• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.5
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• pp.1871-1885
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• 2013

In this study, spatio-temporal distribution of future drought in South Korea was predicted by using the meteorological data generated from GCMs on which a variety of climate changing scenarios are applied. Drought phenomena was quantitatively analyzed using SPI(Standardized Precipitation Index). In addition, potential drought hazard maps for different drought duration and return period were made for the South Koreaby drought frequency analysis after deriving SDF(Severity-Duration-Frequency) curves using the 54 weather stations throughout the country. From the potential drought hazard maps, drought is expected to be severer in Nakdong River basin and Seomjin River basin under A2 scenario. It was also predicted that drought would be severe in the Han River basin by RCP8.5 scenario. In the future, potential drought hazard area would be expanded until the Eastern part of Nakdong River basin as compared with that of past under A2 scenario condition. Research results indicated that future drought would be extensively occurred all areas of South Korea not limiting in the southern part of country.

• Journal of Korea Water Resources Association
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• v.48 no.8
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• pp.685-693
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• 2015

We propose a method for deriving the relationship between channel width and discharge from remote sensing products. Stream widths at points distributed along a river network can be measured from high-resolution remote imagery. Further, corresponding drainage area for these points can be calculated using digital elevation models, making it possible to construct width-drainage area relation. On the other hand, the relationship between the flow discharge and the drainage area is obtained from historical data measured at ground stations. By coupling these two relationships, we can finally derive the width-discharge relationship which comprises an important component of downstream hydraulic geometry. The proposed method was tested for the Nakdong River and the Seomjin River, successfully capturing power-law exponents in the width-discharge relationships reported in earlier studies. The proposed approach can serve as an alternative for obtaining the hydraulic geometry relationship under the limits of ground data.

• Korean Journal of Ichthyology
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• v.18 no.2
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• pp.97-106
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• 2006

In the investigation of geographic variations on the Zacco koreanus distributed widely in southern Korean Peninsula, it was found that there were distinct differences in the nuptial coloration among geographic populations. These color variations were presence of red band on anterior margin of pectoral fin and color patterns of dorsal fin. On the basis of those color variations three color types were recognized in Z. koreanus, that is, HK, NS and NE types. HK types were distributed mainly in Han and Geum River, NS types in Nakdong and Seomjin River, and NE types in Nakdong River and small streams on the east coast. It was noted ecologically and taxonomically that these three types were well separated geographically and two types of them, i.e., NS and NE types cohabit in the Nakdong River and shown a tendency of microhabitat segregation between them.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.3
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• pp.79-91
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• 1993

An analysis of flow duration characteristics of the five major rivers in Korea was conducted with extensive river flow data available. The analysis reveals that, for most river stage-gauging stations at the rivers investigated in this study, the flow duration characteristics have changed drastically at some stations after major dammings in the river basins. Streamflow variability. which is newly defined in this study as the ratio of the 2.5 percents (or 10 day) duration discharge over the 97.5 percents (or 355 day) duration one, was also reduced by the dammings. The result of the study shows that the Han and the Yeongsan rivers have relatively small flow variation, while the Seomjin and the Keum rivers have relatively large now variation, which implies that the latter two river basins need new water resources development.

• Journal of the Korean association of regional geographers
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• v.17 no.5
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• pp.505-520
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• 2011

This study is aimed to examine the change on extreme precipitation events in South Korea. The country is divided into six basins, and seven extreme precipitation indices-related to heavy rainfall are analyzed at sixty weather stations. The increasing trend in amount of heavy rainfall is more stable than that in days of heavy rainfall. The increasing trend is the most stable when days of rainfall are more than 50 mm, or rainfall is over the 95th percentile. The precipitation indices-related to heavy rainfall was mostly increasing during analysis period. Especially, basins of the Han river, the upper Nakdong river, and the Eastern coast show significantly increasing trends compared to the other basins. However, the increasing trends of the Geum river and the Seomjin river are not statistically significant. Heavy rainfall events had stably increased in the Han and the Nakdong rivers since the mid-1970s. However, the number of stably increasing regions has decreased since the mid-2000s. It means that the frequency and intensity of the recent heavy rainfall become more irregular.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.6
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• pp.707-714
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• 2016

In order to prevent secondary pollution of tap water, corrosion characteristics are investigated, and corrosion index are calculated using LI and LR to manage corrosiveness. As targeted water treatment plants from 2014 (July, once) to 2015 (July and October, 2 times), 70 plants are selected by making a division for each area and water system. (treated water samples, n=240, raw water samples, n=72). In result of pH analysis, treated water was lower than raw water to 7.12, and 7.29, respectively. LI were investigated in the order of Seomjin river, Nakdong river, Han river, Geum river, to -2.08, -1.24, -1.11, -1.10 (at raw water), and -2.18, -1.59, -1.51, -1.35 (at treated water), respectively. In case of water quality goal value (LI = -1) in Japan as control of corrosiveness, management object was investigated about 83.3%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.6852-6859
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• 2015

The purpose of this study was to determine the growth characteristics and distribution pattern of a brackish water clam Corbicula japonica in Seomjin River. Field samples were taken from 14 stations with salinity gradients during spring. Salinity at the bottom layer ranged from 1.0 psu to 32.9 psu, with low salinities in the upper area of the river. In particular, salinity at St.11 was decreased drastically to be ca. 15.0 psu, indicating an intermediate salinity zone. The distribution pattern of C. japonica was related to the salinity gradient, with the highest densities of $2,102ind.m^{-2}$ at Station 13, followed by $1,507ind.m^{-2}$ at Station 11. Here, we focused on the growth characteristics of collected C. japonica collected at two stations with different salinity values. The relationship between shell length and total weight was highly correlated ($R^2=0.91$, P<0.001) at Station 13 compared to that at Station 11 ($R^2=0.72$, P<0.001). On the other hands, the degree of correlation between shell length and shell height (SH) or shell width (SW) at Station 11 (SH: $R^2=0.91$, P<0.001; SW: $R^2=0.69$, P<0.001) was higher than that at Station 13 (SH: $R^2=0.64$, P<0.001; SW: $R^2=0.48$, P<0.001). In addition, fatness index of C. japonica at Station 13 was significantly (P < 0.001) higher than that at St. 11 (t-test value=-22.8, p<0.001). This implies that C. japonica at Station 13 might have enhanced their somatic growth, whereas C. japonica at Station 11 might have this kind of defense mechanism their internal organization against the salinity stress. Ecologically, this kind of defense mechanism of C. japonica against salinity flucuation may play an important role in their survival strategy.

• Korean Journal of Environmental Biology
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• v.41 no.2
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• pp.101-108
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• 2023

Recently, in relation to climate change, many studies have been conducted to predict the potential habitat area and distribution range of tilapia and the suitability of habitat for each species. Most tilapia are tropical fish that cannot survive at water temperatures below 10 to 12℃, although some tilapia can survive at 6 to 8℃. This study predicted habitable areas and the possibility of spreading of habitat ranges of tilapia (Oreochromis niloticus and Oreochromis aureus) known to inhabit domestic streams. Due to climate change, it was found that habitats in the Geum River, Mangyeong River, Dongjin River, Seomjin River, Taehwa River, Hyeongsan River, and the flowing in East Sea were possible by 2050. In addition, it was confirmed that tilapia could inhabit the preferred lentic ecosystem such as Tamjin Lake, Naju Lake, Juam Lake, Sangsa Lake, Jinyang Lake, Junam Reservoir, and Hoedong Reservoir. In particular, in the case of tilapia, which lives in tributaries of the Geumho River, Dalseo Stream, and the Nakdong River, its range of habitat is expected to expand to the middle and lower of the Nakdong River system. Therefore, it is judged that it is necessary to prepare physical and institutional management measures to prevent the spread of the local population where tilapia currently inhabits and to prevent introduction to new habitats.

• Water for future
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• v.13 no.1
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• pp.39-48
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• 1980

The purpose of this study was to set up the accurate way of estimating the frequency of the max. daily rainfall of the Korean rivers. The area selected for study were Han.Naktong, Geum, Yeongsan, and Seomjin River. The following five methods of the rainfallfrequency analysis were applied to twenty four subgrouped regions in the basins; 2 parameter lognormal, 3 parameter lognormal, Type I extremal(Gumbel method), Pearson Type III, and log-Pearson Type III. The regression equations were established between the depth of max. daily rainfall given 6 reccirrence interval(100, 50, 20, 10, 5, 2) and the basin area.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.785-790
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• 2009

섬진강 하구역에서 모래채취로 인한 지형변화와, 댐 및 취수장의 증가로 인한 유량감소로 인해 해수의 역류범위가 증가하여 참게나 재첩과 같은 경제성 어종이 감소하고, 염분으로 인한 농업용수사용 불가와 같은 염수피해가 늘어가고 있다. 따라서 본 연구에서는 2차원 수치모형인 RMA-2, 4와 3차원 수치모형인 EFDC를 각각 이용하여 밀물 시 염수가 전파되는 범위 및 염수농도를 모의하고, 동시에 2차원 모형과 3차원 모형을 비교하여 모의목적에 대한 각 모형의 장 단점을 알아보았다. 모의결과를 살펴보면 최저 수위 시 두 모형이 큰 차이를 보이는 것을 볼 수 있었으며, EFDC가 상류쪽으로 더 길게 염수침입이 일어나는 것을 볼 수 있었다.