Numerical Modelling and Experimental Investigation on the Effect of Wave Attenuation Due to Coastal Vegetation
Coastal areas are prone to natural disasters like tsunami and earthquake. The losses occuring due to these disasters are voluminous, since high population densities are generally located along the coastal region. The massive velocity and salinity of waves causes soil erosion and affect the structures present along the coastal belt. Coastal vegetation such as seagrass canopies acts as a natural barrier to soil erosion and to the wave impact. Seagrass is the most abundantly found marine species along the Indian coast. It is located at an ideal depth to dissipate the waves before reaching the shore. The use of seagrass as a buffer zone is gaining momentum in the field of coastal engineering as it also helps in conserving the ecosystem. This paper presents the wave attenuation due to seagrass by numerical modelling and experimental investigation. The Cymodocea Serrulata species (CSS) was selected for the study which is found in coastal regions of India like Palk Bay and Gulf of Mannar. Wave attenuation by the CSS vegetation for different wave heights and wave periods was studied. The numerical model for wave attenuation was created using Flow 3D software and artificial vegetation (silicon rubber tubes) was used for the experimental investigation carried out at wave flume in National Institute of Technology, Tiruchirappalli (NITT). Multiple waves were created from the numerical simulation by varying the wave heights, wave periods and transmitted wave heights at different meadow widths were recorded and analysed. The results of numerical modelling were compared with the experimental investigation. The submergence ratio increases from 0.47 to 0.53. The wave attenuation increases from 60 to 54% of that of original wave height. The model exhibits increased efficiency (the relative plant height (h/d)) in wave height reduction.
KeywordsWave attenuation Submergence ratio Wave–vegetation interaction
The authors acknowledge the National Institute of Technology, Tiruchirappalli (NITT) for the financial support and for allowing the use of FLOW-3D software.
- 1.Kummu M, de Moel H, Salvucci G, Viviroli D, Ward PJ, Waris O (2016) Over the hills and further away from coast: global geospatial patterns of human and environment over the 20th–21st centuries. Environ Res LettGoogle Scholar
- 2.The IUCN redlist of threatened species. http://www.iucnredlist.org
- 13.Beena MJ, Shirlal KG, Rai S, Rajasekaran C (2015) Effect of artificial sea grass on wave attenuation and wave run-up. Int J Mod Eng ResGoogle Scholar