• Journal of Ocean Engineering and Technology
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• v.23 no.4
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• pp.19-24
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• 2009

In order to analysis the variation in vegetation area caused by topographical change at Jinudo in the Nakdong estuary, we used aerial photographs of Jinudo from 1998 to 2006. To extract an accuracy shoreline from these aerial photographs, a tide calibration was performed. We also estimated the annual variation in topographic area and vegetation area, and then analyzed the relationship between them by a correlation analysis. The following results were obtained: 1) The calibrated shoreline distance of Jinudo from 1998 to 2006 was estimated to have a range of (-)1,927 cm to (+)4,671 cm. 2) Annual changes in the topographic area and vegetation area in Jinudo have been increasing gradually from 1998, and the correlation coefficient between topographic area and vegetation area is 0.97. 3) The estimated topographic areas were with following order: southern (III), eastern (IV), northern (II) and western (I), while for the vegetation area, the order was southern (III), northern (II), eastern (IV) and western (I). 4) The vegetation area of the southern region (III) of Jinudo had the largest size among the regions, and was calculated to be $4.3{\sim}5.4$ times larger than the eastern region (IV).

• Journal of the Korean Society for Marine Environment & Energy
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• v.10 no.1
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• pp.13-20
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• 2007

This study was performed to provide fundamental data for long-term geomorphic predictions of estuarine sandbars in the Nakdong River. We monitored the geomorphic changes of Jinudo (Jinu Island), which is located on the far-southern side of the first western sandbar. We evaluated the temporal and spatial dynamics of the sandbar and the relationship between erosion and deposit speed with environmental factors. We found that: 1) The south side of Jinudo showed very rapid water channel closing and shoal generation. This phenomenon was more obvious during autumn (September and October) than during spring, with greater water depth reduction and variation between sides. 2) The mean deposit speed for Jinudo was approximately 0.85 mm/day. The deposit speed was 1.32 and 1.26 mm/day for the east and south sides of Jinudo, respectively. The maximum deposit and erosion speeds were 27 mm/day and 26 mm/day in July and December, respectively, on the east side of the island. 3) Mean surface deposit size was 0.18-0.26 mm. The newly deposited sandbar had a rotatively larger deposit size than the original land. 4) Correlation analysis showed that, on the southern side of the island, deposit activity prevailed in the winter due to low precipitation and a northerly wind, while erosion was dominant in the summer due to high water flow and a southerly wind. In contrast, the correlation analysis for the eastern side of the island showed that deposition is dominant when water flow is high. These results indicate that geomorphic dynamics vary among island sides.

• Journal of the Korean Society for Marine Environment & Energy
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• v.10 no.3
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• pp.148-154
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• 2007

This study investigated the spatial distribution of the marine debris in Jinudo in the Nakdong river estuary. Types of marine debris in Jinudo are analyzed through sampling around some portion of its sandbar shoreline. The present study and its main results are summarized as follow: 1) Monitoring system, for evaluating the volume of marine debris, was established in the coastal region of $50\;m\;{\times}\;50\;m\;(=0.002\;km^2)$ over the southern part of Jinudo. All the marine debris of conceivable form are collected and their amount was also estimated. 2) During the $1^{st}$ collection in May 2007, the total weight of the marine debris was 1,110 kg in this site, which means the density of marine debris around the shoreline is $444\;ton/km^2$. After one month later, the collected marine debris was 23.75 kg and so we have the average density of $9.5\;ton/km^2$. From these results, it is suggested that the marine debris of 316.67kg was being accumulated per day over unit area($1\;km^2$). 3) The most frequent marine debris collected during monitoring campaigns was wooden material amounting to 85.86% of the whole collection; the rest were fishing gears such as nets and buoys(5.13%), household waste(2.34%), glass(0.94%) and metals(0.27%).

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.4
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• pp.630-636
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• 2008

Monitoring the location of the shoreline and foreshore changes through the time and core tasks are carried out by coastal engineers for a wide range of research. With the advent of digital imaging technology, the shore-based video monitoring system provides many advantages than field surveys. This study presents the development and construction(installation) of video monitoring system to assist the study of coastal and shoreline dynamics and evolution, especially sandbar variation at the Nakdong river estuary. For the purpose of this study, at high building near the Dadea-po beach (St. 2) and Jinudo(island) (St. 1) foreshore region, where coastline variation is highly active, 5 video cameras installed; the coastline movement has monitored since Aug. 2007 using the systems. From the image results of video camera, the 'Spit' type sandbar appears at the foreshore region of Doyodeung and Dadea-po beach and measured the deposition process of Jinudo(island) foreshore region. As a result, the monitoring system using video-based technique built in this study would be able to identify changes in the area and width of shoreline and beach of Nakdong river estuary.

• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.2
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• pp.70-77
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• 2008

In this study, to establish countermeasure from marine casualties as a basic study fur long-term prediction of topographical change around Jinudo in the Nakdong river estuary, spatio-temporal topographical change monitoring was carried out. Also, in order to estimate the deposition variations concerning SS (Suspended Solid) flux which moved at St.S1 during neap and spring tide, respectively. From the topographical monitoring, it was found that the annual mean ground level and deposition rate were 141 mm and 0.36 mm/day and all parts except the northern part of Jinudo had the active topographical changes and a tendency to annually deposit. From vertical distribution of SS net fluxes, $SS_{LH}$ (latitudinal SS net flux) during spring tide overall flows average 28 $kg/m^2/hr$ (eastward), and $SS_{LV}$ (longitudinal SS net flux) flows average 11.1 $kg/m^2/hr$ (northward). And, $SS_{LH}$ overall flows average 4.8 $kg/m^2/hr$ (eastward), and $SS_{LV}$ flows average 1.5 $kg/m^2/hr$ (northward) during neap tide similar with spring tide. The depth averaged values of the latitudinal and longitudinal SS net fluxes during spring tide were approximately 6 times higher than those during neap tide. As result of, it was considered that topographical change of southern part of Jinudo was affected by resuspension of bottom sediments due to strong current in bottom layer during flood flow.

• Proceedings of KOSOMES biannual meeting
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• 2017.04a
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• pp.189-189
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• 2017

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.05a
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• pp.131-137
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• 2004

This paper is intended as an investigation of the deposition characteristics and mass transport flux estimation in the Nakdong estuary. In order to understand the effects of the tidal current circulation which influenced to an estuary terrain change, the seawater circulation calculation by the use of 2D numerical model for the three cases of without riverflow, mean and flood riverflow quantity condition practiced and each sectional net-flux of water quantity between sandbars(so called, dung) estimated. It may be that an estuary terrain change due to the large scale construction and reclamation at the Nakdong estuary influence to the long-time deposition characteristics. by the revim for the old research, we know that the development of the local sandbars has been moved toward the east-side from the west-side estuary area after the construction of the Nakdong river dike, at present the strong-acted location is the Bakhap-dung of the front sea of Tadea. The seawater circulation pattern at this large scale area of tidal flat bring on a change due to the water quantity outflowing from the Nakdong river. Base on the calculated results for the section net-flux of water quantity, we see that the accumulating action very strong at the local sea around Jangjado, Bakhapdung and Tadae for the case of flood riverflow quantity condition, but at the local sea around Jinudo for the another cases. Consequently, it is emphasized that in the Nakdong estuary the main sensitive regions which influenced from the discharge of riverflow were the local sea around Jangjado, Bakhapdung, Tadae and Jinudo.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.5
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• pp.545-552
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• 2018

In this study, we performed a mesocosm experiment to estimate the mass balance of Nutrients (DIN, DIP) in a phragmites australis community. We developed 4 mesocosm tanks which is available to circulate seawater with adjustable tide levels and flooding times. Each of the mesocosm tanks were filled with phragmites australis and sediment from Jinudo in Nakdong Estuary. We investigated DIN, DIP concentrations in three layers (seawater-phragmites australis-sediment) to estimate the mass balance of Nutrients and biomass. Growth rates were also investigated. The results can be summarized as follows. 1) In spring, rhizome biomass was higher than that of aerial stem by about 6.3~9.7%. In summer, aerial stem biomass was higher than that of rhizome about 19.2~21.2 %. 2) Th Growth rate of phragmites in Mesocosm Tank A was faster than in Mesocosm Tank D by about 2 to 3 times for aerial stem and rhizome. 3) The Concentration of nutrients (DIN, DIP) in each mesocosm Tank showed 2~3 % variance in spring and summer. 4) The biomass in each mesocosm varied by about 23 % which was higher than the concentration variance for each mesocosm tanks.

• Journal of Ocean Engineering and Technology
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• v.9 no.1
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• pp.120-131
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• 1995

Numerical simulations on the suspended sediment transport in the Nakdong Estuary are carried out Uncoupled flow model and diffusion model of which the governing equations are two-dimensional depth integrated equations are used int his study. Four cases are tested in this numerical simulations in which the Gaduk waterway open boundary condition and Nakdong Estuary barrage boundary condition are considered as the boundary conditions. The simulated results are compared with the measured data which were obtained by NEDECO at hadan site on 1981.2.19. and by Dong-A university at one station in the study area on 1993.4.3. and show a good agreement with them. The construction of the Nakdong Estuary Barrage may affect to reduce the current near Jinudo an Daemadeung and the suspended sediment inflowed from the upstream in the wet season seems to be transported to the Dadae.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.441-444
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• 2006

Nakdong river estuary is located at south-eastern coast if the Korea. Especially, Complicating topography change is generated by interaction of much sediment, wave and tide. This study is investigated into observation data of grading size distribution in the post and surface sediment characteristics is investigated into grading size analysis using sieve analysis in Nakong river estuary. As a result, mean diameter of surface sediment is distributed to front of shoal as a size with 0.1~0.2 mm and mean diameter of the last generated shoal is about 0.2~0.3 mm.