Riparian vegetation, woody debris, and large boulders or cobbles in the channel, along the streambanks, and on the floodplain reduce the velocity of flowing water and dissipate its energy. As the water is slowed down, it loses some of its erosive force. This reduces the amount of sediment coming into the channel from the floodplain or the streambanks. For example, the willows on the left side of Figure 2-4 are much more effective at slowing water and reducing erosion than the bare ground on the right.