Power-law distributions of mass and energy in river basins.

River networks constitute dissipative systems with many spatial degrees of freedom. Previous work by Mandelbrot (1983) and Bak et al. (1987, 1988, 1990) suggests that such systems will follow power law distributions in their mass and energy characteristics. It is shown that this is the case for river networks where the exponent β in the distribution, P[X \u3e x] ∝ x−β, is approximately equal to 0.45 and 0.90 for discharge and energy respectively in the case of several networks analyzed in North America when these variables are calculated for each individual link throughout the drainage network. An explanation of the values of β is offered based on the fractal structure of rivers and on principles of energy expenditure in river basins