Wave Attenuation in Vegetation Based Breakwater

Increase in number of rows of pile results in ___________ of transmitted wave height.
The breaking criteria of waves in shallow water is (where H is wave height, d is the depth of water).
In the equation (Hi/gT2), Hi is?
Wave length is the distance between two successive crest or trough.
Wave rider buoy and Pressure type wave gauge is used to measure wave height.