• Journal of Environmental Impact Assessment
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• v.23 no.2
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• pp.150-156
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• 2014

The aim of this study is to detection of changed vegetation area of Saemangeum tidal flat with comparison of topography and surface sediments during the dyke construction. Sedimentary facies of four seasons of 2001 from inside Saemangeum tidal flat revealed homogeneous layers in the upper part, however near sea side tidal flat were detecting with carried out rapid sediment deposition during the dyke construction using satellite image spatial analysis. The sedimentation types inside Saemangeum tidal flat were classified with vegetation types, which were well matched with the sedimentation pattern revealed by change in vegetation patterns.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.6
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• pp.708-715
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• 2003

Species composition and distribution patterns of shellfish were investigated in Eoeun and Geojeon tidal flat located in the Saemangeum area on the west coast of Korea from May to October 2000. Nineteen species of shellfish were collected in Geojeon tidal flat. The samples in number of individuals included Umbonium thomasi $(90.0\%)$ and Mactra veneriformis $(5.0\%).$ In Eoeun tidal flat, ten species of shellfish were collected and the dominant species in number of individuals were Potamocorbula amurensis $(55.0\%)$ and U. thomasi $(18.6\%).$ These results were compared with previous studies conducted before the beginning of reclamation in Saemangeum. Compared with the results from 1988, a change In species composition was observed. Laternula flexuosa and Nuttallia olivacea appeared, while Mactra chinensis and Coelomactra antiquata disappeared in the deposition area in Geojeon tidal flat. In the erosion area of Eoeun tidal flat, M. veneriformis and Meretrix lusoria appeared, while Cyclina sinensis disappeared. Based on a cluster analysis, the shellfish community in Eoeun tidal flat was classified into three station groups based on sediment types. Geojeon tidal flat was also classified into three station groups. The distribution of shellfish in the Saemangeum area was closely related to the sediment types.

• Ocean and Polar Research
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• v.28 no.4
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• pp.361-368
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• 2006

The Saemangeum tidal flat with an area of approxirnately $233km^2$ is one of the biggest estuarine tidal flats on the west coast of Korea. Because of its location in the estuary of Mangyeong and Dongjin Rivers, the tidal flat receives large amount of sediments. A 33-km long sea dyke, enclosing a coastal zone of $401km^2$, was constructed to reclaim tidal flat in the Saemangeum area. The dyke construction radically changes the local tidal current regime and estuarine circulation. These have an effect on sedimentary environments in the tidal flat. On the tidal flats of the study area net deposition occurred, but net erosion occurred near tidal channel in 2004. The comparison of topography and surface sediments in summer 2004 with those in summer 1988 before the dyke construction showed that elevation increased with maximum 80cm and mean grain sizes were fining at Gwanghwal tidal flats. Sedimentary facies of two cores from Gwanghwal tidal flat revealed homogeneous layers in the upper part suggesting rapid deposition after the dyke construction. The sedimentation rate in Gwanghwal tidal flat(GW 6) using $^{210}Pb$ analysis was about 5.4cm/yr which is well matched with the sedimentation pattern revealed by change in topography.

• Korean Journal of Remote Sensing
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• v.21 no.5
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• pp.405-415
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• 2005

It is difficult to classify tidal flat surface that is composed of a mixture of mud, sand, water and microphytobenthos. We used a Linear Spectral Unmixing (LSU) method for effectively classifying the tidal flat surface characteristics within a pixel. This study aims at 1) detecting algal mat using LSU in the Saemangeum tidal flats, 2) determining a suitable end-member selection method in tidal flats, and 3) find out a habitual characteristics of algal mat. Two types of end-member were built; one is a reference end-member derived from field spectrometer measurements and the other image end-member. A field spectrometer was used to measure spectral reflectance, and a spectral library was accomplished by shape difference of spectra, r.m.s. difference of spectra, continuum removal and Mann-Whitney U-test. Reference end-members were extracted from the spectral library. Image end-members were obtained by applying Principle Component Analysis (PCA) to an image. The LSU method was effective to detect microphytobenthos, and successfully classified the intertidal zone into algal mat, sediment, and water body components. The reference end-member was slightly more effective than the image end-member for the classification. Fine grained upper tidal flat is generally considered as a rich habitat for algal mat. We also identified unusual microphytobenthos that inhabited coarse grained lower tidal flats.

• Ocean and Polar Research
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• v.30 no.4
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• pp.485-495
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• 2008

Tidal ranges of inner Saemangeum were largely reduced after the final dyke enclosure, resulting in the former tidal flats becoming either permanently exposed, still influenced by changing tide, or permanently submerged. The effect of reduced tidal range on survival and population stability of tidal flat macrofauna were investigated at three shifted habitats after the dyke completion. At the exposed area, several species survived for 80 days after the dyke enclosure. However, within 120 days, all macrofauna died off due to the elevated temperature during summer. At the intertidal area, some species were maintained until 170 days after the dyke enclosure with a large decrease of the faunal abundance. Species of the submerged area were seen to be more tolerant of the changed environments. The opportunistic species, such as Sinocorophium sinensis, Theora fragilis and Pseudopolydora Kempi, were massively introduced into the submerged area after the dyke enclosure, in which the benthic ecosystem was severely disturbed.

• Ocean and Polar Research
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• v.30 no.4
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• pp.497-507
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• 2008

With the reduction of tidal currents by the closing of the Saemangeun 4th dyke, sedimentary environments on the Gunsan tidal flat, the nearest inner flat from the 4th dyke, has been severely changed, which might affect macrobenthic assemblages on the habitats. In order to investigate changes in macrobenthic community structure on Gunsan tidal flat, field surveys were seasonally conducted at seven stations from April 2002 to November, 2005. Sedimentary facies on the study area were shifted into muddominant facies. The fine sediment has been greatly deposited on the tidal flat with accumulation of organic materials after closing the water passage of 4th dyke section. These drastic variations in environments gave rise to change in macrobenthic community structure. Since the closure of the 4th dyke, the number of species of macrobenthos has gradually decreased. And the filter feeders and sand-favored species such as Urothoe convexa, Macrophthalmus dilatatus, Umbonium thomasi, and Mactra veneriformis have been replaced by the deposit feeders such as Macrophthalmus japonicus and Ilyoplax pingi. MDS ordination based on Bray-Curtis similarity from forth-root transformed species abundance data showed that the macrobenthic communities have passed through three succession stages from 2002 to 2005. During the third stage of 2005 opportunistic species such as Prionospio japonica, Heteromastus filiformis and Sinocorophium sinensis increased in population on the tidal flat.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.6
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• pp.757-761
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• 2003

Spatial distribution and biomass of commercial shellfish were investigated in the Saemangeum tidal flat on the west coast of Korea during August 1999. Thirteen species of shellifsh were collected. Major dominant species of the study area were Umbonium thomasi with a density of $6.7\;ind.{\cdot}m^{-2}\;(38.2\%)$, Mactra veneriformis with $6.6\;ind.{\cdot}m^{-2}\;(37.4\%)$ and Reticunassa festiva with $1.3\;ind.{\cdot}m^{-2}\;(7.2\%)$. Commercially important species such as M. veneriformis ($90.7\;ind.{\cdot}m^{-2}\;69.3\%$), M. lusoria ($15.6\;ind.{\cdot}m^{-2}\;11.9\%)$), C. sinensis ($8.7\;ind.{\cdot}m^{-2}\;6.7\%)$) were dominant in total weight. Most of the shellfish were distributed between the mid-littoral and sub-littoral zones, but C. sinensis and L. flexuosa were distributed mainly in the polluted areas of the supra-littoral zone. The spatial distribution pattern of each shellifsh species generally resembles the Mangyeong and Dongjin estuary. Biomass of commercially important species, M. veneriformis, M. lusoria, C. sinensis and Ruditapes philippinarum in the tidal flat (ca. 850 ha) was estimated to be 774, 135, 67 and 10 tons, respectively.

• Ocean and Polar Research
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• v.30 no.4
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• pp.475-484
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• 2008

The word 'Saemangeum' indicates an estuarine tidal flat in the southwestern part of the Korean peninsula. The Saemangeum Reclamation Project was launched as a national project in 1991 to reclaim a large coastal area of $401\;km^2$ by constructing a 33-km long dyke. The final dyke enclosure in April 2006 has transformed the tidal flat into lake and land. An integrated oceanographic study has been conducted since 2002 as a part of the Government Action Plan to monitor and assess changes in the marine environment. Prior to the dyke enclosure, the coastal environment in the Saemangeum was a complex system governed by tidal motion, estuarine processes, and coastal circulation of the Yellow Sea. The dyke construction has radically changed not only the estuarine tidal system inside the dyke, but also the coastal marine environment outside the dyke. Post to the dyke enclosure, subsequent changes such as red tide, hypoxia, and coastal erosion/deposition occur successively. Red tides appear almost the year round in the inner area. Even under the condition that the sluice gates are fully open, the water quality does not improve as much as the developers would expect, mainly due to the critical reduction of the hydrodynamic stirring power. We will introduce details of our monitoring program and significant changes in the Saemangeum marine environment, based on observations and model results.

• Journal of the Korean earth science society
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• v.28 no.3
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• pp.357-366
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• 2007

In Gomso Bay, on the west coast of Korea, the surface sediments sampled in 1991 and 2006 were analysed to identify the long-term variations of tidal flat sediments. Silt and clay contents have decreased in the bay-mouth tidal flats whereas sand and clay contents have decreased on the inner-bay and bay-head tidal flats over the last 15 year period. In particular, the clay contents of the tidal flats in 2006 were relatively low when compared to those of both tidal flats adjacent to other semi-enclosed bays and those of the tidal flats in 1991. The variations of textural compositions in the tidal flat sediments have led to changes of the sedimentary facies. It indicates that the changes must have been made by the changes of hydrodynamic conditions impacted by human activities, such as the construction of sea-walls, land reclamation, structures of farms constructed compactly near the low water line, and the Saemangeum dyke constructed in the northern part of the area where this research was conducted.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.3
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• pp.125-132
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• 2012

Saemangeum development project is the world's largest tidal flat reclamation project. It is currently under construction, and proceeding with phased developments. The construction of agricultural areas within the Saemangeum reclamed lands is also a part of this project. These areas will have multi-functional complexes aiming to produce mainly eco-friendly horticultural crops and livestock products for the purpose of export. The major concern is to obtain sufficient water with appropriate quality to supply to those areas. The objective of this study is therefore to provide available water supply plans for agricultural purpose, especially for horticulture and livestock complexes. Alternative methods for water supply are purifying water from the Saemangenm lake or using water supply services providing by K-water or local governments. This study investigates to find an economical water supply plan through comparisons of these methods. As a result, the water purification method with Saemangeum lake water could be advantageous for given water supply conditions to horticulture and livestock complexes.