Shallow Water Formulae for Toe Scour, Requisite Armour Mass and Wave Overtopping for the Concept Design of Rock Armoured Coastal Revetments

This article has investigated concept design formulae for revetment toe scour, rock armour mass stability and wave overtopping discharge for rock armoured coastal revetments. The investigation has utilised data from published scale model studies, normalising the laboratory data using factors based on wave energy. As wave characteristics change significantly in shallow water due to nonlinearities and wave breaking, the depth at half the nearshore wavelength fronting the structures has been adopted as a surrogate for a design wave height. Along with incorporating wave period, this has resulted in developing the formulae with predictions that were more coherent and accurate than those in current use. The Iribarren number has distinguished formulae for toe scour and armour mass stability between spilling and plunging breaking waves. Some model and scale effects have been discussed and recommendations for further investigations have been made.