An evaluation of design factors and performance of groynes

Groynes are among the oldest structures in wide use today for controlling coastal erosion. Due to the complexities of the physical processes involved, predictions of groyne performance are not always reliable despite the prolific use of sophisticated numerical models. Site specific knowledge obtained from post-construction monitoring remains an indispensable source of knowledge for engineers in designing groynes. This paper reports the analysis of a recently conducted questionnaire survey on the most important factors which influence the design of groynes and perception of the performance of existing groynes. It was found that the greatest importance was placed on the effectiveness of groynes in holding sediment locally while the least importance was placed on the negative effects that building groynes can have on both the natural and human environments. It was also found that a large proportion of the existing groynes seemed to have achieved their design objectives with the rock groynes performing particularly well.