Rivers

What is a river drainage basin?

An area of land drained by a river and its tributaries

What is a source?

The starting of a river

What is a tributary?

Smaller rivers that join the main one

What is confluence?

The point where two rivers join

What is a floodplain?

The flat land either side of a river where it usually floods

What is an estuary?

The tidal area where the fresh water meets the sea

What is the mouth?

Where the river flows into the sea

What is the watershed?

An imaginary line that separates drainage basins

What is a long profile?

How the river changes from source to mouth

What is a cross profile?

Shows the shape across the river valley

What is the long profile gradients like of the upper, middle, and lower course?

Steep, gentle slope, shallow/flat

What is the cross profile like of the upper, middle, and lower course?

V-shaped valleys, gentle sloped valley, flat valley

What is the velocity of the upper, middle, and lower course?

Slowest, faster, fastest

What are the features and landforms of the upper, middle, and lower course?

Waterfalls gorges and interlocking spurs , meanders and oxbow lakes, flood plains levees and estuaries

What is the river channel shape of the upper, middle, and lower course?

Narrow + shallow, wider + deeper, widest + deepest

What are the size and shape of the sediment of the upper, middle, and lower course?

Boulders, pebbles, sand and silt

What is lateral erosion?

The widening of the river channel

What is vertical erosion?

The deepening of the river channel

What is a meander?

A bend in the river channel

What is a levee?

Natural embankments

How does prolonged rainfall affect the processes in the water cycle?

The saturated soil causes less infiltration so there is more surface run off which leads to a shorter lag time.

How does heavy rainfall affect the processes in the water cycle?

The infiltration rate is too slow to cope so there is more surface run off which leads to a shorter lag time.

How does geology affect the processes in the water cycle?

Impermeable rock/soil leads to less infiltration so there is more surface run off which leads to a shorter lag time.

How does the relief of the land affect the processes in the water cycle? (steep slopes)

Steep slopes leads to less infiltration so there is more surface run off which leads to a shorter lag time.

How does the relief of the land affect the processes in the water cycle? (low lying land)

Low lying land leads to saturated soil so there is more surface run off which leads to a shorter lag time.

How does urbanisation affect the processes in the water cycle?

Impermeable material leads to less infiltration so there is more surface run off which leads to a shorter lag time.

How does deforestation affect the processes in the water cycle?

No tree roots means no interception so there is less infiltration so there is more surface run off which leads to a shorter lag time.

What is a hydrograph?

A graph that shows how a river responds to a period of precipitation

What is discharge?

The amount of water passing a given point along the river

What is cumecs?

The velocity of the river multiplied by the volume

What is peak rainfall?

The highest amount of rainfall

What is lag time?

The difference in time between peak rainfall and peak discharge

What is the rising limb?

Shows how quickly the discharge rises after the storm

What is peak discharge?

The highest discharge the river reaches after a period of rainfall

What is the falling limb?

Shows the reduced discharge once the main effect of runoff has passed

What is river restoration?

Returning rivers to their natural course

What are some advantages of river restoration?

It creates lots of ecosystems, it is cheap to maintain and it looks nice for tourists

What are some disadvantages of river restoration?

It slows the river down so it is more likely to flood

How does planting trees manage rivers?

It creates more interception so there is less water in the river

What are some advantages of planting trees?

It creates small ecosystems, it reduces erosion, and it looks nice for tourists

What are some disadvantages of planting trees?

It is labour intensive and can block the river so dosen’t work in urban areas

What is flood plain zoning?

Stopping people from building high value land on flood plains

What is an advantage to flood plain zoning?

It minimises damage to high value land

What are some disadvantages to flood plain zoning?

Doesn’t stop floods, and houses are already built on flood plains

What are flood warnings?

News and weather report dangerous weather

What are ways you can act when you receive a flood warning?

Get sandbags, more furniture, and evacuate

What are some disadvantages to flood warnings?

No one can enforce it and you have to have good communication

What are dams?

A barrier built across a river to hold back water and raise its level, creating a reservoir

What are some advantages of dams?

Creates a source of drinking water, highly effective, provides electricity

What are some disadvantages of dams?

Very expensive, displaces people, disruption in fish migration

What is channel straightening?

Meanders engineered to be straighter

What are some advantages channel straightening?

Improves navigation, reduces flood risk, and increases home owner confidence

What are some disadvantages channel straightening?

Increases pollution as chemicals can’t drain, unattractive, and changes the ecosystems

What are embankments?

An artificially raised bank

What are some advantages of embankments?

Provides walking routes, habitats, and it is cheap

What are some disadvantages of embankments?

People can’t fish or sail, prone to erosion, and it gives people a sense of false security

What are flood relief channels?

An artificially made channel designed as a bypass for excess water

What are some advantages of flood relief channels?

Removes risk of flooding in that area, insurance costs are lower, and it provides new habitats

What are some disadvantages of flood relief channels?

Downstream suffer from increased flooding and expensive