Analysis of channel morphology of Sao Francisco River using remote sensing data.

The objective of this paper is to describe qualitatively channel morphology from the reflectance pattern of high sediment concentrations. The spectral behaviour of the aquatic environment is not only a function of water depth, but also the concentration and spatial distribution of suspended sediments, inorganic and organic, among others. We used Landsat 7/ETM+ (Enhanced Thematic Mapper Plus) images for mapping river channel morphology in Sao Francisco river in Brazil. The methodology was based on: (a) the elaboration of the digital elevation model (DEM) of bathymetric data, (b) the development of an algorithm based on bands ratio index of Landsat7/ETM+ digital image, and (c) the comparison between bathymetry and developed index. Our approach was to develop an index for the emission feature in red band (ETM+ 3 band) considering its height. A difference behaviour in relation to the index and the depth for both symmetric and asymmetric channels was observed. Thus, the river morphology was established, in an indirect way, by considering the spatial distribution of the sedimentary plumes. [ABSTRACT FROM AUTHOR]