Characterization and analysis of the drainage network and forms of relief in three soils

Abstract

Through the use of aerial photographs and ground truthing, the significance of the attributes of relief (ratio of relief, maximum slope of the hillside, and ratio of slope) was studied. The study was based on a detailed soil survey. Three units of soil were chosen. They are composed of profiles with distinct morphology and properties. The soils are from sandy sediments of the group "Tubarão" and from clayey sediments of group "Estrada Nova", "Corumbataí" formation to characterize each soil unit. Two third-order watersheds, relatively homogeneous and geometrically similar, were chosen. They were analysed for their drainage patterns and attributes of relief. The characteristics of the watersheds, and of the drainage networks, as well as the ones of relief, vary with the nature of the soil. Within the quantitative characteristics of the drainage networks, the ones that better emphasized the differences between the three soils are: the frequency of the rivers, the ratio of the average texture, and tire density of the drainage determined in circular samples. The three indices of relief, represented by the ratio of relief, maximum slope of the hillside, and the ratio of slope, showed to be reliable, in order to distinguish soils.