Bedload Size

• Theory:

  Attrition is when the load being transported by the river collides with eachother. Abrasion occurs when the load collides with the channel. These erosion processes cause pieces of the load to chip off and become smaller.
• Upper course:

  Energy levels are low (0.2m/s) this means there are fewer collisions between the load and with the channel.

  The rock type is basalt. This igneous rock is harder to erode, especially in low-energy conditions.

  Bedload here has spent less time in the river.
• Lower course: Energy levels are high (1.2m/s). This means there are more frequent and ferocious collisions between the load and the with the channel.

  The rock type is sandstone. This sedimentary rock is easier to erode, especially in high energy conditions.

  Bedload here has spent more time in the river