Análise do uso de lonas plásticas nas encostas da grota da Santa Helena, Maceió-Alagoas

Abstract

Accelerated urbanization and unplanned growth in hillside areas have contributed to increasing geotechnical risks in Brazilian cities. In Maceió (AL), the grotas are natural depressions irregularly occupied and characterized by socio-environmental vulnerability, especially the Santa Helena Grota. This study aimed to analyze the effectiveness of using plastic tarps as a temporary slope-stabilization measure in this area, combined with remote sensing using a Remotely Piloted Aircraft (RPA) and field analysis. Critical instability points were identified, and the performance of the plastic tarps in reducing erosive processes and landslides was evaluated. The results indicated that the installation of the tarps helped reduce surface infiltration and delayed the development of erosional rills, proving to be a low-cost and rapidly implemented alternative. Imagery obtained with an RPA enabled detailed mapping of risk areas and the delineation of zones susceptible to mass movements, while data from the Maceió Civil Defense reinforced the importance of continuous monitoring. It is concluded that the integration of field surveys, remote sensing technologies, and Civil Defense actions constitutes an efficient strategy for geotechnical risk management, allowing rapid and technically grounded responses during the rainy season. Although temporary, the use of plastic tarps proved effective in the immediate mitigation of risks and in protecting the vulnerable communities of the Santa Helena Grota.