• Journal of Korean Society on Water Environment
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• v.34 no.4
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• pp.363-374
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• 2018

The Han River serves as an important water resource for the city of Seoul, Korea and in the neighboring metropolitan areas. From the Paldang dam to the Jamsil submerged weir, the 4 water intake stations that are located for the Seoul metropolitan population were under review in this study. Therefore the water quality management in this section is very important to monitor, analyze and review to rule out any safety concerns. In this study, a 3-D hydrodynamic model, EFDC (Environmental Fluid Dynamics Code), was applied to the downstream of the Paldang Dam in the Han River, which is about 23 km in length, to determine issues related to water resource management. The 3-D grid was composed of 2,168 horizontal grids and three vertical layers. In this case, the hydrodynamic model was calibrated and verified with an observed average daily water surface elevation, water temperature and flow rate data for 3 years (2013~2015). The developed EFDC model proved to reproduce the hydrodynamics of the Han River well. The composition ratios of the noted incoming flows at the monitored intake stations for 3 years and their flow patterns in the river were analyzed using the validated model. It was found that the flow of the Wangsuk Stream depended on the Paldnag dam discharge, and it was noted that the composition ratios of the stream at the intake stations changed accordingly. In a word, the Wangsuk Stream moved mainly along the right bank of the Han River under the condition of a normal dam flow. As can be seen, when the dam discharge rate was low, the incidence of lateral mixing was often seen. The scenario analyses were also conducted to predict the transport of conservative pollutants as in the case of a chemical spill accident. Generally speaking, when scenarios were applied, the arrival time and concentration of pollutants at each intake station was thus predicted.

• Journal of the Korean association of regional geographers
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• v.9 no.2
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• pp.203-216
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• 2003

The process of constructing coastal digital elevation model(DEM), for the 3 dimensional analysis, is composed by abstracting land layers for land elevation and water depth, reprojecting UTM, relocating geographical grid, and interpolating works. The geomorphic set of shallow sea, including tidal current, tidal zone deposition, and water depth distribution, was analyzed by eye search of Landsat TM image, masking of land zone, band combination and regression analysis. Some horizontal differences, between combined DEM and surveyed data of shallow sea, was corrected for analysis. Analyzed geomorphic elements are stream channel, alluvial fan, coastal terrace, tidal current. and shallow sea bank. Results of analysis present that transported fluvial materials influence tidal sedimentation, especially from Gahwacheon river, for the role of artificial draining flooding waters from Jinyang Reservoir, almost in the summer season. In the coastal area with less tidal current, more fine materials are deposited. The influence of currental deposition are higher on small pockets with west coast of well developed terraces. The lower skirt of alluvial fans developed into the tidal zone of shallow sea. Small pocket type bays are closed by coastal current, and less influenced from tidal deposition. The bank of Jinju Bay are developed originally from submerging of remnant erosional mountain ranges, and play on the role of trapping fine materials.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.265-278
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• 2016

In this study, an ascending capability experiment was performed with largemouth bass and bluegill, which are exotic fish species inhabiting (the freshwaters) in Korea. The experiment was performed by dividing the subject fish into four groups according to their size and at four flow rates for each group. The number of fish passing through a reference line was analyzed by recording videos, and their swimming and ascending capabilities were observed by the naked eye. The number of fish passing through the reference line did not include those returning downstream within five minutes due to the high flow rate. The flow rate used for the analysis was the mean of the flow rate values measured at the left bank, the right bank, and in the middle of the stream. The results showed that the number of exotic fish migrating upstream decreased as the flow rate increased, regardless of the species and size of the fish. The comparison between the fish species showed that the ascending capability of bass was higher than that of bluegill, but the difference was not significant when considering the difference in the size of the fish. In addition, the upper limit flow velocity allowing the ascending of the exotic fish species was 1.11 m/s, when considering the fish returning to the downstream after the upstream migration and experimental error. The results of the experiment may be used as fundamental data for the blocking of fish and the management of exotic fish species by means of a high flow rate current. Further experiments, verification, and monitoring may need to be conducted continuously to determine whether the fish are able to pass through the reference line at a high flow rate, when they attain a high or cruising velocity. Additionally, the reaction of the fish species should be investigated by considering the response to external forces as well as pressure differences due to the flow rate.

• Journal of Korean Society of Disaster and Security
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• v.12 no.1
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• pp.23-34
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• 2019

It is an urgent issue to manage and reduce non-point pollution sources for improving the water quality of stream and lakes in rural areas. In this study, in order to reduce non-point pollution sources in rural area, Gabion mattresses was proposed to provide protection of riverbanks with anaerobic and aerobic area. The utilization of this was assessed by lab scale model test and pilot plant test. After filling the inside of the gabion mattresses with aggregate, the filtration zone under anaerobic and aerobic conditions was formed to treat the contaminants. In addition, vegetation was deposited on the surfae of the gabion to prevent the inflow of soil and to promote purification by the plant. COD and nitrogen content (T-N, $NH_4{^+}$, -N, $NO_3{^-}N$) were monitored in model and field tests. The lab scale model test showed removal efficiency of 17% of TCOD, 35% of SCOD, 14% of TN, 62% of $NH_4{^+}$, -N, and 33% of $NO_3{^-}$ N. Also, pilot plant test showed removal efficiency of 24% of TCOD, 29% of SCOD, 47% of TN, 50% of $NH_4{^+}-N$, 33% of $NO_3{^-}$, N and 29% of TP.

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.4
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• pp.96-105
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• 2010

The purpose of this study is to offer raw data on managing naturalized plants and the ecological characteristics of urban streams by researching the naturalized plants distributed in Naedong Stream, Changwon-si. The results are as follows. The numbers of naturalized plants were summarized as 45 taxa: 18 families, 38 genera, 43 species and 2 varieties. There were 3 taxa of invasive alien plants: Rumex acetocella, Ambrosia artemisiifolia var. elatior and Sicyos angulaus. In an analysis of life forms, there were 2 taxa of megaphanerophytes, 1 taxa of nanophanerophytes, 3 taxa of chamaiphytes, 7 taxa of hemicryptophytes, 1 taxa of geophytes and 31 taxa of therophytes. The urbanized and naturalized indices were 16.6% and 25.1%, respectively. The results of an analysis by vertical structures showed that naturalized plants included 30 taxa upstream, 42 taxa midstream and 32 taxa downstream. For the urbanized index, upstream was 11.1%, 15.5% in midstream and 11.8% in downstream. For the naturalized index, upstream was 21.7%, 33.3% in midstream and 37.2% in downstream. An analysis of crossing structures showed at taxa of 39 naturalized plants on bank. 30 taxa along the riverside and 7 in the water. For the urbanized index, banks were 14.4%, riverside 11.1% and waterside 2.6% while the naturalized index included 30.5% on the banks, 30.6% along the riverside and 20.0% in the water. As regards the management of naturalized plants, because Remex acetocella, Ambrosia artemisiifolia var. elatior and Sicyos angulaus have a negative impact on the ecosystem, they need to be efficiently controlled.

• Journal of Korea Water Resources Association
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• v.36 no.3 s.134
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• pp.455-464
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• 2003

In this paper, the experiments with installing a rainfall storage tank in the sub-surface were conducted and the reduction rates of the total runoff volume were investigated. The analysis were conducted based upon the variations of the rainfall intensity, surface coverage and surface slope. The reduction rate of the runoff volume was varied from 42.3% to 52.9% with the soil in the bank of the Seung Gi stream. In the experiments, the rainfall intensities were varied from 40mm/hr to 100mm/hr and the results indicate that the direct runoff reduction can be obtained with the installation of the rainfall storage tank in the sub-surface. The variation of the stored volume in the tank is very large in the mild slope but very small in the steep slope with over 3% slope. With this results, the reduction of the direct runoff volume for the longtime flood is expected with the installation of the rainfall storage tank in the region haying the steep slope such as the mountain area.

• Korean journal of communication and information
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• v.65
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• pp.27-50
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• 2014

This paper analyzed how people of Late Chosun Dynasty communicated through the 8 Korean novels with the assumption that the fictitious world of novels reflect the social circumstances of that time. In oral communication, hierarchical relationship of kin was the most important variable. Between strangers social status was the most important variable. The communication between people and the authorities was performed mostly by oral because the majority of people were illiterate. In village community, information on the common interest diffused by oral communication in bank of stream, parish pump and auberges. Through this process the public opinion of community was formed. In media communication diverse patterns were performed, such as letters, written materials, and diary. Contrary to the western culture, it was analyzed that written material was taken more reliable than oral communication. The fact that reading diaries of others were permitted showed that the concept of privacy had not existed yet. Books were used for the purposes of education and leisure. In conclusion it can be said that the communication of people in Late Chosun Dynasty was mainly by oral communication and supplemented by written materials.

• Journal of Korean Society for Geospatial Information Science
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• v.15 no.2 s.40
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• pp.25-31
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• 2007

The recent frequent heavy rainfall has caused an increased in soil erosion and the soil drain which drained soil has caused decreased in channel radius and environmental problems by turbidity. In this study, the optimum size of the sediment basin was tested with soil erosion estimated from the Universal Soil Loss Equation (USLE) in the basin using by GIS data. The results show that the estimated soil erosion and the designed soil deposit are $72.1\;m^3$ and $85.0\;m^3$ respectively and the size of sediment basin is proper. In this study the water depth was calculated from the Hec-Ras model to test the stability of the bank and to prove submersion of the inside fields from stream overflow.

• Korean Journal of Ecology and Environment
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• v.38 no.spc
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• pp.44-53
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• 2005

The Nakdong River, which lies in a monsoon climate zone with warm rainy summers and cold dry winters, is a typical ecosystem showing the attributes of a regulated river. In 2003, the total annual rainfall (1,805 mm) was higher than the average of the past nine years from 1994 to 2002 (1,250 mm). In September a powerful typhoon, Maemi, caused a big impact on the limnology of the river for over two months. Among the limnological variables, turbidity in 2003 (37.4 ${\pm}$ 94.1 NTU, n = 54) was higher than the annual average for ten years (18.5 ${\pm}$ 2.3 NTU, n = 486) in the lower part of the river (Mulgum: RK 28). Furthermore, physical disturbance (e.g. stream bank erosion within channel) in the upstream of the Imha Dam (RK ca. 350; river distance in kilometer from the estuary barrage) in the upper part of the river was a source of high turbidity, and impacted on the limnological dynamics along a 350 km section of the middle to lower part of the river. After the typhoon, high turbidity persisted more than two months in the late autumn from September to November in 2003. Flow regulation and the extended duration of turbid water are superimposed on the template of existing main channel hydroecology, which may cause spatial changes in the population dynamics of plankton in the river.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1997-2002
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• 2007

This study selected soil erosion source area of Dechung basin by soil erosion estimation model and field survey for effective soil conservation planning and management. First, unit soil erosion amount of Dechung basin is analyzed using RUSLE (Revised Universal Soil Loss Equation) model based on DEM (Digital Elevation Model), soil map, landcover map and rainfall data. Soil erosion model is difficult to analyze the tracing route of soil particle and to consider the characteristics of bank condition and the types of crop, multidirectional field survey is necessary to choice the soil erosion source area. As the result of analysis of modeling value and field survey, Mujunamde-, Wondang-, Geumpyong stream are selected in the soil erosion source area of Dechung basin. Especially, these areas show steep slope in river boundary and cultivation condition of crop is also weakness to soil erosion in the field survey.