Coastal erosion risk assessment in paraná urbanized beaches

Abstract

On the Paraná coast, the municipalities of Matinhos and Pontal do Paraná represent more than 50% of the coast and they are potential areas for tourist and industrial activities. The region faces several problems related to the intensification of erosion, mainly since the 1980s, which caused damages and losses in environmental and socioeconomic terms. In this scenario, this research aims to determine the coastal erosion risk on the Paraná coastline based on the analysis of spatio-temporal indicators (shoreline position, backshore width, density of natural washouts, rain water galleries, sediment transport trends). Collected data were integrated with map algebra techniques attributing values to each of the analyzed variables, according to their negative or positive relationship with the coastal erosion risk. The results show that approximately 70% of the municipality of Matinhos has a high risk of erosion, while Pontal do Paraná has one high risk area. Critically eroded areas along Matinhos coastline refer to places where coastal defense structures were carried away and where backshore width is less extensive or non-existent (Riviera, Flamingo and Praia Brava). With regard to backshore width, temporal analysis of shoreline variation and density of natural and anthropic washouts (rain water galleries) are the most effective indicators in risk assessment. In the other hand, the sediment transport trends has some limitation as an indicator, since its monitoring campaigns take place during different season conditions, therefore it is not possible to evaluate a sediment transport pattern along these beaches. The methodology presented in this research contributes to guidelines that provide advice and may be used for decision-making in the coastal region of Paraná. It is worth mentioning that the methodology must be improved, such as incorporating data sets from a larger temporal scale, contributing to the advancement of scientifical research in the coastal zone.