scholarly journals Seasonal Variation in Sandy Beach Shoreline Position and Beach Width

1999 ◽  
Keyword(s):  
Seasonal Variation ◽  
Sandy Beach ◽  
Shoreline Position ◽  
Beach Width

scholarly journals Environmental signal shredding on sandy coastlines

2019 ◽  
Vol 7 (1) ◽  
pp. 77-86 ◽  
Author(s):  
Eli D. Lazarus ◽  
Mitchell D. Harley ◽  
Chris E. Blenkinsopp ◽  
Ian L. Turner
Keyword(s):  
Sandy Beach ◽  
Shoreline Change ◽  
Storm Events ◽  
Shoreline Position ◽  
Physical Effects ◽  
Sand And Gravel ◽  
Open Question ◽  
Observational Record ◽  
Coastal Research

Abstract. How storm events contribute to long-term shoreline change over decades to centuries remains an open question in coastal research. Sand and gravel coasts exhibit remarkable resilience to event-driven disturbances, and, in settings where sea level is rising, shorelines retain almost no detailed information about their own past positions. Here, we use a high-frequency, multi-decadal observational record of shoreline position to demonstrate quantitative indications of morphodynamic turbulence – “signal shredding” – in a sandy beach system. We find that, much as in other dynamic sedimentary systems, processes of sediment transport that affect shoreline position at relatively short timescales may obscure or erase evidence of external forcing. This suggests that the physical effects of annual (or intra-annual) forcing events, including major storms, may convey less about the dynamics of long-term shoreline change – and vice versa – than coastal researchers might wish.

Seasonal variation of bivalve larvae on an exposed sandy beach on Kashima-nada: Tips for the sandy beach recruitment process

2011 ◽  
Vol 65 (2) ◽  
pp. 275-283 ◽  
Author(s):  
Hideki Sawada ◽  
Hajime Saito ◽  
Kumiko Adachi ◽  
Haruhiko Toyohara
Keyword(s):  
Seasonal Variation ◽  
Sandy Beach ◽  
Recruitment Process ◽  
Bivalve Larvae

scholarly journals A MODIFIED HYPERBOLIC TANGENT EQUATION TO DETERMINE EQUILIBRIUM SHAPE OF HEADLAND BAY BEACHES

2018 ◽  
pp. 106
Author(s):  
Jonathan Kemp ◽  
Benoit Vandeputte ◽  
Thomas Eccleshall ◽  
Richard Simons ◽  
Peter Troch
Keyword(s):  
Sandy Beach ◽  
Equilibrium Shape ◽  
Control Point ◽  
Wave Climate ◽  
Wave Direction ◽  
Hyperbolic Tangent ◽  
Beach Width ◽  
Shape Equation ◽  
New Equation ◽  
Modified Equation

When designing any artificial beach, it’s desirable to avoid (or minimise) future maintenance commitments by arranging the initial beach planshape so that it remains in equilibrium given the incident wave climate. Headlands bays, or embayments, where a sandy beach is held between two erosion resistant headlands, tend to evolve to a stable beach planshape with little movement of the beach contours over time. Several empirical bay shape equations have been derived to fit curves to the shoreline of headland bay beaches. One of the most widely adopted empirical equations is the parabolic bay shape equation, as it is the only equation that directly links the shoreline positions to the predominant wave direction and the point of diffraction. However, the main limitation with the application of the parabolic bay shape equation is locating the downcoast control point. As a result of research presented in this paper a new equation, based on the hyperbolic tangent shape equation was developed, which eliminates the requirement of placing the down coast control point and relies on defining a minimum beach width instead. This modified equation was incorporated into a new ArcGIS tool.

scholarly journals Environmental signal shredding on sandy coastlines

2018 ◽  
Author(s):  
Eli D. Lazarus ◽  
Mitchell D. Harley ◽  
Chris E. Blenkinsopp ◽  
Ian L. Turner
Keyword(s):  
Sandy Beach ◽  
Shoreline Change ◽  
Storm Events ◽  
Shoreline Position ◽  
Sand And Gravel ◽  
Open Question ◽  
Short Time ◽  
Observational Record ◽  
Coastal Research

Abstract. How storm events contribute to long-term shoreline change over decades to centuries remains an open question in coastal research. Sand and gravel coasts exhibit remarkable resilience to event-driven disturbances, and, in settings where sea level is rising, shorelines retain almost no detailed information about their own past positions. Here, we use a detailed, multi-decadal observational record of shoreline position to demonstrate quantitative indications of morphodynamic turbulence – signal shredding – in a sandy beach system. We find that, much like other dynamic sedimentary systems, processes of sediment transport that affect shoreline position at relatively short time-scales obscure or erase physical evidence of external forcing. This suggests that large forcing events like major coastal storms, even when their effects are recorded, may convey less about the dynamics of long-term shoreline change – and vice versa – than coastal researchers might wish.

scholarly journals SEBARAN LOKASI PENELURAN PENYU HIJAU (Chelonia mydas) DI PULAU SANGALAKI KEPULAUAN DERAWAN KABUPATEN BERAU

2016 ◽  
Vol 18 (2) ◽  
pp. 39
Author(s):  
Andi Ibrahim ◽  
Djumanto Djumanto ◽  
Namastra Probosunu
Keyword(s):  
Green Turtle ◽  
Sandy Beach ◽  
Environmental Parameters ◽  
Chelonia Mydas ◽  
Lunar Phase ◽  
The West ◽  
Conservation Area ◽  
Border Line ◽  
Spawning Frequency ◽  
Beach Width

Population of green turtle (Chelonia mydas) that laid their eggs in the Derawan Islands conservation area was declined due to various factors. The aim of this study was to determine the number of egg that was laid down into the nest for each green turtle parent and its correlation to shade, sandy beach width, and moon phase. The study was conducted from 24 January to 31 March 2015 in the Sangalaki Island. The observation of the broods stock was done by walking down the beach in the night to find out the broodstock that laid the eggs and counted the number. A sign was given to the nest of broodstock that finished laying the eggs. On the following day, nest excavation, egg collection, and the environmental measurement were conducted. Environmental conditions were measured include the depth of the nest, substrate temperature, the distance of the nest site to the shading trees and the border line of lowest tide. Data analysis was done descriptively by counting the number of eggs and environmental parameters. The results show that the average number of egg per nest was 97 items with the range of 45 - 127 items, the length of the carapace was 96 cm with a range of 86 - 107 cm, the average depth of the nest hole was 73 cm with a range of 56 - 87 cm. Broods stock of green turtle that laid more eggs would dig nest hole deeper, but there was no correlation between the carapace length and the number of the laid eggs. The average number of green turtle broods stock that lay eggs in the Sangalaki Island was 486 individual/ month with the range of 168 - 1085 individu/month. The west and east seasons affect the frequency of nesting and the laid eggs. The frequency of spawning occured throughout the year and the highest spawning frequency occured in August which coincides with the peak of the East Season. The frequency of spawning during the East Season was four times higher than during the West season. The frequency of green turtle landing was not affected by the lunar phase. Based on the location of laying egg, the beaches that were selected for laying egg are located in the northwest, northeast, and south parts of the Sangalaki Island. The Green turtle nests were commonly found in the vegetation shading areas (64%) than open sand areas (36%).

Effects of a freshwater canal discharge on an ovoviviparous isopod inhabiting an exposed sandy beach

2006 ◽  
Vol 57 (4) ◽  
pp. 421 ◽  
Author(s):  
Juan Pablo Lozoya ◽  
Omar Defeo
Keyword(s):  
Environmental Variables ◽  
Reproductive Output ◽  
Sandy Beach ◽  
Explanatory Variable ◽  
Abiotic Factors ◽  
Reproductive Traits ◽  
Discharge Canal ◽  
Beach Width ◽  
Spatial Trends ◽  
Slope Beach

The present study evaluates the effects of an artificial freshwater discharge (Canal Andreoni) on the ecology of the ovoviviparous isopod Excirolana armata. Bimonthly, 17 environmental variables plus isopod abundance, biomass, fecundity, growth and mortality were compared between three sites: ‘Barra del Chuy’ (undisturbed), at 13 km from the canal, ‘Coronilla’ (moderately disturbed), at 1 km, and ‘Andreoni’ (grossly disturbed), at the canal mouth. Environmental (salinity, slope, beach width, and swash width) and some biological (isopod abundance, biomass and growth rates) variables significantly decreased towards Canal Andreoni. Salinity was the most important explanatory variable of spatial trends in isopod biomass. However, the reproductive output, fecundity, survival and individual weight were not affected, suggesting that E. armata is regulated by density-dependent and abiotic factors operating together: the former were more intense on undisturbed conditions, whereas the latter prevailed in impacted ones. Internal brooding counteracts the effect of fresh water, which explains the lack of effect of environmental harshness on reproductive traits.

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