What are the different processes of erosion that take place in a river?

There are four main different processes of erosion in a river: abrasion, attrition, hydraulic action and solution.Abrasion is when large particles (stones and rocks) being transported in the river's load are thrown against the bed and banks causing them to erode. Attrition is the erosion of the load itself by different particles hitting against one another and wearing one another away. Hydraulic action is the force of the river water compressing the air within the cracks in the rock of the bed and banks and causing the rock to break up. Solution is the dissolution of chemical compounds within the rock of the bed and banks by the river water.