• Journal of Environmental Impact Assessment
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• v.14 no.3
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• pp.135-145
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• 2005

This study was conducted to investigate the characteristics of meteorological environment variation before and after construction of Nak-dong river estuary barrage. We used meteorological data(air temperature, precipitation, relative humidity, visibility, wind) at Gimhae airport meteorological station. The construction of river estuary barrage can change climate at the neighboring districts and influence human's health and vegetable. The construction of Nakdong river estuary barrage brought rise of temperature, decrease of relative humidity and increase of poor visibility frequency.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.1
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• pp.163-173
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• 2023

In this study, topographic change analysis was performed on the Nak-dong River estuary area. The factors affecting the changes in the bathymetry of the Nak-dong River estuary were analyzed using data from the discharge, suspended sediments, and rainfall of the Nak-dong River barrier as analysis data. As a result, erosion and sedimentation are judged to appear repeatedly due to complex effects such as discharge of the estuary barrier of the Nak-dong River and invasion of the open sea waves, and it is judged that there is no one-sided tendency. However, as a result of checking the data in the second half of 2020, it was possible to confirm a large amount of erosion, which is different from the past data. It is clear that this is a result beyond the trend of erosion in the first half and sedimentation in the second half. In the summer of 2020, the rainy season lasted for more than a month and torrential rains occurred, which seems to be due to about three times higher rainfall than other periods, and erosion is believed to have occurred as the discharge increased rapidly compared to the time deposited by river water outflow. In addition, compared to other times, the influence of many typhoons in the summer of 2020 is believed to have affected the topographical change at the mouth of the Nak-dong River.

• Journal of the Korean Society for Marine Environment & Energy
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• v.6 no.3
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• pp.26-36
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• 2003

Collected and analyzed the coastal processes at the estuary of Nak-Dong river and its near coastal area from the history of field measurements. Introduced a numerical model to predict three dimensional topographical change which are evaluated from the nearshore wave and the wave induced current fields for the objective area, and later it were related to the development of beach and shoals. With the comparison between measured and calculated, we found that the changes on the coastline and sand spit and bar development are induced not only by artificial forces due to the construction of river dike, but also by the strong impact of wave induced current. In future days, it is expected that coastline change and sand bar development at the lee side of Jinwoo-Deung and at the front of Dadae beach.

• Journal of the Korean Geotechnical Society
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• v.25 no.11
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• pp.5-15
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• 2009

Dynamic shear properties of Nak-Dong river sand were investigated to build a soil property database for Nak-Dong delta region. Samples were taken from the estuary and the midstream of the river. Laboratory specimens were prepared by air pluviation method, and were tested by using RC/TS apparatus at various confining stresses, relative densities and numbers of cycles. Shear modulus reduction and damping curves were developed using Ramberg-Osgood and Modified Hyperbolic Models. The developed curves, compared to those reported by other investigators, show only a slight difference. The outcome of this RC/TS experiments can be very important resources when accessing the dynamic response of sandy soils in Nak-Dong delta region in the future.

• 한국해양학회지
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• v.7 no.1
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• pp.1-14
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• 1972

Seasonal changes in nutrients and suspended organic particulates were measured in the estuary of Nak-dong River in relation to the black laver bed. Monthly measurements of water temperature, pH, dissolved oxygen, nutrients ( $NH_4$-N, $NO_2$-N, $NO_3$\-N, $PO_4$-P and $SiO_2$-Si) and organic suspended particulates (organic carbon and nitrogen) were determined at five stations from February through December, 1970. PH varied 7.6-8.4 with an average of 8.0, and percent saturation of dissolved oxygen were 71-147% with an average of 100.8%. Studies gave evidence that Nak-dong River estuary is strongly enriched with nutrients. Concentrations of nutrients were: 0.13-12.54 ${\mu}g$-atoms/${\iota}$ (averaging 1.63 ${\mu}g$-atoms/${\iota}$) for $NH_4-N$, 0.12-2.09 ${\mu}g$-atoms/${\iota}$ (averaging 0.71 ${\mu}g$-atoms/${\iota}$) for $NO_2-N$, 3.46-56.79 ${\mu}g$-atoms/${\iota}$ (averaging 21.54 ${\mu}g$-atoms/${\iota}$) for $NO_3$-N, 4.04-57.90 ${\mu}g$-atoms/${\iota}$ (averaging 23.79 ${\mu}g$-atoms/${\iota}$) for total soluble nitrogen, 0.18-5.05 ${\mu}g$-atoms/${\iota}$ (averaging 0.96 ${\mu}g$-atoms/${\iota}$) for $PO_4$-P, and 18.33-133.29 ${\mu}g$-atoms/${\iota}$ (averaging 71.57 ${\mu}g$-atoms/${\iota}$) for $SiO_2$-Si, respectively. These nutrient levels were considerably higher compare with other productive laver beds of Wan do and Pyung-il Do in Korea or Ise Bay in Japan. Concentrations of suspended organic particulates varied 55-648 ${\mu}g/{\iota}$ (averaging 392 ${\mu}g/{\iota}$) with organic carbon, 30-155 ${\mu}g/{\iota}$ (averaging 92 ${\mu}g/{\iota}$) with organic nitrogen, and its carbon-nitrogen ratios were varied within 1.5-8.4 with an average of 4.6.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.6
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• pp.691-696
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• 2001

The first bloom of Cochlodinium polykrikoides was observed in the estuary of Nak-dong river near Pusan in Korea in 1982. Since then, there have been irregular blooms, sometimes spread over the adjoining .to Jinhae Bay even though it was confined to the bay and its vicinites until 1988. It had been outbroken frequently in the adjacent to Tongyeong, Geoje, Namhae and Yeosu coast since 1989. It became widespread along the coast of the South Sea to the East Sea of Korea in 1995. And in October in 1998 and 1999, the bloom had been taken place in Kunsan coast of Yellow Sea. According to the observations in situ, the frequency of occurrence has been increased year by year. The prevailing bloom season was from July to October with peak in September. The duration of the bloom became longer with the year, and sometimes lasted more than one month. The density of the bloom did not exceed 5,000 cells $mL^{-1}$until 1991, but it increased year by year to the highest of 43,000 cells $mL^{-1}$ in 1999. With respect to the assembleges of species in dinoflagellate blooms, C. polykrikoides was one of the important species with diatoms and the other dinoflagellates in 1980s. But since then, C. polykrikoides made an almost monospecific bloom. Based on two decadal observations of C. polykrikoides blooms, it became widespread throughout whole coast of the Korea, persistent for about one or two month long in some year, and monospecisc high density blooms. It was reported that significant fish mortalities were caused by this harmful dinoflagellate blooms especially in the fishfarms accomodating intensive fish cages such as Tongyeong, Namhae-do, Geoje, Yeosu and Geomun-do fishfarming yards. This widespread and persistent harmful algal blooms impede the development of marine aquaculture industries.