Why Do Streams Meander?
Ninety percent of the world’s low-gradient rivers are single-channel, meandering streams (Leopold, 1994). A stream’s pattern develops naturally to dissipate its energy and carry sediment. Streams with steep gradients (source and transport streams) dissipate their energy by creating pools through a series of steps, falls, and plunges (figure 7). Such streams look almost straight on a map. This “step pool” pattern can be thought of as meanders turned on their side. As the stream’s slope (gradient) flattens, the depositional segments of a stream dissipate energy by creating a meandering flow pattern. Meanders cause the river to dissipate energy along the winding path as the water is forced around the bends (figure 8). Meanders in a river are analogous to switchbacks in a mountain road. They reduce the river’s slope and therefore the velocity of the water. Energy is also used up through friction of the water against the bed and banks of the stream. A regular meander pattern can often be se
