scholarly journals BEACH DEVELOPMENT BETWEEN HEADLAND BREAKWATERS IN A LOW WAVE ENERGY ENVIRONMENT, PASIR RIS, SINGAPORE

1986 ◽  
Vol 1 (20) ◽  
pp. 76
Author(s):  
S.Y. Chew ◽  
S.K. Ho ◽  
P.P. Wong ◽  
Y.Y. Leong
Keyword(s):  
Wave Energy ◽  
Logarithmic Spiral ◽  
Wave Action ◽  
Sediment Supply ◽  
Entire Length ◽  
Littoral Drift ◽  
Wave Approach ◽  
Model Study ◽  
Energy Environment ◽  
Permanent Shape

One of the function of the offshore breakwater is to protect the coast from wave action. By dissipating the wave energy along its entire length, the breakwater causes sediments in its lee to deposit and a shore salient is formed. If the offshore breakwater are placed in a series along a coast with a gentle offshore slope and a substantial littoral drift tombolo will form behind the breakwaters between which bays will be sculptured by waves to form stable shapes (1). These attached breakwater would thus form a series of artificial headlands. In nature, beaches between headlands are influenced by the position of the headlands. Where the headlands are closely spaced and a limited sediment supply exists, small pockets beaches are formed. Where the headlands are far apart and an adequate sediment supply exists, long and wide beaches are formed. Generally, between these two extremes most beaches between natural headlands take a shape that is related to the predominant wave approach; on the downcoast sector is a long and straight beach, while on the upcoast end is curbed beach. Silvester (2) in his model study established a relationship between the logarithmic spiral constant ( °^ ) and the angle of predominant wave approach ( & ). A quasi-permanent shape was reached when waves broke simultaneously around the model bay. As it is difficult to measure the curve sector in nature, Silvester and Ho (3) suggested the use of an indentation ratio to relate the bay's shape to wave approach.

scholarly journals USE OP CRENULATE SHAPED BAYS TO STABILIZE COASTS

1972 ◽  
Vol 1 (13) ◽  
pp. 70 ◽  
Author(s):  
Richard Silvester ◽  
Siew-Koon Ho
Keyword(s):  
Wave Energy ◽  
Logarithmic Spiral ◽  
Stages Of Development ◽  
Littoral Drift ◽  
Approach Angle ◽  
Specific Relationship ◽  
The Waves ◽  
Resultant Wave

Crenulate shaped bays are the rule rather than the exception on coastal margins of oceans, inland seas or lakes where sedimentary beaches exist between headlands. They have a particular orientation to the swell or resultant wave energy vector, such that the straight tangent section is downcoast and the curved portion upcoast. The latter is a logarithmic spiral at all stages of development of the bay. When fully stable, that is no littoral drift taking place, the constant of the log-spiral equation has a specific relationship to the approach angle of the waves to the headland alignment. In this condition it is shown that diffraction and refraction are involved when waves sculpture the curved beach in the lee of the upcoast headland. A further ratio to identify stable bays appears to be the ratio of indentation length to clearance between headlands. The application of crenulate shaped bays to stabilization of a reclaimed shoreline suffering strong littoral drift on Singapore Island is described.

Foredune development on Îles de la Madeleine (Quebec), Atlantic Canada

1997 ◽  
Vol 34 (11) ◽  
pp. 1467-1476 ◽  
Author(s):  
P. T. Giles ◽  
S. B. McCann
Keyword(s):  
Wave Energy ◽  
West Coast ◽  
Average Rate ◽  
Atlantic Canada ◽  
High Wind ◽  
The West ◽  
Ammophila Breviligulata ◽  
Cool Temperate ◽  
Energy Environment ◽  
La Madeleine

The foredune, in this cool-temperate, sediment-abundant, relatively high wind and wave energy environment, is generally a single ridge with a mean height of 5.1 m (max. 11.4 m) and width of 25–35 m. Pioneer vegetation is dominated by Ammophila breviligulata. Four foredune types were identified: scarped, scarped with blowouts, scarped with incipient foredune, and nonscarped, the first being the most common, occupying more than 50% of the shoreline. Foredune erosion and retreat is occurring at an average rate of 0.8 m∙a−1. The marked differences in dune character between the west and east coasts of the islands are related to differences in wave energy and shoreline dissipativeness. The higher energy west coast exhibits more dynamic dunes with more frequent blowouts, which may develop into parabolic forms.

On the Efficiency and Transmission Characteristics of a 1:20 Model Fixed Wave Energy Device

2003 ◽  
Author(s):  
E. Vijayakrishna Rapaka ◽  
S. Neelamani ◽  
R. Natarajan
Keyword(s):  
Wave Propagation ◽  
Water Column ◽  
Water Depth ◽  
Wave Energy ◽  
Oscillating Water Column ◽  
Wave Energy Conversion ◽  
Transmission Characteristics ◽  
Energy Device ◽  
Average Value ◽  
Model Study

Wave transmission and pneumatic efficiency of an oscillating water column (OWC) type wave energy device resting on group of piles is investigated using physical model study. The caisson blocks 45% of the water depth. The co-efficient of transmission of the device varies from 0.1 to 0.4 for B/L range of 0.1 to 0.7, where ‘B’ is the width of the caisson in the direction of wave propagation and ‘L’ is the wavelength. The pneumatic efficiency varies from 20% to 50% with an average value of 0.35. The results of the present study can be used in the design of OWC caisson used for both wave energy conversion and breakwater in deeper water.

GRAVEL BEACH NOURISHMENT AT A LOW-WAVE ENERGY ENVIRONMENT TO CONTROL THE EFFECTS OF GLOBAL WARMING

2019 ◽  
Author(s):  
HYUN DONG KIM ◽  
KYU HAN KIM ◽  
SHIN-ICHI AOKI ◽  
SEONG WOOK KOO ◽  
KISU KWAK
Keyword(s):  
Global Warming ◽  
Wave Energy ◽  
Beach Nourishment ◽  
Energy Environment ◽  
Gravel Beach

Shoreline Erosion and Restabilization in the Southern Indian Lake Reservoir

1984 ◽  
Vol 41 (4) ◽  
pp. 558-566 ◽  
Author(s):  
R. W. Newbury ◽  
G. K. McCullough
Keyword(s):  
Water Level ◽  
Wave Energy ◽  
Wave Action ◽  
Shoreline Erosion ◽  
Energy Component ◽  
Minimum Period ◽  
M Wave ◽  
Fine Grained ◽  
Erosion Rates

Prior to a 3-m impoundment in 1976, bedrock comprised 76% of the shoreline of Southern Indian Lake in northern Manitoba. This was reduced to only 14% of the shoreline as the water level rose above the wave-washed zone and flooded into the predominantly fine-grained, frozen overburden materials. Twenty monitoring sites were surveyed annually to determine rates of permafrost melting and solifluction and shoreline erosion. The sequence of shoreline erosion in permafrost materials was found to be cyclic, consisting of melting and undercutting of the backshore zone, massive faulting of the overhanging shoreline, and removal of the melting and fractured debris. Rates of shoreline erosion varied widely, depending on the exposure of the site to wave action and the composition of the backshore materials. At sites in fine-grained frozen silts and clays, representative of over three quarters of the postimpoundment shoreline, rates of retreat of up to 12 m∙yr−1 were observed. The total volume of shoreline materials removed varied from less than 1 to over 23 m3∙m shoreline length−1∙yr−1. Clearing of the forested backshore prior to flooding did not affect the erosion rates. The index of erosion based on the hindcast wave energy component perpendicular to the shoreline was 0.00035 m3∙t-m wave energy−1 (0.036 m3∙MJ−1). The minimum period of restabilization of the shoreline based on the volume of backshore materials that must be eroded before bedrock conditions are reestablished was estimated to be 35 yr for three quarters of the shoreline surrounding the lake.

scholarly journals Seeking the Shore: Evidence for Active Submarine Canyon Head Incision Due to Coarse Sediment Supply and Focusing of Wave Energy

2018 ◽  
Vol 45 (22) ◽  
pp. 12,403-12,413 ◽  
Author(s):  
M. Elliot Smith ◽  
Samuel H. Werner ◽  
Daniel Buscombe ◽  
Noah J. Finnegan ◽  
Esther J. Sumner ◽  
...  
Keyword(s):  
Wave Energy ◽  
Submarine Canyon ◽  
Sediment Supply ◽  
Coarse Sediment
Sign in / Sign up

Export Citation Format

Share Document