Breakwaters have been used since antiquity by coastal communities to protect against coastal erosion from tides, waves, currents, and storm surges. Extreme events and sea level rise due to climate change make these structures even more important. With an increased focus on climate change, engineers are looking for ways to minimize carbon emissions. The design of Icelandic-type berm breakwaters, or IceBB, allows for use of graded-stone from quarries, limiting the need for concrete materials. Natural rock has much lower embodied carbon than concrete, helping mitigate climate change.
Researchers Majid Eskafi, Sigurdur Sigurdarson, Bjorgvin Brynjarsson, and Kjartan Eliasson wanted to find the global warming potential for two types of breakwater projects – IceBB and concrete rubble mount breakwater, ConRMB. They applied a life cycle assessment method to assess the advantages of natural rock IceBB over ConRMB. In their paper “Icelandic-Type Berm Breakwater: A Nature-Based Structure with a Low Carbon Footprint,” the authors used the port of Thorlakshofn in Iceland as a case study and applied their methodology to calculate the construction carbon footprint of the structures. The results of this study in the Journal of Waterway, Port, Coastal, and Ocean Engineering indicate that IceBB structures could have a meaningful effect on climate change mitigation. Learn more about their findings at https://ascelibrary.org/doi/10.1061/JWPED5.WWENG-2010. The abstract is below.
With the ever-increasing emphasis on climate change and sustainability, there is growing interest in using environmentally friendly coastal structures. In addition to engineering and cost factors, the construction global warming potential (GWP) can and should be an influencing factor in the selection and design of the structures. Therefore, knowledge of construction GWP facilitates informed decision-making in coastal projects to achieve climate goals. Considering the number of Icelandic-type berm breakwater (IceBB) structures worldwide, this structure's design method is commonly accepted in coastal protection projects. In this paper, the construction process of an IceBB was assessed for its GWP and compared with concrete armor unit protection of a conventional rubble mound breakwater (ConRMB). The assessment and comparison were made for constructing a breakwater to protect the port of Thorlakshofn in southwest Iceland. The life cycle assessment (LCA) methodology was applied to calculate the construction carbon footprint of the structures using GaBi software, version 10.6.1. Using the International Union for Conservation of Nature (IUCN) criteria for nature-based solutions (NBS) and based on the existing literature, the characteristics of IceBB were briefly explored. The results showed that the construction of IceBB has a lower GWP than ConRMB, mainly due to using natural rock armor instead of concrete armor units. Furthermore, the results indicated that IceBB characteristics meet the IUCN criteria for NBS and thus can be granted as a (hard) NBS coastal structure. Acknowledging the advantages of IceBB, adopting this structure in coastal protection projects could meaningfully contribute to climate change mitigating policies.
See how these findings can be used in your breakwater design at the ASCE Library: https://ascelibrary.org/doi/10.1061/JWPED5.WWENG-2010.