Print Email Facebook Twitter The effectiveness, costs and coastal protection benefits of natural and nature-based defences Title The effectiveness, costs and coastal protection benefits of natural and nature-based defences Author Narayan, Siddharth (University of California) Beck, Michael W. (University of California) Reguero, Borja G. (The Nature Conservancy) Losada, Iñigo J. (Universidad de Cantabria) van Wesenbeeck, B (TU Delft Coastal Engineering; Deltares) Pontee, Nigel (University of Southampton) Sanchirico, James N. (University of California) Ingram, Jane Carter (Columbia University) Lange, Glenn Marie (World Bank) Burks-Copes, Kelly A. (US Army Engineer Research and Development Center) Date 2016 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. To reference this document use: http://resolver.tudelft.nl/uuid:77995966-e22e-4ff8-8fda-671b3e6966ed DOI https://doi.org/10.1371/journal.pone.0154735 ISSN 1932-6203 Source PLoS ONE, 11 (5), 1-17 Part of collection Institutional Repository Document type journal article Rights © 2016 Siddharth Narayan, Michael W. Beck, Borja G. Reguero, Iñigo J. Losada, B van Wesenbeeck, Nigel Pontee, James N. Sanchirico, Jane Carter Ingram, Glenn Marie Lange, Kelly A. Burks-Copes Files PDF file.pdf 1.15 MB Close viewer /islandora/object/uuid:77995966-e22e-4ff8-8fda-671b3e6966ed/datastream/OBJ/view