EROSION SUSCEPTIBILITY MAP OF THE MUNICIPALITY OF JUAZEIRO DO NORTE / CE
Geotechnical cartography; erodibility; map algebra.
Dissertation Summary:
Large Brazilian urban centers have presented several socio-environmental problems. If, on the one hand, the Federal Constitution and the City Statute are legislative instruments that guide the preparation of PDDUs, on the other hand, municipalities have problems aggravated by the disorderly population increase in urban areas, as has occurred in Juazeiro do Norte, located in southern Ceará, northeastern Brazil. Among the problems registered in cities, those related to natural disasters stand out, such as erosive processes, landslides and floods, which led to the emergence of Law 12,608/2012, which instituted the National Policy for Civil Defense and Protection ( PNPDEC), showing the need to prepare geotechnical maps in order to guide the occupation of urban land, to prevent the emergence of new risk areas and prevent disasters. Given this context, the objective of this work is to present the results of a mapping of areas susceptible to erosion processes in Juazeiro do Norte/CE, and thus contribute to municipal managers in the best way to occupy the land, especially in areas with potential urban expansion . This work was developed through Geographic Information Systems (GIS), using thematic maps of: land use and occupation, relief, geology, pedology and rainfall erosivity; with the superposition of these maps through the Hierarchical Process Analysis (AHP), by applying the heuristic method. Through the data analyzed, there was a significant increase in the area of Urban Infrastructure in recent years, whose susceptibility to erosion falls within the very high class, which corresponded to 4% of the municipality's area in 2000, tripling in 2019 (reaching 13% ) and continuing to grow in 2021 (reaching 16%). Some areas of low susceptibility to erosion have scars from this process, clearly accentuated by the absence or insufficiency of drainage networks. The final erosion susceptibility map of Juazeiro do Norte showed 22% of the area classified as high susceptibility, 37% as medium and 41% as low susceptibility. The areas with the best conditions of occupation in terms of susceptibility to erosion are located towards the Missão Velha and on the northern portion of the Salgadinho River, suggesting areas that can be considered as future urban expansion in the municipality. However, it is necessary to implement drainage and soil protection works, for example, so that erosion processes do not occur in an accelerated manner.