• Journal of Korea Water Resources Association
• /
• v.55 no.10
• /
• pp.835-841
• /
• 2022

The water level of the dam reservoir is an important data in the operation of the dam. reservoir storage can be calculated by using water levels or prepared for disasters such as drought and floods. However, the water level is measured near the dam, making it difficult to represent a reservoir with a large area, and there is a high possibility that the water surface will be distorted due to discharge. Furthermore, the results of the survey showed that the water level of the reservoir is irregular rather than constant, and the water level of the reservoir is repeatedly falling and rising by section. In order to calculate such a complex and irregular representative water level, the water level observation density of the reservoir must be increased. In this study, we tried to derive the optimum water level observation density for Hwacheon Dam. A reasonable water level measurement density was derived by investigating the water level elevation of the reservoir and statistically analyzing it. The observation density may vary depending on the size of the reservoir, so the same analysis was conducted on the Goesan Dam and Boseonggang Dam. According to the results, four Hwacheon dams, three Goesan dams, and seven Boseong River dams are needed for observation density.

• 한국해양학회지
• /
• v.6 no.2
• /
• pp.99-103
• /
• 1971

GEK observation had been done in Satsunan sea region (south western region of Kyushu, Japan), mixing sea region of Kuroshio, its count-current and water mass of Eastern China Sea in August 1968. The results are al follows: 1. Observed values by GEK are coincided well with that of ship's drift in the surface water of Kuroshio region. 2. Compared the observed values by GEK with that of dynamic calculation of 800 db, in the eastern area of the surveyed region occupied by Kuroshio water mass, they are coincided well. But not in the western area which is of mixing zone of the Eastern China Sea water mass, Kuroshio and its count-current, showing over 1 knot differences with calculated value are bigger than that of GEK observation.

• Journal of Korean Society on Water Environment
• /
• v.35 no.4
• /
• pp.308-315
• /
• 2019

The objective of this study was to investigate mountain stream water and air temperatures, area, latitude, altitude, and forest coverage in headwater catchments located in Kangwon-do, Mid-eastern Korea from 2015 to 2017. Daily mean value of mountain stream water temperature was approximately $6^{\circ}C$ lower than the daily mean value of air temperature on the monitoring sites during the observation period. Monthly mean value of mountain stream water temperature increased with increasing monthly mean value of air temperature from May to August during the observation period. Seasonal variations of mountain stream water temperature were dependent on air temperature rising and falling periods. Correlation analysis was conducted on mountain stream water temperature to investigate its relationship with air temperature, area, latitude, altitude, and forest coverage of air temperature rising and falling periods. The correlation analysis showed that there exists a relationship (Correlation coefficient: -0.581 ~ 0.825; p<0.05), particularly the air temperature showed highest correlation with mountain stream water temperature. Regression equations could be developed due to contribution of air temperature to affect mountain stream water temperature (Correlation coefficient: 0.742 and 0.825; p<0.01). Therefore, a method using various parameters based on air temperature rising and falling periods, could be recommended for predicting mountain stream water temperature.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2003.10a
• /
• pp.427-430
• /
• 2003

Yi-dong experimental site is operated for research on the rural basin characteristics and accumulation of a long term data by hydrological observation equipments. This basin area is 9,300ha, length 14.4km and slope 0.67%. Hydrological observation network has 3 rainfall meter3, 3 reservoir storage levels and 2 river water levels.

• Journal of the Korean Institute of Navigation
• /
• v.15 no.2
• /
• pp.87-96
• /
• 1991

The change of water level at Mokpo Harbour and its adjacent coastal area due to the construction of the Youngsan Estuary Barrage and the Third Land Reclamation Work of estuary barren had been roughly expected. Periodical floods, which occur 2 times per month, are also being observed at the low lying commercial areas near the Mokpo Old Harbor. Although it is said that the highest tidal current component among the tidal current records at the approaching channel to Mokpo Harbor is reduced to 6 kts, because of the esturary barrage, they do not give any precise statement or a deep analysis for the flooding and periodical water level change under certain environmental conditions. Moreover, they never tried the analysis of development plan considering the natural disaster such as typhoon or other extreme conditions. Thus, it is necessary to collect and analyze the data related to floodings, harbor oscillations, currents, and water quality , etc. because of the development considering the extreme condition. Thus, it is necessary to collect and analyze the data related to floodings, harbor oscillations, currents, and water quality, etc. because of the development considering the extreme condition and to evaluate the field observation and measurement, including the numerical model simulation based on the scientific approaches. This study deals the problem of the water level change among the integrated analyses of the coastal area changes. The result can be used for the integrated planning to give a strong foundation and it will contribute to the development of local area.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.35 no.3
• /
• pp.187-191
• /
• 2012

The methods for constructing network of observational locations for measuring water quality in water reservoirs have been widely proposed, but they had some limitations to be applied to river areas, which lie in awkward clustering and finding representative observational locations among locations within each clustering. In this paper, a statistical approach to detect anomaly locations which were significantly different in important measurements for the water quality from the previous locations and construct observational network with them was proposed. Anomaly was detected with the sampling distribution of each primary principal component score, sum of primary PCs, or sum of residual PCs. The empirical study with the data of Nakdong Dam for guiding how to use our proposed approach and showing limitations of previous studied was described.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.66 no.4
• /
• pp.51-57
• /
• 2024

This study was conducted on how to simulate runoff, which was done using existing physical models, using an LSTM (Long Short-Term Memory) model based on deep learning. Tancheon, the first tributary of the Han River, was selected as the target area for the model application. To apply the model, one water level observatory and four rainfall observatories were selected, and hourly data from 2020 to 2023 were collected to apply the model. River water level of the outlet of the Tancheon basin was simulated by inputting precipitation data from four rainfall observation stations in the basin and average preceding 72-hour precipitation data for each hour. As a result of water level simulation using 2021 to 2023 data for learning and testing with 2020 data, it was confirmed that reliable simulation results were produced through appropriate learning steps, reaching a certain mean absolute error in a short period time. Despite the short data period, it was found that the mean absolute percentage error was 0.5544~0.6226%, showing an accuracy of over 99.4%. As a result of comparing the simulated and observed values of the rapidly changing river water level during a specific heavy rain period, the coefficient of determination was found to be 0.9754 and 0.9884. It was determined that the performance of LSTM, which aims to simulate river water levels, could be improved by including preceding precipitation in the input data and using precipitation data from various rainfall observation stations within the basin.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.9 no.4
• /
• pp.1-12
• /
• 2006

The usages of urban riverine areas for the Gapchoen and Yudungcheon in Daejoen City were evaluated by analyzing riverbed characteristics and water quality and by surveying the status of the floodplain usage including questionnaires of people visiting the rivers. Both rivers appear to be stable with insignificant bed changes as the riverbeds are dominated by gravels. Water qualities of both rivers have been improved significantly over the past decade although there are quite large seasonal fluctuations, which is common in most rivers in Korea. The results of floodplain usage analyses show that Gapcheon is dominated with static uses (>70%) such as promenades and resting facilities, while Yudungcheon by dynamic uses (>44%) such as sports facilities. Overall, both rivers require better plans for riverine area usage management considering a balance between the dynamic uses and the static uses such as natural observation places for education and habitats for birds and fish in the rivers. The questionnaire survey results indicate that overall the present status of both rivers are satisfactory and that water quality improvement is one of the key factors to enhance the value of the riverine areas. Future river restoration should be conducted by taking into account the characteristics of urban rivers in harmony with surrounding natural sceneries.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.14 no.1
• /
• pp.34-40
• /
• 2002

In order to estimate the height of long period wave from character of deep water wave, field observation is carried out three wave gauge are arranged by a straight line from the seashore to offshore direction and the result is analyzed. In addition, the existing theory of the mechanism for long period wave producer is verified by field observation, and the relation between deep water wave and long period wave of shallow area is examined. Observed long period wave is coincided with the existing theory for the most part. In order to add the change of time and space of long period wave, the height of long period wave is calculated by the composition of long period wave in each position. As a result, the relation of long period wave and deep water wave is presented more clear. Estimate formula is drew through them.

• Journal of Fisheries and Marine Sciences Education
• /
• v.28 no.4
• /
• pp.1171-1181
• /
• 2016

The purpose of this study was to verify the formation of satisfaction and dissatisfaction of water leisure tourism participants in Busan area using qualitative study method approach. Research participants were selected 6 water leisure tourism participants by reputational sampling method. Six participants who usually participated in water leisure tourism were selected as research participants. The data for this study included participants' observation and in-depth interview. This study categorized the coding paradigm which was presented by using the findings derived from water leisure tourism background. The results based on in-depth interview were as follows. First, water leisure tourism participants recognized environmental satisfaction of environmentally safe pleasure. Second, water leisure tourism participants recognized social satisfaction of change for leisure recognition. Third, water leisure tourism participants recognized facilities and program satisfaction of clearness and systematic programs. Fourth, water leisure tourism participants recognized instructor satisfaction of kindness and professional. Fifth, water leisure tourism participants recognized safety dissatisfaction of safety ignorance. Sixth, water leisure tourism participants recognized amenities dissatisfaction of lacking convenience. Seventh, water leisure tourism participants recognized accessibility dissatisfaction of public transportations.