Water on Land Revision
Paper 1 – Physical Geography
Question 5
What do you need to know?
1. The shape of river valleys changes as rivers flow
downstream due to the dominance of different
processes.
(1:11)
2. Distinctive landforms result from different
processes as rivers flow downstream. (8:44)
3. Rivers flood due to a number of physical and
human causes. Flooding appears to be an
increasingly frequent event.
(16:08)
What do you need to know?
4. The effects of and responses to floods vary
between areas of contrasting levels of wealth.
(25:38)
5. There is discussion about the costs and benefits
of hard and soft engineering and debate about
which is the better option.
(34:18)
6. Rivers are managed to provide a water supply.
There are a variety of issues resulting from this.
(39:04)
1. The shape of river valleys changes
as rivers flow downstream due to the
dominance of different processes.
Processes
1. Erode material
2. Transport material
3. Deposit material
Erosion
The process where water wears away and
breaks down rock.
There are four types.
-
Hydraulic Action
Abrasion
Attrition
Solution
Hydraulic Action
The force of the water on the sides
of the river bank breaks off earth.
Abrasion
Sediment hits the river banks and
wears it away.
Attrition
Large particles are broken into smaller
pieces as they collide.
Solution
Minerals in the rocks dissolve into the
water.
Lateral And Vertical
Lateral erosion is sideways erosion.
Vertical erosion is downwards erosion.
Transportation
When sediment is carried by a river it is
called load.
There are four ways that the load of the
river is transported.
-
Traction
Saltation
Suspension
Solution
Transportation
Deposition
Largest sediment is deposited first as it
is the heaviest to carry, the smaller the
load the further it can be transported
downstream.
River deposits when there is a decrease in
the speed of the water because energy is
lost.
Features
• Watershed - the edge of
highland surrounding a
drainage basin. It marks the
boundary between two
drainage basins.
• Source - The beginning or
start of a river.
• Confluence - the point at
which two rivers or streams
join.
• Tributary - a stream or
smaller river which joins a
larger stream or river.
• Mouth - the point where the
river comes to the end,
usually when entering a sea.
• Drainage basin - the area of
land drained by a river.
Long Profile
Upper Course
Middle Course
Lower Course
Video
YouTube
River Severn
From Source
to Mouth
Cross Profile
Upper Course
River
• Fast flowing
• Vertical erosion
• Shallow and narrow river
channel
• Deposition of large
material
• Large load
Valley
• Steep gradient
• Steep valley sides
• V-shaped valley
Middle Course
River
• Wider, deeper
channel
• Some vertical erosion,
lateral erosion more
important
• Deposition more
obvious
• Load size reduced
Valley
• Flatter valley
• Wider valley
.
Lower Course
River
• Less erosion, only a
little lateral
• Slowest flow
• Deposition of fine
material
• Large load of small
material
Valley
• Flat gradient
• Widest Valley
.
2. Distinctive landforms result from
different processes as rivers flow
downstream.
Landforms
1. Waterfalls
2. Gorges
Formed by erosion
3. Meanders
4. Ox-Bow Lakes
Formed by erosion
and deposition
5. Levee
6. Floodplain
Formed by
deposition
Waterfall
Waterfall
Gorge
Meander
Meander
Meander
Meander
Ox-Box Lake
Ox-Box Lake
Ox-Box Lake
Ox-Box Lake
Levee
Floodplain
Exam Questions
3. Rivers flood due to a number of
physical and human causes. Flooding
appears to be an increasingly
frequent event.
Discharge
The discharge of a river is the volume of
water passing down a river.
Hydrological Cycle
Hydrographs
Features of a Hydrograph
Discharge (m3/s)
3
Rainfall shown in
mm, as a bar
graph
2
mm
4
1
3
2
0
12
24 36 48
30 72
Hours from start of rain storm
Features of a Hydrograph
Discharge in
m3/s, as a line
graph
Discharge (m3/s)
3
2
mm
4
1
3
2
0
12
24 36 48
30 72
Hours from start of rain storm
Features of a Hydrograph
Discharge (m3/s)
3
The rising flood
water in the
river
2
mm
4
1
3
2
0
12
24 36 48
30 72
Hours from start of rain storm
Features of a Hydrograph
Peak flow
Peak flow
Discharge (m3/s)
3
Maximum
discharge in the
river
2
mm
4
1
3
2
0
12
24 36 48
30 72
Hours from start of rain storm
Features of a Hydrograph
Peak flow
Discharge (m3/s)
3
Falling flood
water in the
river
2
mm
4
1
3
2
0
12
24 36 48
30 72
Hours from start of rain storm
Features of a Hydrograph
Peak flow
3
Maximum
rainfall in the
area
Discharge (m3/s)
Peak
rainfall
2
mm
4
1
3
2
0
12
24 36 48
30 72
Hours from start of rain storm
Features of a Hydrograph
Lag time
Peak flow
Lag time
3
Time difference
between the
peak of the rain
storm and the
peak flow of the
river
Discharge (m3/s)
Peak
rainfall
2
mm
4
1
3
2
0
12
24 36 48
30 72
Hours from start of rain storm
Features of a Hydrograph
Basin lag time
Peak flow
3
Normal
discharge of
the river
Discharge (m3/s)
Peak
rainfall
2
mm
4
1
3
2
0
Base flow
12
Base flow
24 36 48
30 72
Hours from start of rain storm
Hydrographs
What is a flood
A flood is when a river bursts its banks
and the water spills onto the floodplain
because the volume of water exceeds it’s
capacity.
What is a flash flood?
• A flood that occurs without any
warning.
What causes flooding
Water must get into the river channel
quickly to increase the chance of flooding.
This can be
by runoff,
through flow
or ground
water flow.
What causes flooding?
Steep
Slopes
Heavy
Rainfall
Urban
areas
Impermeable
rock
Deforestation
Saturated
ground
What causes flooding?
Name the factor.
How does it affect runoff, through flow
or groundwater flow.
Link it to increased volume of water in
the river until it goes over capacity and
bursts it’s banks.
What causes flooding?
Steep
Slopes
Heavy
Rainfall
Urban
areas
Impermeable
rock
Deforestation
Saturated
ground
UK Flooding
The UK has experienced heavy floods
over the past decade, which have
affected thousands of people and caused
millions of pounds worth of damage.
Computer predictions say that we can
expect to see more extreme weather
events such as flooding in the future.
4. The effects of and responses to
floods vary between areas of
contrasting levels of wealth.
Causes/Effects/Responses
Cause: What made the flood happen
Effect: What happened to people,
buildings, transport and nature when
the flood hit
Response: How people dealt with the
crisis
Rich – Cockermouth UK
1. Where is it?
• It is located in the North
West of England in Cumbria
What type of country is it?
• In the UK a rich country.
3. What is the relief like?
• Hills surround the village,
it is in a valley where the
River Derwent and the
River Cocker meet.
4. How regular are the floods?
• Rare, the flood occurred without warning.
Causes
• In November 2009 there was the
highest ever recorded amount of rain
that fell in a 24 hour period.
• There was already saturated ground.
• There is a confluence.
Effects
• 1 death
• 1,300 people were affected.
• Many homes and business were
without electricity and water.
• All of Cumbria's 1,800 bridges
had to be inspected as many
were damaged or completely
destroyed.
• Insurance companies estimate
the damage to be of £100million.
• Many farmers lost their livestock
and ground was left saturated for
months.
• Walls and fences were destroyed.
• 1m of mud and silt needed to be
removed from shops on the high
street.
Effects
• 1 death
• 1,300 people were affected.
• Many homes and business were
without electricity and water.
• All of Cumbria's 1,800 bridges
had to be inspected as many
were damaged or completely
destroyed.
• Insurance companies estimate
the damage to be of £100million.
• Many farmers lost their livestock
and ground was left saturated for
months.
• Walls and fences were destroyed.
• 1m of mud and silt needed to be
removed from shops on the high
street.
Response
• 200 people had to be
airlifted from the
roofs of their houses
by RAF helicopters.
• People were rescued
from their homes by
boats.
• Many residents had to live in temporary
accommodation for up to 6months.
• The main road bridge over the River
DERWENT was closed to vehicles for two
months.
Poor – Bangladesh
1. Where is it?
• It is located to the East
of India
2. What type of country is it?
• Bangladesh is a poor
country
3. What is the relief like?
• Most of the country is
on a Delta (river mouth)
and is low lying (4/5ths
of the country is under
10m)
4. How regular are the floods?
• Floods are an annual
event.
Causes
Annual flooding is expected due to
• The heavy rainfall experienced annually
• The low lying land
• Snow melt from the Himalayas.
Effects
Response
• Food aid was given by the government and other countries
donated aid.
• Plastic sheets and family kits – containing clothes, cooking
utensils and basic household items – for 98,000 families.
• UNICEF provided 4.3 million water purification tablets.
• Food supplements for 162,000 people.
• Free seeds given to farmers.
• Information leaflets printed and distributed to teach people
about early warning systems and coping with flooding.
• Local people repaired embankments and helped to rescue people.
• Building of raised flood shelters to be implemented. However
conflict over money has hampered some of these attempts.
• Local community leaders trained in raising awareness and
managing early warning systems.
5. There is discussion about the costs
and benefits of hard and soft
engineering and debate about which
is the better option.
Hard and Soft Engineering
Hard engineering involves the use of
technology in order to control rivers.
They may also have a high impact on the
landscape or environment.
Soft engineering options are less
intrusive and work with natural processes.
They are usually more long-term
and sustainable, with less impact on the
environment.
6. Rivers are managed to provide a
water supply. There are a variety of
issues resulting from this.
Water Supply
The average person in the UK uses
between 124 and 177 litres of water per
day.
Demand for water is increasing due to
increases in population and number of
households.
Key Words
Water Stress: this is when there is not
enough water available.
Water Deficit: where there is not enough
water to meet demand and there is a
shortage.
Water Surplus: where there is more
water than is needed.
Water Stress in England
Kielder Water
Kielder Water is a large artificial reservoir
in Northumberland, North East England.
It is the largest artificial lake in the UK in
the amount of water.
Kielder Water was
originally built due to
the demand for water
in industry, during the
1960s.
Benefits
• The reservoir means that whilst the south of England is
often forced to implement drought strategies and
hosepipe bans, the north east of England enjoys a full
water supply.
• It acts as a flood prevention method by storing water and
only releasing it when discharge downstream is low.
• It is home to the largest hydro electric plant in England.
• The scheme includes 8 sites of Special Scientific Interest
(SSSI), containing many unique plants and animals,
including one of the last places for red squirrels in
England.
• Kielder Water has two visitor centres which attract more
than 250,000 visitors a year, providing an income of
£6million every year.
Issues
• The dam meant that many areas were lost,
including a lot of farms, habitats and a
school.
• 58 families were displaced from their
homes, and the lake now lies where their
homes used to be.
• Transport links for the Border Counties
Railway were also removed for the
reservoir.
• By the time the building of the reservoir
had been finished, many of the industries
it was originally set up for were closed.
Water on Land Revision
Paper 1 – Physical Geography
Question 5