• Journal of Korean Society on Water Environment
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• v.33 no.2
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• pp.149-159
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• 2017

After the artificial barrage was constructed in 1990s, the Geumgang estuary has been experiencing considerable changes in nature as well as in socioeconomic and culture in the vicinity villages. In order to understand how the change of estuarine environment bring about conflicts among the local communities, and resolve the conflicts, the research investigated the causes of the conflicts in the Geumgang estuary using in-depth and semi-structured interview method. 100 local people who have lived in the vicinity of Geumgang estuary for more than 30 years were selected for the interviews. Results of the research shows that local people's jobs determine the opinions about the estuary barrage and the way of estuarine management. Understanding environmental change and local conflicts helps to develop a sustainable and integrated estuary management system in the region.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.6
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• pp.15-24
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• 2005

The normalization on the characteristics of water level change at the upstream gauging station was attempted according to the operation of drainage sluice gate of the Geumgang estuary dam. The characteristics were normalized by the analysis of water level change and by the linear-regression of the water level data measured at the inner station of Geumgang estuary dam and upstream gauging station. The results of normalization may be referred to the management of Geumgang estuary lake, the operation of pumping and drainage stations in the shore of the lake. The mean response time of water level change on Ibpo, Ganggyeong and Gyuam water level station were 39,81 and 160 minutes, when sluice gate was opened respectively. The mean velocity of surface wave, the mean displacement of water level change, the mean time of water level change and the mean rate of water level change varied largely depending on the location of gauging station and the characteristics of stream section of the water level gauging station.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.3
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• pp.1-7
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• 2010

The ichthyofauna and passing efficiency of fishways were surveyed in Geumgang estuary from May to October in 2009. The fishes collected were classified into 24 species, 23 genera belonging to 8 families. These 24 species consist of 17 freshwater fish species, 3 migration fish species and 4 peripheral freshwater fish species. Seasonal function of fishways showed the migration from May to June and returning to the reservoir of fishes be washed out to sea when sluice gate open by rainfall in July and August. Most of the fishes catched in fishways moved from middle tide to high tide except for July. Fishes ascended fishways between the middle ebb tide and the ebb tide only July, because small freshwater swim against the fishway for leaching the reservoir through the newly formed flow when the water level at the fishway kept dropping. Small fishes that body length less than 200 mm mainly used gabion type fishways and fishes over 200 mm utilized a cascade type fishways. Based on the total individuals collected, the efficiency of the fishway was 1 % for the anadromous fish and over 80 % for freshwater fish. Therefore, it is concluded that ecological function of the fishway in the Geumgang estuary dike be very important not only for fish migration but also freshwater fishes's returning.

• 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.

• Korean Journal of Ecology and Environment
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• v.55 no.2
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• pp.167-174
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• 2022

The Ministry of Oceans and Fisheries promoted the installation of eel-ladder for the purpose of creating inland water resources. Currently, eel-ladder have been installed and operated at the Geumgang Estuary Bank (2018), Yeongam Embankment (2019), and Asanman Embankment (2020). In this study, the number of glass eels in eel-ladder in 2021 was monitored and factors affecting the rise that from ocean to river of eels were investigated. Glass eels in eel-ladder were found when the salinity was relatively low, and they started when the freshwater and seawater temperatures were above 20℃. Comparing the number of occurrences by year, the largest number of glass eels was observed in 2021, but it is judged that this is not according to the distribution of glass eels in sea, but rather as a result of the investigator's eel-ladder repair and guidance on illegal fishing.

• The Korean Journal of Ecology
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• v.28 no.3
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• pp.129-134
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• 2005

The monthly variations of physico-chemical and microbiological water quality were investigate in the artificial Lake Geumgang near estuary barrage. Sixty heterotrophic bacteria were isolated and identified by amplification and sequencing of 16S rDNA. Water temperature, pH, and inorganic nutrients($NH_4$-N, $NO_2$-N, $NO_3$-N, $PO_4$-P) were measured. Concentrations of DO, BOD, and inorganic nutrients were lower than in the middle-stream of Geum river The population densities of heterotrophic bacteria and total coliforms varied from $4.1{\pm}1.0\times10^2$ to $6.7{\pm}1.1{\times}10^3\;cfu\;ml^{-1}$, and 0 to $2.3{\pm}0.6{\times}10^2\;cfu\;ml^{-1}$, respectively. Among the measured numbers of physiological groups of bacteria, cellulolytic bacteria showed higher population densities than those of other physiological groups. Bacterial community structure was analysed based on 16S rDNA partial sequencing. Among 60 isolates, dominant genus was Pseudomones (20 strains).

• 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.

• Korean Journal of Environment and Ecology
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• v.28 no.2
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• pp.113-122
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• 2014

This study was conducted to clarify the community characteristics of wintering waterbirds in Geum River from September, 2011 to March, 2012 (1st) and from September, 2012 to March, 2013 (2nd). 63 species of waterbirds including raptors were observed during the survey. 50 species of 188,673 individuals recorded during the first survey, and 56 species of 116,611 individuals were recorded during the second survey. The dominant species was high dominance dabbling ducks by Baikal Teals, Mallards, Spot-billed Ducks, Greater White-fronted Geese, Black-tailed Gulls and Common Shelducks. We classified the wintering waterbirds into 9 taxa based on the similar ecological characteristics and analyzed the correlation with temperature. As a result, dabbling ducks, diving ducks and raptors showed positive correlation and herons and waders showed negative correlation. Geese, swans and dabbling ducks were high habitat utilization ratio at the Geumgang estuary barrage upstream area, and diving ducks, herons, waders and gulls were high habitat utilization ratio at the Geumgang estuary barrage downstream area.

• Korean Journal of Ichthyology
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• v.34 no.2
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• pp.127-132
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• 2022

Most of the downstream of the river is blocked by beams, so fishways are required for the movement of conciliatory fish species and connection with the upstream. Therefore, it is very important as an ecological pier that can help free movement of fish. The three previously installed eel ladders use only brushes on the bottom. For find out the effect of the bottom material except to brush, experimented used model glass eel ladders to the ascent of glass eel. The eel ladder model was 1.2 m length, 0.3 m wide, and 0.1 m high, and three gravels of different particles were attached to the bottom of the fish ladder setting on the Geumgang Estuary Bank. The first model ladder was made of gravel with particles of 5 mm, and the second model ladder was made of gravel with particles of 2 mm. The third model ladder was made by solidifying with particles of 1 mm or less cement. All experiments were repeated 5 times for 1 hour. As a result of the experiment, the lower the angle, and the smaller the gravel particles, the more glass eels are ascended to the ladder, but the made of cement was nearly not ascent. The gravel-bottom model ladder has a lower discharge and flow rate than the brush ladder so more glass eels can ascent ladder, and if the glass eel ladder is improved through experiments applying various floor materials and variables in the future, more glass eels are going to ascent glass eel ladder.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1307-1311
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• 2010

수자원의 효율적인 관리를 위해서는 홍수량 자료뿐만 아니라 저 평수량의 자료도 매우 중요하며, 이는 최근의 가뭄 발생으로 인하여 용수공급 및 하천수질관리 문제에서 저수위 유량자료의 파악이 중요한 관심 대상이기 때문이다. 이를 위해서는 저수위에 대해 유량측정을 실시하여 유량자료를 확보해야 하며, 이와 더불어 연속적인 유량자료를 얻기 위해서는 신뢰성 있는 수위-유량관계곡선식이 필수적이다. 일반적으로 자연하천에서 수위-유량관계는 수위의 상승 및 하강에 따라 유량변화가 일정한 경향성을 가지고 변동을 하기 때문에 단일함수 관계로 설명이 가능하다. 하지만 갑문 조작에 영향을 받는 구간에서는 수위와 유량만의 단일함수 관계가 아닌 갑문의 개 폐에 따라 수위와 유량이 변동하는 특성을 가지고 있어 일반하천에 비해 수위-유량관계를 규명하는 것이 매우 어려운 문제이다. 본 연구는 금강 하구둑의 갑문조작에 의하여 배수영향을 받는 규암 수위관측소에 대하여 수위-하강고-유량관계를 이용한 유량환산방법, 수면경사를 매개변수로 추가한 다중 회귀식 개발, 자동유량측정 장치를 이용한 유속지수법, 기존 수위-유량관계곡선식을 이용한 유량환산, ADCP(Acoustic Doppler Current Profiler)를 이용한 유량측정성과에 대하여 비교 분석을 통하여 갑문조작에 의한 배수영향을 받는 지점의 안정적인 유량자료를 제공하는데 목적이 있다. 이와 같이 각 유량환산 방법에 따라 실측 유량과 환산유량 비교의 결과 수위-하강고 유량관계의 경우 평균 26.60%, 기존 수위-유량관계곡선의 경우 130.29%, 유속지수법의 경우 36.48%, 다중회귀식의 경우 24.65%의 상대오차가 발생하였다.