Laser escaner terrestre aplicado ao monitoramento da geomorfologia da praia de ponta negra, natal/rn, nordeste do brasil

Abstract

As well as the entire coastal zone of the Rio Grande do Norte State (RN), the Ponta Negra beach, located in Natal city, suffers intensely with dynamic processes, which, together with anthropogenic actions, cause the degradation of the dune-beach system and infrastructures installed on the beachfront. This article, therefore, evaluates the recent applications of Terrestrial Laser Scanner (TLS) system, high accuracy and precision equipment that by means of a laser beam maps the surface morphology allowing the monitoring of temporal geomorphological changes in sectors of the Ponta Negra Beach. The studies were conducted using survey data carried out on the portion of Ponta Negra beach where the Morro do Careca is located on 08/21/2013 and 01/11/2014, through GIS techniques and preparation of Digital Terrain Models (DTM). The comparison between the DTMs, provided data on the erosion/deposition occurred in the sector in this short-term period. Furthermore, it allowed comparing these results with two surveys performed in 09/14/2012 and 11/28/2012, increasing the evaluation and quantification of local erosion/deposition. In this way, it was possible to evaluate the dynamics of the dune morphology, important factor to prevent the disappearance of this feature, to preserve the installed infrastructure in the vicinity and to maintain the socioeconomic activities in this sector of the beach. The results demonstrated the erosion installed in Morro do Careca in about 302 m³ and the deposition of these sediments along the beach face, indicating the dune as an extremely relevant source of sediments for Ponta Negra beach. It stands out as a possible solution, the beach artificial nourishment through the recomposition of a strip of sand from a loan area.