Wave attenuation by coastal vegetation – An Empirical study on synthetic models

Abstract

The interaction between wave and submerged vegetation is the primary cause of wave-induced attenuation. Studies on wave vegetation interactions mostly considered aquatic monotypic plant meadows and limited work have been reported on heterospecific plant meadows, common in tropical shores of southern India. An attempt was made to understand the heterospecific vegetation meadow-wave interactions through a two-level, four factors, full factorial experimental design-based laboratory flume study under controlled conditions. Simulated vegetation mimics were used as a simplified representation of heterospecific seagrass species, <em>Halophila spinulosa</em><em>, Halophila ovalis </em>to develop a linear empirical model. Four input variables <em>viz</em>., water depth <em>(h)</em>, wave period <em>(T</em>), plant density <em>(N)</em> and bed roughness factor <em>(f)</em>, were considered for the study with the wave attenuation (<em>E </em>%) as a response. The developed model was tested for adequacy by using the analysis of variance (ANOVA) technique. Main and interaction effects of the input variables were analyzed, compared, and validated. The results show that all the four input variables are statistically significant with the <em>T </em>has the highest significant individual effect on wave attenuation followed by <em>f, h, </em>and <em>N. </em>Evidential two-way interaction effects, mainly between <em>h </em>with the rest of the parameters were also observed.