scholarly journals NEW TYPE BLOCKS FOR SEAWALL SLOPE PROTECTION

1984 ◽  
Vol 1 (19) ◽  
pp. 170 ◽  
Author(s):  
Osamu Toyoshima
Keyword(s):  
Coastal Areas ◽  
Beach Erosion ◽  
Shore Protection ◽  
Land Preservation ◽  
New Type

Japan is a mountaineous country, and coastal areas have been looked upon quite valuable. In most cases, shorelines were slightly advancing until 1950, although there are some exceptional coasts which have been under continuous erosion for more than a thousand years. However, in the last thirty years, beaches began to be eroded one after another, and the countermeasure against beach erosion has become one of the most important problems in the national land preservation. Since the early 1960's, many seawalls against the beach erosion have been constructed. The table shows the amounts of the shore protection works constructed in the last twenty years.

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 Shore Protection Structures Increase and Evolution on the Northern Tuscany Coast (Italy): Influence of Tourism Industry

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1647 ◽  
Author(s):  
Enzo Pranzini ◽  
Giorgio Anfuso ◽  
Irene Cinelli ◽  
Marco Piccardi ◽  
Giovanni Vitale
Keyword(s):  
Negative Impact ◽  
Management Plan ◽  
Tourism Industry ◽  
Beach Erosion ◽  
Shore Protection ◽  
Natural Sediment ◽  
Forcing Function ◽  
Hard Structures ◽  
The 19Th Century ◽  
Protection Structures

Analysis of a large shoreline database (from 1878 to 2017) and recompilation of information on type/age of shore protection structures along the Northern Tuscany, allowed a deep insight of the progressive armouring of this coastal sector. The area experienced beach erosion since the end of the 19th century due to reduced sediment inputs from rivers and harbour constructions. Shore protection structures started to develop at the beginning of the 20th century, first to protect settlements and coastal roads, later to maintain a beach for tourist activity. The changing of the goal and the increasing awareness of the negative impact of some structures resulted in an evolution of coastal defence projects: initially, seawalls and revetments, later detached breakwaters and, more recently, groins. Today, a reduction in hard structures is perceived by removing or lowering detached breakwaters and groins below mean sea level. The forcing function of the growing tourism industry is producing a demand for projects and their design is detailed in this paper: results will be of use in the correct design of a long-term, general, erosion management plan to restore the natural sediment circulation patterns.

scholarly journals THE ECONOMIC VALUE OP A NEW BREAKWATER ARMOUR UNIT 'DOLOS'

1966 ◽  
Vol 1 (10) ◽  
pp. 50 ◽  
Author(s):  
E.M. Merrifield ◽  
J.A. Zwamborn
Keyword(s):  
Economic Value ◽  
Full Scale ◽  
Field Conditions ◽  
Test Results ◽  
Shore Protection ◽  
Wave Channel ◽  
New Type ◽  
Rubble Mound ◽  
The Stability ◽  
Made In

The Dolos, a new type of armour unit which closely resembles a normal ship's anchor, was developed and tried out under field conditions on the main breakwater of East London harbour. Since these full-scale Dolosse proved very successful, tests were made in a wave channel to compare the stability of Dolosse with other known types of armour blocks. The test results showed that the Dolos is outstandingly stable, and since manufacture and random placing of Dolosse offers no particular difficulties it is concluded that in many cases the use of Dolosse in armour layers may lead to more economical solutions for rubble mound breakwater and shore protection works.

scholarly journals RECENT ADVANCES IN COASTAL STRUCTURE DESIGN

2011 ◽  
Vol 1 (8) ◽  
pp. 23
Author(s):  
Charles E. Lee
Keyword(s):  
Structure Design ◽  
Beach Erosion ◽  
Scale Model ◽  
Small Scale ◽  
Shore Protection ◽  
Corps Of Engineers ◽  
Modern Design ◽  
Recent Advances ◽  
New Findings ◽  
Design And Construction

The type and scope of work accomplished and responsibility and authority of the office to which he is attached is indicative of the interests of an author and of the information available to him. It is therefore pertinent to cover in this general section a summary of the responsibility and the delegated authority of the Corps of Engineers as regards Coastal Engineering. The subject of recent advances in coastal structures is quite broad and complex and modern design practice incorporates old and new findings. This paper discusses various aspects of proper modern design of breakwaters and jetties with special attention to newer findings, their proper application and the means by which the findings were made. The Corps has the responsibility for the planning, investigation, design and construction of Federal civil works navigation projects. This consists generally of harbor and channel works. Their responsibility extends to the control of all works, private or governmental, to assure that navigation will not be adversely affected. They are also charged with the responsibility of planning, investigation, design and construction of Federal civil works projects involving shore protection from wave and currents, protection from effects of hurricane, tsunamis and tidal flooding, and of beach erosion control. The accomplishment of such a mission therefore includes research of an applied nature to permit advancement in knowledge and technique. Most of this research is based on small scale model studies accomplished at the U. S. Army Engineer Waterways Experiment Station at Vicksburg, Mississippi, and at the laboratory of the Corps of Engineers Beach Erosion Board in Washington, D. C. In addition a limited number of prototype studies are being initiated in the charge of the staffs of various District Engineers.

scholarly journals GENTLE SLOPE SEAWALLS COVERED WITH ARMOUR UNITS

1988 ◽  
Vol 1 (21) ◽  
pp. 147
Author(s):  
Osamu Toyoshima
Keyword(s):  
Laboratory Test ◽  
Beach Erosion ◽  
Reflected Waves ◽  
Gentle Slope ◽  
New Type

Since the early 1960's, many seawalls against the beach erosion have been constructed in Japan, most of which were of vertical type. As a result, some of the seawalls even encouraged the beach erosion due to the reflected waves on the steep front of the seawalls. The author then proposed seawalls of new types with gentle front slope(l to 3) covered with armour units in 1981, and over one hundred fieldworks have successfully been carried out. In 1985, the author proposed reforming the existing vertical type seawalls into the gentler front slope (1 to 5 or 6) seawalls. The laboratory test on the gentle slope seawall was made, and some experimental fieldworks were carried out. At this time, these new type gentler slope seawalls are successful.

scholarly journals HISTORICAL BEACH EROSION OF SOUTHWEST SURUGA COAST AND SHORE PROTECTION

2000 ◽  
Vol 16 ◽  
pp. 601-606
Author(s):  
Takaaki UDA ◽  
Satoquo SEINO ◽  
Toshinori ISHIKAWA ◽  
Masumi SERIZAWA
Keyword(s):  
Beach Erosion ◽  
Shore Protection

scholarly journals CHANGES OP SEA BED DUE TO DETACHED BEEAKWATEES

1976 ◽  
Vol 1 (15) ◽  
pp. 91 ◽  
Author(s):  
Osamu Toyoshima
Keyword(s):  
Flood Control ◽  
Sandy Beaches ◽  
Sediment Supply ◽  
Beach Erosion ◽  
Sea Bed ◽  
Open Sea ◽  
New Type ◽  
Japanese Islands ◽  
Coastal Land ◽  
Sea Cliffs

Since most of the coast lines of Japanese Islands are faced on the open sea and are always attacked by severe waves, beach erosion is one of serious problems in the coastal engineering field. Although Japan has all types of coastal land-forms except the glacial shoreline, remarkable recessions of coast line have been observed at sea cliffs and sandy beaches. The recession of sea cliffs has been found at several districts in Japan since old times. But, beach erosion has become increasingly severe since the early 1950's. The main causes of beach erosion are the reduction in sediment supply from rivers and the interception of the longshore paths of sediment. The former is caused by the river improvement works and by the construction of dams and debris barriers or Sabo works. The later is caused by the coastal structures, such as jetties, groins, breakwaters, and flood-control outlets. In addition a new type of beach erosion has been observed at the coast where coast protection works such as seawalls and bulkheads exist. The beach erosion defence works are being executed at more than 300 sites in Japan. Considerable number of the works were commenced in the 1960's.

scholarly journals SHORE PROTECTION ON THE COAST OP "YAIZU"

1966 ◽  
Vol 1 (10) ◽  
pp. 66
Author(s):  
Goichi Seo ◽  
Tatsuma Fukuchi
Keyword(s):  
Coastal Area ◽  
Beach Erosion ◽  
Shore Protection ◽  
History Of

This report describes the history of beach erosion and the countermeasures against it extending over the last few centuries on the coast of "YAIZU" Pishing Port. It also includes a study on the causes of erosion by analysing geographical, topographical and oceanogrphical conditions of the coastal area.

scholarly journals Modeling Procedure of Coastal Protection Shaped Blocks with High Wave Suppressing and Interlocking Capacity

2019 ◽  
Vol 97 ◽  
pp. 05050
Author(s):  
Irina Iordanishvili ◽  
Inga Iremashvili ◽  
Adam Ujma ◽  
Vladimer Shurgaya ◽  
Nodar Kandelaki ◽  
...  
Keyword(s):  
Construction Material ◽  
Life Time ◽  
Coastal Protection ◽  
Shore Protection ◽  
High Wave ◽  
Suppression Efficiency ◽  
Longshore Drift ◽  
Concrete Blocks ◽  
New Type ◽  
Inner Continental Shelf

A groyne is a shore protection structure built perpendicular to the shoreline of the coast (or river), over the beach and into the shoreface (the area between the nearshore region and the inner continental shelf), to reduce longshore drift and trap sediments. A groyne field or system is a series of groynes acting together to protect a beach. Concret is often used as construction material. On the basis of analysis of wave suppression efficiency and stability on the slope of more than one hundred existing shaped massives the new type of coast protecting reinforced concrete blocks – so called “Hexablock” (“Hexablock” was called because of its 6 facets) characterized with higher wave suppression properties, interlocking capacity, stability on the slope and longer life time is proposed.

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