Fixed-mass multifractal analysis of river networks and braided channels

A fixed-mass multifractal (FMA) analysis was used to investigate natural river networks and braided channels.In particular, while the study of natural river networks was performed with fixed-size algorithms (FSAs)in the past, the analysis of natural braided channels was not pursued before to our knowledge. Results showedthe multifractal and non-plane-filling nature of all the digitalized data sets. Analysis of the digitalization step(constant or not) was performed and showed that it does not exert a strong influence on the assessed values ofthe Lipschitz-Hölder exponents and the support dimensions, even if a constant step permits better reconstructionof the right sides of the spectra, for negative moment orders of probabilities. The FMA approach presentedtwo improvements with respect to the FSA one, in terms of oscillations of the scaling curves for negativemoment orders of probabilities and of error bars. A more precise assessment of the multifractal spectra is ofgreat importance in the development of multifractal models for the simulation of flood hydrographs.