Obtenção de variáveis morfométricas da Sub-bacia do Açude Esguicho, PB / RN, com emprego de geotecnologias.

Abstract

The human occupation of the semiarid region of Brazil occurred in an intense and disorderly way, causing negative impacts on its natural resources. This exploration model, combined with the climate, soil and vegetation characteristics of the region favored the process of environmental degradation over time. In order to plan the use of these resources, the hydrographic basin presents an integrative character of the human and natural activities, and is considered a basic unit for the management of land use. In this sense, it is necessary to know its physical characteristics, which directly influence its hydrological functioning. This procedure involves several determinations for morphometric analysis, starting with the delimitation of the hydrographic basin, whose operations can be carried out with the support of Geographic Information Systems - GIS, operating on altimetric data such as those provided by the SRTM mission. In view of this, the present work was developed with the objective of performing the morphometric characterization of the hydrographic basin of the Esguicho dam using the SIG QGIS e GRASS tools. The results obtained show that the catchment area of the basin is 517.4 km², with an elongated shape, inferred by the coefficients Kc (2,45), F (0,25) and IC (0,16). The composition of the drainage system results in a 4th order hydrographic basin, with a higher number of first order river segments concentrated in the southern part of the basin. In general, there is a predominance of gently undulated to undulated reliefs (69%), followed by flat reliefs (15,3%), strongly undulated (13,2%), mountainous (2,2%) and strongly mountainous (0,3%). The largest area of the basin is exposed to the north face (31%) and its altimetric range is 673 m. The main conclusions show that the SRTM data were satisfactory in the definition of the drainage network and that the tools of the QGIS and GRASS software were efficient to perform the basic operations to obtain the variables studied.