This paper presents a well-controlled laboratory experimental study to evaluate wave attenuation by artificial emergent plants (Phragmites australis) under different wave conditions and plant stem densities. Results showed substantial wave damping under investigated regular and irregular wave conditions and also the different rates of wave height and within canopy wave-induced flows as they travelled through the vegetated field under all tested conditions. The wave height decreased by 6%–25% at the insertion of the vegetation field and towards the downstream at a mean of 0.2 cm and 0.32 cm for regular and irregular waves respectively. The significant wave height along the vegetation field ranged from 0.89–1.76 cm and 0.8–1.28 cm with time mean height of 1.38 cm and 1.11 cm respectively for regular and irregular waves. This patterns as affected by plant density and also location from the leading edge of vegetation is investigated in the study. The wave energy attenuated by plant induced friction was predicted in terms of energy dissipation factor (fe) by Nielsen’s (1992) empirical model. Shear stress as a driving force of particle resuspension and the implication of the wave attenuation on near shore protection from erosion and sedimentation was discussed. The results and findings in this study will advance our understanding of wave attenuation by an emergent vegetation of Phragmites australis, in water system engineering like near shore and bank protection and restoration projects and also be employed for management purposes to reduce resuspension and erosion in shallow lakes.
experiments were conducted in an open wave flume constructed in the Coastal, Harbor and O shore Engine- ering Hydraulics Laboratory at Hohai University, China. A series of experimental runs were performed for waves propagating over an array of plastic artifcial emergent plants Artifcial plastic plants were used in this study to simulate aquatic vegetation. these plants mimicked real species of common reed (Phragmites Australis). ey are produced from material to generate appropriate density and flexural rigidity to approximate the real plants as possible. e plants have biomechanical and morphological resemblance to the real species they mimic and were thus suitable to be used in our studies. four vegetation densities (stems/m2) ranging from 30 to 90 stems/m2 which represent a typical aquatic con gura- tion in most rivers in the eastern china
|Climate change impacts||Effect of Nbs on CCI||Effect measures|
|Storm surge||Positive||wave height reduction wave energy disipation changes in shear stress which is a driving force behind sediment resuspension and erosion - a proxy to infer how they may contribute to erosion reduction|
|Coastal erosion||Positive||wave height reduction wave energy disipation changes in shear stress which is a driving force behind sediment resuspension and erosion - a proxy to infer how they may contribute to erosion reduction|