Análise de riscos à perda de solo para cenários de uso e ocupação atual e potencial da bacia hidrográfica do Rio Abiaí-Papocas

• Autor(a) principal: Bezerra, Ivanhoé Soares
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFPB
• Texto Completo: https://repositorio.ufpb.br/jspui/handle/tede/5484
• topic: Engenharia urbana e ambiental; Bacia hidrográfica Abiaí Papocas; Produção hídrica; Água - qualidade; Perda de solo - risco; Watershed; Ecodynamic; GIS; Risk; ENGENHARIAS::ENGENHARIA CIVIL

The Abiaí-Papocas watershed is considered essential once the main springs for enhancing the supply of the Metropolitan Region of João Pessoa Paraíba are part of it. The determinant elements so that this basin may fulfill its role as hydric source are the maintenance of both the hydric production capacity and the quality of the waters, being the risk assessment of soil erosion a study that characterizes it physically and indicates unstable or stable areas. The Abiaí-Papocas watershed has an area of 462,36km² and it is placed between the 7°32 S and 7°18 S parallels and the 36 08 O and 34 48 O meridians, in the Zona da Mata interface between Paraíba and Pernambuco. The risk assessment of soil erosion is based on the concept of landscape unity that gathers a particular environmental setting with its physical characteristics, the events and interactions that take place in it. In its study, it is noteworthy to know the genesis, physical constitution, form and stage of plant evolution and coverage. The result of several interactions thus is represented in images. In regard to risk assessment of soil erosion for the Abiaí-Papocas watershed, scenarios were constructed to consider the current situation as well as a potential or planned one mapping the following issues: geology, geomorphology, pedology, climate and use and present and potential soil occupation to which values are associated. The arithmetic mean relates propensity of a risk scale to soil erosion that varies according to the morphodynamic category. In a GIS environment (Geographic Information Systems) for each aspect of the territorial basic units, the stability and instability rates were defined to which they were submitted. Afterwards, the map algebra among these issues for risk definition to soil erosion of the Abiaí- Papocas watershed was accomplished. For the spatial analysis that enabled an accurate definition of the territory portions where the adoption of a planned scenario would reduce the risk, the map algebra was used. Therefore, it defined an empirical equation that compares both scenarios and identifies in which spatial portions the lowest propensities to risk occur. The analysis of the aspects enabled to infer that in the Abiaí-Papocas watershed, for the current scenario, there is predominance of moderate levels of risk whereas for the potential the predominance of average levels occurs with balance between stability and instability. While comparing the current and potential scenarios, the first one, in a larger proportion, makes the setting more unstable therefore vulnerable to major soil erosions by means of erosive processes than the potential one. However, the maintenance of the current scenario in some areas would result in more stable levels of soil erosion.