THE APPLICATION OF THE ROSGEN METHOD TO STREAMS OF THE WESTERN OF THE STATE OF PARANÁ, BRAZIL

Abstract

The article presents data collected from 18 stream sections to determine the applicability of the Rosgen Stream Classification System to the basalt plateau of the Parana basin in the Western region of the State of Paraná, Brazil. This classification has four levels of detail: broad morphological characterization (level I), morphological description (level II), stream conditions of stability (level III) and verification (level IV). The classification at level I divides the channels into 9 main types (Aa+, A, B, C, E, F, G, D and DA). Classification at level II provides 94 subtypes, based on the following parameters: channel pattern, entrenchment ratio, width/depth ratio, sinuosity, slope flow and channel material types. In this work we applied the classification at level II because it represents a useful tool to inventory the morphological and sedimentological conditions of the waterways of a region. Among the 18 studied stretches, 12 were classified as subtypes E4, E5 and G5c. In the remaining six channels it was not possible to apply the Rosgen classification due to the lack of consistency of some morphological variables within the classification limits. Among the variables used for the classification, sinuosity and slope flow showed values below the classification limits in 50% and 11% of the analyzed stretches, respectively. The classification has shown its limitations in streams of basalt plateau in the application of sinuosity, which low rates are favored by tectonic lineaments in volcanic rocks.