Modelagem do relevo em bacias hidrográficas: uma abordagem de semidetalhe na Bacia do Rio Espinharas, PB, Brasil

Abstract

Semiarid landscapes studies, even with many Scientific’s researches, still have a lack of approaches, essentially those assigned to environmental and territorial management. Therefore, one kind of landscape's characterization and representation is through morphological approaches as part of the morphological compartmentation studies. In other words, a technique capable of creating homogeneous zoning areas to define criteria for use, fragility, and environmental potentialities. The principal goal of this research is to identify and characterize relief compartments at the Espinharas River Watershed (BHRE), at the Paraiba's semiarid, and look through their environmental fragilities and potentialities. As for the specific objectives, 1 - characterize the landscape elements through thematic maps, 2 - identifying relief compartments at the BHRE, taking as base the methodology proposed by Cavalcanti (2013), and Castro; Salomão (2000), 3 - Assay environmental potentialities at the BHRE based on relief compartments, previously defined, to territorial management purpose. To accomplish the research was considered geoprocessing techniques and images digital processing, based on Cavalcanti (2010) and Castro; Salomão (2000) guidelines, also secondary data from IBGE, CPRM, and fieldwork data. Thereby, it was possible to delimitate seven morphological units. The first one has recessed areas without explicit use - 1, Sunken areas of bland undulating relief for predominantly agricultural use - 2, Short Mountain ranges with a predominance of exposed rock and inselbergs - 3, High Mountain with an undulating relief and with agricultural use - 4, Summits with predominantly litotic soil - 5, summits with predominantly regolith soil - 6, and elevated areas with mountainous character - 7. In general, BHRE presents shallow soils and vegetation with hydric stress, limiting factors for land use purposes, principally, because of a lack of support at rural extension areas in this region. BHRE has an ascending hypsometry north to south, with inselbergs and rock blocks, in other words, areas properly indicated to preservation purposes. Regarding BHRE's vegetation, it is shown a physiognomy composed, approximately 65%, with a savannah-type. Units 1, 2, 4, and 6 presents wavy plane reliefs and bland reliefs, predisposed to agropastoral uses, presenting higher intensity of use. units 3, 5, and 7presents more wavy and mountainous reliefs, making it difficult to use and subject to protection and preservation areas.