• Geomechanics and Engineering
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• v.34 no.4
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• pp.397-408
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• 2023

Pipe pile walls are commonly used as retaining structures for excavation projects, particularly in densely populated coastal cities such as Hong Kong. Pipe pile walls are preferred in reclaimed land due to their cost-effectiveness and convenience for installation. However, the pre-bored piling techniques used to install pipe piles can cause significant ground disturbance, posing risks to nearby sensitive structures. This study reports a well-documented case history in a reclamation site, and it was found that pipe piling could induce ground settlement of up to 100 mm. Statutory design submissions in Hong Kong typically specify a ground settlement alarm level of 10 mm, which is significantly lower than the actual settlement observed in this study. In addition, lateral soil movement of approximately 70 mm was detected in the marine deposit. The lateral soil displacement in the marine deposit was found to be up to 3.4 and 3.1 times that of sand fill and CDG, respectively, mainly due to the relatively low stiffness of the marine deposit. Based on the monitoring data and site-investigation data, a 3D numerical analysis was established to back-analyze soil movements due to the installation of the pipe pile wall. The comparison between measured and computed results indicates that the equivalent ground loss ratio is 20%, 40%, and 20% for the fill, marine deposit and CDG, respectively. The maximum ground settlement increases with an increase in the ground loss ratio of the marine deposit, whereas the associated influence radius remains stationary at 1.2 times the pipe pile wall depth (H). The maximum ground settlement increases rapidly when the thickness of marine deposit is less than 0.32H, particularly for the ground loss ratio of larger than 40%. This study provides new insights into the pipe piling construction in reclamation sites.

• Journal of the Korean association of regional geographers
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• v.15 no.2
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• pp.179-191
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• 2009

This study analyzes and compares the geomorphic characteristics and environmental changes of coastal plains such as the Anju and Hamheung Plains located in the west and east coasts of North Korea, respectively, based on topographic maps of the 1910s and satellite images of the 2000s. The Anju Plain, so called by as Yeoldusamcheonribeol, can be divided into alluvial plains, coastal plains and erosional plains. The Hamheung Plain can be regarded as alluvial plains formed by Seongcheon-river. Approximately 84.98$km^2$ tidal flats have been reclaimed to farmlands and saltpans, and the most channels of medium and small rivers have been straightened at the Anju Plain during the last one hundred years. At the Hamheung Plain, on the other hands, approximately 3.40$km^2$ land has been increased by the advances of coastal line of the Seongcheon-river delta with a maximum of 800m, and channels of Seoseongcheon-river which showed anastomosing channels have been disappeared by reclamation. Gwang-po has been decreased by artificial reclamations and river sedimentary processes.

• Journal of the Korean Geosynthetics Society
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• v.14 no.4
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• pp.97-104
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• 2015

When carrying out design for soft ground improvement before reclamation of dredged soil, it is very important to appropriately evaluate design parameters such as compression index and undrained strength in order to estimate optimum construction cost. In this study, consolidation and strength parameters were estimated by the samples obtained from the similar reclaimed land. Water content and compression index of dredged soil reclaimed by hydraulic fill method were quite decreased in comparison with those of in-situ conditions at Incheon site. Relationships between compression index(Cc) and water content (wn), and between undrained strength (su) and water content (wn) for dredged soil were obtained by field vane test and oedometer test, respectively. Applicability of Schmertmann correction method (compression index) for low plasticity silty soil was discussed according to comparison with designed and measured settlements.

• Journal of the Korean Institute of Landscape Architecture International Edition
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• no.2
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• pp.130-139
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• 2004

Shiwha Lake is an excellent example of a body of water restored from a state of heavy pollution to a cleaner and more ecological state. This paper will explore techniques and methods available to landscape planning for the creation of new migratory birds habitats in Shiwha Lake. Because Shiwha lake is located adjacent to a new industrial site on reclaimed land, any planning effort aimed at restoring bird habitats must carefully consider the existing context. This plan had 3 goals; (1) to restore the coastal environment, (2) to create a habitat for migratory birds, and (3) to administer environmental education programs. To achieve these goals, several objectives were determined and planning criteria were proposed for topology, water environment(fresh, brackish and salt water swamps), zoning(for experts and general visitors), circulations, planting and mounding. The flora and fauna of the site was surveyed, and 5 alternatives were suggested and compared in several aspects. Planting species were carefully selected considering target birds and habitat requirements. In order to increase bio-diversity of the site, the plan proposed multi-staired mounds and extensive drainage systems. Bird watching facilities with natural materials, and the remote observing system using CCTV and the internet were some of the ecological techniques recommended by the plan. The bird watching trails are divided into two different zones for experts and general visitors.

• The Korean Journal of Mycology
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• v.22 no.4
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• pp.394-409
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• 1994

The symbiotic activities of arbuscular mycorrhizal fungi(AMF) such as spore density, symbiotic intensity and vesicle density, phytomasses of higher plants such as Calamagrostis epigeios, Imperata cylindria, Artemisia scoparia, Aster tripolium and Sonchus brachyotus and seasonal change of the AMF activities, electric conductivity and zinc contents in plant and soil were determined in the rhizospheres of higher plants at abandoned old coastal reclaimed lands, where constructed in 12 and 30 years ago. If plants of reclaimed land classified to salinity, symbiotic activities of AMF were high in order of obligate halophyte, facultative halophyte and glycophyte. Also, those plants classified to life form, symbiotic activities of AMF were high in order of annual, biennial and perennial plants. Seasonal variation of spore density, one of symbiotic activities showed that the plateau density maintained continuously from the end of growing season of the higher plants to next spring. For this reason, it regarded that reproduction of AMF spore would be formed in autumn, when the higher plants will be developed. Seasonal change of symbiosis intensity, other symbiotic activities, however, showed that the highest symbiosis intensity occurred in spring and summer but the lowest in autumn. In relationships among symbiotic activities, spore density was directry proportional increase of symbiosis intensity. Moreover, phytomass of higher plants also was directly proportional to increase the spore density as well as symbiosis intensity. Vesicle density, however, did not any correlation with the phytomass, spore density and symbiosis intensity. From these results, it can know that both spore density and symbiosis intensity are strongly possible to use as the measure of symbiotic activity owing to symbiosis of tho-AMF, the more absorption of zinc by the higher plants carried out the less concentration of zinc in the soil.

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.3
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• pp.627-635
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• 2017

Sea level rise caused by climate change has become a global issue. Sea level rise seems to be an important factor of the research for coastal areas as it affects topography and vegetation of coasts and especially for the plan of coastal wetlands restoration which needs to be carried out for a long term, it has to be considered sufficiently. The coastal wetlands in Korea was damaged by the land reclamation project but recent concerns on the restoration have increased as its value is evaluated highly. Suncheon Bay had also reclaimed from wetlands to rice field once however this site is very active for restoration nowadays. This study estimated an effect according to sea level rise by 2100, reappearing the none dike condition of Suncheon Bay so that it can be taken account of a future plan of wetland restoration. The Sea Level Affecting Marshes Model(SLAMM) was selected as predicting model. The input data such as DEM(Digital Elevation Model), slope, wetlands category, sea level rise senario, tidal range and accretion rate was applied for the simulation. The results showed a decrease in tidal flat, an increase in sea area and a change of the rice field to transitional salt marsh consistently by 2100. These results of this study could be used as baseline data in the future plan of ecological restoration in Suncheon Bay.

• Journal of Wetlands Research
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• v.11 no.1
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• pp.105-113
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• 2009

Heat energy exchange is very important processes in the coastal wetland ecosystems. We observed and analyzed the net radiation flux, the sensible heat flux, the latent heat flux and the soil heat flux, which are balanced in the heat energy balance, over a reclaimed land covered with reeds at Goheung, Jeonllanamdo where is horizontally plane. The atmospheric turbulence had been measured in order to estimate the heat transfer during 5 intensive observation periods (IOPs). It was considered that the soil consists of water, fine particles, and vegetation canopy that changes color and density according to the season. We examined the characteristics of the heat flux and the vegetation effect on the air temperature control. It was noted that the heat was transported mainly by latent heat flux in the summer season and the vegetation canopy decreased the daily temperature range due to the heat storage. The air temperature was lower at the IOPs site than near urban area. This showed that the coastal wetland covered with the vegetation control the thermal environment.

• Journal of the Korean association of regional geographers
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• v.3 no.2
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• pp.37-87
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• 1997

As a results of researches on the cultivation processes and settlement developments on the Mangyoung river valley as a whole could be have four 'Space-Time Continuity' through a [Origin-Destination] theory model. On a initial phases of cultivation, the cultivation process has been begun at mountain slopes and tributory plains in upper part of river-basin from Koryo Dynasty to early Chosun Dynasty. At first, indigenous peasants burned forests on the mountain slopes for making 'dryfield' for a cereal crops. Following population increase more stable food supply is necessary facets of life inducing a change production method into a 'wetfield' in tributory plains matching the population increase. First sedentary agriculture maybe initiated at this mountain slopes and tributory plains on upper part of river basin through a burning cultivation methods. Mountain slopes and tributory plains are become a Origin area in cultivation processes. It expanded from up to down through the valleys with 'a bits of land' fashion in a steady pace like a terraced fields expanded with bit by bit of land to downward. They expanded their land to the middle part of river basin in mid period of Chosun Dynasty with dike construction techniques on the river bank. Lower part of river cultivated with embankment building techniques in 1920s and then naturally expanded to the tidal marshes on the estuaries and river inlets of coastal areas. 'Pioneer fringes' are consolidated at there in modern times. Changes in landscapes are appeared it's own characters with each periods of time. Followings are results of study through the Mangyoung river valley as a whole. (1) Mountain slopes and tributory plains on the upper part of river are cultivated 'dryfields' by indigenous peasants with Burning cultivation methods at first and developed sedentary settlements at the edges of mountain slopes and on the river terrace near the fields. They formed a kind of 'periphery-located cluster type' of settlement. This type of settlement are become a prominant type in upper part of river basin. 'Dryfields' has been changed into a 'wetfields' at the narrow tributory plains by increasing population pressure in later time. These wetfields are supplied water by Weir and Ponds Irrigation System(제언수리방법). Streams on the tributory plains has been attracted wetfields besides of it and formed a [water+land] complex on it. 'Wetfields' are expanded from up to downward with a terraced land pattern(adder like pattern, 붕전) according to the gradient of valley. These periphery located settlements are formed a intimate ecological linkage with several sets of surroundings. Inner villages are expanded to Outer villages according to the expansion of arable lands into downward. (2) Mountain slopes and tributory plains expanded its territory to the alluvial deposited plains on the middle part of river valley with a urgent need of new land by population increase. This part of alluvial plains are cultivated mainly in mid period of Chosun Dynasty. Irrigation methods are changed into a Dike Construction Irrigation method(천방수리방법) for the control of floods. It has a trend to change the subjectives of cultivation from community-oriented one who constructed Bochang along tributories making rice paddies to local government authorities who could be gather large sums of capitals, techniques and labours for the big dike construction affairs. Settlements are advanced in the midst of plains avoiding friction of distances and formed a 'Centrallocated cluster type' of settlements. There occured a hierarchical structures of settlements in ranks and sizes according merits of water supply and transportation convenience at the broad plains. Big towns are developed at there. It strengthened a more prominant [water+land] complex along the canals. Ecological linkages between settlements and surroundings are shaded out into a tiny one in this area. (3) It is very necessary to get a modern technology of flood control at the rivers that have a large volume of water and broad width. The alluvial plains are remained in a wilderness phase until a technical level reached a large artificial levee construction ability that could protect the arable land from flood. Until that time on most of alluvial land at the lower part of river are remained a wilderness of overgrown with reeds in lacks of techniques to build a large-scale artificial levee along the riverbank. Cultivation processes are progressed in a large scale one by Japanese agricultural companies with [River Rennovation Project] of central government in 1920s. Large scale artificial levees are constructed along the riverbank. Subjectives of cultivation are changed from Korean peasants to Japanese agricultural companies and Korean peasants fell down as a tenant in a colonial situation of that time in Korea. They could not have any voices in planning of spatial structure and decreased their role in planning. Newly cultivated lands are reflected company's intensions, objectives and perspectives for achieving their goals for the sake of colonial power. Newly cultivated lands are planned into a regular Rectangular Block settings of rice paddies and implanted a large scale Bureaucratic-oriented Irrigation System on the cultivated plains. Every settlements are located in the midst of rice paddies with a Central located Cluster type of settlements. [water+land] complex along the canal system are more strengthened. Cultivated space has a characters of [I-IT] landscapes. (4) Artificial levees are connected into a coastal emnankment for a reclamation of broad tidal marshes on the estuaries and inlets of rivers in the colonial times. Subjectives of reclamation are enlarged into a big agricultural companies that could be acted a role as a big cultivator. After that time on most of reclamation project of tidal marshes are controlled by these agricultural companies formed by mostly Japanese capitalists. Reclaimed lands on the estuaries and river inlets are under hands of agricultural companies and all the spatial structures are formed by their intensions, objectives and perspectives. They constructed a Unit Farming Area for the sake of companies. Spatial structures are planned in a regular one with broad arable land for the rice production of rectangular blocks, regular canal systems and tank reservoir for the irrigation water supply into reclaimed lands. There developed a 'Central-located linear type' of settlements in midst of reclaimed land. These settlements are settled in a detail program upon this newly reclaimed land at once with a master plan and they have planned patterns in their distribution, building materials, location, and form. Ecological linkage between Newly settled settlemrnts and its surroundings are lost its colours and became a more artificial one by human-centred environment. [I-IT] landscapes are become more prominant. This region is a destination area of [Origin-Destination] theory model and formed a 'Pioneer Fringe'. It is a kind of pioneer front that could advance or retreat discontinously by physical conditions and socio-cultural conditions of that region.

• Journal of Plant Biology
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• v.26 no.2
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• pp.53-71
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• 1983

Physicochemical properties of soil, mineral cyclings, production of plants, and relationship between sodium(Na) content and progresses of plant communities were studied in a coastal salt marsh in Incheon. Contents of Na, available phosphorus(A-P) and value of electric conductivity of soil decreased in order of Salicornia herbacea, Limonium tetragonum, Phragmites communis and Zoysia sinica communities, but contents of organic matter, total nitrogen(T-N) and calcium(Ca) of soil were vice versa. Specise diversity index decreased with increase of Na content of soil with correlation coefficient of -0.82. The aboveground biomass of plant communities were 2,981 g.dw/$m^2$ in P. communis, 1,471 g.dw/$m^2$ in Z. sinica, 189g.dw/$m^2$ in S. herbacea and 71 g.dw/$m^2$ L. tetragonum, respectively. Seasonal changes of contents of inorganic nutrients per unit land area coincided with those of biomass of plant communities, however, the maximum contents of K occured earlier than the maximum biomass. Amounts of inorganic nutrients absorbed by plant were directly proportion to its biomass and it was true to reverse in restored amounts of them to soil. In turnover times of nutrients of the communities, it took the shortest time for P but the longest for Ca and P. communis community took the shortest but L. tetragonum the longest. For example, in P. communis turover time of P took one year and that of Na 1,440 years. Lack of P element, therefore, was expected in this study area.

• Korean Journal of Remote Sensing
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• v.36 no.6_2
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• pp.1605-1613
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• 2020

The tidal channel is a coastal sedimentary terrain that plays the most important role in the formation and development of tidal flats, and is considered a very important index for understanding and distribution of tidal flat sedimentation/erosion terrain. The purpose of this study is to understand the changes in tidal channels by a period after the opening of the floodgate of the seawall in the reclaimed land of Sihwa Lake using KOMPSAT high-resolution multispectral satellite image data and to evaluate the applicability and efficiency of high-resolution satellite images. KOMPSAT 2 and 3 images were used for extraction of the tidal channels' lineaments in 2009, 2014, and 2019 and were applied to supervised classification method based on Principal Component Analysis (PCA), Artificial Neural Net (ANN), Matched Filtering (MF), and Spectral Angle Mapper (SAM) and band ratio techniques using Normalized Difference Water Index (NDWI) and MF/SAM. For verification, a numerical map of the National Geographic Information Service and Landsat 7 ETM+ image data were utilized. As a result, KOMPSAT data showed great agreement with the verification data compared to the Landsat 7 images for detecting a direction and distribution pattern of the tidal channels. However, it has been confirmed that there will be limitations in identifying the distribution of tidal channels' density and providing meaningful information related to the development of the sedimentary process. This research is expected to present the possibility of utilizing KOMPSAT image-based high-resolution remote exploration as a way of responding to domestic intertidal environmental issues, and to be used as basic research for providing multi-platform-image-based convergent thematic maps and topics.