• Journal of Soil and Groundwater Environment
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• v.7 no.4
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• pp.31-39
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• 2002

Pollutants from industry, mining, agriculture, and other sources have contaminated sediments in many surface water bodies. Sediment contamination poses a severe threat to human health and environment because many toxic contaminants that are barely detectable in the water column can accumulate in sediments at much higher levels. The purpose of this study was to make optimal treatment and disposal plan o( sediment for water quality improvement in small-scale resevoir based on an evaluation of degree of contamination. The degree of contamination were investigated for 23 samples of 9 site at different depth of sediment in small-scale J river. Results for analysis of contaminated sediments were observed that copper concentration of 4 samples were higher than the regulation of hazardous waste (3 mg/L) and that of all samples were exceeded soil pollution warning levels for agricultural areas. Lead and mercury concentration of all samples were detected below both regulations. Necessary of sediment dredge was evaluated for organic matter and nutrient through standard levels of Paldang lake and the lower Han river in Korea and Tokyo bay and Yokohama bay in Japan. The degree of contamination for organic matter and nutrient was not serious. Compared standard levels of Japan, America, and Canada for heavy metal, contaminated sediment was concluded as lowest effect level or limit of tolerance level because standard levels of America and Canada was established worst effect of benthic organisms. The optimal treatment method of sediment contained heavy metal was cement-based solidification/stabilization to prevent heavy metal leaching.

• Korean Journal of Environmental Agriculture
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• v.30 no.2
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• pp.144-152
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• 2011

BACKGROUND: Eutrophication occurs occasionally in flood control reservoirs around Juam lake in summer and early autumn. Lakeside macrophyte which is one of internal pollutants effects on water quality when it is submerged during water surface is rising after rainy season. METHODS AND RESULTS: To improve water the quality of water from water supply source and to establish the management plan of submerged plants in flood control reservoirs around Juam Lake, the removal and release velocities of nutrients by submerged plants in site 1 and 2 were investigated. Removal or release velocity constant (K) of COD by Carex dimorpholepis Steud in column was 0.07~0.18 $day^{-1}$ at 0~4 days after flooding, -0.23~-0.17 $day^{-1}$ at 5~19 days after flooding and -0.28~0.03 $day^{-1}$ at 20~33 days after flooding. Removal or release velocity constant (K) of T-N by Carex dimorpholepis Steud was 0.02 $day^{-1}$ at 0~4(8) days after flooding, -0.13~-0.10 $day^{-1}$ at 5(9)~33 days after flooding in column. Removal or release velocity constant (K) of T-P by Carex dimorpholepis Steud was 0.05~0.06 $day^{-1}$ at 0~4 days after flooding, -0.14~-0.09 $day^{-1}$ at 5~33 days after flooding. Release velocity constant (K) of nutrients by Miscanthus sacchariflorus Benth was lower than that by Carex dimorpholepis Steud. In site 1, the amount of nutrients release by Carex dimorpholepis Steud was 6,719 kg/month/area for COD, 2,397 kg/month/area for T-N and 466 kg/month/area for T-P. The amounts of nutrients release by Carex dimorpholepis Steud were higher than those by Miscanthus sacchariflorus Benth in both sites. CONCLUSION(s): The results of this study suggest that COD, T-N and T-P in water quality of Juam lake were strongly influenced by submerged plants in flood control reservoirs.

• Journal of Wetlands Research
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• v.20 no.4
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• pp.353-362
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• 2018

The purpose of this study is to suggest a structure plan for improving the utilization of inactive storage in the dam for overcoming the drought. Inactive storage in the dam is composed of the emergency storage and dead storage. The emergency storage can be used for the case of emergency such as drought. But, in general, the dead storage for sedimentation is not used even for the emergency. Therefore, this study considers the part of dead storage that the sedimentation is not progressed yet can be used during the severe drought period and is called "drought storage in a dam". The accurate Sediment Level(SL) analysis for the computation of the drought storage should be performed and so the present and future SL in the dam reservoir is estimated using SED-2D linked with RMA-2 model of SMS. After the consideration of additionally available storage capacity based on the estimated SL, the drought storage is finally determined. Present data based on historical data, future predicted future climate factors by Representative Concentrarion Pathways(RCP) 8.5 scenario. Then, using the TANK model, dam inflows were determined, and future period such as SL and drought storage were suggested. As the results, we have found that the available drought storage will be reduced in the future when we compare the present drought storage with the future one. This is due to a increase variability of climate change. Therefore, we should take the necessary study for the increase of available drought storage in the future.

• Korean Journal of Ecology and Environment
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• v.52 no.3
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• pp.245-265
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• 2019

Biotope, which represents the characteristic habitats of living organisms, need to be identified as essential for the efficient creation and sustainable management of urban ecosystems. This study was carried out to provide the basic information for ecological urban planning by analyzing types and attributes of the biotop established throughout the whole area of the Pohang city, a representative industrial city in Korea. The biotop established in Pohang city is composed of 12 types including forests (coniferous, deciduous, and mixed forests), agricultural fields (rice paddy and upland field), green facilities, river, reservoir, bare ground, residential area, public facilities, commercial area, industrial area, roads, and schools. As a result of analyzing the properties according to biotop types, industrial, commercial and residential areas, which represent urban areas, was dominated by introduced vegetation. Moreover the introduced vegetation is usually composed of exotic plants or modified forms for landscape architecture and horticulture rather than native plants, which reflects ecological property of both region and site. As the distance from the urban center increases, the agricultural field showed a form of typical farmland, whereas the closer it is, the more form of greenhouse farming. Natural green spaces were divided into riparian vegetation established along the stream and forest vegetation. Forest vegetation is consisted of secondary forests (seven communities) and plantations (three communities). The urban landscape of Pohang city is dominated by the industrial area. Among them, the steel industry, which occurs large amounts of heat pollution and carbon dioxide, occupies a large proportion. On the other hand, green space is very insufficient in quantity and inferior in quality. This study proposed several restoration plans and further, a green network, which ties the existing green spaces and the green space to be restored as a strategy to improve the environmental quality in this area.

• 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.