• Journal of the Korean Geographical Society
• /
• v.42 no.1 s.118
• /
• pp.121-132
• /
• 2007

This paper examines the spatial and temporal variability in the water depth caused by artificial structures in Geum Estuary of South Korea. Water depth data set extracted from marine maps of 1979, 1990, 1996 and 2004 were used in a GIS to derive volumetric estimates of gains and losses of sedimentary material. Artificial structures caused above 2m in water depth to be shallow between 1979 and 2002 in the estuary system, particularly through disturbance of a natural transport in suspended sediment concentrations. The mutt significant change in suspended sediment transport were observed in area affected by embankment for fresh water, inducing the water depth shallower than before in almost 80% of the area. This was probably because of an continuous abundant mud supply from coastal river oven after blocking the fresh water. The spatial analysis made it possible to identify area wide patterns of water depth change subject to many different type of artificial structures, which tanner be acquired by traditional field sampling. It is anticipated thai this research could be used as a valuable reference to confirm the outputs from past field researches for sedimental process in more visual and quantitative manner.

• Proceedings of KOSOMES biannual meeting
• /
• 2006.11a
• /
• pp.155-158
• /
• 2006

한국 남해안 거제도 앞바다에 투하된 인공용승구조물에 대한 유통 변화를 파악하기 위해 ADCP(Acoustic Doppler Current Profiler)를 선박에 장착하여 정선관측을 실시하였다. 관측결과 구조물 투하전과 후의 유통비교를 보면 구조물 주변역에서 표층에서부터 수심 $30\sim40m$까지의 충과 그 이심까지의 흐름이 다르게 나타났다. 또한 구조물 주변역에서 연직유동성분의 흐름이 구조물 투하 전에는 하강류의 분포가 많이 나타났으나 구조물 투하 후에는 상승류의 성분이 많이 나타남을 알 수 있었다.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.24 no.3
• /
• pp.179-188
• /
• 2012

Performance analyses of vertical breakwaters were conducted for fictitiously designed breakwaters for various water depths to analyze the influence of climate change on the structures. The performance-based design method considering sea level rise and wave height increase due to climate change was used for the performance analysis. One of the problems of the performance-based design method is the large calculation time of wave transformation. To overcome this problem, the SWAN model combined with artificial neural network was used. The significant wave height and principal wave direction at the breakwater site are quickly calculated by using a trained neural network with inputs of deepwater significant wave height and principal wave direction, and tidal level. In general, structural stability becomes low due to climate change impacts, but the trend of stability is different depending on water depth. Outside surf zone, the influence of wave height increase becomes more significant, while that of sea level rise becomes negligible, as water depth increases. Inside surf zone, the influence of both wave height increase and sea level rise diminishes as water depth decreases, but the influence of wave height increase is greater than that of sea level rise. Reinforcement and maintenance policies for vertical breakwaters should be established with consideration of these results.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.21 no.4
• /
• pp.372-380
• /
• 2015

In order to study the characteristics of physical environment in water column around the artificial upwelling structure, CTD and currents measurements were carried out along line observations. Before installation of artificial upwelling structure was installed, the stratification of water column existed 30m in water depth. After installation of artificial upwelling structure, however, stratification formation depth and strength changed depending on currents directions. It seems that the change of stratification has a close relation with upwelling of lower temperature water. After installing the artificial upwelling structure, the distributions of vertical flows were analyzed. Local upwelling and downwelling flows showed a distinct time and spacial changes. Local upwelling flows caused by artificial upwelling structure appeared 100 times larger than coastal upwelling in the South-East Sea of Korea. Upwelling flows generated by the artificial structure raised the high concentration of nutrients to upper layer from lower layer breaking stratification in the summer. Thus, upwelling structure plays an important role for vertical water circulation improving the food environments by increasing primary production.

• Proceedings of KOSOMES biannual meeting
• /
• 2007.11a
• /
• pp.1-7
• /
• 2007

To illustrate the variation of oceanic condition around artificial upwelling structure which is located in the South Sea of Korea, cm observations were carried out on December, 2005, April, August and October, 2006. Temperature, salinity and density(sigma-t) was nearly homogeneous through the whole depth by mixing of the seawater in winter. Stratification was not clear in spring, and it was only formed weakly in the surface layer shallower than 10m. Stratification was formed about $10{\sim}20$ m depth in summer and about $30{\sim}40$ m depth in autumn. Vertical gradient of temperature was larger than that in the part of western area along the artificial seamount in summer and autumn. The variation of stratification was also occurred around near the artificial structure area after set up structure.

• Journal of Korean Society for Geospatial Information Science
• /
• v.17 no.3
• /
• pp.23-31
• /
• 2009

The border of the shorelines in a nation is an important factor in determining the border of a national territory, but Korea's shorelines are rapidly changing due to the recent rise in sea level from global warming and growth-centered economic policy over the decades of years. This research was done centering on the areas having well-preserved shorelines as they naturally are and other areas having damaged shorelines in their vicinities due to artificial structures at the two beaches located at the neighboring areas and having mutually homogeneous ocean conditions with each other. First, this research derived the shorelines using the aerial photographies taken from 1947 until 2007 and revised the tidal levels sounding data obtained from a hydrographical survey automation system consisting of Echosounder[Echotrac 3100] and Differential Global Positioning System[Beacon]by using topographical data and ships on land obtained by applying post-processing Kinematic GPS measuring method. In addition, this research evaluated the changes and dimensional variations for the last 60 years by dividing these determined shorelines into 5 sections. As a result, the Haewundae Beach showed a total of 29% decrease rate in dimension as of the year 2007 in comparison with the year 1947 due to a rapid dimensional decline centering on its west areas, while the dimension of the Gwanganri Beach showed an increase in its dimension amounting to a total of 69% due to the decrease in flow velocity by artificial structures built on both ends of the beach-forming accumulation; thus, it was found that there existed a big difference in deposition & accumulation tendency depending on neighboring environment in spite of the homogeneous ocean conditions.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2006.05a
• /
• pp.1017-1021
• /
• 2006

인공순환수로에 정육면체 수리구조물을 구간별로 설치하여 흐름특성에 따른 깔따구의 서식경향을 조사하였다. 정밀한 흐름특성을 분석하기 위하여 난류계산을 수행하였으며, 인공순환수로에 깔따구를 투입하고 3일경과 후 깔따구의 개체수를 조사하였다. 인공순환수로는 단면 폭 29cm, 높이 30cm인 구조로 제작되었으며 직선구간의 길이는 120cm이다. 인공순환수로의 직선구간에 길이 10cm의 정육면체 수리구조물을 20cm 간격으로 양쪽 벽면부에 4개씩 균일하게 설치하였다. 자연하천에서 채집된 원수를 수심 20cm가 되도록 투입한 후 유기물을 하상에 고르게 깔고, 회전날개를 이용하여 평균유속 10cm/s로 안정화 시킨 후 깔따구 투입하였다. 실험시작 3일 경과 후, 깔따구의 서식경향을 조사한 결과 깔따구는 수리구조물 직하류부에 주로 서식하였다. 이는 주 흐름방향 유속분포가 수리구조물 후방에서 급격히 작아져 깔따구들이 정착하기 좋은 환경을 제공하기 때문인 것으로 판단된다. 또한 인공순환수로 직선구간의 안쪽 벽면과 바깥쪽 벽면의 깔따구 개체수는 안쪽 벽면이 바깥쪽 벽면에 비하여 2배 정도 많다. 이는 수리구조물 사이 안쪽 벽면 하상의 시계방향 회전흐름 때문으로 분석되며 상대적으로 이러한 흐름은 바깥쪽 벽면에서 작다. 실험 및 수치해석 결과, 깔따구는 상대적으로 유속이 작은 곳에 서식하며, 이차류의 경향에 따라 서식처를 이동하는 것으로 분석되었다. 향후 생태적 기능을 고려하여 다양한 수리학적 조건 하에서 난류계산 및 유속측정을 통한 연구가 필요하다. 이와 같은 연구는 친환경적으로 하천을 복원시키는데 유용한 자료를 제공할 수 있을 것으로 생각된다.은 silt나 clay보다 입경이 큰 모래나 자갈을 경유 하면서 오염물의 저감효과가 감소한 것으로 판단된다. 그러나 유입유량의 대부분이 표면으로 유출된다는 점을 고려할 때 표면유출수의 오염도를 낮추는 것이 유입오염물 저감효과에 보다 큰 효과가 있을 것으로 판단된다.문에 자료의 이상적 유지 관리가 이루어지며 복잡한 2차원 수질해석 모형을 수월하게 운영할 수 있는 시스템으로 개발하였다.제외하면, 부자측정 방법에 의한 유량산정시 가장 큰 오차원인은 홍수시 측정된 유속측선의 위치와 홍수 전후로 측정된 횡단면상의 위치가 일치하지 않는 점과, 대부분 두 측정 구간의 평균값을 대푯값으로 사용한다는 점이다. 본 연구는 다년간의 유량 측정 및 검증 경험과 자료를 토대로 현장에서 부자를 이용하여 측정된 측정성과를 정확도 높은 유량자료로 산정하는데 있어서의 문제점을 도출하고, 이로 인해 발생하는 오차를 추정하여 그 개선방안을 제시해 보고자한다. 더불어 보다 정확한 유량 산정을 위한 기준과 범주를 제시하고자 한다.리적 특성을 잘 반영하며, 도시지역의 복잡한 배수시스템 해석모형과 지표범람 모형을 통합한 모형 개발로 인해 더욱 정교한 도시지역에서의 홍수 범람 해석을 실시할 수 있을 것으로 판단된다. 본 모형의 개발로 침수상황의 시간별 진행과정을 분석함으로써 도시홍수에 대한 침수위험 지점 파악 및 주민대피지도 구축 등에 활용될 수 있을 것으로 판단된다. 있을 것으로 판단되었다.4일간의 기상변화가 자발성 기흉 발생에 영향을 미친다고 추론할 수 있었다. 향후 본 연구에서 추론된 기상변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.28 no.6
• /
• pp.408-415
• /
• 2016

Small fishing ports and coastal structures installed in a relatively low sea water depth disturb the wave induced current and cause the collapse of equilibrium state of sediment transport. These structures creates diffracted waves and matter the concentration of waves to cause the beach erosion. In order to mitigate these eroding problems on the beach, many counter measurements were proposed such as detached breakwater, groin or headland; however, these methods interrupt the aesthetic view of sandy beach due to the exposed structures above the sea level and have difficulty of applying to those beaches with the good scenery. Furthermore, some of these methods create secondary environmental problems after the installations. To eliminate these problems, one of the countermeasures, artificial reefs have been selected and used worldwide to minimize the disturbance of the scenery and secondary effects on the environment. Meanwhile, it is important to set the design elements for installing the artificial reefs such as that of length, opening width, clearing distances from the shoreline and more. Nevertheless, there are no construction manuals or standards for designing the artificial reefs with these important design elements yet. In this study, different conditions of artificial reefs were used with various cases throughout hydraulic model test to precisely analyze the changes of waves and currents to propose the standards of design elements to install the artificial reefs.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2015.05a
• /
• pp.176-176
• /
• 2015

최근 대하천사업을 통하여 낙동강에 총 8개의 다기능보가 설치되었으며, 이러한 하천 내 수공 구조물은 하천에 서식하는 어류의 이동과 군집의 변화, 유전적 단절, 서식처 변화와 같은 다양한 문제점을 유발할 수 있으며, 특히 어류의 산란기에는 하천의 유로를 따라 상류로 이동하거나 하류로 이동하는 회유성 어류들에게는 심각한 문제를 야기한다. 이러한 다기능보의 상 하류의 단절로 인한 문제를 해결하기 위해 낙동강 8개의 다기능보에 자연형 및 인공형 어도가 설치되었으며, 이를 평가하기 위한 어도의 유인효율에 대한 연구가 중요하다. 어류는 최대 유속이 발생하는 지점인 유심선에서 소상하려는 특성을 보이는데, 어도의 입구부의 유속이 중요하게 작용한다. 어도 입구부의 유속분포 및 수심에 따라 유인효율은 다르게 나타날 수 있으며, 2차원 수리해석을 통해 WUA를 산정함으로써 어도의 유인효율을 평가할 수 있다. 본 연구에서는 2차원 흐름해석 모형인 River2D를 이용하여 어류의 소상이 중요한 산란기를 기준으로 강정고령보의 가동보 운영실적을 이용하여 수리해석을 실시하였으며, 연구결과를 바탕으로 자연형어도의 유인효율을 평가하였다.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.12 no.4 s.27
• /
• pp.301-306
• /
• 2006

In order to estimate the characteristics of water movements around artificial upwelling structure, current measurements were carried out along lines E-W and S-N on May 4th(neap tide} and May 30th(spring tide), 2006. In the study area, southeastward flow was dominant during the field observations, and the pattern of water movement in the upper layer above 30m depth was different from that in the lower layer below 30m depth Vertical flow(w-component} around the artificial structure area and western area was shown to be upward flow, but downward flow occurred in the southern, northern and eastern parts at the neap tide. At the spring tide, the ebb current along E-W line showed upwelling flow in the eastern part and western area and showed upwelling flow near the artificial structure area and downwelling flow far away that one. At the spring tide, upward flow was dominant along S-N line during the flood current Volume transport by upward flow was higher than that by downward flow. Volume transport by upward flow during ebb of neap tide was greater than during flood current of neap tide, but was reverse at the spring tide.