Explain what Corrosion is (River)
Corasion is the wearing away of the riverbed and banks by the river load.
Explain what Attrition is (River)
Attrition is the wearing down of the load as the rocks hit the river bed and breaks each other into smaller and smaller bits.
Explain what Solution is (River)
Solution is when the water in the river dissolves the rocks.
Explain what Traction is
Traction is where stones are rolled or dragged along the river bed by the force of water.
Explain what Saltation is
Saltation is where small stones bounce off each other and are carried by the water.
Explain what Suspension is
Suspension is where small particles are lifted in the water and carried long distances.
Explain what Solution is (transportation)
Solution is where the river dissolves minerals from the rocks that are carried in the water.
Explain the Formation of a V-Shaped Valley (Long) (1)
- A river flows downhill quickly and eroded the landscape vertically.
- The river cuts a deep gash into the landscape using hydraulic action and corasion.
Explain the Formation of a Waterfall
- The river flows over bands of hard rock and soft rock. Soft rock is less resistant, it is quickly eroded.
- The river undercuts the harder rock, leaving an overhang of hard rock.
- The river eroded the softer rock below by the waterfall, forms a plunge pool.
Explain the Formation of a Meander (1)
- In the middle stages of a river, gradient is less steep. Width of the river begins to increase and meanders begins to form through the processes of corasion and hydraulic action.
- The bend begins to form as the river finds the course of least resistance.
- Pools form in the slower and deep parts of river, where rittles form in the faster, shallower parts of river.
Explain the Formation of a Meander (2)
- The rate of flow is much slower on the inside bend and this is where the river deposits material.
- On the outside bend, the river is at its fastest and the river erodes the bank.
- Helix peak flow moves materials across the river channel. This leads to river cliffs and beaches developing.
Explain the Formation of an Ox-Bow Lake
- As the size of the meander increases, eventually river may cut a new channel between the narrowest point of bend.
- The feature left behind from the cutoff is an ox-bow lake.
Explain the Formation of a Levee (1)
- The river flows on a flat floodplain in the lower course.
- The water is flowing slowly and deposits silt on the riverbed.
- When the river floods, a lot of silt is deposited on the riverbanks.
Explain what Hydraulic Action is (River)
Hydraulic Action is the breaking away of the riverbed and banks by the force of water getting into small cracks and forcing bits of rock to fall off.
Explain the Formation of a V-Shaped Valley (Long) (2)
- As the river erodes downwards, sides of the valley are exposed to freeze-thaw.
- This process loosens the rocks and fall into the river - helps to produce steep valley sides.
- The rocks which have fallen into the river assist in the process of corasion which leads to further erosion.
Explain the Formation of a Levee (2)
- Regular flooding continues this build up of silt at the sides of the river
- The build up levees (natural embankments) usually protect the land from further flooding.
