EXPERIMENTAL-EVIDENCE OF DYNAMIC SCALING AND INDICATIONS OF SELF-ORGANIZED CRITICALITY IN BRAIDED RIVERS

The evolution of an experimental braided river produced in our laborat ory has been monitored and analyzed. It has been shown that in additio n to the spatial scaling revealed by Sapozhnikov and Foufoula-Georgiou [1996a], braided rivers also exhibit dynamic scaling. This implies th at a smaller part of a braided river evolves identically (in the stati stical sense) to a larger one provided the time is renormalized by a f actor depending only on the ratio of the spatial scales of those parts . The small value of the estimated dynamic exponent z is interpreted a s an indication that the evolution of small channels in a braided rive r system is to a large extent forced by the evolution of bigger channe ls. The presence of dynamic scaling is further interpreted as indicati ng that braided rivers may be in a critical state and behave as self-o rganized critical systems.