• Journal of Environmental Impact Assessment
• /
• v.24 no.3
• /
• pp.287-299
• /
• 2015

If the Nakdong River estuary is to be sustainable, land use management practices need to consider bird habitat requirements, especially given that the area serves as an important migratory bird sanctuary. In this study, bird habitats found in the Nakdong River estuary were classified into 11 different types including Phragmites australiss, mud flat, farmland, open surface in freshwater, sand bar, riparian forest, Scirpus planiculmis, waterway, construction, grasslands, and open surface in sea or brackish water. Taking into consideration the regional characteristics, habitat properties, and landscape indices, a total of 12 study sites were analyzed. Mud flat, construction, farmland, and P. australis account for 80% of the total land area. The high area ratio of construction and farmland to other types of habitat revealed a high amount of historical human activity and intervention in the area. Both patch numbers as well as patch density were high in West Nakdong River, Samrak Waterfront, Maekdo River, and Daejeo Floodgate, with these areas showing the greatest fragmentation as well. Total numbers of species and individuals had a positive correlation with the area and the number of habitat types. Findings suggest that protecting the habitat area, especially in S. planiculmis, is the most important factor for bird habitat management and that future development could result in habitat loss, having a profoundly adverse impact on bird populations. Therefore, it is important that the total area should be carefully protected by land use regulations in order to ensure that the Nakdong River estuary maintains its functional integrity as a migratory bird sanctuary.

• Journal of Korean Society of Transportation
• /
• v.28 no.2
• /
• pp.99-108
• /
• 2010

In this paper I tried to find out changed and improved streetscape through the simulation using components of streetscape abstracted by factor analysis after analyzing present situation and problems of the streetscape for housing developments prepared on publis water surface. An analysis object is located in Haeundae Marine City in Busan. As a result of analysing the streetscape of marine city at present, I could see that main problems were discontinuous street space that did not reflect the characteristic of seashore, uncomfortable and insecure passage owing to coexistence street at seashore, insufficient street facilities for pedestrians, and disordered outdoor signboards. Therefore, I put the causal problems of marine city's streetscape in the insufficient street components, disharmony, and discontinuity so analysed the simulation elements applying selected street components and evaluated them to deduce demand factors having common meaning. As the result, the common demand factors were 'street furniture', 'harmonious streetscape with surrounding', 'landscape with natural openness', and 'landscape with dynamic symbol' in the order. So it needs to stress on a plan for proper arrangement of 'street facilities' and symbolic streetscape having continuity and harmony with surrounding so that the plan can proceed more properly for marine city's identity.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2004.04a
• /
• pp.217-224
• /
• 2004

Open-coast storm surge computations are of value in planning and constructing engineering works, especially in coastal regions. Prediction of typhoon surge elevations is based primarily on the use of a numerical model in this study, since it is difficult to study these events in real time or with use of physical models. A simple quasi-two dimensional numerical model for storm surge is considered. In order to understand the model's underlying assumptions, range of validity, and application, we discussed several aspects of typhoons and the physical factors governing storm generation processes. We also followed the basic governing equation, together with the assumption generally taken in their development, to see the principle characteristics of the model from a physical as well as a mathematical point of view. The equations consistent with the model described here are reduced forms of the basic equations and their effects on the resulting numerical scheme are discussed. Finally we applied the model discussed above to a storm surge problem at Masan Bay, the south coast of Korea Effects of astronomical tide, initial water level, and atmospheric pressure setup are considered. We then analyzed the flood at the coastal city and proposed a reasonable way of flood control.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.18 no.4
• /
• pp.301-307
• /
• 2006

In coastal zones with high tidal ranges like Korean western coast, port construction and reclamation projects have been increased. Most of the projects include sea-dyke construction. In the sea-dykes constructed to protect sea water intrusion, sea water was exchanged through the permeable dykes. The water level inside the area enclosed by the dykes changes with time due to tidal action of outer sea, but the tidal range is smaller than that of outside because of strong friction. In numerical modeling of coastal circulation the water exchange through the dykes has been neglected, which has produced inaccurate estimation neglecting the water exchange. In this study a method, which can consider water exchange through sea-dyke, was suggested and the modeling accuracy was improved. A groundwater theory was utilized to explain the phenomena.

• Water for future
• /
• v.29 no.2
• /
• pp.209-219
• /
• 1996

The existing gate operation rule of Paldang hydroelectric plant has been used since the construction of the dam in 1973 except partial modification due to the construction of Chungju multipurpose dam in 1985. The water level near the downstream of Paldang dam has been lowered about 3 m because of the channel maintenance of Han River development project. Thus, the discharge estimation formula based on the submerged orifice type spillway has to be re-evaluated by considering various patterns of the gate operation rules and lowered channel bed. In this study, three types of gate openings were tested to select the proper gate operation rules through the hydraulic model test for various discharges and opening heights. Also, the numerical analysis has been performed to simulate the flow patterns of downstream. As a result, the gate operation rule, which opens 5 gates each time from the left side, was selected as the proper gate operation rule of Paldang dam.

• Journal of Wetlands Research
• /
• v.17 no.1
• /
• pp.53-61
• /
• 2015

Habitat creation for endangered species Menyanthes trifoliata L. using planting module represents a habitat type such as the rhizome grows horizontally to open water at the margin of the lake. The objectives of this mesocosm experiment are habitat creation with easy construction and low management effort, and to investigate the potential of providing a habitat for aquatic macroinvertebrates. Planting modules had three different substrates of bed soil, perlite and K-SOIL (artificial lightweight soil using bottom ash). These modules were established in two different size of the tub($1170{\times}2250{\times}300mm^3$, $900{\times}1360{\times}190mm^3$). According to the monitoring results, number of leaves and coverage of M. trifoliata showed significant difference with substrate and tub size. The number of leaves showed similar growth responses in bed soil (mean 22.979) and K-SOIL (mean 28.042) substrates but growth was poor in perlite substrate (mean 1.667). The number of leaves in the large tub was more than small tub (p=0.015). Similar responses were obtained with the coverage, the length of rhizome and the number of rhizome in M. trifoliata. A total of 21 taxa of aquatic macroinvertebrates including 1,145 individuals was found in the mesocosm. The Shannon diversity index and colonization index in the mesocosm were similar to the previous studies. These results suggest that the experimental mesocosm could provide sufficient habitats for aquatic macroinvertebrates. If planting modules use bed soil or K-SOIL by planting substrate, establish that taking into account open water surfaces for M. trifoliata growth and manage about 30cm of water depth control, then habitat creation for M. trifoilata will be successful.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.51 no.3
• /
• pp.1-20
• /
• 2023

The present study has monitored the changes in the biodiversity of Dunchon-Dong ecological and landscape conservation area after the restoration of the wetland, identified and analyzed the threats to the ecosystem, and presented a management plan accordingly. In this area which was forests and rice paddies in the past, apartment reconstruction is currently underway, with some hinterland forests and wetlands remaining. When we look into the change in the floras, the total number of species was 193 in 2000 before the restoration, it decreased from 2004 to 2006, and as of 2019, it was 149, showing an increasing trend. The result of comparing the species that emerged before and after the restoration showed an increase in Cyperaceae herbs such as Carex maximowiczii and Carex dispalata growing in wetland areas within forests and Schoenoplectiella juncoides and Schoenoplectus tabernaemontani growing in areas within wetlands where shallow water is maintained. As a result of analyzing the change in the area ratio of each type of extant vegetation, the wetland native herbs formed the power at the highest ratio after the restoration. The change in the power of the wetland native herbs was on an increasing trend until 2007, after which it decreased much in 2010 and then gradually increased, showing values of 26.6% in 2000, 44.6% in 2002, 49.0% in 2005, 53.3% in 2007, 28.7% in 2010, and 37.3% in 2019. The cause of the decrease in 2010 was judged to be due to the vegetation management conducted to secure open water and remove organic matter in freshwater reservoirs. The amphibia which emerged from 2000 to 2019 was a total of 9 species including Hynobius leeshii, Bufo gargarizans, Kaloula borealis, and Rana uenoi. As a result of the changes in the emerging wild birds, the species diversity index before the restoration was 0.9922 in 2000, and the species diversity index after the restoration gradually increased to 1.2449 in 2005, 1.2467 in 2010, and 2.2631 in 2019. The amphibia and wild birds inhibiting in the Dunchon-Dong forest and wetland were judged to have increased through continuous wetland maintenance such as naturalized plant removal management, native plant maintenance, and open water securing management. For the ecosystem preservation management of the Dunchon-Dong ecological and landscape conservation area, it was suggested to minimize the impact of the Dunchon-Dong reconstruction project, reorganize the indiscriminate access roads adjacent to the wetland, and reorganize the main entrance to the wetland. For ecosystem restoration management, systematic restoration and ecological buffer planting were suggested to be carried out at the time of construction fence demolition.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.5 no.1
• /
• pp.39-44
• /
• 1993

This paper is concerned with developing a finite element model incorporating boundary damper techniques which is applicable to the prediction of wave agitations in harbors. Based on the linear wave theory, a mild-slope equation is used. In order to consider the wave energy dissipations on solid boundary. the partial reflecting boundary condition is introduced. Radiating boundary condition is modeled by using tile second-order boundary damper developed by Bando et al. (1984). The near field region in harbor is discretized using 8-noded isoparametric elements, the boundary conditions are presented using 3-noded line elements. The numerical model is applied to a fully open rectangular harbor to prove its validity. Numerical experiments are also performed to investigate the effects of the wave reflection coefficients of solid boundary and the types of the dampers.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2021.06a
• /
• pp.286-286
• /
• 2021

벽골제는 전북 김제시에 위치하고 있으며 우리나라의 고대 저수지이다. 벽골제는 고대 농경사회의 대규모 토목사업으로 건설되었다. 약 2.5km의 제방이 현존하고 있다. 축조 시기는 삼국시대 서기 330년이다. 이후 통일신라 원성왕(AD.790)과 고려 현종 및 인종 때 보수되었으며 조선 태종(AD.1415)에 대대적인 보수를 하였다. 세종 2년(AD.1420)에 심한 폭우로 유실되었다. 그 후 일제강점기 1925년에 김제 간선수로로 개조함으로써 원형이 크게 훼손되었다. 벽골제는 우리나라뿐만 아니라 동아시아 고대 저수지로서 중요하다. 벽골제의 축조방식(부엽공법)과 측량기술은 일본 오사카부의 사야마이케(저수지)에 영향을 주었다. 사야마이케는 고대저수지로서 원형이 보존되어 있으며 유네스코 세계 유적으로 등재하기 위한 준비가 충실하게 진행되어 왔다. 본 연구에서는 벽골제가 고대저수지로서 가치를 인정받고 보존하기 위해 발굴되고 있다. 더불어 벽골제의 수공학적 능력 평가가 필요하다고 판단된다. 벽골제 유역을 대상으로 현재 지형과 최근이 수문자료를 이용하여 평가하였다. 발굴된 벽골제를 기준으로 유역을 설정하였다. 벽골제 유역 특성을 토대로 강우 분석을 수행하여 홍수량과 벽골제를 기준으로 수면적과 용적을 산정하였다. 벽골제에는 5개 수문이 있으며 3개는 Sluice Gate 형식(장생거, 중심거, 경장거)이고 2개의 월류형 형식(수여거, 유통거)으로 구성되어 있다. 최근에 수여거는 발굴 중이며 유통거는 미발굴 상태이다. 발굴된 수문의 규모를 토대로 수문 개방 정도에 따라, 웨어의 첨단고에 따라, 제내지의 수위를 조합하여 시나리오를 구성하였다. 시나리오에 따라서 최고수위를 산정하여 벽골제의 능력을 평가하였다. 이를 근거로 벽골제의 붕괴 원인을 추정해 보았다.

• Journal of the Korean Geographical Society
• /
• v.49 no.3
• /
• pp.321-338
• /
• 2014

This study aims to identify spatial distribution of estuarine wetlands in Korea, and to assess temporal variation of the wetlands in the last few decades. Widely known in environmental and coastal management, watershed-based regions which composed with Han-river(western and eastern parts), Keum-river, Yeoungsan-river, Seomjin-river, Nakdong-river, and Jeju, are analyzed to evaluate temporal change of estuarine wetlands in the 1980s, 1990s, and 2000s, through the land-cover map. Results show that estuarine wetlands dramatically decreased in Han-river(western part), Keum-river, Yeoungsan-river that estuarine circulation have been interrupted with man-made structures such as dyke and drainage. But, estuarine wetlands surrounded by forests and grasslands has been relatively less damaged. Habitat diversity providing healthy estuary ecosystem is lower in interrupted estuaries than circulated estuaries, which are composed of tidal-flat, open water, salt marsh, rocky coasts and sandy shoreline. This study indicates that spatial distribution and temporal variation of estuarine wetlands are different with estuary type and region, so estuary type with seven regions can be applied to provides a framework for estuary management strategies and to establish estuary restoration plans.