Gcse Geography - Rivers

Front 1

Where is the source and where is the mouth of a river?

Back 1

A rivers source is where it starts, and it's mouth is where it ends and is either a lake or the sea.

Front 2

What are these key features:
1) A Tributary
2) A Confluence
3) The Watershed
4) A Drainage Basin
5) Discharge

Back 2

1) Where a smaller river that flows into a larger river.
2) Where two rivers meet.
3) The imaginary line surrounding a drainage basin.
4) The area served/drained by a river and it's tributaries.
5) The amount of water flowing into the drainage basin.

Front 3

How do rivers transport material and what is the difference between these methods of transportation?

Back 3

There are four different methods:
1) Solution:- material dissolved in the water.
2) Suspension:- Fine light material that is carried along the river.
3) Saltation:- Small pebbles are bounced along the river bed.
4) Traction:- Large boulders and rocks are rolled along the river bed.

Front 4

When does the river carry more material?

Back 4

Energy levels are usually higher at the rivers source where the course is steep and narrow, energy levels drop as the river reaches the mouth. When the river loses energy it will deposit it's material.

Front 5

What are the four different methods of river erosion and the differences between them?

Back 5

1) Hydraulic Action:- The force of the river causes air to be trapped in cracks. This pressure gradually weakens the river bed.
2) Abrasion:- Rocks carried along the river wear down the banks and bed.
3) Attrition:- Rocks being carried by the river smash into one another breaking into smaller smoother particles.
4) Solution:- Soluble particles are dissolved into the river.

Front 6

Upper course, middle course and lower course river features.

Back 6

U.C features: Steep V-Shaped valleys, interlocking spurs, rapids,waterfalls and gorges.
M.C features: Wider shallower valleys, meanders and ox-bow lakes.
L.C features: Wide flat bottomed valleys, flood-plains, levees and deltas.

Front 7

How are upper course features created?

Back 7

Vertical erosion happens as the river winds and bends to avoid areas of hard rock which creates interlocking spurs, when a river erodes over areas of hard and soft rock rapids and waterfalls may form.

Front 8

How are ox-bow lakes formed?

Back 8

The meanders become larger and the horseshoe shape gets tighter, when the river breaks through in flood or when it has more energy or discharge the ends join, when the energy decreases an ox bow lake is formed.

Front 9

How are meanders created?

Back 9

Lateral erosion widens the river channel, it erodes from left to right which forms the horse shoe meander shape, this is encouraged by the inside of the bend having a slower flow and so deposition occurs here. The force of the water is greater on the outside of the bend and so erosion occurs.

Front 10

How are lower course features created?

Back 10

The river, in the lower course has floodplains which are areas of land covered in flood. Levees are also formed from a build up of alluvium (the sediment deposited by rivers). Deltas are formed at the mouth of rivers, there are three different deltas and these are:
arcuate or fan-shaped
cuspate or arrow like
birds foot.

Front 11

Causes of Flooding

Back 11

1) A channel surround by steep sides has faster surface run-off (water running over the land).
2) Deforestation
3) A drainage basin existing of mainly impermeable rock.
4) Drainage basin in an urban area (faster surface run-off).

Front 12

River Management

Back 12

1) Dam construction
2) River engineering
3) Afforestation
4) Managed Flooding
5) Planning