topic 4 - river landscape

Question 1

the upper course
gradient -
valley and channel shape

Answer 1

steep gradient
the valleys are steep-sided and shaped like a v
water flows through a narrow and shallow channel
In the upper course,
erosion
erosion dominates over the deposition

Question 2

the middle course
gradient -
valley and channel shape-

Answer 2

medium gradient
valleys have a gentle slope
wider and deeper channel than the upper course

Question 3

the lower course
gradient -
valley and channel shape

Answer 3

gentle gradient
very wide and flat valley sides
the channel is wide and deep

Question 4

cross

profile

Answer 4

shows you what a cross-section of the river looks like.

Question 5

long

profile

Answer 5

Shows you how the gradient of a river changes along its length.

Question 6

Types of River Erosion

Answer 6

vertical erosion

lateral erosion

Question 7

lateral erosion

Answer 7

lateral erosion makes the river valley wider

lateral erosion dominated in the middle and lower Course

Question 8

vertical erosion

Answer 8

vertical erosion makes the river valley deeper
vertical erosion dominates the upper course
due to high turbulence causing the rough and angular particles to be scrapped along the river bed

Question 9

processes of transportation

Answer 9

solution
traction
saltation
suspension

Question 10

process of erosion

Answer 10

hydraulic action
abrasion
attrition
solution

Question 11

solution

Answer 11

soluble material dissolved in the water and are carried along

Question 12

suspension

Answer 12

small particles like slit and clay are carried along by the water

Question 13

saltation

Answer 13

when small particles bounce along the river bed by the force of the water

Question 14

traction

Answer 14

is where large panicles eg boulders are dragged along the river bed by the force of the water

Question 15

disposition is when a river drops eroded material

4 reasons why rivers slow down and deposit material

Answer 15

the water becomes shallow
the river reaches the mouth
reduced volume of water in the channel
the number of sediments in the channel increases

Question 16

what features are found in the upper course

Answer 16

waterfalls and gorges

Question 17

formation of waterfall

Answer 17

as the river passes over bands of hard and soft rocks, the less resistant (soft) rocks begins to erode because of abrasion and hydraulic action.

as the softer rock is eroded away by the river a step or notch forms creating a river rapid

overtime the the softer rocks gets more eroded and a steep drop is eventually a waterfall forms

the hard rocks is eventually undercut by erosion and the overhanging harder rocks becomes unsupported and collapses

the hard rocks crumble into the base and abrasion between the hard rocks and soft rocks creates a plunge pool

hydraulic action keeps undercutting and causes more collapses
the waterfall will retreat leaving behind a steep-sided gorge

Question 18

formation if interlocking spurs

Answer 18

in the upper course , valleys are steep and v-shaped because most erosion happens vertically downwards

and rivers are don’t have the energy to erode laterally Instead, they follow the winding path through the valley.
These interlocking hillsides are the interlocking spurs.

Question 19

features in the lower and middle course

Answer 19

meanders

Question 20

formation of meanders

Answer 20

meanders are large bends in a river.
when the river bends the current in the fastest at the outside of the bend so more erosion takes place on the outside of the bend forming a river cliff

the current is the slowest on the inside of the bend because the water is the shallowest so eroded material is deposit because the current has less energy to carry it along the river. This creates slip-off slopes.

Question 21

formation of ox-bow lakes

Answer 21

Over time, meanders get bigger until eventually an ox-bow lake forms.
erosion causes the outside bends to get closer
until there’s only small bit of land left between the bends and eventually the river breaks through this land deposition eventually cuts off the meanders forming an ox bow lake

Question 22

River Landforms Caused by Deposition

Answer 22

flood plains
levees
deltas

Question 23

floodplains

Answer 23

flood plain are flat and wide areas of land that floods

Flood plains are created by meander migration close to the mouth of the river.
Meanders widen floodplains by migrating across them.
Meanders make valley floors flatter by migrating downstream.

Question 24

levees

Answer 24

are natural embankments along the edge of a river channel
during a flood the eroded material is deposited. the heaviest material is deposited first closest to the river channel over time the deposited material build up on the sided of the river

Question 25

deltas

Answer 25

deltas are low-lying areas where the river meets the sea or lake

deltas forms because the river are forced to slow down when they meet the sea or lake causing them to deposit their sediments
The river’s channel can be blocked by this build-up of material. This splits the river into lots of tiny rivers named distributaries.
If this material builds up enough, a piece of land called a delta is created.

Question 26

factors Affecting River Landscape and Sediment Load

Answer 26

climate
geology
slope processes

Question 27

factors Affecting River Landscape and Sediment Load- geology

Answer 27

rivers flowing through areas of hard rocks have a slower rate of erosion because hard rocks are more resistant so a river will have a lower sediment load.
landscape with more resistant rocks have steep-sided valleys

whereas areas of softer rocks will experience more erosion which adds material to the rivers sediment load.
landscape with less resistant rocks have gentle sloping valleys sides

Question 28

factors Affecting River Landscape and Sediment Load- climate

Answer 28

rivers in wetter climate have a higher discharge because more water entering the river channel
higher discharge increases the rate of erosion
transportation also increases when there’s a high discharge

Question 29

factors Affecting River Landscape and Sediment Load- slope processes

Answer 29

vertical erosion by rivers makes valleys more steeper and increases the movement of material down the slopes

Question 30

what does the bar chart show on a hydrograph

Answer 30

rainfall

Question 31

what does the line graph show

Answer 31

river discharge

Question 32

What is river discharge measured in?

Answer 32

cubic meters per second m^3/s

Question 33

what Affects the Shape of a Hydrograph?

physical factors

Answer 33

slope-A steeper valley will funnel more rainfall into a river faster, increasing river discharge.

geology - impermeable rocks will absorb less water and channel more rain into a river, increasing discharge (infiltration is lower).

soil type - Impermeable soils will have higher runoff and channel more water into a river.

drainage basin type
antecedent conditions

Question 34

What Affects the Shape of a Hydrograph?

human factors

Answer 34

deforestation - cutting down trees means less water would be absorbed by the tress which increases discharge and runoff

urbanisation -Impermeable building materials are used for housing and buildings in urban areas. This will reduce infiltration and increase the discharge

Question 35

How does flooding threaten the people?

Answer 35

Floodwater can easily get contaminated with sewage, leaving water unsafe to drink.

floods can wash people away and kill them.

Possessions can be destroyed or lost.

businesses and homes can be damaged.

Question 36

How does flooding threaten the environment?

Answer 36

Habitats can be polluted by floodwater.

vegetation can be uprooted and killed by forceful floodwater.

Question 37

the risk of flooding can increase due to

Answer 37

increase in the frequency of storms - this could be a consequence of global climate change

land-use change - lots of development eg houses taking place on floodplains .these areas are naturally prone to flooding