Knickpoints na bacia hidrográfica do Rio Chapecó: distribuição e condicionantes na paisagem

Abstract

This dissertation aimed to characterize and analyze the knickpoints in the Chapecó River Basin (CRB) using morphometric, cartographic, and field observation methods. A total of 56 channels were analyzed, applying the Hack Index to identify slope/length variations and potential instability zones along the longitudinal profiles. The methodology combined statistical analysis, geomorphological and geological cartography, and field validation, allowing for the correlation of knickpoints with lithology, geomorphological compartmentalization, scarps, faults, and altimetric gradients. The results indicate a higher concentration of knickpoints in the middle basin, suggesting greater erosive activity and potential influence of neotectonic processes, while the upper basin exhibits lower knickpoint density. Field observations revealed wide morphological diversity, ranging from centimeter-scale steps to rapids, waterfalls with considerable height differences, and morphologies associated with fallen blocks and fractures. It is concluded that knickpoints play a central role in fluvial dynamics, acting as indicators of lithological resistance, contacts between geological units, and energy dissipation zones, providing important insights into the geomorphological and sedimentary evolution of the CRB.