• Biomedical Science Letters
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• v.8 no.1
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• pp.7-11
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• 2002

This study was performed to investigate the infection status with Clonorchis sinensis metacercariae in Pseudorasbora parva from a tributary stream of Naktonggang (River) in Kangso-gu, Pusan. A total of 325 P. parva was collected in 4 sites using fish traps. They were transferred in the laboratory, measured the length and examined by artificial digestion method. In the site I, a total of 72 (80.0%) out of 90 fish examined was infected with 1~665 (112 in average) metacercariae of C. sinensis. The average number of metacercariae infected by the size of fish was 146 in the group of over 8 cm, 61 in 7.0~7.9 cm and 86 in below 6.9 cm. In the site II, a total of 50 (83.3%) out of 60 fish examined was infected with 1~178 (31 in average) metacercariae. The average number of metacercariae was 40 in the group of over 8 cm 35 in 7.0~7.9 cm, 23 in 6.0~6.9 cm and 25 in below 5.9 cm. In the site III, a total of 68 (97.1%) out of 70 fish examined was infected with 1~2,662 (508 in average) metacercariae. The average number of metacercariae was 679 in the group of over 7.0 cm, 444 in 6.0~6.9 cm and 426 in below 5.9 cm. In the site IV, a total of 103 (98.1%) out of 105 fish examined was infected with 1~1,536 (416 in average) metacercariae. The average number of metacercariae was 532 in the group of over 7 cm, 353 in 6.0~6.9 cm and 262 in below 5.9 cm. From the above results, it is confirmed that there are wide differences in the infection status of C. sinensis metacercariae in P. paeva according to investigation sites, and P. parva collected from the lower stream are more heavily infected than those from the upper stream.

• Journal of Korean Society on Water Environment
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• v.31 no.2
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• pp.110-119
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• 2015

The construction of the eight large weirs in the Nakdong River, the second largest river in Korea, caused big changes in the physical environment of the water system. Algal communities and their correlations with environmental factors, mainly nutrients were studied at five weir areas in the Nakdong River from 2010 to 2013. Water quality, hydrodynamics and algal composition were investigated. Results showed that flow velocities were reduced compared with that before weir construction near the areas where are located in the mid and upstreams of the Nakdong River. A seasonal algal community succession was observed and it was mainly correlated with temperature and phosphorus. Diatoms were dominated from winter to spring months and massive diatomic blooms of Stephanodiscus sp. occurred early in March during survey period. Cyanobacterial blooms of Microcystis sp. occurred from July to September 2013 and was preceded by the lower total phosphorus concentration of $0.05mg\;L^{-1}$. The correlations between total phosphorus concentrations and algal abundances were not significant during the survey periods. However, significant correlation with cyanobacteria was found in the period of weir construction after only at the GG survey site and blooms periods of 7 times in the survey sites, and its correlation coefficients were 0.53 (p<0.001) and 0.42 (p<0.01) respectively. When algal bloom was observed, partially low nutrient concentration was observed in the Nakdong River. In conclusion, partially low nutrient concentration which may result from algal bloom was observed, and we presume it caused the reduction of algal abundunces.

• Journal of Korean Society on Water Environment
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• v.23 no.3
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• pp.339-347
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• 2007

Zooplankton community dynamics were studied after establishment of an artificial vegetation island (AVI) in Lake Paldang, from April 2005 to November 2006. There were distinct seasonal and inter-annual changes of total zooplankton abundance at the survey site. Total zooplankton abundance rapidly increased in spring and fall, while it remained low throughout winter. During summer, the dynamics of zooplankton community seemed to be largely affected by hydrological parameters such as, precipitation and inflow. Total zooplankton abundance and biomass below AVI was much higher than that of pelagic zone (L1) in Lake Paldang. Copepoda and cladocera represented the main bulk of the zooplankton community from summer to fall at the both sites. Copepods were more dominant at AVI area, while cladocera were more dominant at pelagic zone (L1). Water quality, prey and habitat condition, species competition between zooplankton seemed to play important roles in dominance of the copepoda and cladocera in zooplankton community at AVI area. Our results conclude that artificial vegetation island provide the stable habitat and besides phytoplankton, diverse food to zooplankton, and consequently influence the diversity and richness of zooplankton community.

• International journal of advanced smart convergence
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• v.9 no.3
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• pp.1-8
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• 2020

Water consumption has grown at more than 2.5 times, comparing the past century. About 2.8 billion people live in river basins with some form of water deficit, because more than 75 % of the river flows are withdrawn for agriculture and other needs. Challenges faced by more and more countries in their struggle for economic and social development are increasingly related to water. This paper proposes a test of an effective local river field environment management solution. And describing a part of a pilot project for the ministry of water resources of Uzbekistan. Current work focused on direct action items of the existing project and describe an IoT routing based solution for local river field environment management solutions. Suggested technological decisions provided by needs and on-site testing results. The paper describes the backbone of IoT routing based river water resources management system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.5
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• pp.173-181
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• 1993

Under natural conditions, rivers do not in general take straight courses but instead take winding courses. This is known as meandering of rivers. Meandering of rivers are so complicated because of the mutual interactions between flow and movable boundaries. In quantitative information, it is important to predict the future location of a river channel(channel migration) because in selecting a bridge site or a location of a road. It may be valuable to know the future impact of a nearby river on those structures. When the prediction model of the migration of channel is used in domestic rivers with high coefficient of river regime, it is rational to use the periodical dominant discharge (PDD), which is named firstly by the author, instead of the average discharge. According to the analysis of the erosion coefficient, the mean deviation on the channel migration, and the bed scour factor, it can bring shedding light on the fact that the discharge is one of the dominant components in channel migration. In project area, the discharge that can shift the channel is slightly greater than 6,000CMS. The prediction model of the migration of channel estimated the erosion coefficient, $E_0$ by the data from the South Han River. This estimated value from the South Han River was also used to predict the migration of the South Han River in year 2000.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.18 no.3
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• pp.233-240
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• 2000

A small rivers take advantage of not only a site of superb scenic beauty, a play space, a rest place but also a momentous waters reservoir, a drainage on territory residents. Likewise, part of the most massed a life space to a region dwellers shall be extremely in harmony with coexistence space in that every kind plant, animal over again a human being and so on. For improvement planning of small river, various way and model are presented. But, it's want of ability for small rivers of a adaption many-side and throwing in a lot of financial resources. Because the improvement planning of small river was designed all small river in a county, the priority must be preprocessed. Now, the counties prioritized for improvement planning of small river are a few, and acquisition and manipulation of the data are time-consuming. Geo-Spatial Information System (GSIS) is specifically designed to manage and analyze spatial data. It will be to offer the benefit to the determination of the improvement priority in a small river. The purpose of this study is to offer priority for improvement planning of small river using GSIS. For this purpose, it was developed using Arc/Info software and AML was used as a developing tool.

• Korean Journal of Agricultural Science
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• v.2 no.1
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• pp.265-279
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• 1975

This study was conducted to investigate the development of Gab river-basin which was a part of the farm land enlargement to contribute to the increased production of food. The results were as follows; 1. Gab river has the upper stream which occupy 50 percent in moumtains and the mid-stream in the Daejeon city area, and the downstream in a field which is about 22.9 percent in which farming area per household is 0.82 ha., agricultural population is 76 percent except of Daejeon city. Also, urban enlargement of mid-stream basin and development of industrial area in the lower stream diminish farm land. Consequently, this area should be developed to farm land to increase farming size. 2. There is no possibility to develop farm land in mountains of which (64.9 percent) is forests and in midstream which was constructed river-improvement. But Weonjeong area and Yongcheon area will be effective area. 3. If river banks of Weonjeong area will make straight with cost of construction 195,000,000 won, bank length 6 km will be useless, water will flow smoothly, flood will be prevented, farm land will develop 21.66 ha in which rice will produce annually 81.698 M/T which is about 10,860,000 won. 4. This area has good conditions of development. that is, investment efficiency (B/C) is 1.47 more than 1.00. 5. This area is a multiple purpose development district. The reasons are that there are beautiful mountains and a reservoir to be expected to construct, so it will be a sight seeing district in the vicinity of Daejeon city. 6. If Honam railway double line and river straight construction had executed simultaneously, cost of construction 50,000,000 won would have saved.

• Journal of Environmental Science International
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• v.30 no.6
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• pp.487-500
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• 2021

To evaluate the geochemical characteristics and assess the pollution in surface sediments of the Nakdong River estuary, two sites adjacent to the estuary bank (Hh1 and Hh2) and one site at the upper part of the estuary bank (Hh3) were investigated. The surface sediments were analyzed for their contents of metals (Cu, Pb, Ni, Cr, Zn, and Al), organic matter (IL, COD, TOC, and TN), and grain size from 2018 to 2020. As a result of the pollution assessment, there was little anthropogenic contamination by most of the metals. The surface sediments in Hh2 had comparatively abundant silt and clay, whereas the other sites were mainly composed of sand. The organic index and contents of organic matter were highest at Hh2. Multivariate statistical analyses (cluster analysis and Pearson correlation analysis) showed that the contents of organic matter and pollution were associated with fine sediment. These results suggest that the geochemical characteristics were changed by the estuary bank built in the research area and that the increase in fine sediment attributable to the low-energy environment resulted in an increase in organic matter pollution.

• Journal of Wetlands Research
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• v.24 no.4
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• pp.320-330
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• 2022

The Hangang river estuary, which is a natural estuary without structures such as estuary barrage, is an ecological pathway connecting the sea and rivers. Accordingly, Hangang river estuary has various species, and there is very valuable. Sediment classification in Hangang river estuary is three-dimensionally and diversely is distributed. Sediment classification in Hangang river estuary is also sensitively changed according to various factors such as climate change and river development. It is typically cause to landform and to develop a compound cross section. In Janghang wetland, the plant success is remarkable according to the morphological change at river bed. The purpose of this study is to identify the mechanism of wetland formation based on the observation on-site. As a result of the observation, Janghang wetland where was artificially created, has been grown according to the river bed change based on the flow rate and the plant success. The viscous surface layer material(fine grains of wash rod properties), which is not the main material(sand) of the river bed, but sub-materials of river bed, jas been settled on the pioneer plants(bolboschoenus planiculmis, etc.). It is an important role in the growth of a compound cross section and a wetland. After the wetland developed to the compound cross section, it is observed that the pioneer plants are transferred to other plant species.

• Journal of Soil and Groundwater Environment
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• v.18 no.2
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• pp.19-26
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• 2013

This study developed the classification of National Soil Quality Monitoring Network (NSQM) and its site selection criteria to meet the recently established purposes of the NSQM. The NSQM were suggested by this study to classify into the six-purposes site groups from the current classification of land uses. The six purposes site groups were 1) intensive observation sites, 2) contaminant loading sites, 3) human activity sites, 4) background sites, 5) river soil sites, and 6) sites near the groundwater quality monitoring wells. Furthermore, this study developed the site selection criteria of NSQM utilizing the accumulated NSQM data, road traffic data, chemical emission data, census, soil information, and the literature related to soil quality variation due to contaminant loads. For selecting suitable sites for NSQM, this study used road traffic, chemical emission, the distance from the contaminant sources, and population information as specific criteria. The suggested site classification and criteria were appled for the current 100 NSQM sites for evaluation. Forty sites were met to the criteria suggested by this study, but sixty sites were not met to the criteria. However, some of the sixty sites also included the obscure sites that their addresses were not apparent to find them.