Rivers And Landscape

Question 1

3 sections of a river

Answer 1

Upper cource-rivers start as many tributaries which are in a v shape valley,
Middle-the tributaries then merge together and form deeper and rounder rivers,area around river is flat and low lying
Lower cource-carries the largest volume of water,has levees around the sides of river

Question 2

River landforms for each cource

Answer 2

Upper-waterfalls,interlocking spurs,vshaped valley
Middle-gorges,meanders
Lower-floodpains,oxbow lake

Question 3

How do waterfalls form and how are gorges formed

Answer 3

In area where river flows over hard and soft rock,soft rock is eroded away faster
The erosion of softer rock created a a step
Soft rock undercuts the hard rock,hard rock overhangs,creating plunge pool,
Due to gravity the unsupported harder rock falls into plunge pool deepening it

Gorges form from waterfalls as it retreats upstream leaving behind a steap valley

Question 4

How do meanders form

Answer 4

Water travels faster outside the bend meaning lateral erosion takes place here
On the opposite end water travels slowly and deposits sediment
Water wears away cliff on the outer bend and creates a slip slope on the other

Question 5

How are oxbow lakes formed

Answer 5

Same processes as a meander UNTILL gradually the meanders travel towards each other
Neck of meander will eventually break creating a straight river and a bend
The old meander becomes sepourated from the main river and creates an ox bow lake

Question 6

What physical and human factors increase flood risk

Answer 6

Human
Urbanisation-by increasing the amount of impermeable surfaces,increasing risk of flash flooding
Deforestation-trees intercept rain and makes it take longer to travel into river
,increasing risk of flash flooding

Physical-
rate and volume of rain-increases risk of flash flooding
Geology-if area has many impermeable rocks the rainwater can’t run tono underground storage,increasing risk of flash flooding

Question 7

Risks of river flooding

Answer 7

Abnormally heavy and prolonged rain-rivers overflow and burst
High tides-bring along a raised sea level and they prevent water to getting to the sea

Question 8

Soft enginerring techniques

Answer 8

River channel concrete restoration-Meanders are rebuilt to slow down water
Pros-more natural resources and concrete is discouraged
Natural environment benefits
Cons
Land will still flood

Wetlands
Vegitation is planted to stop building on wetlands
Pros
When it floods no houses are damaged
Creates valuable habitats
Cons
Takes a long time to establish and grow

Question 9

Hard engendering example

Answer 9

Dredging-rubbish and sediment are dug up from bottom of river
Pros
Widens the river channel
Dosnt alter the look for the river
Cons
Takes time to complete

Question 10

Flood management strategies

Answer 10

Putting sandbags in the doorway
Closing roads this reducing the risk of people being swept away