scholarly journals ECO-SYSTEM BASED BEACH EROSION CONTROL BY BERM NOURISHMENT COMBINED WITH BURIED SAND TUBE

2018 ◽  
pp. 102
Author(s):  
Shinji Sato ◽  
Keisuke Murakami ◽  
Kunihiro Watanabe ◽  
Yuuichi Okamura ◽  
Shin Hashimoto ◽  
...  
Keyword(s):  
River Mouth ◽  
Erosion Control ◽  
Beach Erosion ◽  
Sand Transport ◽  
Wave Direction ◽  
Large Variability ◽  
Longshore Transport ◽  
The Pacific ◽  
Beach Sediments ◽  
Sand Nourishment

Miyazaki Coast is a 10 km stretch sandy beach between the Miyazaki Port and the Hitotsuse River, located south of Japan facing the Pacific Ocean. Significant beach erosion has been observed owing to the entrapment of sand in the harbor area and the blockage of longshore sand transport by the river mouth jetties. Sato et al. (ICCE 2010) estimated that the direction of the long-term longshore sand transport is to the southward on the basis of thermo-luminescence measurement of beach sediments. Continuous bathymetry surveys indicated the southward longshore sand transport rate at 200 thousand m3/year. However, a large variability of the incident wave direction suggested the variability in the direction of the longshore transport. Occasional attacks of typhoon storms appeared to accelerate the erosion. As a countermeasure to mitigate the erosion, sand nourishment has been introduced since 2008 with the amount of 50 to 80 thousand m3/year. Three groins were constructed to decrease the longshore transport. However, further erosion has been observed by typhoon storms even on the nourished area. This paper describes the results of on-site monitoring of waves, currents and topography change to understand the role of typhoon storms in beach erosion and to investigate the performance of eco-system based erosion control works.

BEACH PROCESSES AND SHORE PROTECTION ALONG THE NORTHERN COLOMBIA COAST

2020 ◽  
Vol 1 (2) ◽  
pp. 60-85
Author(s):  
PING WANG
Keyword(s):  
Beach Erosion ◽  
Trade Wind ◽  
Sand Transport ◽  
Shore Protection ◽  
Tropical Zone ◽  
Longshore Sediment Transport ◽  
Longshore Transport ◽  
Shoreline Protection ◽  
Beach Processes ◽  
Northeast Trade Wind

The shoreline of northern Colombia is located in the tropical zone along the south coast of Caribbean Sea. Its coastal processes are strongly influenced by the northeast trade wind, which results in the dominating northeasterly approaching wave occurring over 95% of the time. This drives a persistent southwestward longshore sand transport. The state of the beach along the generally northeast-southwest trending northern Colombia coast is strongly influenced by this constant unidirectional longshore sediment transport. At locations where this westward longshore sand transport is interrupted, naturally or  anthropogenically, beach accretion occurs along the updrift shoreline coupled with erosion at the downdrift side. Natural interruption of longshore transport can be caused by tidal inlets, protruding headland, shoreline orientation change, and nearshore bathymetry variations. Anthropogenic interruption of the longshore transport along the northern Colombia coast is mainly caused by the construction of groins, as well as harbors at some locations. Numerous groins were constructed due to their local success in creating beach accretion at the drift side. However, severe beach erosion occurs along the downdrift shoreline. Shoreline protection along the northern Colombia coast, and coasts in the tropical area in general, should carefully consider the persistent unidirectional longshore sand transport and should not be misguided by the local updrift accumulation as being a successful project.

scholarly journals STABILIZATION OF COAST BY CONSTRUCTION OF HEADLANDS ON THE KASHIMANADA COAST, JAPAN

1988 ◽  
Vol 1 (21) ◽  
pp. 207
Author(s):  
T. Uda ◽  
M. Sumiya ◽  
H. Sakuramoto
Keyword(s):  
Pacific Ocean ◽  
Beach Erosion ◽  
Wave Direction ◽  
Shoreline Position ◽  
Follow Up Study ◽  
Field Investigations ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Periodic Changes

Eleven artificial headlands were constructed on the OhncKashima Beach facing the Pacific Ocean to prevent further extension of beach erosion and to form the dynamically stable beach. This paper summarizes the results of the follow-up study of the new works applied on the actual coast. Field investigations such as bottom sounding around headlands and aerial photographing were conducted. It was found that the periodic changes of the shoreline configuration correpsonding to seasonal change of the wave direction exist on this coast and these variations of the shoreline position can be reduced by the effect of these headlands.

scholarly journals SAND ACCUMULATION IN WAVE-SHELTER ZONE OF OHARAI PORT AND CHANGE IN GRAIN SIZE OF SEABED MATERIALS ON NEARBY COAST

2011 ◽  
Vol 1 (32) ◽  
pp. 63
Author(s):  
Takeo Matsu-ura ◽  
Takaai Uda ◽  
Takayuki Kumada ◽  
Michio Sumiya
Keyword(s):  
Fine Sand ◽  
Beach Erosion ◽  
Annual Rate ◽  
Sand Transport ◽  
The South ◽  
Bathymetric Survey ◽  
Deposition Zone ◽  
The Pacific ◽  
Sand Accumulation ◽  
The Pacific Ocean

Beach changes around Oharai Port facing the Pacific Ocean were investigated using bathymetric survey data collected over 25 years between 1979 and 2004. Between the south and offshore breakwaters of Oharai Port, 1.50×106 m3 of fine sand was deposited in this period, i.e., at an annual rate of 6.0×104 m3/yr, which was originally supplied from the Naka River 3 km north of the port. Also in the wave-shelter zone of the offshore breakwater south of the port, 7.0×106 m3 of fine sand was deposited between 1979 and 2004 at an annual rate of 2.8×105 m3/yr, which was transported by the northward longshore sand transport induced from outside to inside the wave-shelter zone of the offshore breakwater, resulting in severe beach erosion on the south coast outside the wave-shelter zone. Taking into consideration the fact that sand transport to the Kashimanada coast is now completely obstructed by the port breakwaters, sand bypassing and sand back passing to the coast from the sand deposition zone of Oharai Port are required.

scholarly journals Further spreading of the non-indigenous bryozoan Celleporaria brunnea in the Mediterranean Sea: port to port morphological variations

2015 ◽  
Author(s):  
Jasmine Ferrario ◽  
Agnese Marchini ◽  
Martina Marić ◽  
Dan Minchin ◽  
Anna Occhipinti-Ambrogi
Keyword(s):  
Mediterranean Sea ◽  
Western Mediterranean ◽  
Indigenous Species ◽  
Large Variability ◽  
Morphometric Characters ◽  
Morphological Variations ◽  
The North ◽  
Western Mediterranean Sea ◽  
The Pacific ◽  
The Mediterranean

The Pacific cheilostome bryozoan Celleporaria brunnea (Hincks, 1884), a non-indigenous species already known for the Mediterranean Sea, was recorded in 2013-2014 from nine Italian port localities (Genoa, Santa Margherita Ligure, La Spezia, Leghorn, Viareggio, Olbia, Porto Rotondo, Porto Torres and Castelsardo) in the North-western Mediterranean Sea; in 2014 it was also found for the first time in the Adriatic Sea, in the marina “Kornati”, Biograd na Moru (Croatia). In Italy, specimens of C. brunnea were found in 44 out of 105 samples (48% from harbour sites ad 52% from marinas). These data confirm and update the distribution of C. brunnea in the Mediterranean Sea, and provide evidence that recreational boating is a vector responsible for the successful spread of this species. Previous literature data have shown the existence of differences in orifice and interzooidal avicularia length and width among different localities of the invaded range of C. brunnea. Therefore, measurements of orifice and avicularia were assessed for respectively 30 zooids and 8 to 30 interzooidal avicularia for both Italian and Croatian localities, and compared with literature data, in order to verify the existence of differences in the populations of C. brunnea that could reflect the geographic pattern of its invasion range. Our data show high variability of orifice measures among and within localities: zooids with broader than long orifice coexisted with others displaying longer than broad orifice, or similar values for both length and width. The morphological variation of C. brunnea in these localities, and above all the large variability of samples within single localities or even within colonies poses questions on the reliability of such morphometric characters for inter and intraspecific evaluations.

scholarly journals IODP Expedition 330: Drilling the Louisville Seamount Trail in the SW Pacific

2013 ◽  
Vol 15 ◽  
pp. 11-22 ◽  
Author(s):  
A. A. P. Koppers ◽  
T. Yamazaki ◽  
J. Geldmacher ◽  
Keyword(s):  
Mantle Plume ◽  
Mantle Source ◽  
Isotope Geochemistry ◽  
Oceanic Lithosphere ◽  
Similar Amount ◽  
Mantle Plumes ◽  
Large Variability ◽  
Sw Pacific ◽  
Integrated Ocean Drilling Program ◽  
The Pacific

Deep-Earth convection can be understood by studying hotspot volcanoes that form where mantle plumes rise up and intersect the lithosphere, the Earth's rigid outer layer. Hotspots characteristically leave age-progressive trails of volcanoes and seamounts on top of oceanic lithosphere, which in turn allow us to decipher the motion of these plates relative to "fixed" deep-mantle plumes, and their (isotope) geochemistry provides insights into the long-term evolution of mantle source regions. However, it is strongly suggested that the Hawaiian mantle plume moved ~15° south between 80 and 50 million years ago. This raises a fundamental question about other hotspot systems in the Pacific, whether or not their mantle plumes experienced a similar amount and direction of motion. Integrated Ocean Drilling Program (IODP) Expedition 330 to the Louisville Seamounts showed that the Louisville hotspot in the South Pacific behaved in a different manner, as its mantle plume remained more or less fixed around 48°S latitude during that same time period. Our findings demonstrate that the Pacific hotspots move independently and that their trajectories may be controlled by differences in subduction zone geometry. Additionally, shipboard geochemistry data shows that, in contrast to Hawaiian volcanoes, the construction of the Louisville Seamounts doesn’t involve a shield-building phase dominated by tholeiitic lavas, and trace elements confirm the rather homogenous nature of the Louisville mantle source. Both observations set Louisville apart from the Hawaiian-Emperor seamount trail, whereby the latter has been erupting abundant tholeiites (characteristically up to 95% in volume) and which exhibit a large variability in (isotope) geochemistry and their mantle source components. <br><br> doi:<a href="http://dx.doi.org/10.2204/iodp.sd.15.02.2013" target="_blank">10.2204/iodp.sd.15.02.2013</a>

scholarly journals Spatial Variability of Beach Impact from Post-Tropical Cyclone Katia (2011) on Northern Ireland’s North Coast

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1380 ◽  
Author(s):  
Giorgio Anfuso ◽  
Carlos Loureiro ◽  
Mohammed Taaouati ◽  
Thomas Smyth ◽  
Derek Jackson
Keyword(s):  
Tropical Cyclone ◽  
Morphological Changes ◽  
Response Prediction ◽  
Beach Erosion ◽  
North Coast ◽  
Engineering Structures ◽  
Wave Energy Dissipation ◽  
The North ◽  
Longshore Transport ◽  
Offshore Wave

In northern Europe, beach erosion, coastal flooding and associated damages to engineering structures are linked to mid-latitude storms that form through cyclogenesis and post-tropical cyclones, when a tropical cyclone moves north from its tropical origin. The present work analyses the hydrodynamic forcing and morphological changes observed at three beaches in the north coast of Northern Ireland (Magilligan, Portrush West’s southern and northern sectors, and Whiterocks), prior to, during, and immediately after post-tropical cyclone Katia. Katia was the second major hurricane of the active 2011 Atlantic hurricane season and impacted the British Isles on the 12–13 September 2011. During the Katia event, offshore wave buoys recorded values in excess of 5 m at the peak of the storm on the 13 September, but nearshore significant wave height ranged from 1 to 3 m, reflecting relevant wave energy dissipation across an extensive and shallow continental shelf. This was especially so at Magilligan, where widespread refraction and attenuation led to reduced shore-normal energy fluxes and very minor morphological changes. Morphological changes were restricted to upper beach erosion and flattening of the foreshore. Longshore transport was evident at Portrush West, with the northern sector experiencing erosion while the southern sector accreted, inducing a short-term rotational response in this embayment. In Whiterocks, berm erosion contributed to a general beach flattening and this resulted in an overall accretion due to sediment influx from the updrift western areas. Taking into account that the post-tropical cyclone Katia produced £100 m ($157 million, 2011 USD) in damage in the United Kingdom alone, the results of the present study represent a contribution to the general database of post-tropical storm response on Northern European coastlines, informing coastal response prediction and damage mitigation.

Current countermeasure of beach erosion control and its application in Taiwan

2010 ◽  
Vol 53 (9) ◽  
pp. 552-561 ◽  
Author(s):  
Ray-Yeng Yang ◽  
Ying-Chih Wu ◽  
Hwung-Hweng Hwung ◽  
Jiing-Yih Liou ◽  
Igor V. Shugan
Keyword(s):  
Erosion Control ◽  
Beach Erosion

scholarly journals Collapse and recovery process of the sand spit at the Tenryu River mouth on the Pacific Coast of Japan

2018 ◽  
Vol 60 (4) ◽  
pp. 532-547
Author(s):  
Yoshimitsu Tajima ◽  
Tomohiro Takagawa ◽  
Shinji Sato ◽  
Satoshi Takewaka
Keyword(s):  
Pacific Coast ◽  
River Mouth ◽  
Recovery Process ◽  
The Pacific ◽  
Sand Spit ◽  
Pacific Coast Of Japan
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