Various factors affect erosion, transportation and deposition work of a river. Important factors include the following : 

1. Velocity of water : Erosion and transportation are both maximum when velocity is high. Deposition, on the other hand takes place when velocity of water is low. 

2. Volume of water : The larger the volume of water, the greater is the power of erosion and transportation. Deposition, on the other hand, takes place better when there is reduced volume of water as well as when the load is greater. 

3. Load : Load is the material transported by a river. The load of a river, does all the work of erosion and deposition. Mass wasting, deepening of river valleys and formation of landforms depend on the load a river carries.