Performance Comparison of Hybrid Protection Methods in Weakening coast Waves

Considering the strategic importance of coastal areas from various aspects, their protection against waves is a coast management necessity. Since long ago, strong coastal structures have protected coasts, but since they disturb the coastal ecosystem balance, effort has been made to use them less or make them more compatible with the coast. This research is specifically aimed to estimate the efficiency of environment-based methods such as the combined tree planting-structural methods compared with merely structural methods, in damping the coastal waves and, hence, protecting the coasts. In this research, coastal dikes with 3 different height situated in 3 different locations in combination with 3 rows of tree under the influence of 5 wave heights are investigated. Experimental results showed that the highest wave damping (80%) occurs by positioning the structure in the beginning of the protected area, covered by trees at its tail. To check the force reduction rate, the most effective protection plan is when the structure is in the middle of the protected area and the tree cover lies in front as well as in the back of the structure. In this case, the wave force damping is 10.7 times the :case when: the coast has no obstacles; when there are no trees and the structure is alone, the wave force damping is more than 50%. This mode, compared to the best performance mode - the structure lies alone at the beginning of the protected area, has increased the wave force damping efficiency by about 14%.