WAVE DRAG COEFFICIENT USEFUL FOR NATURE: SEAGRASS-BASED COASTAL PROTECTION DESIGN IN ESTUARIES

Abstract

Wave attenuation provided by coastal ecosystems, including seagrass, mangroves, and saltmarsh, has been well studied in coastal engineering literature, but results are often not comparable due to differences in experimental methods, reporting units and a lack of complete published datasets. Many coastal ecology and conservation studies aim to qualitatively quantify the value of these ecosystems for coastal protection. However, without data reported in a comparable format, quantitative values are not finding their way into the ecology literature, contributing to the misconception that ‘rules of thumb’ exist for predicting coastal protection. To alleviate the challenges of non-comparable data and incomplete datasets, the drag coefficient (CD) is a useful tool to quantify and compare wave attenuation provided by different ecosystems. Using seagrass as a case study, we conducted a meta-analysis of 119 seagrass-wave attenuation studies both in the field and in laboratory experiments, of which 11 were eligible for inclusion in our study (Twomey et al., 2020).