• Ecology and Resilient Infrastructure
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• v.2 no.4
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• pp.324-329
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• 2015

For the restoration of lateral connectivity between rivers and floodplains, it is important to find the isolated former floodplain (IFF) and to characterize its land use in Korean rivers which were channelized by levee constructions for flood protection. The aim of this study is to map the IFF and to assess its land use pattern in the Nakdong River, Korea. The isolated former floodplain was explored by being overlapped on a digital elevation model (DEM), digital topographic map and design flood level using a geographical information system (GIS) in the Nakdong River basin. The land use of the identified IFF was classified by land-use map. The total number of IFFs was 384 and their total area was $291km^2$. While IFFs were usually surrounded by mountain forest in the upper river area, they tended to be located on wide plain areas in the downstream area of Nakdong River. The land use pattern of IFFs was mostly farmland (73.9%) and urban areas (12.7%) in the river. The results of delineation and land use analysis of isolated former floodplain in the Nakdong River will be used as a base line data for planning stream restoration.

• Journal of the Korean Geographical Society
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• v.40 no.6 s.111
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• pp.716-729
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• 2005

In the Yeongpyeong River, one of the branches of Hantan River, there 4 fluvial terraces are identified. During the Quaternary, lava flow from Hantan River had gone 4.5km into upstream Part of the Yeongpyeong River and damed its entrance, and resultantly its lower basin had become a lava-damed paleolake. This study deals with fluvial terrace surface classification, stratigraphic analysis, deposits analysis, and OSL age dating in from Gungpyeongri to Seongdongri in lower reach of Yeongpyeong River, in order to identify Seomorphological Process of the terrace landforms relating to duration of lava-damed paleolake. Terrace surface T4, named Baekeuiri Formation, has been located under Jeongok lava layer to indicate pre-lava river bed. Terrace surfaces T3 and T2 are supposed to be formed during paleolake time, based on $3{\~}4m$ thick sand deposits including pebble and cobble layers, and clay and silt layers intersected with sand ones in nearly horizontal bedding. Terrace T1 is estimated to be formed as post-lake fluvial terrace after dissection of lava dam, based on the more fresh phase of deposits and very low height from present riverbed. The results of the OSL age dating for the T3 deposit layers indicate approximately $33{\~}40ka$, and still lake phase at that time.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.43-43
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• 2021

Sesan강과 Srepok강은 베트남, 캄보디아, 라오스가 공유하는 3S강 유역 (Sesan강, Srepok강, Sekong강)의 일부로 국제 공유하천으로 관리되고 있다. 3S강 유역은 Mekong강의 중요한 지류이며 Mekong강 유역의 상당 부분을 구성한다(Mekong강 유역 면적의 10%, 연간 총 유출량의 20%). 베트남에 속해 있는 Sesan강 유역면적은 11,255km², Srepok강 유역면적은 18,162km²이다. Sesan강과 Srepok강의 상류는 베트남 중부 고원의 긴 산맥에 위치하고 있으며, 하류는 캄보디아에 위치해 있어 상·하류간 긴밀한 협력이 필요하다. Sesan강과 Srepok강 유역은 기후변화에 따른 홍수, 가뭄, 수력발전소 건설로 인한 유출량 변동에 따른 상·하류 분쟁, 사면침식 및 퇴적 등 많은 문제와 도전에 직면할 것으로 예측되고 있다. 본 연구에서는 World Bank의 "Viet Nam Mekong Integrated Water Resources Management (M-IWRM) Project의 일환으로 베트남 정부 차원에서 처음으로 구축한 수자원관리 의사결정지원시스템인 "DSS-2S"를 활용하여, Sesan-Srepok강 유역의 수자원 계획을 수립하였다. DSS-2S는 MIKE Hydro Basin을 기반으로 SWAT모델 등과 연계 하여 구축되었다. DSS-2S는 2S 유역의 모든 주요 하천과 지류를 반영하였으며. 여기에는 17개의 수력발전 댐과 주요 지류에서 용량이 3백만 m³ 이상인 기타 저수지가 포함되었다. 이 보다 작은 용량의 저수지는 대표적인 저수지로 그룹화 되어 반영되었다. 기후변화 및 사회-경제적 발전계획 등을 반영하여, 2030년과 2050년을 목표연도로 생활, 공업, 농업, 관광, 유지용수 등 용수 수요를 추정하였다. 50% 및 85% 빈도의 공급 가능성을 고려하여 물 배분은 물 수요를 충족하고 지하수 개발 최소화를 기준으로 고려되었다. 분석 결과에 의하면 2S강 유역의 총 수자원은 32.2억 m³으로 그중 지표수자원은 29.2억 m³, 안정적으로 이용 가능한 지하수자원은 2.97억 m³으로 분석 되었으며, 지표수와 지하수 연계를 고려하면 전체 2S 강 유역에 물 부족하지는 않으나, 개별 공급 지점을 고려할 때 4월과 5월에 일부 지역에서 물 부족이 나타날 것으로 예측 된다. 장래 물 부족 해결을 위한 대안들을 제시하였으며, 본 성과는 베트남 중앙 정부의 장기수자원 종합계획 수립의 기본 자료로 활용 될 예정이다.

• 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.

• Korean Journal of Ecology and Environment
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• v.43 no.1
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• pp.44-54
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• 2010

In this study, a comprehensive exploration and evaluation of washland candidate locations by means of field monitoring as well as spatial analysis in six major river system (Han, Nakdong, Nam, Geum, Youngsan, and Seomjin Rivers). Washland(in other words, river detention basin) is an artificial wetland system which is connected to streams or rivers likely to riverine wetlands. Major purpose of washland creation is to control floodings, water supply and purification, providence of eco-cultural space to human and natural populations. Characteristics and functions of riverine wetlands can be expected as well, thus it is believed to be an efficient multi-purpose water body that is artificially created, in terms of hydrology and ecology. Geographical information and field monitoring results for the washland candidate locations were evaluated in 2009, with respect to optimal location exploration, ecosystem connectivity and educational-cultural circumstances. A total of $269\;km^2$ washland candidate locations were found from spatial analysis (main channel of Rivers South Han, 71.5; Nakdong 54.1; Nam, 2.3; Geum, 79.0; Youngsan 46.4; Seomjin 15.7), and they tended to be distributed in mid- to lower part of the rivers to which tributaries are confluent. Field monitoring at 106 sites revealed that some sites located in the Rivers Nam and Geum is appropriate for restoration or artificial creation as riverine wetlands. Several sites in the Nakdong and Seomjin Rivers were close to riverine wetlands (e.g., Upo), habitats of endangered species (e.g., otters), or adjacent to educational facility (e.g., museums) or cultural heritages (e.g., temples). Those sites can be utilized in hydrological, ecological, educational, and cultural ways when evidence of detailed hydrological evaluation is provided. In conclusion, determination of washland locations in the major river basins has to consider habitat expansion as well as hydrological function (i.e. flood control) basically, and further utility (e.g. educational function) will increase the values of washland establishment.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.5
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• pp.147-155
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• 1993

An urban runoff model is proposed in this study, which is composed of a surface runoff model and a channel routing model. ILLUDAS is selected as the best fit model for the surface runoff computation, and the dynamic wave model using weighted four-point implicit finite difference scheme is used to perform the channel routing. The 3rd Seongbook bridge basin located in Seoul is selected as the test basin for the proposed model, and the rainfall-runoff data are collected to calibrate and verify the urban runoff model. The computed results by this model showed the fair accuracy when compared with the observed hydrographs. So the model proposed in this study could be used to compute the urban river flow as well as the outflow from the urban drainage area.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.4
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• pp.52-60
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• 2004

In order to analysis of the water pollution of the Anyang stream(one of the biggest branch streams of the Han River) and its main tributaries, the geological and topographical and rainfall features in its basin were investigated. To do this, the water samples were collected 23 points of the upper, mid and down of Anyang stream and its tributaries and were analyzed based on the chemical methods, Korean Biotic Index(KBI) and Saprobien systems. The Anyang stream basin has a characteristic of topographical torrential heavy rainfall like a typical rainfall feature in Korea. The concentration and the outflow rate of rainfall is very different in seasonal, and water pollution in dry season is especially severe. After 1997, although the water quality status of stream has been improved gradually, the concentration of T-N and SS at the upstream is increased due to the deficiency of facility used for collecting wastewater released from industrial factories, livestock farms and residential areas. The mainstream of the Anyang stream is classified into the 5th grade water as polysaprobic water area according to Saprobien system and the biotic index is over 2.5 in overall. Most of tributaries have 1~3 grade water limit with ${\alpha}$- and ${\beta}$-mesosaprobic except the upper and mid streams of Samsung tributary, in which pollution status is the lowest part. Though Sambong tributary is ${\alpha}$-mesosaproboic, biotic index is low because of the appearance of abundant benthos animals in farming and fishing villages.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5B
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• pp.481-488
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• 2006

This paper suggests a novel approach of integrating the quasi-distributed watershed model SWAT with the fully-distributed groundwater model MODFLOW. Since the SWAT model has semi distributed features, its groundwater components hardly considers distributed parameters such as hydraulic conductivity and storage coefficient. Generating a detailed representation of groundwater recharge, head distribution and pumping rate is equally difficult. To solve these problems, the method of exchanging the characteristics of the hydrologic response units (HRUs) in SWAT with cells in MODFLOW by fully combined manner is proposed. The linkage is completed by considering the interaction between the stream network and the aquifer to reflect boundary flow. This approach is provisionally applied to Gyungancheon basin in Korea. The application demonstrates a combined model which enables an interaction between saturated zones and channel reaches. This interaction plays an essential role in the runoff generation in the Gyungancheon basin. The comprehensive results show a wide applicability of the model which represents the temporal-spatial groundwater head distribution and recharge.

• Parasites, Hosts and Diseases
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• v.21 no.2
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• pp.193-204
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• 1983

The Jinyang Lake is dammed up Nam River, and surrounded by Jinju city and four counties; Jinyang, Sanchong, Hading, and Sachon in kyongsang-Nam-Bo, Korea. The areas around this man-made lake have been known as an endemic focus of clonorchiasis in Korea. The present study was first aimed to know the distribution of freshwater mollusks including medically important snails, and larval trematodes shed from Parafossarulus manchouricus and Semisulcospira libertina. In addition to above studies, water analyses in each snail habitat were carried out in order to figure out a part of their environmental factors. This malaco-ecological survey was done at the sirs areas around upper, middle and lower parts of the lake for 4 months, August-November, 1983. Total nine species of freshwater mollusks were collected throughout the study: 4 species of gastropods: Semisulcospira libertina, Cipangopaludina chinensis, Parafossarulus manchouricus and Radin auricularia, and 5 species of bit.alves; Unio dcuglasiae, Ancdonta woodiana, Lamprotula gottschei, Corbicula yuminea and Limncperma lucustris. Out of nine species of freshwater mollusks, three species of gastropods; S. Zibertina, p. manchouricus and R. auricularia were medically important in terms of the transmission of digenetic trematodes to humans. P. manchouricus and R. auricularia were mainly collected from the shallow ponds and the irrigation channels with the muddy basin, but S. libertine and the bivalves were only collected from the stream of Nam River where the gravels and rocks were dominant. The levels of dissolved oxygen (D.O.) and biochemical oxygen demand \(B.O.D._5)\ of the water specimens sampled from the study areas ranged from 6.0 to 9.6 ppm and from 0.4 to 1.6 ppm respectively. As a result, it is considered that water system around the Jinyang Lake might be relatively clean without any heavy pollution of aquatic microorganisms and organic materials during the period of this study. On the other hand, eight metalic constituents from the water samples were also assayed, and all metalic ions detected were remarkably low below the legal criteria. However, calcium ion in the water samples from the habitats of P. manchouricus was considerably higher than others. Infection rates of digenetic trematodes in the snails were 6.9% in P. manchouricus and 4.8% in S. libertine, respectively. P. manchouricus snails harboring with thc cercariae of Clonorchis sinensis were only 0.14% among the snails examined, and other trematode cercariae except cercaria of C. sinensis were: furcocercus cercariae, cercaria of Loxogenes liberum type I and II. S. libertine snails parasitized with the cercariae of Metagonimus yokogawai were 1, 5% out of the snails examined, and no cercaria of Paragonimus westermani was found in S. libertine snails in the present study. Digenetic trematode cercariae other than M. yokogawai observed in S. libertina snails were: Cercaria yoshidae (B type) , Cercaria cristata, Cercaria innominatum, Cercaria of Centrocestus formosanus and Cercaria nipponensis.

• Journal of Korean Society on Water Environment
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• v.30 no.3
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• pp.329-339
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• 2014

This study aims to estimate chlorophyll-a concentration in rivers using multi-spectral RapidEye imagery and Spectral Mixture Analysis (SMA) and assess the applicability of SMA for multi-temporal imagery analysis. Comparison between images (acquired on Oct. and Nov., 2013) predicted and ground reference chlorophyll-a concentration showed significant performance statistically with determination coefficients of 0.49 and 0.51, respectively. Two band (Red-RE) model for the October and November 2013 RapidEye images showed low performance with coefficient of determinations ($R^2$) of 0.26 and 0.16, respectively. Also Three band (Red-RE-NIR) model showed different performance with $R^2$ of 0.016 and 0.304, respectively. SMA derived Chlorophyll-a concentrations showed relatively higher accuracy than band ratio models based values. SMA was the most appropriate method to calculate Chlorophyll-a concentration using images which were acquired on period of low Chlorophyll-a concentrations. The results of SMA for multi-temporal imagery showed low performance because of the spatio-temporal variation of each end members. This approach provides the potential of providing a cost effective method of monitoring river water quality and management using multi-spectral imagery. In addition, the calculated Chlorophyll-a concentrations using multi-spectral RapidEye imagery can be applied to water quality modeling, enhancing the predicting accuracy.