Geotecnologias aplicadas à análise de suscetibilidade a inundações: estudo de caso na sub-bacia do alto curso do rio Uraim, Paragominas/PA

Abstract

The flooding processes are one of the main disasters in the Amazon Region, in which during intense and/or prolonged rainfall events, added to other conditioning factors, several hydrographic basins are affected by an increase in the water level that can cause damage to the population. The municipality of Paragominas (PA), as well as others in the Region, is among those that have repeatedly sought to act to minimize the effect of flooding. For these reasons, identifying and mapping areas susceptible to flooding is essential for decision makers. The Geographic Information Systems, used to enable this study, are currently excellent support tools, accurate and valuable for the definition of these susceptible areas at different spatial scales. The present work represents an innovative analysis of flood mapping through the "Gaussian" Hierarchical Process Analysis, disseminated from 2021, but without experiments in the area of environmental sciences and geotechnologies. This study also evaluates the impact of different conditioning factors on the mapping of susceptibility to floods and their importance in the construction of an accurate mapping of regions with flood potential. Eleven factors conditioning the susceptibility to floods are considered: land use and land cover, soil cover, hypsometry, slope, geomorphon units, rainfall distribution, HAND parameter, accumulated flow, Topographic Wetness Index, Stream Power Index and distance from the river. Established along the flood susceptibility map generated, it turns out that about 38% of the built-up areas of the municipality are under a condition of high to very high susceptibility. To attest to the resulting zoning, the reports and records of occurrences of the Civil Defense and Geological Survey of Brazil (CPRM) were consulted. The areas of greatest susceptibility to flooding are found on the banks of the Uraim River and Paragominas stream, aggravating in the vicinity of the confluence between these. The study allows the definition of corrective, preventive and urban planning measures.