• Atmosphere
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• v.16 no.2
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• pp.55-65
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• 2006

The characteristics of Depth-Area-Duration (DAD) for 50 storms over the Geumgang river basin have been analysed in terms of various storm causes using the precipitation data during the period from 1984 to 2003. Results show that the ratio of the precipitation depth to duration, and the ratio of decrease in the precipitation depth to area are the largest in the case of the tropical cyclone. Storm maximization ratios are in the range 1.03 to 2.66 for the 50 selected heavy precipitation cases over Geumgang river basin, with the largest value for the tropical cyclone case, suggesting that the tropical cyclone could cause heavier precipitation than the other storms. In addition, the 24-hour probable maximum precipitation for the Geumgang river basin is estimated to be about 745 mm in the maximum precipitation area.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.509-514
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• 2005

Geumgang canal is planned to connect Geumgang lake with Saemangeum reservoir to accelerate desalinization and dillute polluted water in Saemangeum reservoir. The purpose of this study is to evaluate the variations of water quality by divesion of Geumgang lake flow to the Saemangeum reservoir. WASP5 model was used to estimate water quality concentration of Geumgang lake. Model calibration and verification was done for water quality data for 2001 and 2002. As a result of simulating water quality concentration for 4 scenarios, which was considered whether Geumgang canal will be built, there was little influence on water quality in Geumgang lake though Geumgang lake flow diverted to Saemangeum reservoir.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.963-969
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• 2011

The river-bed sediments from the major river basins were analysed for the chemical and physical properties to evaluate environmental safety for the agricultural uses. The samples were taken from 16 sites of Han river, 36 of Geumgang river, 27 of Yeongsan river, and 140 of Nakdong river. The total of 219 samples from the 28 counties were taken from the surface of the sediments at the depth of 50 cm. The particle density of the sediments was greater than $2.63Mg\;m^{-3}$ and the whole range of the density was $2.60{\sim}2.69Mg\;m^{-3}$, the average particle size was 0.7 mm whereas the size range was 0.075~0.85 mm. The analyses of the particle sizes by basins showed that Han and Geumgang river had particle sizes of 0.075~0.85 mm, while Geumgang and Yeongsan river had particle sizes of 0.25~0.85 mm. Geumgang and Yeongsan river tended to have greater particle sizes. The average values of the chemical properties were 6.3 for pH, $0.16dS\;m^{-1}$ for EC, $8g\;kg^{-1}$ for organic matter, $101mg\;kg^{-1}$ for available phosphate, 0.39, 3.47, and $0.93cmol_c\;kg^{-1}$ for exchangeable potassium, calcium, and magnesium respectively. The greatest property at each basin was pH for Han river, Ec, available phosphate and exchangeable sodium for Geumgang river, organic matter, exchangeable calcium and magnesium for Yeongsan river, and exchangeable potassium for Nakdong river.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.5
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• pp.661-669
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• 2013

River-water quality has been greatly improved during past several decades with the extraordinary expansion for the wastewater treatment capacities by the government. Research aims to select the priority restoration streams based on the chronicle data for tributaries in Geumgang watershed as the main stream area in the Chungchungnamdo province. The quality of BOD, phosphorus and percent of sewered population on 15 branch streams were compared by the grouping methods. The results of group D streams by category I that exceed 3.0 mg/L for BOD and 0.1 mg/L for phosphorus were Seuksung, Ganggyung and Bangchuk stream. The results of group D streams by category II that exceed 3.0 mg/L for BOD and less than 63.5 % of average percent of sewered population were Ganggyung, Gilsan, Bangchuk and Seuksung stream. The final results of selected streams drawn by the chronicle data which exceeded the standard quality and lower than the average percent of sewered population were Seoksung, Gangeyung and Bangchuk stream. The pollution of rivers in the down streams were more serious than in the upper streams. Their watersheds have to be improved river water quality, especially to extend sewer systems as well as wastewater treatment facilities.

• Journal of Korean Society of Rural Planning
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• v.29 no.4
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• pp.191-200
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• 2023

This study aims to estimate the value of environmental services that could be generated by seawater flowing in the Geumgang Estuary by using meta-regression for benefit transfer. The environmental services that can be generated by seawater flowing are assumed to be improved water quality, increased biodiversity, and enhanced water-friendly effect. The analysis was conducted using 122 data from 28 studies from EVIS. The results show that households in the neighborhood where seawater is distributed are willing to pay about KRW 46,918, KRW 7,752, and KRW 7,859 per year for improved water quality, increased biodiversity, and enhanced water-friendly, respectively. The WTP of the national households other than neighboring households was found to be KRW 19,401, KRW 3,206, and KRW 3,250 for the three environmental services, respectively. The WTP for water quality improvement is higher than that for biodiversity increase and water-friendly effect increase, which may be due to the fact that water quality improvement is an environmental service that is close to the use value. In addition, neighboring households have a higher WTP than national households because neighboring households are more likely to evaluate the benefits of seawater flowing as a use value, while national households are more likely to evaluate it as a non-use value.

• Development and Reproduction
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• v.20 no.2
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• pp.135-140
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• 2016

Genomic DNAs isolated from crucian carp of four rivers, belonging to the family Cyprinidae was amplified by seven oligonucleotides primers. In the present study, we employed hierarchical clustering method in order to reveal genetic distances and variations. Crucian carp was acquired from Hangang river (CAH), Geumgang river (CAG), Nakdonggang river (CAN) and Yeongsangang river (CAY). The primer BION-12 generated the most loci (a total of 50) with an average of 10 in the CAY population. The primer BION-10 generated the least loci (a total of 19), with an average of 3.8 in the CAG population, in comparison to the other primers used. Seven oligonucleotides primers made 16.7 average no. per primer of specific loci in the CAH population, 7.4 in the CAG population, 8.6 in the CAN population and 0.9 in the CAY population, respectively. The specific loci generated by oligonucleotides primers revealed inter-individual-specific characteristics, thus disclosing DNA polymorphisms. The dendrogram obtained by the seven oligonucleotides primers indicates four genetic clusters. The genetic distance that displayed significant molecular differences was between individuals no.06 and no.08 from the CAG population (genetic distance = 0.036), while the genetic distance among the five individuals that displayed significant molecular differences was between individuals no.08 and no.09 from the CAG population (genetic distance = 0.088). With regard to average bandsharing value (BS) results, individuals from CAY population ($0.985{\pm}0.009$) exhibited higher bandsharing values than did individuals from CAH population ($0.779{\pm}0.049$) (P<0.05). Relatively, individuals of CAY population were fairly closely related to that of CAN location (genetic distance between two populations<0.016).

• Ecology and Resilient Infrastructure
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• v.10 no.4
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• pp.135-142
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• 2023

A various technology of remote sensing and image analysis are applied to study landscape changes and their influencing factors in stream corridors. We developed a method to detect landscape changes over time by calculating the optical index using multispectral images taken from satellites at various time points, calculating the threshold to delineate the boundaries of water bodies, and creating binarized maps into land and water areas. This method was applied to the upstream reach of the weirs in the Geumgang River to track changes in the sandbar formed by the opening of the weir gate. First, we collected multispectral images with a resolution of 10 m × 10 m taken from the Sentinel-2 satellite at various times before and after the opening of the dam in the Geumgang River. The normalized difference water index (NDWI) was calculated using the green light and near-infrared bands from the collected images. The Otsu's threshold of NDWI calculated to delineate the boundary of the water body ranged from -0.0573 to 0.1367. The boundary of the water area determined by remote sensing matched the boundary in the actual image. A map binarized into water and land areas was created using NDWI and the Otsu's threshold. According to these results of the developed method, it was estimated that a total of 379.7 ha of new sandbar was formed by opening the three weir floodgates from 2017 to 2021 in the longitudinal range from Baekje Weir to Daecheong Dam on the Geumgang River. The landscape detection method developed in this study is evaluated as a useful method that can obtain objective results with few resources over a wide spatial and temporal range.

• Journal of Environmental Science International
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• v.32 no.11
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• pp.789-800
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• 2023

A vascular flora survey was conducted in 2020 to identify flora and analyze changes in the numbers of vascular flora species over the past 10 years at Gongju-weir (GW) and Baekje-weir (BW) in the Geumgang River, Republic of Korea. A total of 241 taxa were found in GW and 279 taxa in BW, and 208 taxa (88% of total taxa) were common species. The distribution of invasive species in GW and BW were seven and eight taxa, respectively. Rare plants were not identified in any of the weirs. The Poaceae family dominated in terms of number of species, followed by Asteraceae, Legumes, Cyperaceae, and Polygonaceae. Additionally, Therophytes accounted for a high proportion of Raunkiaer life forms. The numbers of vascular plant species, total taxa, naturalized plants, and invasive species have been increasing over the last 10 years. However, long-term alterations in invasive species before and after the opening of the weirs increased much more significantly in the partially opened BW than in the fully opened GW. These results indicate that the degree of barrier opening does not affect the invasion and establishment of non-native species.

• Journal of Environmental Science International
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• v.24 no.8
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• pp.1085-1099
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• 2015

The purposes of this study were to suggest the methodology to select prior areas in the environmental pollution survey for livestock excreta (EPSLE) as well as to elucidate the validity of the methodology. In this study, the prior areas in the EPSLE were determined by examining the number of compost facilities categorized according to the three levels of size including the basin, the sub-basin and the watershed, respectively, based on the data from "Annual Nation-wide Pollution Sources Survey (2012)". The results suggested that the list of prior basins were Nakdong, Geum, Youngsan and Han river basins in order. Also, it was examined that the prior sub-basins in the four river basins including Nakdong, Geum, Youngsan and Han rivers were Naesung Stream, Geumgang Gongju, Juam Dam and Namhan Downstream, respectively. The prior watersheds in the sub-basins of Naesung stream, Geumgang Gongju, Juam Dam and Namhan Downstream were Seocheon Downstream, Geum Stream, Gyeombaek Suwipyo and Yanghwa Stream, respectively. The validity of the methodology used in this study was elucidated by analyzing the correlation of the number of compost facilities with the concentrations of T-N and T-P observed in the end-points of sub-basins. The results of correlation analysis showed that the concentrations of T-N and T-P increased with the number of compost facilities. Specifically, there was the stronger correlation between the number of compost facilities and the concentrations of T-N than that for T-P. Consequently, it was proved that the methodology used in this work was valid and rational for the selection of prior areas in environmental pollution survey for EPSLE.

• Korean Journal of Remote Sensing
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• v.35 no.6_4
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• pp.1351-1361
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• 2019

In this study, the annual surface soil erosion amount of before (2007 year) and after (2015 year) the river improvement projects were calculated using RUSLE (Revised Universal Soil Loss Equation) in the Geumgang basin (Daecheong-Dam to Geumgang Estuary-Bank). After the results were classified into five classes, the results were compared and analyzed with the results of the change in the land cover. In order to generate each factor of RUSLE, various spatial information data, such as land cover maps for 2007 and 2015 years, national basic spatial information, soil map, and average annual precipitation data were utilized. The results of the analysis are as follows: 1) annual surface soil erosion in the study area increased the area of class 1 in 2015 years compared to 2007, 2) the area of class 2, 3 and 5 decreased, 3) the area of class 4 increased. It is believed that the average annual amount of surface soil erosion decreased in most areas due to the reduction of annual average precipitation, the formation of ecological parks, the expansion of artificial facilities, and the reduction of illegal farmland.