Author(s): Maria Maza; Javier L. Lara; Inigo J. Losada; Fernando Lopez-Arias
Linked Author(s): Maria Maza
Keywords: Coastal protection; Wave attenuation; Standing biomass; Saltmarshes
Abstract: Estimating the flow energy dissipation induced by a saltmarsh taking into account its characteristics (i.e. biomechanical properties, morphology, density) and the incident hydrodynamic conditions is crucial if ecosystem-based coastal protection measurements want to be undertaken. The characterization of a plant ecosystem by measuring leaf features, biomechanical properties of plants and the number of individuals per unit area is very demanding. This work present a new set of experiments performed to explore the potential of the use of the ecosystem standing biomass as the key variable defining the ecosystem wave attenuation capacity. A new set of experiments is proposed in which real saltmarshes with contrasting morphology and biomechanical properties and subjected to different incident flow conditions are used. Four species of saltmarshes are considered: Spartina maritima, Salicornia sp., Halimione sp. and Juncus sp. After collecting the different species in the field using boxes where the vegetation was introduced with a layer of sediment, they were located in a flume leading to a 9.05 m long meadow. The meadow was tested under regular and random wave conditions considering three water depths. Wave height evolution was measured using 15 capacitive free surface gauges and standing biomass was evaluated at different stages throughout the experiments, measuring the dry weight of the different species. A new formulation was obtained that relates standing biomass to the induced attenuation. This new relationship will help to quantify the expected coastal protection provided by the different saltmarsh species avoiding the use of any calibration parameter.