Coastal erosion and accretion on the Caribbean coastline of Costa Rica long-term observations

Abstract

Several studies show erosive processes on the Caribbean coastline of Costa Rica. These processes may be accelerated as a result of an increase in the sea level. This study covered the entire Caribbean coastline of Costa Rica between 1986 and 2019. This allowed reporting new sites with accelerated coastal accretion and erosion processes, as well as confirming other processes that have already been identified. The methodology was based on shoreline rising images obtained from Landsat and on their processing in a Geographical Information System supported with the “Digital Shoreline Analysis System” (DSAS) tool. The presence of important accretion areas related to the mouth of significant fluvial systems, such as Colorado, Parismina, Matina, Estrella, and Sixaola rivers is highlighted. Moreover, eight beach sectors showing erosion problems have been analyzed. The beach located to the south of Isla Portillos and beaches located on Cahuita Point stand out due to their intensity. Additionally, an intense beach erosion process has been detected at Soropta in Panamá. It should be highlighted that six of the eight sites showing erosion are located within protected zones. This confirms the little anthropic interference on these processes. It was not possible to find a difference between the north and the south of the Caribbean Coast in terms of the magnitude of coastal erosion. The contribution of the rivers is a key factor in the North Caribbean while the responses to the 1991 earthquake conditioned the behavior on the South coast. The results may serve as a basis for management plans or adaptation to climate change proposals.