Which type of sediment load travels along the bottom of the stream?

The bed load is the type of sediment load that travels along the bottom of a stream. This sediment consists of larger particles such as gravel and sand that are too heavy to be carried by the water column. Instead, these particles are moved by rolling, sliding, or hopping along the streambed due to the force of the flowing water. This mode of transport is characteristic of bed load, which can affect the stream's morphology over time by causing erosion and sediment deposition at various points along the stream's path.

In contrast, suspended load refers to finer particles that are held in suspension within the water column, dissolved load consists of minerals and nutrients that are dissolved in the water, and surface load generally pertains to material that may gather on the surface rather than settling to the bottom or moving with the water flow. Understanding these distinctions emphasizes the unique characteristics and behaviors of sediment transport within a stream ecosystem.