River bedrock erosion can occur by abrasion and by the removal of entire blocks. We observe that when there is no or few fractures most erosion occurs by abrasion, whereas with more fractures, blocks can be removed at once leading to different patterns of erosion and riverbed morphology. Fractures affect barely mean erosion rate but change the location and occurrence of block removal. Our results highlight how river bedrock properties influence erosion processes and thus landscape evolution.