Experimental study on wave damping potential of seaweed aquaculture systems on the Portuguese coast

Abstract

The sea-level rise and intensification of extreme weather events pose a significant threat to coastal regions and their communities worldwide. With significant wave heights reaching over 5 m, and wave periods over 10 s (Mendes & Oliveira, 2021), the Portuguese coastline is exposed to major coastal erosion, due to the marine harsh conditions of the North Atlantic. In the last decades the preferred strategy to protect the coastline from coastal hazards has been the construction of hard-engineering structures such as seawalls and breakwater, which tend to be expensive and unsustainable, often becoming obsolete and were not designed to account for the increasing sea level. As such, there has been a growing trend over the adoption of soft, adaptative, and nature-based coastal protection measures (Pranzini et al., 2015). Longline seaweed aquaculture systems have long been identified as a nature-based, soft structure with wave damping potential by several studies performed by Mork (1996), Liu et al. (2015) among others. The AquaBreak Project aims at exploring the synergetic applications of seaweed aquaculture systems on food production, coastal protection, and sea decarbonization on the Portuguese coast with the creation of the AOS - the AquaBreak Offshore System (Miranda et al., 2023; Proença et al., 2023). However, in order to create a strategic and effective implementation plan for the AOS, it is important to assess the wave damping potential of such structure exposed to the common maritime conditions of the Portuguese Coast.