<P> Stream load is a geologic term referring to the solid matter carried by a stream (Strahler and Strahler, 2006). Erosion and bed shear stress continually remove mineral material from the bed and banks of the stream channel, adding this material to the regular flow of water . The amount of solid load that a stream can carry, or stream capacity, is measured in metric tons per day, passing a given location . Stream capacity is dependent upon the stream's velocity, the amount of water flow, and the gradation (because streams that occur on steeper slopes tend to have greater flow and velocity) (Strahler and Strahler, 2006). </P> <P> There are two main sources of stream erosion: hydraulic action and abrasion . All of the materials added to normal stream flow through these processes increase the overall stream load (Strahler and Strahler, 2006). </P> <P> Hydraulic action describes the erosion caused by the dragging of water over the stream bed and bank . This dragging, coupled with the impact of small parties, easily loosens and erodes smaller alluvial matter, such as gravel, sand, silt and clay (Mangelsdorf, 1990). One powerful example of hydraulic action is bank caving, which normally occurs when a stream loosens sediment and undercuts a bank . Consequently, large masses of sediment slump and collapse into the stream, adding significantly to the stream's load (Strahler and Strahler, 2006). The severity of hydraulic action increases with stream velocity and current stream load . </P>

Which of the following is not a component of the stream load