.59-84
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• 2012

계획가들은 지자체가 기후변화로 심화되고 있는 홍수에 대해 더욱 관심을 가지고 적절한 홍수예방정책을 도시계획에 통합하고 반영한다면 홍수피해를 줄이는데 기여할 수 있을 것이라고 믿고 있다. 이러한 계획가들의 생각을 검증하기 위한 첫 번째 단계로 지자체 도시기본계획에 채택된 홍수예방정책들의 종류와 수준을 계획평가 방법론을 활용하여 평가하였다. 주요 홍수예방정책들로 구성된 프로토콜을 바탕으로 플로리다 53개 지자체 도시기본계획이 분석되었다. 본 연구의 분석결과 도시별로 도시기본계획에서 채택한 수해예방정책의 종류와 수준이 상당히 다양함을 보였다. 플로리다에서는 홍수터의 토지이용 규제, 습지개발허가제 등 토지이용규제를 활용한 홍수예방정책들이 폭넓은 동의를 얻어 활용되고 있는데 반해, 취약지에 대한 토지수용, 인센티브를 활용한 홍수예방정책들은 자주 채택되고 있지 않았다. 또한 해안가 도시들이 내륙도시보다는 도시계획을 통한 홍수예방에 훨씬 더 높은 관심을 보였다. 연구대상인 53개 계획의 평가점수는 평균 38.55로, 획득가능한 점수의 약 35.69%에 해당하여 여전히 지자체 차원에서 다양한 홍수예방정책이 수립되고 활용되고 있지 않으며 이러한 결과는 앞으로 더 많은 관심과 개선이 필요함을 의미한다. 본 연구에서 활용된 계획평가의 개념과 방법론은 기존계획의 수준을 평가하거나, 새로운 정책이나 계획을 준비하는데 유용한 틀을 제공하므로 우리나라에서도 다양한 환경, 재해 이슈에 적용할 수 있다.

• 한국산학기술학회논문지
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• 제15권4호
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• pp.2419-2427
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• 2014

본 논문에서는 제방축조 전후 하천기능의 변화를 추정하기 위하여 하천 고유의 수문 지형학적 공간을 정의하고, GIS를 이용하여 하천공간을 산정하는 방법을 제안하였다. 하천공간의 경계는 제방에 의한 홍수범람 차단효과를 무시한 100년 빈도의 잠재최대 홍수범람범위로부터 결정하였고, 토지이용이 불명한 저수로변 나지를 대상으로 사행대 경계를 설정하였다. 이를 위하여 1918년 토지이용 수치지도를 제작하였고, 동일한 범례로 2007년 환경부 토지피복도를 변환하여 제방 축조 전후 토지이용 변화를 분석하였다. 분석 결과, 제방 축조 후 만경강 하천공간 내 취락지구는 0.4% 증가하였고, 농경지는 11.6% 증가하였으며, 나지는 10. 0% 감소하여 기존 범람원이 토지의 생산성 측면에서 효율적으로 활용됨을 확인하였다. 현재의 하천구역 면적은 사행대 면적과 비슷하였으나, 상 하류 전 구간에서 면적이 감소한 것으로 나타나 생물서식처로서 하천 환경기능의 저하를 추정하였다.

• 한국해안·해양공학회논문집
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• 제21권6호
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• pp.453-461
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• 2009

새만금 방조제 건설 이후 새로운 갯벌 생성이 보고되고 있는 1호 방조제 앞 대항리 갯벌의 지형 변화에 대한 영상 관측을 수행하였다. 갯벌 지역은 이동상의 어려움과 밀/썰물에 따른 시간상의 제약으로 국지 혹은 소수 기선의 현장 관측만으로 제한되는 경우가 많다. 본 연구에서는 밀물시 조간대 갯벌에서 이동하는 수륙 경계선은 간조와 만조 정선 사이의 등고선을 나타낸다는 자연적인 원리를 이용하여 연속 촬영된 영상에서 관측된 수륙 경계선에 대한 실제 공간 좌표를 계산하고 이를 모두 통합함으로서 조간대 지형에 대한 3차원 지형정보를 획득하였다. 2005년 9월부터 2009년 9월까지 6차례의 영상 관측 결과를 분석한 결과 1호 방조제 외측 갯벌은 매년 평균 0.127 m 씩 퇴적된 것으로 나타났으며 공간적 및 시간적으로 다양한 변화를 보였다.

• 한국환경과학회지
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• 제22권3호
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• pp.291-301
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• 2013

Sediment from the upstream channel has been deposited near the Nakdong River Estuary Barrage (NREB) due to the mild slope and decreased velocity. The annual mechanical dredging to ensure the flood capacity has been performed to remove the deposited sediment. However, the dredging method is not considered as an effective countermeasure due to high cost and long time to operate. Therefore, many methods for sedimentation reduction have been proposed for NREB. Especially, the channel contraction method to mitigate sedimentation problem by changing the channel geometry from 2 km to 3 km upstream of NREB has been recently suggested as an effective countermeasure. However, there is the possibility that the channel contraction method induces flood level increase compared to original condition. Therefore, it is necessary to investigate quantitatively the flood level changes in the upstream and downstream section due to the channel contraction method for NREB. In this study, water level changes by 10% channel contraction of whole width has been evaluated using the HEC-RAS model and simulated with and without channel contraction for various flood discharge. As a result, water level in the section where the channel was contracted was decreased by 0.02 m and flood level at the upstream of channel contracted was increased up to 0.015 m for the 500-year flood.

• Ocean and Polar Research
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• 제30권4호
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• pp.379-399
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• 2008

Spatial-temporal variations in physiochemical water qualities (temperature, salinity, DO, SPM, POC and nutrients) of surface and bottom waters were investigated along the mid-western coastal area (Taean Peninsula to Gomso Bay) of Korea. Spatial distribution patterns of temperature and salinity were mostly controlled by the physical mixing process of freshwater from Geum River and/or Gyunggi Bay with nearby coastal water. A strong tidal front is formed off Taean Peninsula during spring and summer. Seasonal variations in nutrient concentrations, lower in spring and summer and higher in fall and winter, are primarily regulated by magnitude of phytoplankton occurrence rather than freshwater loadings into the bay. Based on seasonal and spatial variability of physicochemical parameters, water quality of the study area can be divided into four water masses; Gyunggi Bay-influenced Water Mass (GBWM), Geum River-influenced Water Mass (GRWM), Yellow Sea Bottom Cold Water Mass (YSBCWM) and Cheonsu Bay Water Mass (CBWM). Water quality of the GBWM (Taean Peninsula coastal area), which has relatively low salinity and high concentrations of nutrients, is strongly controlled by the Gyunggi Bay coastal water, which is under influence of the Han River freshwater. In this water mass, the mixed layer is always developed by strong tidal mixing. As a result, a tidal front is formed along the offshore boundary of the mixed layer. Such tidal fronts probably play an important role in the distribution of phytoplankton communities, SPM and nutrients. The GRWM, with low salinity and high nutrients, especially during the flood summer season, is closely related to physiochemical properties of the Geum River. During the flood season, nutrient-enriched Geum River water mass extends up to 60 km away from the river mouth, potentially causing serious environmental problems such as eutrophication and unusual and/or noxious algal blooms. Offshore (<$30{\sim}40m$ in water depth) of the study area, YSBCWM coupled with a strong thermocline can be identified in spring-summer periods, exhibiting abundant nutrients in association with low temperature and limited biological activity. During spring and summer, a tidal front is formed in a transition zone between the coastal water mass and bottom cold water mass in the Yellow Sea, resulting in intensified upwelling and thereby supplying abundant nutrients to the GBWM and GRWM. Such cold bottom water mass and tidal front formation seems to play an important role in controlling water quality and further regulating physical ecosystem processes along mid-western Korean coastal area.

• 한국측량학회지
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• 제24권3호
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• pp.299-309
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• 2006

최근 세계적인 기상이변으로 대규모의 자연재해가 발생되고 있으며, 도시지역의 인구 과밀화와 시설물의 대형화로 피해규모도 대형화되고 있다. 본 연구에서는 매미 태풍 시 침수피해가 크게 발생하였던 마산시 월영동지역에 대해 도시홍수량을 추정할 수 있는 SWMM모형을 이용하여 빈도강우와 해수위별 침수예상지를 추정하고 이것을 GIS데이터베이스와 연결하여 침수예상피해를 분석하였다. 그 결과, GIS자료를 이용하여 대상지역을 소유역으로 구분하고 홍수추정모형인 SWMM을 이용하여 침수위치와 침수심을 예측함으로서 빈도강우와 해수위 상승에 따른 침수예상지역을 정확하게 예측할 수 있었다. 또한 침수가 예상되는 지역에 대해 건물용도별로 침수위험도를 예측하거나 침수에 따른 대피계획수립에 이용할 수 있는 자료를 제공할 수 있었으며, 향 후 웹이나 무선통신기술 등과 연계된 재난관리체계구축에 대한 연구가 이뤄질 경우 활용성이 증대될 것으로 판단된다.

• 한국해양공학회지
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• 제23권2호
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• pp.37-46
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• 2009

Typhoon Rusa in 2002 was recorded as causing the biggest damage due to flood in our country. With the enormous damage to the land, the flood was totally discharged to the open sea. As a result, in the coastal area, the discharging of a river had a big influence in comparison to the scale of the coastal area, which suffered damaged due to the discharging of the river. As it cleared the land, the load was totally discharging into the sea, where it caused various problems due to its influence on the ecosystem. These included changes to the environment, like a difference in salinity and the inflow of a land load. Therefore, in this study, a Lagrangian particle tracking model was constructed using a flow model capable of solving the behavior of a river plume, supposing Sachon Bay. It is performed the research able to tendency-like valuation and reappearance about real event. The result was that the model was well approximated the sea area tendency and the river plume of the specific event.

• 한국안전학회지
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• 제29권6호
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• pp.104-110
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• 2014

The Han River is the only waterway in Korea where estuary is not blocked by dykes so that tidal water is flowing in and out through the tidal reach. The extreme tidal range in the Yellow Sea causes an intense flood current, stretching over horizontal extents of tens of kilometers into the rivers. To elucidate the flow reversal by discharge conditions and transient tidal level in the Han river, numerical simulations were conducted under 7 boundary conditions for two days with 10 minute time step. As the flow conditions changed from low discharge and high tidal difference to high discharge and low tidal difference, the flow reversals became weaker and the velocity of forward flow direction became higher due to the increased flow momentums and decreased tidal differences. In the case of normal flow, the maximum reverse velocity was 0.4 m/s, which was equivalent to the maximum forward velocity. In addition, the pattern of the development and decay of forward and reverse flow was presented.