Estilos fluviais do alto curso do Rio Piranhas, ambiente semiárido (PB)

Abstract

The Brazilian semi-arid is an environment that has water deficit in most of the year, due to the few rainfall, when compared to the humid environment. Precipitation events occur in an intense and concentrated way, in short periods of time, where this dynamics prevents the permanence of most of these water resources on the surface. Thus, it is necessary to generate measures that can store some of these resources, allowing the use of them by the population that lives in the dry perimeter. However, the interventions generated do not always occur in a planned way, which often refers to environmental degradation.From this perspective, the studies of semi-arid river environments, besides providing a theoretical framework on this subject, provide the basis for generating measures that do not cause degradation.Currently, the Projeto de Integração do São Francisco (PISF) is aimed at the population that suffers from drought, where water from the São Francisco basin has already been integrated into the municipalities of the Eixo Leste and the Northern Axis is at the end of his work, to function in the same perspective.However, the impact that this type of work can bring to the fluvial environment is still little known, which makes necessary the studies about the normal functioning of the semi-arid rivers courses, so that they can serve as parameters for future research.Given the above, this research had the objective of identifying and characterizing the riverine styles of the Upper Piranhas River Course, through the methodological approach of Brierley and Fryirs (2005), in order to understand the fluvial behavior of the main channel, from the dissection of the basin to the geomorphic units.The identification of the stability of the main channel margins was also one of the focuses of this research, since it was possible to understand the degree of degradation / preservation of the margins according to the fluvial style identified. In this way, the river styles identified in the basin were: PCSSH - Partially Confined Sandstone Style of Headboard; PCRSB - Partially Confined Style of Rocky and Sandy Bed; CRBS - Confined Rocky Bed Style; CSSSB - Confined Style of Sandblasted and Sandy Bed; USSB - Unconfined Style of Sandy Bed; USRGB - Unconfined Style of Rocky and Gravel Bed; PCSCAB - Partially Conformed Style of Castile and Argilous Bed. For each style identified, the stability of its margins was defined, thus, generating the possibility of inference about the degree of degradation of the respective river styles.