River landscapes

Question 1

The river valley

Answer 1

Upper course – gradient = steep shallow channel
Middle course – gradient = medium, deeper channel
Lower course – gradient = gentle, deep channel very wide
Vertical erosion – deepens River Valley
Lateral erosion – widens river valley

Question 2

Processes of erosion

Answer 2

Hydraulic action – Force of water breaks rock particles
Abrasion – thrown against side and scrapes sides
Attrition – pebbles collide
Solution – chemicals in river dissolve material

Question 3

Transportation

Answer 3

Traction – boulders pushed along river bed
Suspension – small particles carried along by water
Saltation- pebbles bounce along river bed
Solution - chemicals dissolve material

Question 4

Waterfalls and gorges

Answer 4

Soft rock is worn away by hydraulic action and abrasion
Hard rock can’t support itself
Collapses falls into foot creating a plunge pool
This retreats overtime leaving a steep sided gorge

Question 5

Interlocking Spurs

Answer 5

In upper course most erosion is vertical creating v-shaped valleys
Water then flows around them

Question 6

Meanders

Answer 6

Current is faster outside of bend as it’s deeper
More erosion takes place on outside of bend forming river cliffs
Current is slow on inside as shallow so more material deposited creating slip off slope‘s

Question 7

Oxbow lakes

Answer 7

Erosion causes outside bend to get closer
River Breaks through land (usually during food)
River flows along shortest course and the deposition cuts off meander

Question 8

River landforms – deposition

Answer 8

Flood plains are flat areas of land that flood

Question 9

River discharge and flooding

Answer 9

River discharge is the volume of water that flows in a river per second - Hydrographs show this – peak discharge, lag time, rising limb, falling limb
Prolonged rainfall, heavy rainfall, geology, relief, increases flood risk
Land use – impermeable surfaces increase run-off to rivers increasing flooding

Question 10

Hard vs soft engineering

Answer 10

Hard engineering – dams and reservoirs, channel straightening, embankments, flood relief challenge hard engineering – dams and reservoirs, channel straightening, embankments, flood relief channels
Soft engineering – flood warnings, precipitation, floodplain zoning, planting trees, river restoration

Question 11

Flood management scheme example

Answer 11

Banbury Oxford

Management- roads raised, embankement made