Author(s): Josep R. Medina; Esther Gomez-Martin; Jorge Molines; Patricia Mares-Nasarre; Mireille Escudero; Itxaso Oderiz; Edgar Mendoza; Rodolfo Silva

Linked Author(s): Rodolfo Silva

Keywords: Coral reefs; Green infrastructure; Low-crested structures; Armor units; Wave transmission

Abstract: Ocean temperature rise and ocean acidification due to climate change, as well as other impacts resulting from human activities, seriously threaten the coral reefs of the world. The retreat of coral reefs in recent decades, and their progressive degradation, is a clear indicator of the poor health of coastal ecosystems, which also affects the stability of the beaches protected by these coral reefs (Silva et al., 2016). Besides the importance of coral reefs for the resilience of coastal ecosystems, they produce on average 1,000 m3/km2 of biogenetic sediment per year, which is important in maintaining the long-term stability of sandy beaches in the Tropics. Sea-sand-sun tourism is critical for the economic development and social stability of many coastal communities worldwide. Tourism in coastal areas is often directly related to the quality of their natural resources; primarily their beaches. The HOLOBREAK Project is focused on developing and using Homogeneous Low-Crested Structures (HLCS), a new type of coastal structure composed of large rocks or pre-cast concrete units, similar to low-crested structures (LCS) without a core. These structures mimic the protection provided by coral reefs to adjacent beaches and, at the same time, provide a porous substrate which allows colonization of the structure by local species. Contrary to LCS with core, the height and crest freeboard of a HLCS can only be adjusted changing the unit size, the number of layers or the placement grid. The placement grid of the HLCS is relevant in the economic, logistic and functional perspectives; it affects the feasibility of construction, the costs involved and its effectiveness as beach protection. Different placement grids have been analyzed using the results of physical and numerical placement tests (Molines et al., 2021). The hydraulic stability and performance of different Cubipod HLCS have been analyzed in 2D small-scale physical tests (Medina et al., 2019). REFERENCES Medina, J.R., Gómez-Martín, M.E., Mares-Nasarre, P., Odériz, I., Mendoza, E., Silva, R., 2019. Hydraulic performance of homogeneous low-crested structures, Proc. of the Coastal Structures Conference 2019, Bundesanstalt für Wasserbau (BAW), Karlsruhe (GE), 60-68. Molines, J., Centi, R., Di Risio, M., Medina, J.R. (2021). Estimation of layer coefficients of Cubipod homogeneous low-crested structures using physical and numerical model placement tests. Coastal Engineering, 168 (2021) 103901. Silva, R., Mendoza, E., Mariño-Tapia, I., Martínez, M.L., Escalante, E., 2016. An artificial reef improves coastal protection and provides a base for coral recovery. Journal of Coastal Research, 75, 467-471.

DOI: https://doi.org/10.3850/IAHR-39WC252171192022755

Year: 2022