• Journal of Korean Society on Water Environment
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• v.37 no.1
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• pp.32-46
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• 2021

South Korea has been divided into quantities and water quality, and due to a revision of the Government Organization law in June 2018, the controversial water management system was integrated into the Ministry of Environment. The total Maximum Daily Loads System has been called the flower of water quality control, and since 2004, all three major river systems which have been introduced into the Han River system, despite its various difficult environments, and subsequently leading to all of the four major rivers undergoing obligatory implementation since 2013. Currently, the target TMDL (Han River Phase 1 and Other Water Systems Phase 3) for the 2020 stage has been implemented. The domestic TMDL established a basic plan for calculating the load which complies with the unit watershed's target water quality, as well as an implementation plan for annual load management, both which have been institutionalized in order to evaluate load compliance on a repeated annual basis. Local governments ask external organizations to conduct investigations every year in order to assess the transition, which thereby requires tens of millions of won every year. Therefore, an assessment and management model that can be easily operated at the TMDL personnel level is required. In this study, when the Han river Water System TMDL was implemented in earnest, we confirmed the the water quality improvement effect when TMDL was introduced to major inflow tributaries (TancheonA, JungnangA, AnyangA) under the Seoul City's jurisdiction through the use of the total amount control unit basin evaluation technique. By presenting customized management measures, we propose the guidelines that are necessary for determining more effective water environmental policies.

• Journal of Korean Society on Water Environment
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• v.22 no.6
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• pp.1004-1013
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• 2006

To effective a watershed management, it is necessary to have one or more quantitative measures that can be used to evaluate the relationship between pollutant sources and their impact on water quality. Such measurable quantities are termed indicators. Once an indicator has been selected, a target value for that indicator must be established that seek to distinguish between the impaired and unimpaired state of the waterbody. Various factors will be considered for the selection of an appropriate watershed management indicator. For example, available data, application, management conditions, cost, etc. This paper lists various factors that should be addressed in choosing a watershed management indicators and investigates applicable indicators during watershed management period.

• Journal of Korea Water Resources Association
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• v.48 no.1
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• pp.1-8
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• 2015

General features of sediment budget for the Nakdong River before the Four Rivers Restoration Project were analyzed using surveying, dredging, and mining data for the past 20 years, as well as sediment data measured from the tributaries, and numerical modeling, etc. As a result of the sediment budget analysis of the Nakdong River before the Four Rivers Restoration Project, sediment inflow supplied from the watershed is $2,100,000m^3/yr$ and sediment outflow including mining and dredging volumes is $10,180,000m^3/yr$. Therefore, the bed change volume estimated by the sediment budget analysis is $-8,080,000m^3/yr$ of the bed erosion volume which is similar to the analysis result ($-8,300,000m^3/yr$) of natural and artificial bed changes using the surveyed data.

• Journal of Korean Society on Water Environment
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• v.31 no.5
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• pp.569-575
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• 2015

The current Total Pollution Load Control (TPLC) sets the Target Water Quality (TWQ) by utilizing the delivery ratio, unit loads, and water quality modeling, it also allocates the watershed's permitted discharge load. Currently, common target pollutants of every unit watershed in TPLC are BOD and T-P. This study has reviewed the 1th and 2th of TWQ setting process for the Nakdong River 3th TWQ setting in Total Pollution Load Control (TPLC). As a result of review, 1th and 2th were divided into one management basin (mulgeum) for setting management goals. However, 3th was divided into six management basins (mulgeum, gnagjeong, geumho river, nam river, miryang river, end of nakdong river). The principle of management goal setting were to achieve the objective criteria of Medium Areas for the linkage of the water environment management policy. And Anti-Degredation (principle of preventing deterioration) were applied to the 3th TWQ. Also, additional indicators were considered in accordance with the reduction scenarios for the final management goals.

• Journal of Korea Water Resources Association
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• v.31 no.1
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• pp.71-84
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• 1998

The SSARR model adopting IS(integrated snowband) watershed model is applied to the Nakdong River basin for low flow analysis. The IS watershed model is added to new version of the SSARR which has functions of simulating evapotranspiration. infiltration and lower zone routing. It provides annual water budget information as an output file and can be operated by interactive mode. Sensitivity analysis for both cases of high and low flows was carried out, which becomes the knowledge base for model calibration. Model verification was performed using the relative errors of high flows and absolute errors of low flows at the control points. Monthly water budget analysis was done by IS watershed model. and it reveals that runoff coefficient is 52.6%

• Journal of Wetlands Research
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• v.5 no.2
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• pp.43-55
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• 2003

Vegetation structure was investigated in the Hyeonchang wetland and its watershed around the Nakdong-gang, Changryeong-county, Gyeongsangnamdo, Korea. from May to August, 2001. The vegetation type of the Hyeonchang wetland was classified into 12 communities based on the actual vegetation map: Phragmites communis community, Zizania latifolia community, Phragmites communis - Persicaria perfoliata community, Salix koreensis community, Persicaria perfoliata - Phragmites communis community, Spirodela polyrhiza community, Persicaria perfoliata community, Cyperus amuricus community, Cyperus amuricus-EchinochJoa crus-galli var. frumentacea community, Phragmites communis-Zizania latifolia community, EchinochJoa crus-galli var. frumentacea community, and Persicaria maackiana community. Among them, Phragmites communis community was the largest (4.3 ha, 24%). The dominant vegetation type were Phragmites communis community, Echinochloa crus-galli var. frumentacea-Persicaria maackiana community, and Cyperus amuricus subcommunity based on the phytosociological method. The vegetation type of the Hyeonchang wetland watershed was classified into five communities based on the actual vegetation map: Pinus densilflora community, Pinus rigida community, Pinus densiflora-Quercus acutissima community, Pinus densiflora-Larix gmelini var. principis-ruprechtii community, and Populus tomentiglandulosa community. Among them, Distribution area of Pinus densiflora community was largest (399.3 ha, 61.8%). And the degree of green naturality of the Pinus densiflora community was 7 and 8 degree.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2007.04a
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• pp.219-222
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• 2007

• Journal of Korean Society of Water and Wastewater
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• v.27 no.2
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• pp.197-206
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• 2013

Recently, climate change causes climatic anomaly such as global warming, the typhoon and severe rain storm etc. and it brings damage frequently. Climate change and global warming are prevalent all over the world in this century and many researchers including hydrologists have studied on the climate change. In this study, Seonakdong river watershed in the Nakdong river basin was selected as a study area. Real-time monitoring system was used to draw the rating curves, which has 0.78 to 0.96 of $R^2$. To predict runoff change in Seonakdong river watershed caused by climate change, the change in hydrologic runoff were predicted using the watershed model, SWAT. As a result, the runoff from the Seonakdong river watershed was increased by up to 45 % in summer. Because of the non-point sources from the farmland and the urban area, the water quality will be affected by the climate change. In this study, the operating plan of the water gates in Seonakdong river will be suggested by considering the characteristics of the watershed runoff due to the climate change. The optimal watergate opening plan will solve the water pollution problems in the reservoir-like river.

• Journal of Environmental Impact Assessment
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• v.11 no.3
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• pp.117-127
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• 2002

This study tested the usefulness of landscape indices for quantifying forest fragmentation due to linear development projects. Research was carried out in the middle-upper Nakdong River watershed, which has been affected by the expressway building, or national road-widening. Landscape indices were calculated from the forest cover maps before and after road-building using FRAGSTATS 3.1. We could successfully demonstrate the forest fragmentation based on landscape indices; (1) patch size decreased, and edge density and patch density increased (2) roads simplified patch shapes, especially in the larger patches, (3) patch core area size decreased, and core area density increased, (4) the distance increased between the focal patch and each of the other patches within the search radius (=1km) as a result of roads. We suggest several important needs for future researches, including continued investigation of scaling issues, development of indices that measure specific components of spatial pattern, and study of the relationships between forest fragmentation and ecological processes.

• The Journal of Engineering Geology
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• v.17 no.4
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• pp.507-510
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• 2007

The correlation between groundwater level(GWL) and the moving average of precipitation was analyzed based on the observation data in Nakdong river watershed. The precipitation data was compared and analyzed with the GWL data from adjacent observation point to the precipitation gauge station. The correlation between the moving average of precipitation with several averaging periods and GWL were analyzed and we could choose the averaging period that produces maximum correlation. A severe drawdown was observed from December to April. The maximum correlations between GWL and the moving average of precipitation were occurred from 20-day to 80-day averaging period.