Processo erosivo e defesas costeiras das praias de Ponta Negra e Via Costeira, Natal/RN: uma análise estrutural e ambiental

Abstract

Coastal agents such as waves, nearshore currents, winds and tides are capable of transporting sediments from one place to another, to generate a positive or negative sediment balance in coastal areas. Ponta Negra beach and part of Via Costeira in Natal/RN suffer erosion and their sediment supply is compromised due to disorderly urbanization from the 1990s onwards. Several problems were installed on the beach caused by the energy of the waves, which no longer had space to dissipate, since urbanization advanced on the beaches and solidified an environment that was still part of a dynamic process. As it is one of the biggest tourist places in the city of Natal, the region attracted the government's attention to the elaboration of a beach recovery plan with the implementation of new coastal defense works: sediments replacement, containment structure and adequacy of the rainwater drainage system that flows into the beach face. This work analyzes the coastal erosion status and evaluates the coastal defense works implemented and in planning at Ponta Negra beach and Via Costeira. Making use of satellite images, LANDSAT and Sentinel-2, and geoprocessing tools such as CASSIE and QGIS, it was possible to perform the automatic extraction of shorelines and verify the sedimentary balance in area in the long (last 30 years) and medium term (last 06 years) area. The study also analyzes the pathologies of the coastal protection works installed since 2012 and the weaknesses that they will cause to the process of fattening the beach. With geoprocessing, it is noted that Ponta Negra Beach faces continuous erosion, as well as the southern portion of Via Costeira Beach. About beach recovery projects, there is a lack of integration and harmony between them, which favors the emergence of flaws in the definition of relevant points for the proper functioning of the recovery work.