• Journal of Preventive Medicine and Public Health
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• v.51 no.4
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• pp.213-214
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• 2018

Lyme borreliosis (LB) is the most common tick-borne infectious disease in North America, and it was designated as a national notifiable infectious disease in Korea in December 2010. While no cases in Jeju-do were recorded from 2012 to 2016, a recent survey reported that the seroprevalence of Borrelia burgdorferi using enzyme-linked immunosorbent assays in horses in Jeju-do was 19.0% (95% confidence interval, 12.0 to 28.3%). This fact suggests that horses may be a potential reservoir of LB in Jeju-do and that individuals in close contact with horses may be a high-risk group. Thus, a serological study in this high-risk group is urgently needed.

• Korean Journal of Microbiology
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• v.38 no.4
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• pp.287-292
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• 2002

The composition of bacterial communities was detected in surface water of Cheonho Reservoir dominated by cyanobacteria, using fluorescent in situ hybridization (FISH) method. Total bacterial numbers were very high ranging from 0.6～$1.3{\times}10^7 \cells{\cdot}ml^-1$, whereas the ratio of Eubacteria to total bacteria was 29.8~45.8%, which was lower than that in other freshwater ecosystems. On average only 2.1% of DAPI-stained bacteria were detected by FISH with probes for $\alpha$, $\beta$, and $\gamma$-groups, respectively. Unknown eubacteria which was not bound to any probes except EUB 338, was relatively high. On the other hand, the Cytophaga-Flavobacterium group increased following the change of dominant species from Anabaena sp. to Microcystis sp. This result showed that bacterial communities could be affected by phytoplanktons, especially cyanobacteria.

• Korean Journal of Ecology and Environment
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• v.39 no.1 s.115
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• pp.131-137
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• 2006

Most South Korean lakes are middle/small size artificial reservoirs, which are almost agricultural reservoirs (17,956). A total of 67 species (21 families) were recorded and collected from 65 agricultural reservoirs though field samplings and literature surveys. Dominant species was Pseudorasbora parva (relative abundance 24.5%), and Carassius auratur (41 sites) was the highest frequency. Feeding group of fish communities in the reservoirs was as follows: carnivorous (16.2%), omnivorous (79.5%) and herbivorous fish (4.3%). The number of individuals (P=0.024), species number (P=0.047) and carnivores number (P=0.024) were significantly correlated with reservoir ages. Reservoirs were classified into 3 groups according to feeding patterns of carnivore, omnivore and herbivore groups. The omnivores were dominant group in agricultural reservoirs. Detailed studies on fish community will be a base for the understanding of food web structure and biomanipulation in reservoir systems.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.6
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• pp.1-12
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• 2018

The objectives of this study were to develop a system linking hydrologic and water quality models considering the mechanisms of agricultural reservoir and paddy cultivation and to evaluate whether the developed system simulates hydrologic and water quality processes better than a hydrologic model that do not consider the mechanisms. The system consisted of Hydrological Simulation Program-Fortran (HSPF) as a watershed model, Module-based hydrologic Analysis System for Agricultural watersheds (MASA) as reservoir water balance model, and Chemical, Runoff and Erosion from Agricultural Management System-Paddy (CREAMS-PADDY) as a hydrologic and water quality model for paddy fields. This study carried out on the Seolseong-Cheon watershed in Icheon, and the water level and water quality had been monitored for two years at the outlet of the watershed. According to the results of this study, the performance of the simulation using HSPF-MASA-CREAMS-PADDY system was better than others, but they did not show a statistically significant difference. This seemed to be due to the uncertainty of the farming data and the water quality data of the reservoir. Therefore, if accurate input data for the system is obtained, HSPF-MASA-CREAMS-PADDY system could be used to model an agricultural watershed to obtain more realistic results. The results of this study could be utilized to the modeling of agricultural watersheds in Korea where paddy rice cultivation is dominant.

• Journal of Wetlands Research
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• v.21 no.spc
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• pp.80-89
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• 2019

The purpose of this study is to analyze the relationship between SPI (Standardized Precipitation Index) meteorological drought and RDI (Reservoir Drought Index) agricultural drought for Geum river basin. Drought Indices was calculated by collecting data of precipitation and agricultural reservoir water storage rate from 2014 to 2016. To evaluated the correlation between meteorological and agricultural drought, the Pearson correlation and the Receiver Operation Characteristic (ROC) analysis were conducted to evaluate the correlation between meteorological and agricultural droughts. The SPI-6 and RDI showed the highest relationship with Pearson coefficient 0.606 and ROC hit rates 0.722 respectively, and the spatial occurrence patterns of drought using overlapped SPI-6 and RDI, the big differences between the 2 indices were occurred in the upstream areas of Miho stream and Nonsan stream from August to October 2015. The analysis using reservoirs specifications for areas where reservoir droughts occurred was conducted, and the areas showing severe drought of RDI were the reservoir areas having relatively small value of basin magnifying power (BMP). This means that a reservoir has the reaction capability for agricultural drought mainly depending on the reservoir BMP.

• Korean Journal of Ecology and Environment
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• v.39 no.2 s.116
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• pp.219-225
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• 2006

Bacterial community structure in the Juam Reservoir was analysed using fluorescent in situ hybridization (FISH) technique from April 2005 to January 2006. Total bacterial numbers varied in the range of 1.58 ${\sim}\;2.73{\times}\;10^6\;cells\;mL^{-1}$ proportional to the concentration of chi-a and had the minimal value in January. The ratios of ${\alpha}\;{\cdot}\;{\beta}\;{\cdot}\;{\gamma}$-subclass proteobacteria and Cytophaga-Flavobacterium (CF) group to total bacteria ranged from 45.1% to 77.5%, and the ratios of ${\alpha}\;{\cdot}\;{\beta}\;{\cdot}\;{\gamma}$-subclasses to total bacteria in June and September with the concentration of chi-a measured were lower than those ratios in April and January. It suggests that enriched growth of Microcystis aeruginosa may inhibit the metabolic activlty of ${\alpha}\;{\cdot}\;{\beta}\;{\cdot}\;{\gamma}$-subclass proteobacteria. However, the ratio of CF group bacteria represented no large change depending on algal bloom. In terms of nitrifying bacteria, the numbers of ammonia-oxidizing bacteria ranged from 9.9 ${\times}\;10^4\;to\;25.5\;{\times}10^4\;cells\;mL^{-1}$ with sharp fluctuation whereas those of nitrite-oxidizing bacteria varied in 8.7${\sim}9.8{\times}10^4\;cells\;mL^{-1}$ without noticeable change except the maximal value of $20.3{\times}10^4\;cells\;mL^{-1}$ in January maybe due to the high DO.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.411-418
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• 2013

The Saemangeum Reservoir was constructed in 2006 as a part of Saemangeum reclamation project in which desalination has been also carried out. The purpose of this study is to provide basic data for predicting changes in fish distribution in the Saemangeum area with respect to the desalination processand to identify current status of fish distribution along with salinity levels. Fish sampling and measurement of salinity were conducted 4 times from February to October in 2012 at 10 sites within the Saemangeum Reservoir. A total of 71 species classified into 34 families were confirmed, and dominant and subdominant species were Thryssa kammalensis (16.1%) and Konosirus punctatus (12.8%), respectively. Saltwater fishes were still dominant at the Saemangeum Reservoir. Study sites were classified into four groups (A=St. 1, 6; B=St. 2, 3, 7, 8; C=St. 4, 9, 10; D=St. 5) by Bray-Curtis cluster analysis. Species composition of each group was closely related with salinity level: group A corresponding to 0.2 psu, B to 14.2 psu, C to 19.5 psu, and D to 23.5 psu.

• Magazine of the Korean Society of Agricultural Engineers
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• v.35 no.2
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• pp.65-72
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• 1993

When a drought occurs in an area irrigated by multi-reservoirs, onerating a single reservoir separately to control the reservoir' storage is not a desirable solution. In order to reduce damages effectively for the areal drought, the storage of the reservoirs within the areal boundary should be managed as a group. Storage management procedures are as follows : 1. Collecting and checking the present storages of all reservoirs 2. Computing the drought frequency and depth; and finally, establishing a suitable storage saving strategy based on the estimated drought depth. For the purpose of this storage management, the RESTOMS(Reservoirs Storage Management System) was developed and the system was composed of the PRIME computer and the ORACLE as a distributed database management system, which was the host computer of Rural Development Corporation and would be on-lined with the regional offices throughout the country. Reservoirs operated by Farm Land Improvment Association were comprised in the DB system. Using the RESTOMS, the drought frequencies and drought depths were calculated with respect to the reservoir storage records(1967 to 1992). It was obvious that the results were closely corresponding to the real drought records.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.1
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• pp.1-11
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• 2010

Generation and transportation of runoff and pollutant loads within watershed generated eutrophication at Daecheong reservoir. To improve water quality at Daecheong reservoir, the best management practices should be developed and applied at upper watersheds for water quality improvement at downstream areas. In this study, two small watersheds of upper Daecheong reservoir were selected. The Long-Term Hydrologic Impact Assessment (L-THIA) model has been widely used for the estimation of the direct runoff worldwide. To apply the L-THIA ArcView GIS model was evaluated for direct runoff and water quality estimation at small watershed. And the Web-based Hydrograph Analysis Tool (WHAT) was used for direct runoff separating from total flow. As a result, the $R^2$ (Coefficient of determination) value and Nash-Sutcliffe coefficient value for direct runoff comparison at An-nae watershed were 0.81 and 0.71, respectively. And the $R^2$ value and Nash-Sutcliffe coefficient value at Wol-oe were 0.95 and 0.93. The $R^2$ value of BOD, TOC, T-N and T-P at An-nae watershed were BOD 0.94, TOC 0.81, T-N 0.94 and T-P 0.89. And the $R^2$ value of BOD, TOC, T-N and T-P at Wol-oe watershed were BOD 0.80, TOC 0.93, T-N 0.86 and T-P 0.65. The result that estimated pollutant loadings using the L-THIA ArcView GIS model reflected well the measured pollutant loadings except for T-P in Wol-oe watershed. With L-THIA ArcView GIS model, the direct runoff and non-point pollutant (NPS) loadings in the watershed could be analyzed through simple input data such as daily rainfall, land uses, and hydrologic soil group.

• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.5
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• pp.49-62
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• 2021

The objective of this study was to evaluate the flood control capacity of the agricultural reservoir based on state-of-the-art climate change scenario - SSP (Shared Socioeconomic Pathways). 18 agricultural reservoirs were selected as the study sites, and future rainfall data based on SSP scenario provided by CMIP6 (Coupled Model Intercomparison Project 6) was applied to analyze the impact of climate change. The frequency analysis module, the rainfall-runoff module, the reservoir operation module, and their linkage system were built and applied to simulate probable rainfall, maximum inflow, maximum outflow, and maximum water level of the reservoirs. And the maximum values were compared with the design values, such as design flood of reservoirs, design flood of direct downstream, and top of dam elevation, respectively. According to whether or not the maximum values exceed each design value, cases were divided into eight categories; I-O-H, I-O, I-H, I, O-H, O, H, X. Probable rainfall (200-yr frequency, 12-h duration) for observed data (1973~2020) was a maximum of 445.2 mm and increased to 619.1~1,359.7 mm in the future (2011~2100). For the present, 61.1% of the reservoirs corresponded to I-O, which means the reservoirs have sufficient capacity to discharge large inflow; however, there is a risk of overflowing downstream due to excessive outflow. For the future, six reservoirs (Idong, Baekgok, Yedang, Tapjung, Naju, Jangsung) were changed from I-O to I-O-H, which means inflow increases beyond the discharge capacity due to climate change, and there is a risk of collapse due to dam overflow.