Monitoring and maintenance of breakwaters which protect port entrances

Abstract

Paper presented at the 28th Annual Southern African Transport Conference 6 - 9 July 2009 "Sustainable Transport", CSIR International Convention Centre, Pretoria, South Africa.

While ports are gateways to the country's transport networks, breakwaters protect Port entrance channels, into and out of the Ports (Figure 1). The entrances to most of the Ports in South Africa are protected by rubble mound breakwaters which have dolos armouring. These require regular monitoring and maintenance, especially in the light of predicted sea level rise and extreme sea conditions caused by global warming. TNPA, the local Port Authority, has commissioned the CSIR to annually monitor the main breakwaters of the SA ports to ensure they remain in good condition.This paper presents a brief description of the performance of the dolos breakwaters in South Africa, and the field monitoring techniques used to record the annual damage to the armouring.Examples are also given of recent storm damage and typical repairs carried out.