Describe the four main types of river erosion? [4]

The four main types of river erosion are abrasion, attrition, hydraulic action and solution. Abrasion is the process of sediments wearing down the bedrock and the banks. Attrition is the collision between sediment particles that break into smaller and more rounded pebbles. Hydraulic action is the force of water against the banks compressing air pockets into cracks, which expand and fracture the rock over time. Solution is the process of acidic water dissolving soluble sediment.