Geography - rivers

The area of land drained by a river

the area within the drainage basin

The edge of highland surrounding a drainage basin. It marks the boundary between two drainage basins.

The beginning or start of a river

The pont at which two rivers or streams join

A stream or smaller river which joins a larger stream or river

The point where the river comes to the end, usually when entering the sea

Erosion involves the wearing away of rock and soil found along the river bed and banks. Erosion also involves the breaking down of the rock particles being carried downstream by a river.

The force of the river against the banks can cause air to be trapped in cracks and crevises. The pressure weakens the banks and gradually wears it away.

Rocks carried along by the river wear down the river bed and river banks

Rocks being carried by the river smash together and break into smaller, smoother, and rounder particles.

Soluble particles are dissoved into the river

When a river loses its energy, it will drop off some of the material it is carrying. This may take place when a river enters an area of shallow water or when the volume of water decreases.

e.g after a flood or during times of drought

Deposition at the mouth of a river can form Deltas

e.g The Mississippi Delta

• steep - sided V - shaped valleys
• Interlocking spurs
• Rapids
• Waterfalls
• Gorges

• Wide, shallow valleys
• Meanders
• Oxbow lakes

• Wide flat - bottomed valleys
• Valleys
• Floodplains
• Deltas

In a river, when a large bend becomes a horseshoe it is eventually cut-off and becomes an oxbow lake.

As the river erodes to the right side and to the left side, it forms large bends and then horseshoe - like hoops called meanders

A floodplain is the area around a river that is covered in times of flooding. It is a very fertile area due to the rich alluvium deposited by floodwaters. Making them good for agriculture.

These are found at the mouth of large rivers e.g. the Mississippi. A delta is formed when a river deposits its material faster than the sea can remove it.

A flood occurs when a river bursts its banks and the water spills onto the floodplain. Flooding tends to be caused by heavy rain as the water reaches the river channel more quickly; making it more likely to flood.

A lack of vegetation or woodland may also encourage flooding as they intercept precipitation. Without these surface run off will be high. Also a steep - sided channel as they willl cause faster surface run - off.