Investigation of hydraulic design parameters of coastal structures

Abstract

The wave field in the vicinity of a coastal structure may be treated in terms of dissipated, reflected and transmitted components. These structures are designed to dissipate a significant proportion of the incident wave energy and will' reflect or transmit the remainder. The transmitted energy has two components namely transmission through the structure and transmission by over topping. The need to absorb or dissipate wave energy demands that coastal structures offer some significant degree of porosity. Most armoured slopes are constructed with voids between and sometimes within the armour units in order to increase wave energy dissipation. The voids matrix offers a conducive configuration for wave energy dissipation arising from wave structure interaction. The ability to predict the levels of reflection, transmission, run-up and run-down for various types of coastal structures play an important role in the assessment of their hydraulic performance. These design parameters together with the hydraulic, geotechnical and structural stability of the individual components and of the structure as a whole determine the overall performance of the structure. The porosity and permeability of the structure too has a significant influence on the hydraulic performance and the economies of construction.