• Journal of environmental and Sanitary engineering
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• v.5 no.1
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• pp.46-53
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• 1990

Analyzing the water quality biologically by the biotic index ($\beta$) of Beck-Tsuda method, for four sites of the water system of Namcheon River which reaches a length of 19.5km and flows through the kyungsan-town and Namcheon-myun in Kyungsan-gun of the suburbs of Taegu and extends to the Gumho-river on the lower, the results are summarized as follows: 1) An indicator species collected from the water system of Namcheon River comprises 78 species. Among them, 27 species are intolerant species and 51 species are tolerant species to water pollution. 2) The water of 2 sites, Weondong-bridge, Sanjeon-iron bridge was clearly water, oligosaprobic zone. The water of Youngdae-bridge was slightly polluted water, $\beta$-measosaprobic zone. But the water of Maehoildong bridge was severely polluted water, polysaprobic zone. 3) The Namcheon River was mainly polluted with sewage from the kyungsan town, with industrial wastes and products from many factories surviving the town. 4) The pH wate system of Namcheon River was alkalescent. 5) The map showing a class of water quality analyzed biologically was also prepared for each site of the water system of Namcheon River, Kyungsan. 6) It is requested that a waste water disposal plant should be established near Youngdae-bridge and Maehoildong-bridge respectively.

• Korean Journal of Environmental Biology
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• v.28 no.4
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• pp.188-195
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• 2010

The Abundance of zooplankton was studied in the pelagic and the littoral zone in four shallow reservoirs along with the Nakdong river basin of S. Korea. In the pelagic zone, there was a higher zooplankton density ($477.5{\pm}312.4$ ind. $L^{-1}$) than in the littoral zone during our study period (t=2.337, p<0.05). Overall, Rotifers were the most abundant group in the studied reservoirs. However, there are no significant correlations between the pelagic and the littoral zone in physical and chemical parameters. In the pelagic and the littoral zone, zooplankton density usually increased with increasing density of aquatic plants in the littoral zone. However, this study showed different trends. Although macrophyte abundance was higher in the littoral zone than in the pelagic zone, zooplankton abundance was higher in pelagic zone. Moreover, when macrophytes (Trapa japonica and Spirodela plyrhiza) covered the complete water surface of the reservoir, zooplankton abundance was higher. It appears that comparisons between the pelagic and the littoral zone give important cues on the selection of habitats by zooplankton. It is assumed that a higher density of aquatic plants does not always imply a higher density of zooplankton in the littoral zone. Furthermore, when the water surface was covered with aquatic plants, the zooplankton communities showed the highest density in the pelagic zone. These results imply that habitat selection of the zooplankton community (Rotifers) is influenced by aquatic plant density with an associated decrease in predation pressure during summer.

• Journal of Korean Society on Water Environment
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• v.30 no.4
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• pp.429-440
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• 2014

This study was conducted to investigate the main cause of water quality deterioration during the spring season in the transition zone between the South Han River and the river-reservoir Paldang. A water quality model modified from QUAL2E (U.S.EPA) was used, and the model showed that eutrophication and algal production in the low flow season affected about 60% of the organic pollution at the downstream of the South Han River. This result means that phosphorus control is prior to external organic material management to ameliorate the deterioration of water quality in the water body.

• Journal of environmental and Sanitary engineering
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• v.9 no.2
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• pp.63-71
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• 1994

An analytic and comparative study on the level of concentration on heavy metals in silt of Han- River was described. The Paldang lake supplies tap water resources for the 20 million residents in the metropolitan zone. It is composed that three steps for water works by the water volume in all 35,072 thousand tons : the first section is 7,251 thousand tons, the second is 15,980 thousand tons and the third is 11,841 thousand tons. However, recently it has becoming a serious social issue for water contamination on Paldang by heavy metals due to gathering of silt. It has concentrated on analysis and comparison study on the level of heavy metals between contamination- estimated zone and the other zones. After all, Concentration on heavy metals of expected none pollute's zone and expected pollute's zone indicate almost similar results. In the end, heavy metals within silt of Han- River consider not to effect on pollution but quantity of natural condition.

• Journal of Environmental Impact Assessment
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• v.27 no.6
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• pp.647-657
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• 2018

This study was carried out to review as criteria for zoning at management plan for river restoration, in case of naturalness of river environment and suitability of water friendly activity suggested at assessment system of river environment in Korea. As a result of reviewing law and guidelines concerned, historic & cultural resources used as criteria for preservation zone, it was judged that the historical and cultural value as the preservation zone needs to be examined in connection with waterfriendly activity zone. In this study, we propose a sequential evaluation method to distinguish the waterfriendly activity zone by applying suitability of waterfriendly activity reflecting land use social characteristics, followed division of preservation and restoration zone at the first stage by the naturalness of river environment reflecting the natural environmental characteristics as a result of application to the test bed, Gap and Yudeung streams. In particular, it was concluded that the results of the present study provided more clear criteria for the problem that the last criteria for zoning did not reflect the difference between the left and the right side of stream, or the designation of the excessive water friendly zone. On the other hand, the criteria for designation in this study reflect the characteristics of various river environments as well as the setting of assessment unit based on the physical characteristics of rivers, and other legal regulations and local situations should be adjusted and supplemented in administrative procedures.

• Economic and Environmental Geology
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• v.50 no.4
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• pp.277-286
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• 2017

Mt. Baekdu which located the border of North Korea and China, is known as a potentially active volcano in a typical mountainous terrain. A lahar on the volcanic area is one of the important hazard that can cause the loss of life and property damage. In order to comprehensively address the impact of lahar hazard at Mt. Baekdu, we simulated lahar inundation area using Laharz_py. We assumed 750 m of additional elevation for DEM to draw proximal hazard zone boundary (PHZB) of Mt. Baekdu that H/L ratio are selected 0.10. And lahar volumes for simulation were estimated to $1{\times}10^6$, $5{\times}10^6$, $1{\times}10^7$, $5{\times}10^7$, $1{\times}10^8$, $5{\times}10^8$, $1{\times}10^9m^3$, respectively. In the results, 15 streams are located near a proximal hazard zone boundary, Amnok (Yalu) river (south), Toudaosonghua river, Jinjiang river and Huapi river (west-southwest), Songjiang river, Xiaosha river, Caozi river and Sandaosongjian river (west-northwest), Toudaobai river, Erdaobai river and Sandabai river (north), Wudaobai river-1, -2, -3 (northeast) and Duman (Tumen) river (east). The results of this study can be used as basic data to make a hazard map for reduce the damage that can be caused by volcanic hazards occurred on Mt. Baekdu.

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.665-671
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• 2018

This paper represents an investigation into the pattern of carbon transportation and composition on an open estuary in the transition zone between the river and marine environment in Tamjin River where stream water flows into the Gangjin Bay. To conduct the study, seven plots were established along an environmental gradient from river and estuary to the ocean. Surface water samples were collected thrice during the summer rainfalls and non-flooding seasons in 2017. The samples were then measured for the concentrations of dissolved organic carbon ([DOC]), particulate organic carbon ([POC]) and dissolved inorganic carbon ([DIC]). An analysis of the results showed that [POC] did not increase in the river even during the summer rainfall. However, [DOC] increased resulting in a higher [DOC]:[POC] ratios for the non-flooding season compared to summer rainfall events. On the other hand, the marine site of the estuary bay showed the highest [DIC] which was stable relative to those of river sites. The results suggest that in an open estuary zone, river and ocean supplied the open estuary zone with different types of carbon materials; mainly DOC supplied from the river and DIC sourced from the ocean.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.67-73
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• 2007

Anhui Province, with a total north-south length of 570km and an east-west width of 450km and a total area of 139.6 thousand km2, accounts for 1.45% of China's total area. The landform and land feature of Anhui Province is diverse, and generally it can be divided into 5 natural regions: (1) Huaibei Plain; (2) Jianghuai Hillocks; (3) Dabie Mountains in the West of Anhui Province; (4) Yanjiang Plain, (5) Mountain Area of southern Anhui Province. Anhui Province is located in the transitional zone of warm and humid zone and subtropical zone, and its mean annual precipitation is 800-1800mm. The province, which has diverse climate, multiple land forms and many rivers and lakes, passes three basins (Huaihe River, Yangtze River and Xin'an River) and has large differences in the time distribution and regional distribution of water resource. Therefore, the development and usage conditions of the water resource in different regions are different.

• Journal of The Geomorphological Association of Korea
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• v.23 no.2
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• pp.1-13
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• 2016

This study analyzed pollen compositions in archaeological site on alluvial plain of Taehwa River, Taehwa-dong, Ulsan-si vegetational and environmental change during 6,200~3,000 yr BP. The results consist upward of Pollen Zone I (Inner Bay environment), Pollen Zone II (Quercus-Alnus stage) and Pollen Zone III (Alnus stage). The pollen grains of Fagopyrum and reddish gray silty horizon including artifacts of the Bronze Age suggest that there was cultivation on dry-field around the study site, although it is not sure that there was paddy-field cultivation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.2B
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• pp.131-137
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• 2012

River areas are classified as conservation, restoration, and recreation zones depending on engineers' opinions from their experiences at present. For conservation zones, almost all engineers have the same opinions because natural characteristics are considered for classification. However, it is difficult to decide a basis in classifying restoration and recreation zones in mixed areas by urban and rural streams. This study attempted to prove an application of a previous study (Song & Yoon, 2008) that suggested two classification techniques to classify conservation or maintenance zones, and reclassify maintenance zones into restoration or recreation zones. The suggested classification techniques of river zones were used to estimate 46 reaches of 20 urban streams, 47 reaches of 29 rural streams, and 48 reaches of 19 mountainous streams to achieve a purpose of this study. The conservation, restoration, and recreation zones were reasonably divided by results of the suggested techniques. A possibility that quantified criterion could be used to classify river zones was proven in this study.