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Jeong, J.B.; Woo, H.J.; Jung, H.-S.; Park, H.N.; Kim, T.-J, and Lee, J.-H., 2021. Monsoon-influenced deposition systems in a rhodolith beach on Udo Island, Korea. In: Lee, J.L.; Suh, K.-S.; Lee, B.; Shin, S., and Lee, J. (eds.), Crisis and Integrated Management for Coastal and Marine Safety. Journal of Coastal Research, Special Issue No. 114, pp. 41–45. Coconut Creek (Florida), ISSN 0749-0208. A beach on Udo Island, off the coast of Jeju Island, Korea was formed by long-term deposition of rhodoliths, which comprise more than 99% of all deposits on the beach. This phenomenon is very rare on the global scale. This rhodolith beach in 2004 was designated a natural monument to preserve its geoheritage. However, to date, no geological studies have been conducted to examine its sedimentary mechanisms and properties. Recent tourist developments and climate change have raised the possibility of erosion on the rhodolith beach. The objective of the present study was to examine the evolution and sedimentation characteristics of this beach through analysis of grain size and aerial photographs, and seasonal beach surveys. Geomorphologically, the beach is divided into reef areas to the north, with high altitudes and rocks mainly distributed along the coastline, and sandy beach to the south, which is strongly affected by waves and tidal currents. Particle sizes decrease toward the upper part of the beach, with gravel-sized sediments in the south and sand-sized sediments in the north. The mean grain size of deposited sediments increases from spring to autumn. In spring, the beach experiences greater erosion in the north and deposition in the south, whereas in summer, the opposite trends are seen. The sediment deposition volume is largest in autumn. There is also annual variation, where the beach was dominated by erosion in three recent years due to a decrease in sediment volume toward the south. The beach increased in volume from 1985 to 2003, and decreased thereafter. Due to the influence of the East Asian Monsoon, the beach experiences typhoons in summer and north-northwesterly waves and tidal currents in autumn and winter. However, erosion occurs in in the south due to a lack of berm for rhodoliths deposition.

Lee, J.-H.; Woo, H.J.; Jung, H.-S.; Park, H.N.; Jeong, E.-Y., and Jeong, J.B., 2021. Characteristics of the wind distribution using automatic weather system observation data over the Doyo-deung barrier islands off the coast of the Nakdong River estuary, Busan, South Korea. In: Lee, J.L.; Suh, K.-S.; Lee, B.; Shin, S., and Lee, J. (eds.), Crisis and Integrated Management for Coastal and Marine Safety. Journal of Coastal Research, Special Issue No. 114, pp. 36–40. Coconut Creek (Florida), ISSN 0749-0208. This study was conducted to the Nakdong marine environmental information system (N-MEIS) using automatic weather station (AWS) observation data to elucidate the characteristics of the wind distribution, focusing on and land and sea breezes, over the Doyo-deung barrier islands in the brackish water zone off the coast of the Nakdong River Estuary, Busan, South Korea. From May 2015 to the present, the N-MEIS was run in real-time using 4th Generation (4G) long term evolution (LTE) communication, with a coverage rate of approximately 98% from AWS, along with periodic marine observations recorded one to four times per year. From April 2016 to August 2020, the average monthly wind speed over the Doyo-deung barrier islands was 3.82 m/s (range, 2.10–5.10 m/s) and the maximum wind speed, recorded in February 2019, was 46.80 m/s. These values are generally influenced by low-pressure cyclones or gusty winds. However, the maximum monthly mean velocity may be influenced by typhoons occurring in early autumn, from August to September. Based on the percentage of each wind direction, the prevailing winds are from the N, NNE, SSW, and NNW. The distribution of wind directions in summer was similar to that in spring, while that in autumn tended to be similar to that in winter. However, considering only wind speeds of 5.00 m/s or more, which can cause the movement of sand particles, N, SSW, and NNW winds are overwhelmingly dominant, at 38.7%. Research into the dynamic wind distribution is essential to effectively managing erosion and sedimentation around barrier islands, beach pollution from floating materials transported overland, coastal sand dune activity, changes in migratory bird habitats, and impacts on ecosystem health. The evolution and development of the N-MEIS will facilitate this process. Future studies should integrate real-time data with periodic marine observations and predictions and environmental sensitivity index maps.

Choi, J.U.; Lee, Y.G.; Jeong, D.U.; Choi, Y.H., and Woo, H.J., 2018. Effects of Abalone Farming Cage Removal on the Benthic Foraminiferal Assemblages. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 321–325. Coconut Creek (Florida), ISSN 0749-0208. To improve the aquaculture environment of an abalone farm near the Bogil Island, relocation was executed via the partial relocation of cages. The surface sediments were collected from nine stations to analyze the grain size, geochemical characteristics, and benthic foraminiferal assemblages in May (before) and August (after) 2015. Although no distinct environmental changes in the cage area were observed, the relocation area had an increased sand content caused by water circulation. In addition, despite the increase in the sediment temperature, the ignition loss decreased while the dissolved oxygen in the se...

Jeong, E.J.; Woo, H.J.; Kang, J.; Lee, J.-H., and Choi, J.U., 2018. Study of Holocene paleo-environmental evolution using cores from the downstream area of the Nakdong River Delta, Korea. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 626–630. Coconut Creek (Florida), ISSN 0749-0208.The Nakdong River Delta in Korea consists of wide and thick sediments, which are excellent for undertaking highresolution investigations of paleo-environmental evolution. This study describes the horizontal evolution of the sediment environment during the Late Quaternary based on the KND-3 and ND-3 cores obtained from the downstream area of the Nakdong River Delta. The lowest sediments in these cores differ markedly, with KND-3 mainly being composed of olive gray coarse, sandy sediments with pebbles of c. 2-cm diameter, which are interpreted as representing a paleo-channel environment, and ND-3 mainly consisting of red silty sediments (paleosol), which are interpreted as representing alluvial deposits that were exposed to the atmosphere. By contrast, the upper sediments above 40.00 m in both cores were deposited when the sea level rose to a similar level as seen today, at which time both cores evolved through a succession of environments from estuary complex, through to shallow-marine, prodelta, delta front, and the present-day delta plain.

Woo, H.J.; Lee, J.-H.; Kang, J., and Choi, J.U., 2018. Sedimentary processes of barrier-lagoon system in the Nakdong river estuary, Busan, South Korea. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 1–5. Coconut Creek (Florida), ISSN 0749-0208.The Nakdong River Estuary on the southeastern coast of the Korean Peninsula is enclosed by two large estuarine dams, one constructed in 1934, and one between 1983 and 1987. The estuary has been characterized as a barrierlagoon system with various subenvironments and micro-tidal ecosystem and a mean tidal range of 1.07 m. The monitoring short-term sedimentation rates and suspended sediment characteristics were investigated to understand sedimentary processes in the barrier-lagoon system of the Nakdong River Estuary. The surface sediments generally showed sand sediment was dominated along the seaward side of the barrier islands and muddy sand sediment was dominated within the lagoon. The short-term sedimentation rates for a year showed that deposition dominated the tidal flats between the mainland and Jinudo (JW-line) and the mainland and Sinjado (SJ-line), with net deposition rates of 10.09 and 12.38 mm/year, respectively. Erosion dominated the tidal flat for two years at the southern end of Eulsukdo (ES-line), which is located on the eastern side of the system, at an annual rate of −12.76 mm/year. Four 12.5-hour anchoring surveys conducted at the inlets and channel revealed that net suspended sediments were transported to the open sea during a tidal cycle in summer. The sedimentary processes of the Nakdong River Estuary showed that sediments were transported into the lagoon through inlets during floods and moved westward and/or northwestward; they were then deposited on the tidal flats and in channels near the dams under low energy conditions. Within the eastern side of the system, sediments flowed out of the sea with discharge from the Nakdong Dam during ebb conditions. The major control factors for seasonal variations in these sedimentary processes within the barrier-lagoon system were waves, tidal currents, and dam discharges.

Lee, J.-H.; Jeong, K.-S.; Lee, D.-H.; Park, K.S., and Woo, H.J., 2018. Elemental (C/N Ratios) Isotope compositions (δ13CTOC and δ15NTN) of surface sediments from the barrier islands in the Nakdong river estuary, South Korea. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 36–40. Coconut Creek (Florida), ISSN 0749-0208.The Nakdong River Estuary (NRE) in South Korea is a typical, artificially manipulated estuary that is blocked by two large dams. The estuary is characterized by a barrier-lagoon system with various subenvironments and a microtidal domain with a mean tidal range of 1.07–1.50 m. The stable isotopic values (δ13CTOC and δ15NTN) and elemental (C/N ratios) compositions of organic matter, including those of halophytes, from the barrier islands were investigated in the NRE. In May (n = 94) and August (n = 90) 2015, sediment samples were collected on and around three islands in the NRE. The mean grain size of the barrier island system in the NRE ranged from 1.1 to 8.9 Φ (average 3.9 Φ) and the sediment types included muddy sand, sandy mud, and mud. The relative low C/N ratios (average 5.88) imply that the deposited organic matter originated from autochthonous algae derived-sources. The δ13CTOC ranged from −28.2 to −16.8‰VPDB (average −22.5‰VPDB), with δ15NTN in the range 6.2–12.5‰AIR (average 9.4‰AIR). Two halophytes (Phragmites communis and Scirpus planiculmis) had δ13CTOC values that ranged from −29.0 to −25.3‰VPDB (average −26.5‰VPDB) at ES-R and ES-5. The isotope and elemental composition of sedimentary organic matter (δ13CTOC and δ15NTN) indicated the deposition of algae-derived organic matter with limited input from terrestrial organic matter. These results suggest that the microphytobenthos contribution was greater than the inflow of surrounding land vegetation and sediments to the north of the barrier islands had a marine origin. To the south, the effect was considered mixed. Further studies should determine the effects of end-member discrimination on the origins of the organic matter, such as the advance signature proxy. It is necessary to continue measuring sediments and water in the brackish water zone around the barrier system with on-site monitoring of dam discharge, tidal currents, waves, and, etc.

Lee, J.-H.; Jeong, K.-S.; Kang, J.; Park, K.-S., and Woo, H.J., 2017. Benzene, toluene, ethylbenzene, xylene, and styrene (5VOCs) distributions at the barrier island system in the Nakdong River estuary, South Korea. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 89–93. Coconut Creek (Florida), ISSN 0749-0208. Total Volatile Organic Compounds (TVOCs) were extracted from 18 surface sediment samples collected in and around barrier island system in the Nakdong River Estuary (NRE) on the southeastern Korean Peninsula in May 2015. TVOC emissions from sediments were measured using a Thermal Desorption System-Gas Chromatograph-Mass Selective Detector (TDS-GC-MSD) for 30 min at 25°C at the National Center for Inter-university Research Facilities (NCIRF), Seoul National University, South Korea. The thermal extractor (Gerstel, Germany) was equipped with an adjustable oven (temperatu...

Woo, H.J.; Kang, J.; Lee, J.-H., and Jang, S., 2016. Seasonal changes in sediment characteristics on the tidal flat in Geunso Bay, west coast of Korea. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 1412 - 1416. Coconut Creek (Florida), ISSN 0749-0208. Geunso Bay, located in Taean, western Korean Peninsula, is a semi-enclosed-type bay with a mean tidal range of about 6 m. Tidal flats are largely developed along the sides of the bay. A digital elevation model showed that 95% of the total area of the bay is tidal flat. Observations in both winter and summer of 2009 revealed that the surface sediments in the bay were mainly muddy sand, and the sediments were classified into five sedimentary facies: sandy silt, slightly gravelly sandy mud/sandy mud, slightly gravelly muddy sand/muddy sand, silty sand, and sand. In the eastern tidal flat, the...

Lee, J.-H.; Woo, H.J.; Jung, H.-S.; Jeong, J.B., and Park, H.N., 2020. Application of a Marine Environmental Information System (MEIS) Data to marine spatial planning (MSP) in the Nakdong River Estuary, Busan Metropolitan City, South Korea. In: Malvarez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 860–864. Coconut Creek (Florida), ISSN 0749-0208.The Nakdong River in South Korea is nearly 526 km long, and has a drainage basin of around 23,817 km2. It is subject to natural erosion and sedimentation, and there is also the potential for disturbance by various human activities, including water diversion and reservoir construction, and other large construction projects in the river estuary. The Noksan dike, built in April 1934, blocks the flow of the west Nakdong River. The Nakdong River Estuary (NRE) barrage in Busan Metropolitan City was completed in November 1987 to regulate the flow of the Nakdong River. In this study, Marine Environmental Information System (MEIS) data collected after May 2015 were used to support marine spatial planning (MSP) in the brackish water zone. The NRE and surrounding locations can be divided into areas managed by the government, protected marine areas, areas for sand mining, areas for the development of tourist attractions, areas of research conservation, areas where an environmental risk assessment would be required prior to use by ships, military areas, and coastal areas subject to safety management measures. Data on environmental changes in the estuarine watershed were used during the preparation of the NRE for partial opening and drainage extension in 2019. Data supporting MSP in the target area should be collected, processed, and analyzed to facilitate future decision-making, and databases should be established based on geological field surveys. Furthermore, protected areas should be designated according to governmental guidelines. All scientific data used in these processes should be validated, and spatial data to facilitate MSP should be produced.

Jeong, D.U.; Lee, Y.G.; Kang, J.; Woo, H.J., and Choi, Y.H., 2020. Sediment geochemistry and benthic foraminiferal response to fish farming after conversion from a red laver (seaweed) farm. Journal of Coastal Research, 36(3), 559–574. Coconut Creek (Florida), ISSN 0749-0208.To understand the effects of biodeposits discharged from a fish farm (which was previously a red laver farm) on geochemistry of the sediment and benthic ecology, trace metals and element analyses, 210Pb dating, and benthic foraminiferal analyses were conducted on sediment cores collected below the fish farm cages. Sediment core sampling was also carried out at a control plot (160 m away) to understand the spreading of biodeposits. The geochemical effect of fish farming is pronounced. There was an increase in silt content and sedimentation fluxes of Znex (Zn in excess fractions), Cuex, Asex, and TPex (total phosphorus in excess fractions) after red laver farming. The silt content increased from 45.01% to 50.07%, with a sediment accumulation rate of ∼0.61 cm/y, on average. TPex, with 0.15% ± 0.06% on average, showed that the fish farming effects increased by 0.22% ± 0.07%. Znex, Cuex, Cdex, and Asex showed a positive relationship with TPex increase: 19.92 ± 1.79, 10.23 ± 3.99, 0.57 ± 0.19, and 0.92 ± 0.04 µg/cm2/y, respectively. The high sedimentation fluxes of Znex and Asex in the control plot may signify an expansion of influence of the fish farm by tidal currents. Seven benthic foraminifera appeared during the fish and red laver farming periods, with the dominant species being Cribroelphidium excavatum; however, they were characterized by a high similarity index of 88.1% and very low frequency of abundance, indicating bad habitat conditions. Among them, the C. excavatum–Ammonia beccarii–Ammonia ketienziensis–Cribroelphidium subarcticum assemblage ranged from 21 cm depth to the uppermost layer, characterized by increases in A. beccarii. This increase may have been caused by the accumulation of organic matter discharged from the fish farm after red laver farming, rather than from an increase in the trace metals. A. beccarii may be a species tolerant to fish farming.

Lee, J.-H., Choi, J.U., Jung, H.-S., Kwon, J.-I., and Woo, H.J., 2019. Development of a Marine Environmental Information System (MEIS) using data on Land–Sea interactions in the Nakdong River Estuary, South Korea. In: Lee, J.L.; Yoon, J.-S.; Cho, W.C.; Muin, M., and Lee, J. (eds.), The 3rd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 91, pp. 191-195. Coconut Creek (Florida), ISSN 0749-0208.The Nakdong River in South Korea is about 510 km long and is subject to natural erosion and sedimentation and various potential sources of human pollution, such as urban dumping and input from industrial complexes and many cities. This study developed a marine environmental information system (MEIS) to understand the land–sea interactions and provide data on the characteristics of the brackish water zone around the barrier islands. The MEIS was run in real time (1-s intervals) and made periodic marine observations (one to four times a year). The real-time data were largely obtained from a closed-circuit television and automatic weather stations using long-term evolution communication at two stations in March 2016. Since May 2015, the data have included periodic observations of surface sediment distributions (n = 90), the characteristics of suspended sediments in inlets and channel (n = 4), the brackish water zone environment during spring tide ebb and flood (n = 14, three lines), the seasonal variation in sedimentation along tidal flats (n = 29, three lines), and landscape classifications of the sub-environment (n = 30) in the barrier islands. The collected information includes real-time and a huge heterogeneous dataset characterized by multi-dimensional, multivariate, and spatiotemporal distribution variability. The system enables data management, and open access is necessary. The MEIS will enable effective estuary management and contribute to reducing the damage caused by natural disasters. Real-time prediction information has been integrated with environmental sensitivity index maps, which are provided using a geographic information system to enable a response strategy.

Lee, Y.G.; Kim, S.; Jeong, D.U.; Kim, J.K., and Woo, H.J., 2013. Effects of heavy rainfall on sedimentation in the tidal salt marsh of Suncheon Bay, South Korea. Tide observations, geographic surveys, sediment composition, and sediment accretion rate monitoring were conducted to investigate the relationship between general pattern changes and control factors of the accretion rate at 10 localities of the tidal salt marsh of Suncheon Bay over 2 years (June 2007–May 2009). The substrate sediments of the tidal salt marshes that are distributed between the mean sea level and the high water of ordinary spring tide are mainly composed of silt (37.98%) and clay (60.45%) and have a high average annual accretion rate of 28.88 mm/y. The high substrate sedimentation of tidal salt marshes is caused by: (1) a high concentrated suspended sediment supply from the tidal flat; (2) considerable marsh grass vegetation; (3) undeveloped tidal salt marsh creek; and (4) marsh elevation distributed between the mean sea l...