• Journal of the Korean Society for Marine Environment & Energy
• /
• v.19 no.3
• /
• pp.218-226
• /
• 2016

Field observations were used to study the characteristics and influence of groundwater level fluctuations on vegetation development on the natural beach of a sandy barrier island, in the Nakdong River estuary. The spatial/temporal fluctuations of the groundwater level and the interactions with the external forces (weather, ocean wave and tide) were analyzed. The results indicated that when it rains the groundwater level rises. During summer, when precipitation intensity is greater than 20 mm/hour, it rose rapidly over 20 cm. Subsequently, it fell gradually during periods of no precipitation. Seasonal characteristics indicated that the groundwater level was high during the summer rainy season and tended to fall in the winter dry season. The time-averaged groundwater level, observed from the four observations over 3 years (2012-2014), was about 1.47 m, higher than mean sea level (M.S.L.). It was shown that the average annual groundwater level rises toward the land rather than showing intertidal patterns observation. Differences in the presence or absence of a coastal sand dunes affected the progress of vegetation. In other words, in environments of saltwater intrusion where the groundwater level varies, dependent on the distance from the shoreline and bottom slope, sand dunes can be provided to affect soil conditions and groundwater, so that vegetation can be grown reliably.

• Journal of Forest and Environmental Science
• /
• v.30 no.4
• /
• pp.383-392
• /
• 2014

In this study, we investigated the Fukiage sand dunes of southern Kyushu, Japan. We surveyed the status of recovery of coastal Japanese black pine forests damaged by pine wilt disease and their disaster prevention capability. We placed two transects: Transect 1, in an area that was severely damaged (80-90% damage rate) by pine wilt disease, and Transect 2, in an area that was mostly undamaged (<10% damage rate). Then, we installed survey lines, carried out vegetation surveys, and measured the depth and pH of humus soil. The survey lines were placed perpendicular to the coastline from the top of the fore-dune to the inland area, and divided into five 50 m sections. Before the point 100 m inland from the top of the fore-dune, the number of invasive hardwoods and of Japanese black pines were small because of the poor growth environment in both transects. Past the 100 m point, the species and number of Japanese black pines and broad-leaved trees increased further inland because the growth environment improved. In addition, the recovery metrics of tree height, diameter at breast height, age, and number in Transect 1 were much lower than those in Transect 2, and the basal area of broad-leaved trees and the depth of humus soil in Transect 1 were lower than in Transect 2, and the soil pH of humus soil in Transect 1 was higher than that of Transect 2. The shape ratio of the Japanese black pine forests indicated that they were insufficient for disaster prevention. Therefore, in order to fully promote the disaster prevention capability of coastal Japanese black pine forests, we should not only focus on prevention of pine wilt disease but also undertake continuous control efforts taking into consideration the sound growth environment such as appropriate density and soil management and removal of invasive broad-leaved trees.

• Journal of Wetlands Research
• /
• v.22 no.2
• /
• pp.66-72
• /
• 2020

The coastal sand dunes have transitional characteristics of marine and inland ecosystems, and they have abundant biodiversity. This study investigated flora and vegetation and analyzed the landscape structure at seven beaches in Busan metropolitan city. As a result, the vascular species of the coastal sand dunes in Busan were identified as 178 taxa of 140 families. Vegetation landscape was damaged to the extent that no natural vegetation was found in 4 of 7 beaches (57%). The coastal dune vegetation was dominated by the Carex pumila community and Carex kobomugi community. The halophyte and invasive alien species were classified into 18 taxa (10% of all species) and 40 taxa (22% of all), respectively. The vegetation that made up the largest area was the Phragmites communis community of the salt marsh, and the species number of halophyte increased as the wetland area increased. This means that the maintenance and management of salt marshes is important to conserve the unique plant diversity of the region.

• Journal of the Korean Geographical Society
• /
• v.46 no.6
• /
• pp.693-706
• /
• 2011

The Geomorphological properties and ages of river-mouth bar at Song-cheon River in the East Coast of Korea, Yeongdeok-gun, Gyeongbuk Province are estimated, and the long-term and short-term changing processes and causes are analyzed. Sand grains of the bar near the coastline show the finer trends from south to north and these can be attributed to the northward movement of waves and long-shore currents. The absolute ages of bar and nearby coastal sand dune are less than approximately 100 years ago, indicating that the bar has experienced the active geomorphological changes. While the inlet located at south part of the bar between 1971 and 1995, the inlet has located at north or middle part since 1995. These may caused by the changes of movement directions of waves and long-shore currents due to the apparent northward movements of winds and currents. In short-term, the higher elevation, larger area, simpler landform relief and more variable location of inlet and morphology of bar can be observed between September and March due to the dominance of sedimentary processes by wave and wind processes.

• Journal of Environmental Impact Assessment
• /
• v.11 no.1
• /
• pp.51-66
• /
• 2002

The purpose of this study is to analyze the geomorphological environment changes of tidal flat in the Cheonsu Bay. Especially, it centers on the changes in the sedimentary environment using remote sensing data. Multi-temporal Landsat data and topographic maps were used in this study. The results are summarized as follows: the tidal flat of Cheonsu Bay changes in many ways depending on the direction of the tidal current. In the neighborhood of Ganwoldo, the scale of the tidal flat has continuously been expanded due to the superiority of sedimentation after a tide embankment was built. When we analyzed the grain size of sediments and implemented in-situ field survey, it was found that the innermost part of the bay consists of a mud flat, with the midway part mixed flat, and the nearest part to the sea sand flat. On the other hand, in the neighborhood of Seomot isle and its beach, sedimentation is superior in the eastern part whereas erosion is superior in the western part. In other words, the western coast of the beach is contacted with the open seas and under much influence of ocean wave. The eastern coast is placed at the entrance of the bay and has sand bar and tidal flat developed due to submarine deposits that are accumulated on the sea floor by the tidal current. In conclusions, remote sensing methods can be effectively applied for quantitative analysis of geomorphological changes in tidal flat, and it is expected that the proposed schemes can be applied to another geomorphological environments such as beach, sand dune, and sand wave.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2002.05a
• /
• pp.3-16
• /
• 2002

This article describes some of the recent and on-going research developments of the author at Colorado State University. Advances in the field of sedimentation and river mechanics include basic research and computer modeling on several topics. Only a few selected topics are considered here: (1) analytical determination of velocity profiles, shear stress and sediment concentration profiles in smooth open channels; (2) experiments on bedload particle velocity in smooth and rough channels; (3) field measurements of sediment transport by size fractions in curved flumes. In terms of computer modeling, significant advances have been achieved in: (1) flashflood simulation with raster-based GIOS and radar precipitation data; and (2) physically-based computer modeling of sediment transport at the watershed scale with CASC2D-SED. Field applications, measurements and analysis of hydraulic geometry and sediment transport has been applied to: (1) gravel-bed transport measurements in a cobble-bed stream at Little Granite Creek, Wyoming; (2) sand and gravel transport by size fraction in the sharp meander bends of Fall River, Colorado; (3) changes in sand dune geometry and resistance to flow during major floods of the Rhine River in the Netherlands; (4) changes in hydraulic geometry of the Rio Grande downstream of Cochiti Dam, New Mexico; and (5) analysis of the influence of water temperature and the Coriolis force on flow velocity and sediment transport of the Lower Mississippi River in Louisiana. Recent developments also include two textbooks on "Erosion and Sedimentation" and "River Mechanics" by the author and state-of-the-art papers in the ASCE Journal of Hydraulic Engineering.

• Journal of the Korean earth science society
• /
• v.32 no.3
• /
• pp.265-275
• /
• 2011

The Hamo and Hyeopjae beaches in the western part of Jeju Island were studied in terms of seasonal variations of surface sediment and beach profile. Seasonal drift direction of the beach sands also was investigated. The Hamo beach of $7.3^{\circ}-10.8^{\circ}$ steep is composed of medium sand containing volcanic clasts and shell fragments. The Hyeopjae beach of $2.8^{\circ}-6.5^{\circ}$ steep is composed of coarse shelly sand. Hamo beach deformation is probably caused by the jetties constructed in the western part of the beach. In the Hyeopjae beach, surface sands were drifted into the dune side by the northwestern stormy wind during winter season.

• Journal of the Korean association of regional geographers
• /
• v.9 no.3
• /
• pp.385-394
• /
• 2003

Authors tried to classify landforms of civilian-restricted trans-border coastal region of the East Sea by using both field survey and remote sensing data including IKONOS images and digital maps. As a result, authors can draw the boundaries of landform units on satellite images and classify landforms effectively. Typical landforms of undisturbed depositional coastal area such as coastal sand dune, sand bar, lagoons, and tombolo are found within the study area. Also, riverine wetlands and estuarine wetlands are readily discernable on both satellite image and field survey. Even though landforms within the study area are relatively small, they are so dynamically connected that their preservation value is very high.

• Korean Journal of Environment and Ecology
• /
• v.23 no.2
• /
• pp.177-186
• /
• 2009

In the flora of the whole area of Jakeundang at Byeonsanbando National Park, a total of 105 taxa were identified including 50 families, 88 genera, 98 species, 6 varieties and 1 form. These were again divided into 31 taxa (29.5%) of woody plants and 74 taxa (70.5%) of herbaceous plants. In addition, 4 taxa of the Korea Forest Service, designated rare plants in the flora were identified to grow there including Phacelurus latifolius (Preservation priority order: No. 194), Aristolochia contorta (No. 151), Koelreuteria paniculata (No. 115), and Glehnia littoralis (No. 203). Indigofera koreana, Viola seoulensis that are on the list of Korean endemic plants were also identified and the plants approved for export were identified similarly to rare plants. In addition, among the floral region-based specific plants, the plant group belonging to class V, class IV and II didn't appear and a total of 16 taxa 3 taxa including Elymus mollis, Salsola collina and Koelreuteria paniculata in class III, and 13 taxa including Ischaemum anthephephoroides, Phacelurus latifolius, Asparagus cochinchinensis, Melandryum oldhamianum for. roseum, Calystegia soldanella, Messerschmidia sibirica, Scutellaria strigillosa and Aster spathulifolius, etc. in class I were identified. Among the naturalized plants in the surveyed sites, 6 families, 10 genera, and 10 taxa were identified to grow, such as Bromus unioloides, Phytolacca americana, Lepidium apetalum, Robinia pseudoacacia, Oenothera biennis and Xanthium canadense, etc. and the naturalization rate was analyzed to be 9.5% of all 105 taxa of vascular plants. This research analyzed the coverage ratio and importance value by dividing the community into a sand dunes and back swamp and divided the sand dune area into Vitex rotundifolia community and the back swamp into Phacelurus latifolius community. Jakeundang is designated as a sand dune plants observation area and managed by the office of Byeonsanbando National Park. To preserve this place, it is desirable to take a systematic management measure, such as a visit to this place on a subscription basis or education and publicity on sand dune plants.

• Animal cells and systems
• /
• v.6 no.3
• /
• pp.201-206
• /
• 2002

Three halacarid species belonging to the genus Copidognathus are recorded from the shallow subtidal sands at Ko Taenae Islet (sand dune) off Ko Pha-Ngan Island, Thailand: Copidognathus thailandicus n. sp., C. euryalus Bartsch, 1997 and C. orarius Otto, 2001. Copidognathus thailandicus n. sp. comes close with C. cribrosoma (Police, 1909) and C. cribellus Bartsch, 1993 due to dorsal plates completely covered with rosette pores. Dissimilarities among them are discussed. Copidognathus euryalus and C. orarius are recorded hove for the first time from Thailand and away from its type locality. The present paper is also the first contribution on the taxonomy of Halacaridae (Acari) from Thailand.