INUNDAÇÕES NA REGIÃO DOS LENÇÓIS MARANHENSES: Ocorrência e impacto no bairro Alto Formoso, Santo Amaro do Maranhão

Abstract

The study of disasters has been increasingly highlighted in the scientific community due to the increased visibility of these events in contemporary society, with a view to preventive management. Among the events that most impact society, flooding is a natural phenomenon that causes damage when there is occupation in the intensely affected areas. In the state of Maranhão, the flood records point to an exceptionality of events with high magnitude, as occurred in 1985, when a situation of emergency was declared in almost 100% of the municipalities, and in 2009, with 63% of the municipalities, when damages were also registered in the region of Lençóis Maranhenses. Among the most affected municipalities, Santo Amaro do Maranhão has a history of flood damage records, in the Alto Formoso district, one of the most susceptible and high-risk locations for this category of disaster, enhancing the water transmission of pathogenic vectors by contamination of groundwater, due to the precariousness of basic sanitation and public supply. Given the history of damage caused by disasters, the aim of this research is to discuss the occurrence, conditioning factors, as well as the impacts of flooding in the Alto Formoso neighborhood. The methodological procedures for the development of this study include a bibliographic and documental survey about flood damage, information obtained from residents and the use of geoprocessing techniques, such as the generation of a Digital Elevation Model - DER, to assist in the delimitation of the flood area. From the data collected, 12 points with flood records were listed, corresponding to the quota of 4.5 meters, used to delimit the flood area. Considering the data analyzed, it can be inferred that during the great flood of 2009, the water level of the Santo Amaro Lake rose approximately 4 meters above the usual level of the flood period. It was found that the flood points in the Alto Formoso neighborhood correspond to the areas with lower altimetric quotas and lower slope where the houses are more prone to damage in years of exceptional rainfall.