• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.4
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• pp.55-63
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• 2013

This study investigates the trends and uncertainty of the impacts of climate change on paddy rice production in the Geumho river basin. The Long Ashton Research Station stochastic Weather Generator (LARS-WG) was used to derive future climate data for the Geumho river basin from 15 General Circulation models (GCMs) for 3 Special Report on Emissions Scenarios (SRES) (A2, A1B and B1) included in the Intergovernmental Panel on Climate Change (IPCC) 4th assessment report. The Food and Agricultural Organization (FAO) AquaCrop, a water-driven crop model, was statistically calibrated for the 1982 to 2010 climate. The index of agreement (IoA), prediction efficiency ($R^2$), percent bias (PBIAS), root mean square error (RMSE) and a visual technique were used to evaluate the adjusted AquaCrop simulated yield values. The adjusted simulated yields showed RMSE, NSE, IoA and PBIAS of 0.40, 0.26, 0.76 and 0.59 respectively. The 5, 9 and 15 year central moving averages showed $R^2$ of 0.78, 0.90 and 0.96 respectively after adjustment. AquaCrop was run for the 2020s (2011-2030), 2050s (2046-2065) and 2090s (2080-2099). Climate change projections for Geumho river basin generally indicate a hotter and wetter future climate with maximum increase in the annual temperature of $4.5^{\circ}C$ in the 2090s A1B, as well as maximum increase in the rainfall of 45 % in the 2090s A2. The means (and ranges) of paddy rice yields are projected to increase by 21 % (17-25 %), 34 % (27-42 %) and 43 % (31-54 %) for the 2020s, 2050s and 2090s, respectively. The A1B shows the largest rice yield uncertainty in all time slices with standard deviation of 0.148, 0.189 and $0.173t{\cdot}ha^{-1}$ for the 2020s, 2050s and 2090s, respectively.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.245-245
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• 2023

This paper examines the extent to which the Mekong River Basin countries have achieved socioeconomic benefits based on regional cooperation through the Greater Mekong Subregion (GMS) Program, focusing on hydropower development and the Mekong Power Grid. This study pays attention to the time period from 2012 to 2022. The benefit sharing approach is employed to evaluate the extent to which hydropower development and the Mekong Power Grid have contributed to the regional energy trade in the GMS program. The GMS program was launched by the Asian Development Bank (ADB) in 1992, and the Chinese provinces of Yunnan and Guangxi, Myanmar, Lao PDR, Thailand, Cambodia, and Vietnam have taken an active part in the program. The goals of the GMS program are to achieve poverty alleviation, economic development, and regional cooperation in various sectors, including energy, tourism, and transportation. The GMS Economic Cooperation Program Strategic Framework 2030 (GMS-2030), in 2021, provides a new framework for prosperous and sustainable development in the river basin. In the energy sector, the GMS program has been instrumental in facilitating hydropower development and creating the Mekong Power Grid with the Regional Grid Code (RGC), contributing to economic benefits and promoting regional trade of hydroelectricity. It is argued that the GMS program has enhanced regional cooperation between the riparian countries. Despite such achievements, the GMS program has faced challenges, including the gap of economic development between the riparian countries, socioeconomic and environmental concerns regarding hydropower development between the Upper and Lower Mekong countries, and geopolitical tensions from the US-China rivalry. These challenges should adequately be addressed within the program, which can guarantee the sustainability of the program for the river basin.

• Journal of Environmental Health Sciences
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• v.49 no.5
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• pp.247-250
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• 2023

This case report aims to introduce the safety campaign activities for preventing chemical accidents that were cooperatively conducted by an environmental office and chemical-handling workplaces located in the Ulsan area. A chemical safety campaign was initiated to examine and manage chemical-handling facilities at high risk for chemical accidents, specifically valves, flanges, and switches (VFS) from October 2020 to December 2022. The VFS safety check campaign was conducted to raise workers' safety consciousness based on a campaign of advertisements in the workplace from October 2020 to December 2021. In addition, a VFS plus [+] campaign was initiated to encourage actual management activities for chemical-handling facilities at high risk of chemical accidents in 2022. A total of 49 corporations participated in the VFS plus [+] campaign. In contrast to the VFS safety check campaign, which simply focused on publicity and resulted in changes in worker awareness, practicable safety management activities focusing on the handling facilities were carried out. Although notable short-term impacts have yet to be discerned from the campaigns, it is expected that they will eventually serve as a starting point for developing a proper safety culture and environment.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.469-472
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• 2002

This study was conducted to show how to manage the water quality of Kyung-an river. The water quality and hydrologic data were obtained at the main river and branch streams in Marc $h{\sim}April$ 1998. First of all, we surveyed the contribution of branches for the pollution of water quality at Kyung-an river. It was in order of Kongiam(25.5%)>Yong-in Pollutant Treatment Complex (15.26%)^gt;Shin-won(13.99%)>Buen(11.86%)>Yangji(8.68%)>Yooun(7.43%)>Kwang-ju Pollution Treatment Complex(5.50%)>Osan(5.04%). The hydrological model using mass balance and BOD reduction formula suggested that if the quality of water Yoo-un and Shinn-won stream (branch streams of Kyung-an River) which is lowest in the basin is controlled adequately and outlet water from Yong-in pollutant treatment complex is adequately treated, the quality of Kyung-an river will be improved by 90% compared to current level.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.1
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• pp.23-32
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• 2003

The objective of this study is assessing water management efficiency using water withdrawals from rivers and water requirements for paddies. The water management efficiency was defined by the ratio of water requirements and water withdrawals. Water withdrawals were estimated using the operating times and pumping capacity of the pumping stations from 1992 to 1999 in the Han River and Nakdong River basins. Water requirements were estimated by adding the evapotranspiration of the crops and infiltrations in the irrigated area. Evapotranspiration from the paddies was calculated by the FAO modified Penman method with observed daily weather data. The monthly water management efficiency was analyzed for each pumping stations and the district offices of KARICO (Korea Agricultural and Rural Infrastructure Corporation). The efficiencies of 59 pumping stations in the Han River basin varied from 19% to 135%, and the average was 61%. The efficiencies of 146 pumping stations in the Nakdong River basin ranged from 17% to 190%, and the average was 72%. There were no good correlations between the water management efficiency and pump capacity or irrigated area, it showed that the water management efficiency was affected by the traditional water management practices rather than the scale of irrigation district.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.691-694
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• 2008

The results of research, which proposes the optimum flow considering the habitation environment of fishes in determining the instream flow, have been drawn by many researchers in Korea. In this study, the relations of weighted usable area to discharge are researched. In addition, River2D, which is the simulation model of 2D physical habitats, is applied to the main tributaries of the Geum River basin on the instream flow incremental methodology proposed in the U.S. in order to calculate optimum flow in each growth step of fish, which are the dominant species living in the river, considering the habitat of fishes in streams.

• Journal of Korea Water Resources Association
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• v.50 no.12
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• pp.815-825
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• 2017

Groundwater management vulnerability was assessed using TOPSIS (Techniques for Order Performance by Similarity to Ideal Solution) for 21 administrative districts in Nakdong river basin. Ten indicators were selected for 21 administrative districts in the Nakdong river basin by collecting natural, human, and social data sets. The selected indicators were standardized using rescale method, and each indicator was weighted by considering the questionnaire of expert group. The results of the weights determination survey showed that the annual average groundwater level index was 0.157 and this is the highest value. The annual average precipitation index was 0.154 and the annual groundwater recharge index was 0.152. The lowest weighted index was 0.043 for population density. Finally, the result of assessment of groundwater management vulnerability showed that Sangju-si was the most vulnerable to groundwater management among 21 administrative districts in Nakdong river basin because the annual average precipitation, annual average groundwater recharge, and annual average groundwater use indicators were highly vulnerable. The second and the third vulnerable regions were Yecheon-gun and Haman-gun respectively. The assessment of groundwater management vulnerability for the five major river basins in Korea can be a essential basis for the establishment of groundwater management policy.

• The Korean Journal of Quaternary Research
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• v.20 no.2
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• pp.1-10
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• 2006

Flooding hazard caused by natural and artificial environmental changes is closely associated with change in river bed configuration. This study is aimed at explaining a river-bed change related to soil erosion in the Keum river basin using GIS and RS. The USLE was used to compute soil erosion rate on the basis of GIS. River-bed profiles stretching from Kongju to Ippo were measured to construct a 3D-geomorphological map. The river-bed change was also detected by remote sensing images using Landsat TM during the period of 1982 to 2000 for the Keum river. The result shows that USLE indicates a mean soil erosion rate of $1.8\;kg/m^2/year$, and a net increase of a river-bed change at a rate of $+5\;cm/m^2$/year in the Kangkyeong area. The change in river-bed is interpreted to have been caused by soil erosion in the downstream of the Keum river basin. In addition river-bed change mainly occurred on the downstream of the confluence where tributaries and the main channel meet. Other possible river-bed change is caused by a removal of fluvial sand aggregates, which might have resulted in a net decrease of exposed area of sediment distribution between 1991 and 1995, while a construction of underwater structures, including a bridge, a reclamation of sand bars for rice fields and dikes, resulted in an increase of the exposed area of river-bed due to sediment accumulation.

• Journal of Korea Water Resources Association
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• v.53 no.1
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• pp.71-82
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• 2020

The objective of this study is to evaluate the instream flow in the North Han River basin according to the operation of Imnam Dam in North Korea. The water budget and instream flow satisfaction were analyzed using hourly, daily and monthly data of Water Management Information System (WAMIS) from Jan. 1991 to Dec. 2018. As a analysis result of water budget using hourly data in the North Han River basin, although inflows compared with dam release in the upstream basin of Peace Dam-Hwacheon Dam and Chuncheon Dam-Soyanggang Dam-Uiam Dam were calculated as negative values, the reasonable results using daily and monthly average data were estimated. It showed that the results of water budget analysis of dam inflow and total release may be different by time units of data. The monthly average inflow of Hwacheon Dam decreased significantly after the construction in 2003 of Imnam Dam, which confirmed that the operation of Imnam Dam had a significant effect on the dams in the North Han River basin. The operation of Imnam Dam is one of the main reasons for the lack of instream flow and total shortage amounts and shortage period increased up to +330% due to the decrease in inflow and total release of dams in the North Han River water after the operation of Imnam Dam. It is necessary to study various plans to secure instream flow including transboundary river management

• Water for future
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• v.20 no.4
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• pp.267-278
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• 1987

This study aims at the decision of geomorphologic instantaneous unit hydrograph(GIUH) model parameter fore the ungaged or the data deficiented Basin, to analyze rainfall runoff relation in river basin by applying queueing theory with geomorphologic factors.The concept of GIUH model is based upon the principle of queueing theory of rain drops which may follow many possible routes during rainfall period within watershed system to ist outlet. Overland flow and stream flow can be simulated, respectively, by linear reservoir and linear channel conceptual models. Basically, the model is a mon-lineal and time variant hydrologic system model. The techniques of applying are adopted subarea method and mean-value method, the watershed is divided according to its stream number and order. To prove it to be applicable, the GIUH model is applied to the Wi-Stream basin of Nak-Dong River(Basin area; 475.53$\textrm{km}^2$), southen part of Korea. The simulated and the observed direct runoff hydrographs are compared with the peak discharge, times to peak and coefficients of efficiency, respectively, and the results show quite satisfactory.Therefore, th GIUH model can be extensively applied for the runoff analysis in the ungaged and the data deficiented basin.