Morphometric analyses of high paraiba river basin, semiárid region of paraiba state

Abstract

The Paraíba basin is important for the use and management of water resources in the State of Paraíba. Waters of the São Francisco River have been launched in the Paraíba basin since 2017. The objective of transposition is to perpetuate Paraíba River and ensuring water security for the reservoirs. Several morphometric index were applied to better understand the fluvial morphodynamics in the relief genesis of the Upper Paraíba River basin. Digital Elevation Model was obtained from SRTM, with spatial resolution of 30 m and the drainage network was obtained in the scale 1:100,000. The morphometric parameters used were: hierarchical order of the channel (U), number of channels (Nu), length of channels (Lu), length of the basin (Lb), bifurcation ratio (Rb), area (A), perimeter (P), drainage density (Dd), river density (Dr), drainage texture (T), elongation ratio (Re), circularity index (Ic), form factor (Ff), maximum altitude (Hmax), minimum altitude (Hmin), basin amplitude (Bh), roughness index (Ir) and concentration time (Tc). The results showed that the Upper Paraíba River basin is classified as 7th hierarchical order; the sub-basins of the Sucuru and Umbuzeiro Rivers are 6ª order, whereas the one of Monteiro River is classified as 5ª order. Drainage density and river density are low. All the basins are elongated, being the Monteiro River sub-basin the most elongated of all. The altimetric amplitude is high (> 800 m) and it yields high energetic potential for water flows. Drainage network is extensive and complex, 7th hierarchical order and with strong structural control. The highest relief levels are associated with granitoids in the municipality of São João do Tigre. As much for the river hierarchy as for the amplitude of the relief, the Umbuzeiro River is, from the point of view of morphometry, the most important of the basin.