Rivers: Processes That Affect Rivers Flashcards
What is erosion
The wearing away or removal of rocks by the actions of water, wind or ice
What is bedload
Larger particles moving along a river bed
What is freeze- thaw
The continued freezing and thawing of moisture in rocks that will eventually cause them to break
What is weathering
Breaking up the rocks by the action of weather, plants, animals and chemical processes
Why are the rates of erosion greater after heavy rainfall
Because there is more water flowing, smashing the rocks and wearing them away.
What happens in hydraulic action
Waves smash river banks causing it to crack and wear away. Water then washes broken rock down the river
What is abrasion
Rock carried by the river, smashing into the river bed and banks, wearing them away
What factors contribute to a high risk of flooding
Frozen ground, heavy rain, permeable rock, lots of surface run off, buildings and roads
What factors contribute to a low risk of flooding
Forests, light rain, dam on river, little surface run-off, water sinks into soil, countryside
