Which factors impact sediment transport in streams?

Sediment transport in streams is fundamentally influenced by several key physical factors, with sediment supply, discharge, and slope being among the most critical.

Sediment supply refers to the amount of sediment available for transport, which can come from various sources like eroding banks or upstream areas. A higher sediment supply can increase the overall sediment load in a stream, which directly affects the transport dynamics.

Discharge, or the volume of water flowing through the stream over time, plays a crucial role as well. A higher discharge typically increases the speed of the water flow, allowing the stream to transport more sediment, whereas lower discharge can result in sediment settling out of the water column.

Slope, or the gradient of the streambed, affects the velocity of water flow as well. Steeper slopes generally lead to faster flow rates, which can enhance sediment transport capacity. A gentler slope may result in lower flow velocities, which could limit the stream's ability to carry sediment.

While the other factors in the options — such as soil type and vegetation, biological activity, and water chemistry — do influence stream dynamics and can indirectly affect sediment transport, they are not as directly impactful on the mechanism of sediment movement as supply, discharge, and slope. This makes the correct choice the