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Saltmarsh Management Manual |  |
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What is Saltmarsh |
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Wave Attenuation Over Saltmarsh Surface |
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Wave height • Water depth • Width & edge characteristics Topography & bed friction • Vegetation density Wave Height At Stiffkey, on the north Norfolk coast, an average wave height reduction of 61% has been measured over saltmarsh, which is approximately four times the 15% reduction observed over an equivalent width of adjacent sand flat (Möller et al., 1999; and tables below). Total wave energy reduction over the saltmarsh of 82% was nearly three times that over the unvegetated sand flat (average 29%). On the Dengie Peninsula, at Tillingham, wave height attenuation of 21% was measured over the mudflats and 87% over saltmarsh, while at Bridgewick, offshore wave heights actually increased across mudflats by 24% and decreased by 44% over a much narrower (10 m) strip of saltmarsh (Möller and Spencer, 2002). Associated decreases in wave energy were observed over the saltmarsh at Tillingham (35%) and Bridgewick (79%). In The Wash, overall wave energy attenuation over saltmarsh of between 72% and 97% has been measured, with associated decreases in wave height of between 64% and 91% (Cooper, 2001). Measured levels of wave attenuation across UK saltmarshes and intertidal flats
Measured wave attenuation rates across UK saltmarshes and intertidal flats
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