• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.2222-2227
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• 2008

금강 본류에 위치하고 있는 공주, 금남 지점은 복잡한 하도 형상과 지점특성으로 인하여 수문관측에 어려움이 많은 지점으로 유출분석 결과가 좋지 못하기 때문에 정밀한 유량측정을 통하여 신뢰도 높은 유량값을 제시하여야 할 필요가 있는 지점이다. 본 연구에서는 2007년 금남, 공주 지점의 수문관측 자료 및 유량측정성과를 이용하여 수위-유량관계곡선식을 개발하고 기존 성과(2006년) 및 상류에 위치하고 있는 갑천, 미호천등의 지점들과 연유출률, 상 하류 유출, 평 저수시 동시유량 등의 유출특성을 검토하였다. 금남 지점의 수위자료는 2007년 1월${\sim}$9월 20일까지의 수위자료를 이용하였으며 이 기간의 순 유출률은 57.6%이고, 공주 지점의 수위자료는 2007년 수위자료를 이용하였으며 순 유출률은 58.6%로 적절한 상 하류유출률을 보이고 있다. 본 연구에서 수행한 금남, 공주 지점의 측정성과를 이용한 유출특성 분석 결과, 기존의 성과에 비하여 좋은 결과를 얻은 것으로 판단되지만, 본 연구에서 수행한 유량측정에서도 많은 문제점이 발생하였기 때문에 이런 경험과 기술들을 지속적으로 축적한다면 향후 더 정밀한 유량측정성과를 확보할 수 있을 것으로 판단되며, 효과적인 치수 및 이수계획의 수립 등 수자원 개발에 가장 기초가 되는 정확한 수문분석 자료의 확보를 위한 기반을 마련할 수 있을 것이다.

• Korean Journal of Environment and Ecology
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• v.36 no.4
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• pp.381-389
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• 2022

This study investigated the ecological characteristics of Microphysogobio yaluensis at Dugye Stream of Geum River basin from January to December 2021. The river bed structure of this species' habitat was rich in pebbles and gravel. The water depth ranged from 12 to 85 cm with an average of 23 cm, which was shallow. The stream velocity was rapid at 1.03±0.34(0.72-1.47) m/sec. The ratio of females to males was 1:0.86. The age according to the total length-frequency distribution as of summer (June, July) indicated that the group with less than 50 mm (30.4-49 mm) in total length was one year old, the group with 50-69 mm was two years old, and the group over 70-92 mm was three years old. Both male and female fish sexually matured at 50 mm long and two years old in June and July. The spawning season was from July to August, and the water temperature was between 25.8℃ and 28.2℃ during the period. The prosperous spawning season was July. The matured eggs were yellowish and spherical with a mean diameter of 0.52±0.16 (0.33-0.77) mm, and the average number of eggs found in the ovaries of mature female fish was 2,593 (1,343-4,672). As for the food of M. yaluensis, only attached algae, which grow by attaching to stones and gravel of the stream rapids, were identified. The feeding habit of M. yaluensis was reported to be herbivorous, ingesting Cyanophyta, Chlorophyta and Bacillariophya. Also, the species belonging to Bacillariophya and Chlorophyta were abundant in Dugye Stream.

• Journal of Korea Water Resources Association
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• v.41 no.2
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• pp.149-162
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• 2008

The Soil and Water Assessment Tool (SWAT) developed by the USDA-Agricultural Research Service for the prediction of land management impact on water, sediment, and agricultural chemical yields in a large-scale basin was applied to Daecheong Reservoir basin to estimate the amount of soil losses from different land uses. The research outcomes provide important indications for reservoir managers and policy makers to search alternative watershed management practices for the mitigation of reservoir turbidity flow problems. After calibrations of key model parameters, SWAT showed fairly good performance by adequately simulating observed annual runoff components and replicating the monthly flow regimes in the basin. The specific soil losses from agricultural farm field, forest, urban area, and paddy field were 33.1, $2.3{\sim}5.4$ depending on the tree types, 1.0, and 0.1 tons/ha/yr, respectively in 2004. It was noticed that about 55.3% of the total annual soil loss is caused by agricultural activities although agricultural land occupies only 10% in the basin. Although the soil erosion assessment approach adopted in this study has some extent of uncertainties due to the lack of detailed information on crop types and management activities, the results at least imply that soil erosion control practices for the vulnerable agricultural farm lands can be one of the most effective alternatives to reduce the impact of turbidity flow in the river basin system.

• Journal of Korea Water Resources Association
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• v.48 no.5
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• pp.379-391
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• 2015

Multi-functional weirs has been installed in four rivers are hydraulic structures across the river. The structures were divided into movable and fixed weirs. Hence, riverbed-level variation and sediment transport can be varied due to water gate operation. In this study, the long-term riverbed-level variation of Geum river basin due to water gate operation of multi-functional weirs was studied. Result of this study shows that the variation of thalweg elevation was greater than the variation of annual average riverbed elevation due to multi-functional weirs construction and water gate operation. Maximum riverbed degradation of thalweg elevation that occurred was 2.79m and riverbed aggradation was 1.90m. Maximum riverbed degradation of the annual average riverbed elevation that occurred was 2.16m and riverbed aggradation was 1.24m. Analysis result of flood stage by the variation of riverbed-level shows that flood stages were increased in majorities area. The maximum increase in the value of flood stage was 2.23m. For this reason, flood stages can be greater than the freeboard of the levees. Therefore, we should consider the water gate operation of multi-functional weirs when planning and managing sediment in the river. We are expecting to use the result of this study in river planning for river management and selecting the river regime.

• Journal of Ecology and Environment
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• v.48 no.1
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• pp.32-48
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• 2024

Background: Longitudinal connectivity in river systems strongly affects biological components related to ecosystem functioning, thereby playing an important role in shaping local biodiversity and ecosystem health. Environmental DNA (eDNA)-based metabarcoding has an advantage of enabling to sensitively diagnose the presence/absence of species, becoming an efficient/effective approach for studying the community structure of ecosystems. However, little attention has been paid to eDNA-based biomonitoring for river systems, particularly for assessing the river longitudinal connectivity. In this study, by using eDNA we analyzed and compared species diversity and composition among artificial barriers to assess the longitudinal connectivity of the fish community along down-, mid- and upstream in the Hotancheon from the Geum River basin. Moreover, we investigated temporal variation in eDNA fish community structure and species diversity according to season. Results: The results of species detected between eDNA and conventional surveys revealed higher sensitivity for eDNA and 61% of species (23/38) detected in both methods. The results showed that eDNA-based fish community structure differs from down-, mid- and upstream, and species diversity decreased from down to upstream regardless of season. We found that there was generally higher species diversity at the study sites in spring (a total number of species across the sites [n] = 29) than in autumn (n = 27). Nonmetric multidimensional scaling and heatmap analyses further suggest that there was a tendency for community clusters to form in the down-, mid- and upstream, and seasonal variation in the community structure also existed for the sites. Dominant species in the Hotancheon was Rhynchocypris oxycephalus (26.07%) regardless of season, and subdominant species was Nipponocypris koreanus (16.50%) in spring and Odontobutis platycephala (15.73%) in autumn. Artificial barriers appeared to negatively affect the connectivity of some fish species of high mobility. Conclusions: This study attempts to establish a biological monitoring system by highlighting the versatility and power of eDNA metabarcoding in monitoring native fish community and further evaluating the longitudinal connectivity of river ecosystems. The results of this study suggest that eDNA can be applied to identify fish community structure and species diversity in river systems, although some shortcomings remain still need to be resolved.

• Journal of Korea Water Resources Association
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• v.45 no.1
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• pp.75-89
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• 2012

This study attempted to analyze statistical characteristics of historical drought of Korea through trend, periodicity and drought spell analysis by using the drought indices. Standard Precipitation Index (SPI) and Palmer Drought Severity Index (PDSI) were calculated using weather data of 59 weather stations under Korea Meteorological Administration (KMA). As a result of analysis, SP13 and SP16 showed trend of drier spring, drier winter and wetter summer in all basin of Korea. However, SPI12 and PDSI showed different trends with shorter duration drought indices. In case of wavelet transform analysis for drought periodicities, in a band of 1~2 years or below 6 years showed significant spectrum. SP13 showed strongest power spectrum near the band of 1~2 year variance, and SPI12 and PDSI showed 6 years periodicities. The results from drought spell showed that Nakdong River Basin, Geum River Basin and Youngsan River Basin were appeared as severe drought vulnerable area of Korea.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.1 s.24
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• pp.57-66
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• 2007

The purpose of this study is both the variation of hydrologic topographical informations extracted by using WMS and the quantitative effect of rainfalll-runoff simulation due to dividing watershed. Miho stream basin in Geum river was selected by this study. Watershed dividing method are determined by area, channel slope and channel length. Hydrological response of divided watershed using Clark method, SCS method and Snyder method was compared with actual measured flood hydrograph. As a results, area-based watershed dividing method are particularly suitable the hydrologic applications using SCS method. This study can be used as basic data for the phase of the runoff variation in Miho stream basin.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.695-698
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• 2008

The SWAT model was used to assess the impacts of potential future climate change on the hydrology of the Upper Geum River Basin(UGRB). Calibration and validation of SWAT were performed on a monthly basis for 1982-1995 and 1996-2005, respectively. The impact of ten 15-year(1988-2002) scenarios were then analyzed relative to a scenario baseline. Among them, scenario 1-6 were set to show the sensitivity response. A doubling of atmospheric CO2 concentration was predicted to result in an maximum monthly flow increase of 11 percent. Non-linear impacts were predicted among precipitation change scenarios of -42, -17, 17, and 42 percent, which resulted in average annual flow changes in UGRB of -55, -24, 26, and 65 percent.

• Korean Journal of Heritage: History & Science
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• v.52 no.2
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• pp.268-291
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• 2019

In this paper, the features and meanings of the Yocoanabo (cave tombs) excavated in the Gongju and Buyeo regions were examined. The creation of the Yocoanabo in the Korean Peninsula was related to the situation in which the powers of the Northern Kyushu (九州) and Yeongsangang (榮山江) River Basin played certain roles and maintained power in the interactions of Wa and Baekje in the late 5th century until the early 6th century. The people buried in the Yocoanabo in the Gongju and Buyeo regions are most closely related to the Buzen (豊前) area in northern Kyushu. They also interacted with the Yeongsangang River Basin communities. The Yocoanabo in Gongju and Buyeo confirms the settlement of the Wa people. There were collective settlements such as the Danjiri (丹芝里) site on the outskirts of Woongjin (熊津). However, most of them were mixed with small local groups located on the main roads connecting Woongjin and Sabi (泗?) through the Geum River and land routes. Unlike the keyhole-shaped tombs of the Youngsangang River Basin, the Yocoanabo was not built until the 7th century. This explains differences in the backgrounds of the two types of graves. The people buried in the Yocoanabo are considered to have settled in the Baekje Kingdom and to have been responsible for practical work in the political and economic negotiations between Baekje and Wa. They came to the Baekje Kingdom collectively in connection with certain historical events. However, it had been presumed that most of the people came individually and dispersed to the local communities of Gonju and Buyeo.

• Korean Journal of Ecology and Environment
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• v.43 no.1
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• pp.44-54
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• 2010

In this study, a comprehensive exploration and evaluation of washland candidate locations by means of field monitoring as well as spatial analysis in six major river system (Han, Nakdong, Nam, Geum, Youngsan, and Seomjin Rivers). Washland(in other words, river detention basin) is an artificial wetland system which is connected to streams or rivers likely to riverine wetlands. Major purpose of washland creation is to control floodings, water supply and purification, providence of eco-cultural space to human and natural populations. Characteristics and functions of riverine wetlands can be expected as well, thus it is believed to be an efficient multi-purpose water body that is artificially created, in terms of hydrology and ecology. Geographical information and field monitoring results for the washland candidate locations were evaluated in 2009, with respect to optimal location exploration, ecosystem connectivity and educational-cultural circumstances. A total of $269\;km^2$ washland candidate locations were found from spatial analysis (main channel of Rivers South Han, 71.5; Nakdong 54.1; Nam, 2.3; Geum, 79.0; Youngsan 46.4; Seomjin 15.7), and they tended to be distributed in mid- to lower part of the rivers to which tributaries are confluent. Field monitoring at 106 sites revealed that some sites located in the Rivers Nam and Geum is appropriate for restoration or artificial creation as riverine wetlands. Several sites in the Nakdong and Seomjin Rivers were close to riverine wetlands (e.g., Upo), habitats of endangered species (e.g., otters), or adjacent to educational facility (e.g., museums) or cultural heritages (e.g., temples). Those sites can be utilized in hydrological, ecological, educational, and cultural ways when evidence of detailed hydrological evaluation is provided. In conclusion, determination of washland locations in the major river basins has to consider habitat expansion as well as hydrological function (i.e. flood control) basically, and further utility (e.g. educational function) will increase the values of washland establishment.