..• Journal of Hydrology ELSEVIER Journal of Hydrology 187 (1996) i37-144 On the fractal description of natural channel networks M. Veltri*, P. Veltri, M. Maiolo Dipartimento di Difesa del Suolo "Vincenzo Marone", Universit~ della Calabria, C. da S. Antoneilo, 87040 Montalto Uffugo (CS), Italy Received 19 January 1994; accepted 19 October 1995 Abstract Fractal suggestions find interesting applications in the matter of stream networks hydraulics. Remarkable results have been obtained about the value of fractal dimensions both of a whole network and of a single channel. In this paper 17 fiver networks in Southern Italy are investigated in terms of their fractal nature and fractal dimension. The results confirm the fractal structure of both fiver networks and of stream channels. Geological constraints and features deriving from the maturity of the basins seem to reduce the capability of stream reaches to develop a purely branching process. Consequently the fractal dimension of stream networks turns out to be appreciably different from the one predicted by the topological randomness model. Thus the values we found for the fractal dimensions are less than 2 for the networks and not equal to I for fiver reaches. 1. Introduction Morphometric features of fiver catchments are an important subject of investigation in fiver dynamics as well as in hydrology at the basin scale. Fractal geometry introduced by Mandelbrot (Mandelbrot, 1977, 1983) appears to be an effective tool for an adequate understanding of drainage basin processes. Before Mandelbrot, different approaches had been followed in order to carry out parametrical studies of river catchments. Such approaches can be divided into three different classes: the first one is related to the map scales investigations; another one deals with basin and fiver network empirical relation- ships; the third approach corresponds to quantitative geomorphology. With regard to the first approach, Giusti and Schneider (1962) found a change of single reaches, per unit area, greater than one order of magnitude when different map scales are used. McDermott and Pilgrim (1982) obtained fiver length changes with respect to the logarithm of map scales. * Correspondingauthor. 0022-1694/96/$15.00 © 1996 - Elsevier Science B.V. All rights reserved PII S0022-1694(96)03091-0