Journal ArticleDOI
An analysis of beach profile changes subsequent to the Colombo Harbor Expansion Project, Sri Lanka
Nalin Prasanna Ratnayake,Amila Sandaruwan Ratnayake,Amila Sandaruwan Ratnayake,PV Keegle,M. A. K. M. Mallawa Arachchi,Hmr Premasiri +5 more
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In this paper, the authors measured monthly variations of beach width, beach profile and the mean grain-size of the sediments at mean sea level for complete annual monsoon cycle.Abstract:
Man-made coastal structures directly affect sediment balance and sediment dynamics on the surrounding beaches. The Colombo Harbor Expansion Project has created about 5-km-long breakwater nearly perpendicular to the beach. The present study is focused on quantitatively and qualitatively analyzing the effect of the Colombo Harbor Expansion Project on economically important beaches in and around Colombo city area. In this study, the authors measured monthly variations of beach width, beach profile and the mean grain-size of the sediments at mean sea level for complete annual monsoon cycle. Data were analyzed to establish site-specific erosion vulnerability. Monitoring results show that cumulative beach erosion has increased after the construction of the breakwater (rate = 0.7 m/year from May 2000 to April 2011 and rate = 28.2 m/year from April 2011 to June 2012). In addition, the cumulative and site-specific sand accretion and erosion patterns have a clear relationship with the monsoon seasonality. Beaches were narrower during the stormy southwestern monsoon, whereas beaches were wider during fair weather of northeast monsoon and inter-monsoon periods. In contrast, the constructed breakwater obstructs natural longshore sediment dynamics. For example, a significant amount of sediments from the Kelani-Ganga River were buried in the Colombo Harbor due to alteration of prominent longshore sediments transportation on the western coast of Sri Lanka. Therefore, this study shows enhancement of coastal erosion in the studied southern beaches due to a lack of sediment deposition.read more
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Journal ArticleDOI
Influence of nearshore sediment dynamics on the distribution of heavy mineral placer deposits in Sri Lanka
Kananathan Amalan,Amila Sandaruwan Ratnayake,Amila Sandaruwan Ratnayake,Nalin Prasanna Ratnayake,Shanaka Maduranga Weththasinghe,Nimila Dushyantha,Nalika Lakmali,Ranjith Premasiri +7 more
TL;DR: In this article, the authors used the time-series satellite images to identify the prominent directions of monsoon-influenced longshore currents, coastal sediment accretion and depositional trends and their relationships to the provenance of the heavy mineral occurrences.
Journal ArticleDOI
Erosion processes driven by monsoon events after a beach nourishment and breakwater construction at Uswetakeiyawa beach, Sri Lanka
Nalin Prasanna Ratnayake,Amila Sandaruwan Ratnayake,Amila Sandaruwan Ratnayake,Rukshan M. Azoor,Shanaka Maduranga Weththasinghe,Indunil Seneviratne,Nilupul Senarathne,Ranjith Premasiri,Nimila Dushyantha +8 more
TL;DR: The first beach nourishment project in Sri Lanka was carried out in 2012 over a 1.8km stretch in the Uswetakeiyawa area by the Coast Conservation Department as mentioned in this paper.
Journal ArticleDOI
Sea-level inundation and risk assessment along the south and southwest coasts of Sri Lanka
Lakshika Palamakumbure,Amila Sandaruwan Ratnayake,Amila Sandaruwan Ratnayake,H. M. Ranjith Premasiri,Nalin Prasanna Ratnayake,Nalin Prasanna Ratnayake,Jinadasa Katupotha,Nimila Dushyantha,Shanaka Maduranga Weththasinghe,W. A. Panchala Weerakoon +9 more
TL;DR: In this paper, the authors examined sea-level inundation during the middle Holocene highstands based on paleo sea level indicators along the south and southwest coasts of Sri Lanka.
Potential for bias in 21st century semi-empirical sea level projections
TL;DR: In this article, the authors examined the limitations of a semi-empirical model characterized by a sea level projection of 73 cm with RCP4.5 scenario by 2100.
Journal ArticleDOI
Coastal zone management in Sri Lanka: A lesson after recent naval accidents.
TL;DR: In this paper , the authors proposed a framework for the integrated coastal zone management in Sri Lanka, based on the national acts and laws, existing regulations, and analysis of international experiences.
References
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Impact of Humans on the Flux of Terrestrial Sediment to the Global Coastal Ocean
TL;DR: Global estimates of the seasonal flux of sediment, on a river-by-river basis, under modern and prehuman conditions are provided, showing African and Asian rivers carry a greatly reduced sediment load; Indonesian rivers deliver much more sediment to coastal areas.
Journal ArticleDOI
Impact of Humans on the Flux of Terrestrial Sediment to the Global Coastal Ocean
James P. M. Syvitski,James P. M. Syvitski,James P. M. Syvitski,Charles J. Vörösmarty,Charles J. Vörösmarty,Charles J. Vörösmarty,Albert J. Kettner,Albert J. Kettner,Albert J. Kettner,P. A. Green,P. A. Green,P. A. Green +11 more
TL;DR: In this article, the seasonal flux of sediment, on a river-by-river basis, under modern and prehuman conditions, is provided, and the authors show that humans have simultaneously increased the sediment transport by global rivers through soil erosion (by 2.3 ± 0.6 billion metric tons per year), yet reduced the flux reaching the world's coasts (by 1.4 ± 0 3 billion metric ton per year) because of retention within reservoirs.
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Global Warming and Coastal Erosion
TL;DR: In this paper, the authors present an analytical treatment that indicates there is a highly multiplicative association between long-term sandy beach erosion and sea level rise, and use a large and consistent data base of shoreline position field data to show that there is reasonable quantitative agreement with observations of 19th and 20th century sea levels and coastal erosion.
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Sea-level rise and shoreline retreat: time to abandon the Bruun Rule
TL;DR: The Bruun Rule has no power for predicting shoreline behaviour under rising sea level and should be abandoned as mentioned in this paper. But, despite the lack of understanding, many appraisals have been undertaken that employ a concept known as the "Bruun Rule" and many studies disprove it in the field.
Journal Article
Wave runup, extreme water levels and the erosion of properties backing beaches
TL;DR: In this article, a model was developed to evaluate the susceptibility of coastal properties to wave induced erosion, including analyses of the probabilities of extreme water levels due to tides affected by various oceanographic and atmospheric processes, and the runup elevations of storm waves on beaches.