Question

the critical unit stream power changes with the sediment grain size. if the grain size in a river is larger, than must be larger so that the river can transport the larger sediment. explain in 1-3 sentences how will vary with grain size if all other variables are not changing.

Answer 1

The critical stream power needed for a river to transport sediment increases as sediment grain size increases, requiring the river to have higher velocity or depth if all other variables remain unchanged.

Step-by-step explanation:

The critical unit stream power that a river needs to transport sediment increases with the size of the sediment grains. If the grain size in a river is larger, a greater stream power is required so that the river can transport the larger sediment. This is because larger grains have more mass and are therefore more resistant to movement; they require more energy from the water flow to be lifted and carried downstream. For instance, gravel and pebbles require more energy to be transported than finer sand or silt. If all other variables are constant, such as water volume and channel slope, the river must exhibit a higher velocity or depth to achieve this greater power.