Environmental Fragility: a Proposal of Applying Geomorphs to a Relief Variable

Abstract

Considering the importance of the relief variable as a determinant for the identification of landscape units and for the analysis of dynamics and processes related to soil erosion and the occurrence of floods, the present article proposes the incorporation of morphological data from the automated classification of the elements (Geomorphons), in the analysis of the Environmental Fragility. We developed maps of Potential Fragility and Emergent Fragility using three models: A) With morphological parameters (elements of relief forms) extracted from an analogously elaborated geomorphological map and morphometric parameters (slopes), as recommended by Ross (1990, 1994); B) Only the slope as a morphometric parameter; and, C) With morphological parameters (elements of relief forms) automatically extracted from MDE (geomorphons) and morphometric parameters (slopes). To evaluate each model, the coefficient of linear determination (r²) was applied between the determined levels of environmental fragility and the occurrence of linear erosive processes identified by IPT (2012). The comparison of the three models showed that the insertion of morphological parameters allows to determine and delimit of the fragility levels in a more precise and detailed way than when only morphometric parameters such as slope are used. Moreover, the possibility of identifying areas of fluvial plains in the models that include morphological parameters avoids the classification of such areas as being unrestricted areas from the physical environment to the occupation.