TL;DR: The comparison of costs of nature-based defence projects and engineering structures show that salt-marshes and mangroves can be two to five times cheaper than a submerged breakwater for wave heights up to half a metre and, within their limits, become more cost effective at greater depths.
Abstract: There is great interest in the restoration and conservation of coastal habitats for protection from flooding and erosion. This is evidenced by the growing number of analyses and reviews of the effectiveness of habitats as natural defences and increasing funding world-wide for nature-based defences-i.e. restoration projects aimed at coastal protection; yet, there is no synthetic information on what kinds of projects are effective and cost effective for this purpose. This paper addresses two issues critical for designing restoration projects for coastal protection: (i) a synthesis of the costs and benefits of projects designed for coastal protection (nature-based defences) and (ii) analyses of the effectiveness of coastal habitats (natural defences) in reducing wave heights and the biophysical parameters that influence this effectiveness. We (i) analyse data from sixty-nine field measurements in coastal habitats globally and examine measures of effectiveness of mangroves, salt-marshes, coral reefs and seagrass/kelp beds for wave height reduction; (ii) synthesise the costs and coastal protection benefits of fifty-two nature-based defence projects and; (iii) estimate the benefits of each restoration project by combining information on restoration costs with data from nearby field measurements. The analyses of field measurements show that coastal habitats have significant potential for reducing wave heights that varies by habitat and site. In general, coral reefs and salt-marshes have the highest overall potential. Habitat effectiveness is influenced by: a) the ratios of wave height-to-water depth and habitat width-to-wavelength in coral reefs; and b) the ratio of vegetation height-to-water depth in salt-marshes. The comparison of costs of nature-based defence projects and engineering structures show that salt-marshes and mangroves can be two to five times cheaper than a submerged breakwater for wave heights up to half a metre and, within their limits, become more cost effective at greater depths. Nature-based defence projects also report benefits ranging from reductions in storm damage to reductions in coastal structure costs.
TL;DR: In this article, an approximate solution to conventional rubble mound breakwater designs is formulated in terms of an equivalent rectangular breakwater with an additional consideration for wave breaking, and experimental and theoretical results are compared and evaluated.
Abstract: A theory is derived to predict ocean wave reflection and transmission at a permeable breakwater of rectangular cross section. The theory solves for a damped wave component within the breakwater and matches boundary conditions at the windward and leeward breakwater faces to predict the reflected and transmitted wave components. An approximate solution to conventional rubble mound breakwater designs is formulated in terms of an equivalent rectangular breakwater with an additional consideration for wave breaking. Experimental and theoretical results are compared and evaluated.
TL;DR: Water Waves: Wave Theories and Measurement Short-Term Wave Analysis Long Term Wave Analysis Wave Generation Predictable Water Level: Tides Seasonal Fluctuations Long-Term Water Level Changes Including Global Climate Change Unpredictable Water Levels: Storm Surge Impulse Waves (Land Slide Generated Waves, Tsunamis) Wave Transformation and Breaking Design of Structures Breakwaters Coastal Management Coastal Sediment Transport Basic Shore Processes Coastal Design and Decision-making Coastal Modeling One-dimensional Modeling of Coastal Morphology Failure and Resilience Shore Protection Problems.
Abstract: Water Waves: Wave Theories and Measurement Short-Term Wave Analysis Long-Term Wave Analysis Wave Generation Predictable Water Level: Tides Seasonal Fluctuations Long-Term Water Level Changes Including Global Climate Change Unpredictable Water Levels: Storm Surge Impulse Waves (Land Slide Generated Waves, Tsunamis) Wave Transformation and Breaking Design of Structures Breakwaters Coastal Management Coastal Sediment Transport Basic Shore Processes Coastal Design and Decision Making Coastal Modeling One-Dimensional Modeling of Coastal Morphology Failure and Resilience Shore Protection Problems.
TL;DR: In this paper, the authors describe the development of the "Hudson formula" for the stability of armor on a breakwater, which was used for the first time in the World War II era.
Abstract: Paper describing the development of the "Hudson formula" for the stability of armor on a breakwater.
TL;DR: The results of the European Union Marine Science and Technology (EU MAST) III project "Scour Around Coastal Structures" (SCARCOST) as mentioned in this paper were summarized under three headings.