• Title/Summary/Keyword: Beach area

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The morphological changes of the beach and dune using by periodical measurements (주기적 지형 측량을 통한 해빈과 해안사구의 지형변화: 충남 보령시 소황사구를 사례로)

  • KANG, Dong Kyun;SEO, Jong Cheol
    • Journal of The Geomorphological Association of Korea
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    • v.19 no.2
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    • pp.69-79
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    • 2012
  • The aim of this study is to analyze the mid-term changes of beach and dune morphology at Sohwang beach, Korea using by Total Station. Measurements executed 4 times during two year. Based on ArcInfo as point cloud obtained through precise measurement data by Total Station, alteration of beach and dune was analyzed at DEM, of which cell size is about 1m. Since these artificial constructions have influenced current systems of this region, the large-scale sand movements above mentioned have occurred around the jetty and the sea-wall. There occurred sedimentation in the north of the Jetty and erosion in the south of the Jetty, which is installed at the central part of object area. The direction of recent topographic development does not coincide with that of wind, and, rather, topographic changes occurred mainly at beaches and dunes due to the transformation of coastal water flow caused by artificial structure nearby. If precise measurement is conducted periodically, and long term monitoring is carried out by installing equipment measuring movement pattern of sediment around artificial structure, cause of topographic change around the object area could be discovered.

Topographic Variability during Typhoon Events in Udo Rhodoliths Beach, Jeju Island, South Korea (제주 우도 홍조단괴해빈의 태풍 시기 지형변화)

  • Yoon, Woo-Seok;Yoon, Seok-Hoon;Moon, Jae-Hong;Hong, Ji-Seok
    • Ocean and Polar Research
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    • v.43 no.4
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    • pp.307-320
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    • 2021
  • Udo Rhodolith Beach is a small-scale, mixed sand-and-gravel beach embayed on the N-S trending rocky coast of Udo, Jeju Island, South Korea. This study analyzes the short-term topographic changes of the beach during the extreme storm conditions of four typhoons from 2016 to 2020: Chaba (2016), Soulik (2018), Lingling (2019), and Maysak (2020). The analysis uses the topographic data of terrestrial LiDAR scanning and drone photogrammetry, aided by weather and oceanographic datasets of wind, wave, current and tide. The analysis suggests two contrasting features of alongshore topographic change depending on the typhoon pathway, although the intensity and duration of the storm conditions differed in each case. During the Soulik and Lingling events, which moved northward following the western sea of the Jeju Island, the northern part of the beach accreted while the southern part eroded. In contrast, the Chaba and Maysak events passed over the eastern sea of Jeju Island. The central part of the beach was then significantly eroded while sediments accumulated mainly at the northern and southern ends of the beach. Based on the wave and current measurements in the nearshore zone and computer simulations of the wave field, it was inferred that the observed topographic change of the beach after the storm events is related to the directions of the wind-driven current and wave propagation in the nearshore zone. The dominant direction of water movement was southeastward and northeastward when the typhoon pathway lay to the east or west of Jeju Island, respectively. As these enhanced waves and currents approached obliquely to the N-S trending coastline, the beach sediments were reworked and transported southward or northward mainly by longshore currents, which likely acts as a major control mechanism regarding alongshore topographic change with respect to Udo Rhodolith Beach. In contrast to the topographic change, the subaerial volume of the beach overall increased after all storms except for Maysak. The volume increase was attributed to the enhanced transport of onshore sediment under the combined effect of storm-induced long periodic waves and a strong residual component of the near-bottom current. In the Maysak event, the raised sea level during the spring tide probably enhanced the backshore erosion by storm waves, eventually causing sediment loss to the inland area.

Plant Species Selection Program for Ecological Restoration of Coastal Reclaimed Land -Focused on the Dumped Soil Area at Inchon Airport- (해안간척지의 생태적 환경복원을 위한 식물 선정에 관한 연구 -인천공항 사토장지역을 중심으로-)

  • Bae, Young-Hun;Lee, Dong-Kun
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.4 no.3
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    • pp.66-74
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    • 2001
  • The main purpose of this thesis is to select the appropriate plants for the ecological restoration of coastal land. The soil and vegetation environment survey of the beach where the halophytes live now was executed for the sake. Firstly, the soil survey was done by the physical and chemical survey of beach soil and dumped soil. The soil is mostly sandy loam and sandy clay loam which has silty much. The beach soil where the salt plants live has more organic matters in the content than dumped soil because of the influx of the dead halophytes, a pioneer plant to this area. Secondly the vegetation survey was executed by the halophytes survey in the beach area in order to select the appropriate plants for ecological restoration. The shows two different areas in the vegetation divided by the salt density of soil. Artemisia fukudo, Juncus haenkei, Carex pumila, Silene armeia, Polyponum aviculare etc live in the less salt density area and it doesnt show collected. Salicornia herbacea, Suaeda asparagoides, Aster tripolium, Limonium tetragonum, Suaeda maritima, Scirus fluvitilis, Phragmtes communis, Suaeda japonica, Zoysia sinica etc halophytes live in the more salt density area and there are a few advent plant but many collected. So the salt density of soil limits the vegetation. The selection of appropriate plants for the ecological restoration programs was designed with 3 different standards considering the salt density of soil in the dumped soil area. The plan selection guidelines of thick salt density due to the salt density of soil, and economical efficiency and maintenance because the area is large. The guidelines of middle salt density area were made considering economical efficiency and maintenance because there are salt as well, and it is effective for the scenery if they have normal ecology but their leaves have good color and the flowers are beautiful. However I suggest beautiful flowery plants for the neutral plan area because this area is the entry point of the airport so the view is very important.

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Shoreline Change Analysis of Haeundae Beach Using Airborne LiDAR Survey (항공 LiDAR 측량을 이용한 해운대 해안의 해안선 변화 분석)

  • Lee, Jae One;Kim, Yong Suk;We, Gwang Jae
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.4D
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    • pp.561-567
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    • 2008
  • In this study, shoreline change was analyzed by RTK-GPS and advanced airborne LiDAR survey. For extraction of coastline, first of all, tide correction was conducted at all RTK-GPS points through the comparing with the corresponding tidal height, and cross section providing coastline was produced using Autocad Civil3D program. Comparing with two results of RTK-GPS (first, 29 Aug 2007; second, 6 Oct 2007) surveys, coastline of the first result had been decreased about 21m compare with that of the second. And it was also demonstrated that the length of coastline by the first RTK-GPS was 15m shorter than that by the airborne LiDAR survey (Dec. 2006). In addition, we recoquized that the erosion appeared in the top right-hand (dock area); the sediment in the bottom left-hand (Chosun beach area) of the Haeundae beach. As a result, therefore, it was learned that artificial sand filling for beach open and natural effects such as a typhoon, current drift, wind direction gave cause for area changes and coastline.

Sediment Characteristics of the Beach and Subtidal Zone in Shindu Marine Protected Area (신두 해양생태계보호구역 해빈과 조하대의 퇴적물 특성)

  • Shin, Young Ho;Seo, Jong Cheol
    • Journal of the Korean Geographical Society
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    • v.49 no.6
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    • pp.812-832
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    • 2014
  • We analyzed physical and chemical properties of sediments from 20 subtidal points and 9 beach points to define sedimentary environment between summer and winter of Shindu Marine Protected Area. Means of particle size in summer were generally finer than winter's. There was distinctively spatial pattern that particle sizes became increasingly fine as west direction and apart from beach in summer, but this pattern was not shown in winter. Coarse sediments were prevailed in winter. To explain these patterns, we propose possible two causes which are spatially different water depth condition related with seasonal wave climate or fine sediment input from an estuary located in south of this area during summer rainy season. Contents of exchangeable cations of sediment in summer were shown $Na^+$>$Ca^{2+}$>$Mg^{2+}$>$K^+$ in order, but those of winter were shown $Na^+$>$Mg^{2+}{\fallingdotseq}Ca^{2+}$>$K^+$. Contents of $Na^+$, $Mg^{2+}$, and $K^+$ were related with contents of fine sediment and showed high correlation in each other. These relations were not shown between $Ca^{2+}$ and others. Our results show that there are spatio-temporal unique sedimentary environments between subtidal zone, beach, and dune near Shindu Marine Protected Area. Therefore, we should consider these spatio-temporal patterns for environmentally sound management of Shindu coastal system.

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Seasonal Changes of Shorelines and Beaches on East Sea Coast, South Korea (동해안 해안선과 해빈의 계절적 변화)

  • Kim, Dae Sik;Lee, Gwang-Ryul
    • Journal of the Korean Geographical Society
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    • v.50 no.2
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    • pp.147-164
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    • 2015
  • This study analyzed characteristics and tendencies of seasonal change on shoreline and beach with 8 beaches at East Sea coast by topographical survey for 2 years from March 2012 to February 2013. The shorelines of East Sea coast appeared that amount of seasonal change was bigger than amount of annual change. The seasonal change tendencies between Gangwon-do and Gyeongsangbuk-do coast areas existed some regional differences. To synthesize seasonal changes on 8 beaches of East Sea coast, shoreline advance and beach deposit showed clearly in summer and shoreline retreat and beach erosion showed clearly in autumn. This result is different from tendencies of seasonal change in many mid-latitude coast areas of the world, but generally corresponds with reference studies in west coast and east coast. The major factor of beach erosion showing mostly in summer is storm wave caused by typhoon. The beach erosion by storm wave also occurred in late winter. And it assumes that the beach deposit showing mostly in autumn is result of equilibrium processes of coast area against strong erosion in summer.

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Data Acquisition using Terrestrial Laser Scanner and RTK-GPS for Implementation of Beach Model (해빈 모형 구현을 위한 지상용 레이저 스캐너와 RTK-GPS의 자료 획득)

  • Lee, Hyung-Seok;Kim, In-Ho
    • Journal of the Korean Association of Geographic Information Studies
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    • v.12 no.1
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    • pp.54-63
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    • 2009
  • Various methods have been employed for acquiring beach surface data, which are used to monitor shoreline changes due to beach erosion. This study explores the possibility of constructing and implementing a surface model of beach using data acquired with a terrestrial laser scanner and RTK-GPS. Digital images and three-dimensional data of beach areas acquired at 20 cm intervals using a laser scanner were used to create a digital surface model covered with digital image. Seven months later, the beach area was surveyed using an RTK-GPS, and another beach model was constructed using the data collected with an accuracy of 1.9 cm. The use of a terrestrial laser scanner is expected to ensure acquisition of good quality results and help deal with seasonal changes in beach areas. Because readings obtained with the RTK-GPS are dependent on the number of sampling points in beach model, difficulties are encountered when fixing the survey points. However, RTK-GPS could be used to implement a three-dimensional model by correcting the hidden parts in images obtained using a terrestrial laser scanner. Therefore, an RTK-GPS and a terrestrial laser scanner can be used in combination to obtain more precise data for the construction of beach model data.

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Time-series Analysis of Baramarae Beach in Anmyeondo Using Aerial Photographs and Field Measurement Data (항공사진과 기준목 측정자료를 이용한 안면도 바람아래 해빈의 시계열 변화 분석)

  • KIM, Jang-soo;JANG, Dong-Ho
    • Journal of The Geomorphological Association of Korea
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    • v.18 no.2
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    • pp.39-51
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    • 2011
  • In this study, the shape of the Baramarae beach, Anmyeondo Area in West Coast of Korea and the changes in the sedimentation and erosion environment were analyzed in time series. As a result of the time series analysis of the shape of the Baramarae beach using aerial photographs from 1967 to 2009, the sand spit that developed in the southern part of Halmi Island was found to have had an EEN direction, but it was changed to a NNS direction, as reflected in the 2009 aerial photographs, as it gradually shifted to the west. In the onsite measurement, the H-3, H-4, H-5, and H-6 spots showed a superior sedimentation environment and the H-7, H-8, and H-9 spots showed a superior erosion environment. It was thus found that sedimentation is superior in the southwest beach and that erosion is superior in the northeast beach. The results in the spots between H-3 and H-6 indicate that the sand in the beach could not move to the northeast beach of Halmi Island due to the bank that had been established in the southwest beach of the island. On the other hand, it seems that superior erosion takes place in spots H-7 to H-9 in the northeast beach, where sand is not provided from the southwest beach of Halmi Island. It was found from the seasonal analysis that the season when superior sedimentation takes place in all the spots is autumn, and that the season when superior erosion takes place is summer. Superior sedimentation takes place in winter and spring in the southeast side and in summer in the northwest side.

Investigation of Characteristics of Rip Current at Haeundae Beach based on Observation Analysis and Numerical Experiments (관측자료 분석과 수치모의에 의한 해운대 이안류 발생 특성 연구)

  • Yoon, Sung Bum;Kwon, Seok Jae;Bae, Jae Soek;Choi, Junwoo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.32 no.4B
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    • pp.243-251
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    • 2012
  • To investigate the characteristics of rip current occurring at Haeundae beach, observations obtained from a buoy and a CCTV were analyzed and numerical experiments were conducted. During observed rip-current events, the CCTV images showed that a couple of wave-trains, which are close to regular waves with slightly different directions, propagated to the beach, and wavelet analyses of data from the buoy showed very narrow-banded spectra with a peak frequency. From the evidences, it was inferred that a known mechanism of generating rip current due to the nodal line area of honeycomb-patterned wave crest was one of the significant factors of rip current occurrences of Haeundae beach. The mechanism has been explained by the following: When two wave-trains with slightly different directions propagate to a beach, wave crests of the incident wave-trains form honeycomb pattern due to nonlinear interaction. The nodal lines of honeycomb pattern are developed in the cross-shore direction. And longshore currents flow toward the nodal line area which has very low wave energy. Consequently their mass flux is expelled through the area toward the sea direction. To confirm the generation, numerical experiments were performed using a nonlinear Boussinesq equation model. In the cases with two incident wave-trains with slightly different directions and with a monochromatic wave propagating over a submerged shoal, it was seen that the honeycomb pattern of wave crests was well developed, and thus rip currents were evolved along the nodal lines.

A Spatio-Temporal Variation Pattern of Oiling Status Using Spatial Analysis in Mallipo Beach of Korea (공간분석 기법을 이용한 만리포 유분의 시·공간 변동 패턴 분석)

  • Kim, Tae-Hoon;Choi, Hyun-Woo;Kim, Moon-Koo;Shim, Won-Joon
    • Journal of the Korean Association of Geographic Information Studies
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    • v.15 no.4
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    • pp.90-103
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    • 2012
  • Mallipo is a representative beach contaminated by Hebei Spirit oil spill accident in December 2007. This study aims to compare the differences of two seasons (winter and summer) for the spatio-temporal variation patterns of oiling status in the whole area and divided five regions of Mallipo beach. In the whole area, the decreasing rate of average TPH (total petroleum hydrocarbon) in winter was twice greater than summer during four years. According to the spatial variation pattern analysis of oiling status using weighted mean center and weighted standard distance, the oil concentration was clustered on southwestern region in winter, however, the TPH was dispersed in the whole area in summer. Temporal variation pattern of TPH in each of Mallipo's five regions showed that TPH had been consistently decreased in winter, but oil concentration had not been changed in summer since 2009 except the southwestern region. Therefore, in order to evaluate and predict the progress of oiling status, it is needed to analyze the spatio-temporal variation pattern of TPH using spatial analysis after separating data into seasons (e.g., winter and summer). In addition, time series analysis is useful in the regional scales through spatial partitioning rather than the whole beach area for the understanding of temporal variation pattern.