Avaliação morfométrica aplicada à identificação de áreas suscetíveis a inundação e à erosão hídrica na bacia hidrográfica do rio Real (SE)

Abstract

The National Water Resources Policy (Law No. 9,433/1997) establishes the watershed as the fundamental unit for water resources planning and management in Brazil. In this context, the study of the physical, hydrological, and geomorphological characteristics of these units becomes essential to support efficient and sustainable management actions. Therefore, the present study aims to evaluate the morphometric indices of the Sergipe portion of the Real River Watershed through the use of geotechnologies, seeking to interpret its hydrological behavior and susceptibility to flooding and erosive processes. The indices related to basin geometry, such as form factor (0.13), compactness coefficient (2.63), circularity index (0.14), and elongation ratio (0.40), indicate an elongated shape that favors the distribution of runoff over time. This behavior is reinforced by the high concentration time (78.8 h), characterizing a slow hydrological response. On the other hand, the relief parameters reveal conditions favorable to soil erosion processes. The high altimetric amplitude (604.39 m), associated with the ruggedness index (116.65) and relief ratio (4.44), indicates rugged terrain. Drainage density (1.77 km/km²) and hydrographic density (1.107 streams/km²) demonstrate a well-developed drainage network, contributing to efficient water runoff, but also to sediment transport. Additionally, the low slope of the main channel (0.00221 m/m) may favor sediment deposition along the watercourse. Therefore, the watershed presents low susceptibility to flooding; however, it exhibits favorable conditions for the occurrence of water-induced erosive processes, especially in areas with steeper slopes.