Climate Change Impact on the Hydraulic Performance of Breakwaters

Global warming, associated to climate change, is producing a progressive sea level rise. This situation results in greater and more frequent extreme events in the coastal areas such as flooding, damage to material goods and higher risk of loss of human lives.

In general, rubble mound breakwaters are the main maritime structures used to protect ports and coastal areas, not only due to their effectiveness but also because of their cost, design complexity and environmental and socioeconomic impacts. The selection of a breakwater type and the dimensions of its sections and elements depend on the project requirements, site characteristics and wave climate.

Although during last years research on climate change has significantly increased, there is still much work to be done to understand how existing structures will perform under higher sea levels as well as improving the design of new maritime infrastructures against sea level rise.

In this work we focus on two of the main failures modes that specially affect the operability of a rubble mound breakwater: overtopping and the loss of stability of toe berms and mounds. In both cases a lot of research has been done in the last few years (EurOtop 2016, CEM 2002) but in general existing formulations do not take into account the energy transformation and its interaction with the structure and what is more important, they are analyzed separately without knowing how they interact with each other (Vílchez, 2016).

As a consequence, this paper aims to quantify the effect of the sea level rise on the stability and overtopping of two breakwaters typologies (a composite breakwater with a protection berm and a rubble mound breakwater), taking into account the wave-structure interaction. For that purpose, a series of experimental test have been done at the Andalusian Institute for Earth System Research (IISTA) wave flume, including the simulation of the actual sea state (scenario 0) and two scenarios of mean sea level rise according to the IPCC (2014). In the conference the damage results of each failure mode will be presented as well as their relationship and some technical recommendations for the design of breakwaters.