• Journal of Wetlands Research
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• v.11 no.3
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• pp.71-80
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• 2009

Due to the various characteristics of urban river, rehabilitation project for natural river requires distinct alternative approach and selection method for each different types of river. In this study, naturalness of a river was used to establish such alternative for the business and rehabilitation plan for natural river. To assess the naturalness of a river, through AHP, designed to fit the environmental conditions in Korea, was employed. Furthermore, a method that conveniently compares and selects an alternative for rehabilitation plan for natural river by referencing Urban River Basin Enhancement Methods (URBEM) was proposed. After selecting the evaluation items for assessing the naturalness of the river based on the characteristics of the river, multiple alternatives were constructed and the naturalness of river for each of those alternatives were estimated. Comparing the estimated values has made the measurement of the natural recovery effect and the product of river rehabilitation plan for each alternative efficient. In conclusion, selecting the items for evaluating the naturalness of a river with respect to its characteristics was found to be effective for establishing the rehabilitation plan for natural river.

• Journal of Environmental Impact Assessment
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• v.16 no.3
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• pp.187-194
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• 2007

It started road constructions around river in 1990s. These maintenances concentrate on city river. Because river lives no living things and men don't come near there. But in spite of these river environment go to rack, river maintenances still keep on using preexistence method since 1990s. Only a part of city river environment maintenances consider environmental ability of passive river, river maintenance of a purpose of flood control still don't consider in the concrete. Because propulsion device that consider environment ability of passive river and possible application techniques don't complete. In accordance, A natural river maintenance needs absolutly a series of river projects. Because a natural river maintenance prevents a damage of environment ability. This study is to assume the flood really happened and to carry out the flood damage simulation needed in overflow simulation about the inundated zone. Also, This study examine unstable part about the hydraulic characteristic as velocities, stream power, shear, hydraulic depth, flow area in basin. And this study applied the HEC-RAS(river analysis system) model to predict flood overflow in youngsan river basin. Project flood is used the return period 100 year and inputed data that was calculated in intensity figures of illumination.

• Journal of Environmental Science International
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• v.22 no.2
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• pp.195-203
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• 2013

I investigated the river morphology and river naturality according to the environment of the Hwang River. The numbers of flexions at the upstream regions were more than those of downstream regions. The Hwang River showed very low overall diversity of the flow. Materials of river shore at low channel width were mainly boulders or gravel at the upstream regions, and the middle and downstream were silts and clay. Artificial masonry and natural materials were mixed from materials of river levees. The Hwang River was some of the natural herbaceous vegetation to riparian zones. Land utilities for floodplain were extremely overall farmland were predominant, and partly used by natural vegetation in the forest, a soccer field, some park facilities, residential, and commercial facilities. The water was width sleep / rivers beam ratio of 10 to 20%. Currently estimation for river naturality widely used in rivers were consisted of a narrow wide a variety of items and did not reflect the actual.

• Journal of Korean Society on Water Environment
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• v.23 no.3
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• pp.332-338
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• 2007

In this study the flow duration curves for Nakdong river basin are analyzed. The TANK model is used as a hydrologic simulation model whose parameters are estimated from 8-day intervals flow data measured by NIER Nakdong River Water Environment Laboratory. As a comparison result between generated natural and present river flow, the present river flow is higher than the natural river flow in the up- and mid-stream of Nakdong river, while the present river flow is lower than the natural river flow in the down stream of Nakdong river.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.2
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• pp.95-104
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• 2010

The purpose of this study is to analyze the correlation between physical stream characteristics and bed materials in natural rivers. Accordingly, four natural rivers were selected reference streams, they were Nam river, Sumjin River, Naesung River and Han River. Grain size distributions of bed materials were gravels, cobbles and boulders in Han river and Nam river, were sand, gravels, cobbles and boulders in Sumjin river and were sand in Naesung river. Four reference streams were divided into each two reference reaches (straight and bend) by plan and profile characteristics of naturally meandering stream. Therefore various reference reaches were chosen in the aspect of physical stream characteristics and grain size distributions. The results investigated and analyzed are as follows. The streams that grain sizes distributions of river bed materials were coarse were stable because they had variety of bed slope without sediment deposition, and then the riffles frequency and the physical characteristics were various. Also, velocitydepth regime were various in four kinds, and the response parts for water level change were small, so that channel flow status were stable and excellent condition. On the other hand, sand river that grain sizes distributions of river bed materials were fine had not the variety of parameters as velocity-depth regimes, sediment deposition, channel flow status and riffles frequency, so that the physical stream characteristics were not various.

• 한국생태학회:학술대회논문집
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• 2002.08a
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• pp.113-118
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• 2002

Vegetation and riverine structures were compared among urban and several semi-natural rivers by applying direct gradient analysis and ordination method. Urban rivers showed different species composition from the semi-natural ones. Species composition of semi-natural rivers depended on the geographical positions, such as the upstream, midstream, and downstream and on micro-topographies, such as the waterside, flooding bed, and embankment. Semi-natural rivers showed gentle change in micro-topography, whereas urban one did not so. Our restoration plan to improve the ecological quality of the degraded urban river by imitating semi-natural river was prepared based on those data.

• The Korean Journal of Ecology
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• v.25 no.4
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• pp.247-252
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• 2002

Vegetation and riverine structures were compared among urban and several semi-natural rivers by applying direct gradient analysis and ordination method. Urban rivers showed different species composition from the semi-natural ones. Species composition of semi-natural rivers depended on the geographical positions, such as the upstream, midstream, and downstream and on micro-topographies, such as the waterside, flooding bed, and embankment. Semi-natural rivers showed gentle change in micro-topography, whereas urban one did not so. Our restoration plan to improve the ecological quality of the degraded urban river by imitating semi-natural river was prepared based on those data.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.5
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• pp.19-29
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• 2012

The purpose of this study is to suggest improvements of Eco-Natural map preparation guideline by presenting assessment methods that can be applied to the result of river ecosystem health survey and assessment, using the Geographic Information System. The area for studying is the main stream of the Hwang River where is easy to collect data and available to compare before and after of river assessment. It was reevaluated by reflecting the result of river ecosystem health assessment of the Ministry of Environment. As the result, Eco-Natural map of the study area reflecting the river assessment, the changes in the area ratio by grade have been increased from 1.14% to 14.03% in the first-grade and from 24.64% to 43.91% in the second-grade. It is considered to present more realistic grade due to the assessment of the rivers that have not been reflected in the meantime. Consequently, the result of this study will be useful for establishing the development projects on the rivers, providing the foundation for more realistic and active protection.

• Journal of Wetlands Research
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• v.12 no.2
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• pp.87-93
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• 2010

River restoration plan and selection method are needed to reflect the diversity of river. Meanwhile, the ultimate purpose of river restoration is natural recovery of the river. Recently. hydrophilic enhancement is a tendency to include. In this study, naturalness of a river was used to establish alternative for the natural river recovery. Also, naturalness of a river calculated by using the evaluation of river naturalness that was developed using multi-criteria decision making to fit the environmental conditions in Korea. After selection the evaluation items for assessing the naturalness of the river based on the characteristics of the river, multiple alternatives were constructed and the naturalness of river for each of those alternatives were estimated. Comparing the estimated values has made the measurement of the natural recovery effect for each alternative efficient.

• ALGAE
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• v.18 no.2
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• pp.157-167
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• 2003

Effect of the effluent of the sewage and wastewater plants on the algal growth was investigated from the 19 plants located in the Nakdong river basin. Most of the samples showed high values of the algal growth potential (AGP) when they were mixed with natural river water at 20% of final concentration. At 20% of the mixing ratio, the mixed effluents of sewage and wastewater showed 3.5 and 1.8 times higher AGP than those of the natural river water. The higher AGP values are attributable to the high contents of phosphorus and ammonium in the effluent. The mixing ratio of effluents of the discharge/river flow was highest in the Kumho River (42.8%) followed by the middle of Nakdong River (22.7%), Kam Stream (13.9%), Byungsung Stream (13.3%), Yangsan Stream (7.9%), and Young River (5.4%). Comparison of the trophic state of the effluents with natural river water indicated that the effluents showed higher trophic values than natural water. Concentrations of total phosphorus, total nitrogen and conductivity in the effluents were 12.3, 4.9 and 5.3 times higher than the those found in natural river water respectively. The AGP values were highly related with the trophicity of the water especially on the concentrations of phosphate and ammonium. Toxicities of the treated sewage water, wastewater and livestock waste water tested by the luminescent bacteria, Vibrio fischerii were generally low.