The plan form oscillations of the meandering rivers are analysed using the fractal and chaotic theory. Periodicity reflects a high degree of regularity and order. Frequently, one encounters irregular oscillations, like damped which are also called chaotic, aperiodic, or erratic. Irregularity does not imply that the oscillation is completely arbitrary. The frequency by some oscillations seems to vary only slightly. This discussion will present how chaos arises in water resources systems and characterize the structure in chaos. (c) 2006 Elsevier Inc. All rights reserved.