Sandbar Breakwater: An Innovative Nature-Based Port Solution

Abstract

The nature-based concept of the Sandbar Breakwater was born based on the typical natural dynamics of the West African coast (Gulf of Guinea). Learning from the development and coastal impact of the existing port infrastructure in West Africa, the application of sand as a construction material for marine infrastructure seemed very obvious. Along this coast, ports experience heavy sedimentation at the western updrift side of the breakwaters, leading to the rapid burying of valuable armour rock. The Sandbar Breakwater concept is based on this principle by using natural accretion as the basis for the port protection. Such a concept is advantageous as a large sediment drift naturally supplements the sand filling works during construction and the required rock volumes are reduced significantly, saving construction time and minimising the environmental impact. To counteract the downdrift coastal retreat, a replenishable sand engine completes the scheme. The realisation of a Sandbar Breakwater at Lekki, Nigeria, in 2018, with subsequent safe and continuous port operations, proves the feasibility of the concept. Sustainable future development is further pursued by integrated maintenance campaigns following the Building with Nature principles to guarantee the operability of the port while preserving the alongshore sediment balance and minimising the environmental impact.