Rivers Flashcards
(24 cards)
Attrition
Rocks being carried by the river smash together and break into smaller, smoother and rounder particles.
Abrasion
Rocks carried along by the river wear down the river bed and banks.
Cross profile
The side to side cross-section of a river channel and/or valley.
Discharge
The quantity of water that passes a given point on a stream or river‐bank within a given period of time.
Flood plain
The relatively flat area forming the valley floor on either side of a river channel, which is sometimes flooded.
Flood plain zoning
This attempts to organise the flood defences in such a way that land that is near the river and often floods is not built on. Could be used for pastoral farming, playing fields etc. The areas that rarely get flooded would therefore be used for houses, transport and industry.
Gorge
A narrow, steep sided valley, often formed as a waterfall retreats upstream.
Hard engineering
Involves the building of entirely artificial structures using various materials such as rock, concrete and steel to reduce, disrupt or stop the impact of river processes.
Soft engineering
Involves the use of the natural environment surrounding a river, using schemes that work with the river’s natural processes. Soft engineering is usually much cheaper and offers a more sustainable option as it does not interfere directly with the river’s flow.
Hydraulic action
The force of the river against the banks can cause air to be trapped in cracks and crevices. The pressure weakens the banks and gradually wears it away.
Interlocking spurs
A series of ridges projecting out on alternate sides of a valley and around which a river winds its course.
Lateral erosion
Sideways erosion by a river on the outside of a meander channel. It eventually leads to the widening of the valley and contributes to the formation of the flood plain.
Levees
Embankment of sediment along the bank of a river. It may be formed naturally by regular flooding or be built up by people to protect the area against flooding.
Long profile
The gradient of a river, from its source to its mouth.
Precipitation
Moisture falling from the atmosphere - as rain, hail, sleet or snow.
Saltation
Particles bouncing down the river bed.
Solution
Soluble particles are dissolved into the river.
Suspension
Fine solid material held in the water while the water is moving.
Traction
The rolling of boulders and pebbles along the river bed.
Channel straightening
Removing meanders from a river to make the river straighter. Straightening the river (also called channelising) allows it to carry more water quickly downstream, so it doesn’t build up and is less likely to flood.
Vertical erosion
Downward erosion of a river bed.
Waterfall
Sudden descent of a river or stream over a vertical or very steep slope in its bed. It often forms where the river meets a band of softer rock after flowing over an area of more resistant material.
Hydrograph
A graph which shows the discharge of a river, related to rainfall, over a period of time.
Embankment
Raised banks constructed along the river; they effectively make the river deeper so it can hold more water. They are expensive and do not look natural but they do protect the land around them.
