The world’s coastal zones are experiencing rapid development and an increase in storms and flooding. These hazards put coastal communities at heightened risk, which may increase with habitat loss. Here we analyse globally the role and cost effectiveness of coral reefs in risk reduction. Meta-analyses reveal that coral reefs provide substantial protection against natural hazards by reducing wave energy by an average of 97%. Reef crests alone dissipate most of this energy (86%). There are 100 million or more people who may receive risk reduction benefits from reefs or bear hazard mitigation and adaptation costs if reefs are degraded. We show that coral reefs can provide comparable wave attenuation benefits to artificial defences such as breakwaters, and reef defences can be enhanced cost effectively. Reefs face growing threats yet there is opportunity to guide adaptation and hazard mitigation investments towards reef restoration to strengthen this first line of coastal defence.

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The effectiveness of coral reefs for coastal hazard risk reduction and adaptation

Evolution of Design Method Against Random Waves Statistical Properties and Spectral of Sea Waves Transformation and Deformation of Random Sea Waves Design of Breakwaters Design of Coastal Dikes and Seawalls Probabilistic Design of Harbor Facilities Harbor Tranquility and Vessel Mooring Hydraulic Model Tests with Random Waves Theoretical Description of Random Sea Waves Statistical Theory of Irregular Waves Techniques of Random Wave Analysis 2D Computation of Wave Transformation with Random Breaking and Nearshore Currents Statistical Analysis of Extreme Waves Prediction and Control of Beach Deformation Processes.

Random seas and design of maritime structures

One of the most abundant energy sources exists in this world is the ocean wave energy. By far, it has shown to be the most clean, renewable, predicted energy and has raised the potential to compete with the current use of non-renewable energy sources. Recent research conducted on wave energy invention has opened a new dimension to slowly reduce the dependency on fossil fuel by introducing new technology on the renewable world but relatively lacking in economical aspect. This review brings the latest status on integration of wave energy device with other marine facilities, which is the breakwater structure that may possibly aid to cost sharing. Most researches done on this field highlighted countries experiencing rough sea condition and focused less on countries with medium wave condition as faced by the Asian continent. The potential for energy extraction and wave dissipation for medium wave condition will be discussed in this review by considering several aspects including reliability, effectiveness and performance. Finally, this review shows that the integration opens up a new dimension to acknowledge the technology harnessing ocean wave, especially for the Asian countries experiencing medium wave condition.

Wave energy device and breakwater integration: A review

http://www.vandermeerconsulting.nl/downloads/functional_b/2005_vandermeer_briganti.pdf

Wave transmission and reflection at low-crested structures: Design formulae, oblique wave attack and spectral change

The present invention is embodied in a digital communication system where multiple media data sources are time multiplexed into a packetized data stream, each packet having an assigned priority and the packetized data stream transmitted in substantially the order of assigned priority. At both the transmit side, and the receive side, audio packets are given priority processing over video packets, which in turn have priority over text/graphics data packets. Continuous real time audio playback is maintained at the receiver by delaying the playback of received audio in a first in/first out (FIFO) buffer providing a delay at least equal to the predicted average packet delay for the communication system. Optionally, the average system delay is continuously monitored, and the audio playback delay time is adjusted accordingly. Audio playback is slowed or accelerated in order to shrink or grow the difference in time between the sender and receiver. In another aspect of the invention, a conference of three or more callers is created by broadcasting a common packetized data stream to all conference callers.

Method and apparatus for multiple media digital communication system

Although detached, low-crested breakwaters are frequently employed for beach stabilization, no design tool is available nowadays that reliably predicts the transmissivity of these structures for a wide range of engineering conditions. With this in view, the paper presents a semiempirical model where the predictive equations have been obtained starting from a crude schematization of the physical processes that govern wave transmission. The obtained results are encouraging and show good agreement with a large ensemble of experimental data.

Conceptual Approach for Prediction of Wave Transmission at Low-Crested Breakwaters

2D Wave setup behind submerged breakwaters

The Seawave Slotcone Generator (WAVEnergy SAS, 2003) is a wave energy converter based on the overtopping principle. Although it has been effectively researched during the last decade, no design tool has been supplied to estimate the hydrodynamic loads the waves exert on its front face. In this article a set of well reliable 3D experiments has been re-analyzed, in order to get indications on possible calculation methods. It is shown that the Japanese design tools for monolithic sea dikes may be reasonably adapted to the present case. Finally a new approach is presented, which is based on the so called momentum flux principle; the resulting predictive equation fits the experimental data remarkably well.

https://www.mdpi.com/1996-1073/5/11/4779/pdf

Non Breaking Wave Forces at the Front Face of Seawave Slotcone Generators

Functional design of low crested breakwaters requires an accurate prediction of wave transmission and set up in the protected areas. Nevertheless, commonly used formulae do not appear to be reliable enough, especially for structures located in shallow waters. The paper describes results from large-scale model tests conducted on rubble mound breakwaters exposed to breaking waves. Tests were carried out at the “Grosser WellenKanal” of Hannover, Germany. The model dimension, near to prototype, allowed minimizing scale effects connected to wave breaking. Existing formulas on wave transmission have been verified and influence of crest width and breaker index have been highlighted. Moreover the wave set-up behind the structure has been analysed showing the importance of momentum release of breaking waves for submerged breakwaters and of the mass balance for low crested ones. 8.

Mario Calabrese

Papers

Conceptual Approach for Prediction of Wave Transmission at Low-Crested Breakwaters

2D Wave setup behind submerged breakwaters

Non Breaking Wave Forces at the Front Face of Seawave Slotcone Generators

Large-scale experiments on the behaviour of low crested and submerged breakwaters in presence of broken waves

Nature and Magnitude of Wave Loadings at Seawave Slot-cone Generators