The evidence is when there is degradation. it is characteristic of channel networks in which either bedrock<span> erosion is taking place, or in systems that are </span>sediment<span>-starved and are therefore entraining more material than is being deposited. When a stream degrades, it leaves behind a </span>fluvial terrace<span>. This can be further classified as a </span>strath terrace<span>—a bedrock terrace that may have a thin mantle of </span>alluvium<span>—if the river is incising through bedrock.</span>
