Rivers - AQA GCSE Geography

Hydraulic action

The force of the water hitting the river bed and banks. This is most effective when the water is moving fast and when there is a lot of it.

Abrasion

When the load carried by the river repeatedly hits the bed or banks dislodging particles into the flow of the river.

Attrition

When stones carried by the river knock against each other, gradually making the stones smaller and more rounded.

Solution

When the river flows over limestone or chalk, the rock is slowly dissolved. This is because it is soluble in mildly acidic river water.

Mouth

The place where the river ends, usually where the river joins the sea.

Source

The place where a river starts, usually in an area of highland.

Watershed

The edge of a river basin.

Tributary

A small stream which joins a larger river.

Confluence

The point at which 2 rivers meet/ where a tributary joins a larger river.

Catchment

The area where water drains into a drainage basin.

Drainage basin

the area of land drained by a river and its tributaries

Condensation

When a gas cools and turns into a liquid. This forms clouds at high altitudes.

Transpiration

When plants release water vapour from their bodies.

Precipitation

The fancy word for rain, sleet, snow, hail etc

Evaporation

When a liquid turns to a gas and rises.

The Hydrological (Water) Cycle

This cycle shows how water moves between the land, seas and atmosphere via precipitation, evaporation etc

Upper course

This is the name given to the start of a river's journey, here it is small, youthful and full of energy.

V-Shaped valleys

These are formed in the upper course of a river due to vertical erosion.

Interlocking spurs

These are formed in the upper course of the river as it flows downhill and winds its way between harder and softer rock.

Waterfalls

These are formed in the upper course of a river when it flows over hard and soft rock. The soft rock is cut back more quickly than the hard rock and a plunge pool is formed. This creates overhangs which collapse due to gravity.

Plunge pool

This is a feature formed at the bottom of a waterfall, it is created by the force of the water hitting the riverbed. It is deepened by corrasion between the boulders.

Steep-sided gorge

This is a feature left behind when a waterfall retreats upstream.

Vertical erosion

This is the type of erosion that occurs mostly in the upper course of a river, after it has used most of its energy to overcome the force of friction.

Lateral erosion

This is the type of erosion that occurs mainly in the lower course of a river, it is erosion in a sideways direction.

Middle course

This is the middle section of the river's journey.

Meanders

Bends in the river that occur in the middle course.

River beach/slip-off slope

This is a feature formed on the inside bend of a meander due to deposition (due to low velocity and high friction).

River cliff

This is a feature formed on the outside of a meander where the river erodes the banks through hydraulic action and corrasion.

Meander migration

This is the name of the process in which a meander moves and becomes more curvy due to constant erosion and deposition.

Erosion

This is the destructive action of the water in the river which wears away land.

Ox bow lakes

This is a feature formed when the neck of a meander narrows so much that the river simply cuts through.

Lower course

This is the last section of a river's journey, here it is large and fast flowing.

Levees

These are natural barriers formed by the continuous flooding onto the flood plain. The river deposits heavier materials at the front and lighter materials further away.

Floodplain

This is a feature formed when the river floods and deposits sediment. These are usually very fertile.

Solution

When smaller particles of bedload are transported by dissolving it in the water.

Traction

When big boulders are transported by rolling along the bed of the river.

Saltation

When small rocks are transported by bouncing on the bed of the river.

Suspension

When very small bits of rocks are transported by it being suspended and carried along with the water flow.

River Management

Plans and processes implemented on rivers to control water flow and discharge or for a profit.

River discharge

How much water is flowing in to the river at a given location and time.

Peak discharge

The greatest volume of water that flows in the river at a given time.

Flood hydrograph

Graph of stream discharge over a time period for a specific place, lag time, peak, rising limb, falling limb, base flow

Permeable rock

The ability of a rock or sediment to let fluids pass through its open spaces, or pores.

Impermeable rock

Rock that does not allow liquid or gas to flow through it.

Groundwater

Water that fills the cracks and spaces in underground soil and rock layers.

Estuary

the area where a freshwater stream or river merges with the ocean