Transcript Rivers past exam questions quiz

Rivers past exam questions
quiz
For each question (1-33), choose
the most appropriate or the best
answer from either a, b or c.
1/ 1999 P3H Explain the differences in the size and shape
of the material on the river bed in the upper and lower
courses of a river
• a/ In the upper course load is smaller and more rounded
than in the lower course because of erosional processes
such as attrition and corrasion.
• b/ As a river moves through its course, because of the
greater incidence of larger settlements, more
supermarket shopping trolleys are likely to be found in
rivers, adding to the load that has already been
deposited.
• c/ In the lower course load is smaller and more rounded
than in the upper course because of erosional processes
such as attrition and corrasion.
2/ P2F 2001 A river may erode by the processes of
corrosion, attrition, corrasion or hydraulic power. For
hydraulic power describe how it works
• a/ This is when river water and its load are
thrown against the river banks causing erosion.
• b/ Water and air are forced into cracks on the
river bank, exerting a pressure. When this
process is repeated many times it causes
erosion.
• c/ A river carries large amounts of load that are
constantly smashing into each other and
breaking into smaller particles. This makes the
load smaller and more rounded over time.
3/ 1999 P2F Traction, saltation, suspension and solution
are the 4 methods of transport of material along a river. For
saltation explain how each it works
• a/ small peebles bounce along the river
bed.
• b/ large boulders roll along the river bed.
• c/ fine material is carried along,
suspended in the water.
4/ Give reasons for the differences in cross
sections of rivers in the upper and lower courses
• a/ In the upper course rivers are narrow and swallow
because the river is less powerful and discharge
relatively low. In the lower course the river is wider and
deeper as the river carries more load, discharges more
and has more power to erode.
• b/ In the upper course rivers are wide and deep because
the river is less powerful and discharge relatively low. In
the lower course the river is narrow and shallow as the
river carries more load, discharges more and has less
power to erode.
• c/ As a river moves from its upper to its lower course, it
tends to carry more load, is wider, deeper, faster flowing
and discharge increases.
5/P3H 2001 explain the formation of a waterfall and gorge
(6)
• a/ Niagara Falls is one of the best known waterfalls in
the world. There are actually two waterfalls together
which have been formed as a gorge has worn down the
Niagara river. Angel falls, in Venezuela is the biggest
waterfall in the world.
• b/ Sometimes water takes a short cut to the sea by going
over a waterfall. A good example of a gorge is Ironbridge
gorge, Shropshire. It has a fantastic iron bridge over the
river Severn.
• c/ If a river flows over hard rock which lies on top of
exposed softer rock, the softer rock may be undercut by
erosion, forming a waterfall. If the waterfall retreats
upstream it can form a steep sided valley called a gorge.
6/ What features are associated with waterfalls
• a/ Niagara, Victoria, Angel, High Force.
• b/ Plunge pool, undercutting, hard and soft
rock.
• c/ Weathering, erosion, transportation and
deposition.
7/ What river features and landforms are associated with
a cross section or profile of a river valley in its upper
course.
• a/ river source, V-shape, interlocking
spurs, narrow and shallow river channel.
• b/ delta, flood plain, river mouth, levees,
wide and deep river channel.
• c/ sheep farming, wind turbines, HEP
(hydro-electric power) stations and dams
and reservoirs.
8/ 1999 P2F of the following features are not formed by
river deposition.
• a/ levee
• b/ gorge
• c/ delta
9/ What are meanders
• a/ they are bends in a river formed by a river as
the volume of water increases in its lower
course. The shaping of a meander bend is
helped by erosion on the outside of the bend
and deposition on the inside of the bend.
• b/ meanders migrate across their flood plain,
widening the river valley and helping to form a
flood plain.
• c/ they are bends in a river.
10/ P1H 2005 Explain how the features of a meander are
formed (4)
• a/ a river cliff forms on the inside of a river bend as a
result of faster flowing water and its load causing erosion
and undercutting the river bank. A slip off slope forms on
the outside of a river bend where the river is flowing
more slowly and deposition takes place.
• b/ a river cliff forms on the outside of a river bend as a
result of faster flowing water and its load causing erosion
and undercutting the river bank. A slip off slope forms on
the inside of a river bend where the river is flowing more
slowly and deposition takes place.
• c/ a river cliff forms on the outside of a river bend as a
result of faster flowing water and its load causing
deposition on the bank. A slip off slope forms on the
inside of a river bend where the river is flowing more
slowly and erosion takes place.
11/ 1998 P3H & P1H Explain the formation of an ox bow
lake. You may use diagrams to help you
• a/ These lakes were dug out by farmers to
provide fresh water for their cattle and oxen.
• b/ These are formed when an alien head is
guillotined by a river, leaving a horse shoe print.
• c/ It forms where a river channel erodes through
the neck of two meander bends that are eroding
towards each other. The river then flows more
directly and is diverted away form the meander
bend. The neck is then sealed off from the rest
of the river channel through deposition, leaving a
arc shaped lake isolated from the rest of the
river.
12/ P3H 2000 Explain how a river flood plain is formed.
• a/ These are formed in the upper course of a
river. The river valley has a typical V shape and
the river flows around ridges of land.
• b/ Meanders migrate across a river valley due to
erosion. This helps to wider out the valley
forming a plain. When a river overflows its bank
it floods its plain. As the flood waters retreat they
deposit river load over the valley floor, helping to
build up the flood plain through deposition.
• c/ A river flood plain is the flat area of land either
side of the river channel that is flooded when a
river rises above its banks.
13/ P2f 2002 Explain how levees are formed
• a/ Levees have been built around New Orleans to stop
the city from flooding. However, several levees gave way
in August 2005 as New Orleans took a direct hit from
hurricane Katrina. The levees surrounding New Orleans
were not built to cope with a storm surge from a F4
hurricane.
• b/ These are raised river banks on either side of the river
channel. They can form naturally or can be heightened
by humans as part of a river management strategy.
• c/ The river banks on the sides of a river channel are
heightened over time as a result of successive flooding
of a river’s flood plain. As the flood waters retreat the
frictional drag and slow moving water leads to further
deposition of sediment on the banks.
14/ P1H 2007 Identify 3 features of the lower course of a
river
• a/ waterfalls, sheep farming, large
boulders.
• b/ v-shaped valley, interlocking spurs, river
source.
• c/ flood plain, meander, delta.
15/ Explain how a delta forms
• a/ It forms at the mouth of a river, where the river meets
the sea. The river and its load spread into the sea
slowing down and depositing load. Over a period of
time large amounts of load are deposited in a triangular
pattern. The river may split into lots of channels
because its course is diverted by deposition. These
channels are called distributaries.
• b/ This is where the fresh water of a river meets the salt
water of the sea. They often make excellent harbours.
When the tide goes out large areas of mudflats can be
seen.
• c/ It forms at the source of a river, where the river meets
its valley. The river and its load spread into the valley
speeding up and depositing load. Over a period of time
large amounts of load are deposited in a circular shape.
The river may split into lots of channels because its
course is diverted by erosion. These channels are
called tributaries.
16/ Sp 3H Explain one disadvantage of the area of the
upper course of a river for human activity
• a/ There are fewer settlements.
• b/ It is accessible.
• c/ It is often more inaccessible.
17/ P2f & 3H 2000 What factors affect the location of a
reservoir
• a/ A reservoir needs a ready supply of water, that
can be easily transferred to consumers. The
water should be stored securely and the flooding
impact of creating a reservoir limited.
• b/ These are walled in by dams that may
produce HEP (hydro electric power) which help
to contribute towards the energy requirements of
a country.
• c/ These are often close to large populations to
supply households and businesses with water.
18/ What is river discharge
• a/ This is how a river responds to a period of
rainfall. It is the amount of water that passes a
point in a river over a period of time. It is
measured in Cumecs (cubic metres per second).
• b/ This is the height of the river. When it rains
the river rises and then later returns to its base
flow.
• c/ This is shown on a hydrograph. It has a rising
limb and a falling limb. It shows rainfall, including
peak rain. It is also possible to calculate the lag
time from the difference between peak rain and
peak discharge.
19/ Sp P2F Name two features which may affect the
discharge of the River Severn
• a/ The level of urbanisation in the area.
• b/ The amount of industry in the area.
• c/ The amount of rainfall and interception
by vegetation
20/ P2F 2001 How long is the lag time shown on the
hydrograph
• a/ 8 hours 30
mins
• b/ 9 hours 30
mins
• c/ 10 hours 30
mins
21/ P2F and P3H 2001 Using the hydrograph, how much
water did the river carry before it began to flood
Above this level of
discharge and
flooding will occur
• a/ 40 mm
• b/ 40 metres
• c/ 40 cumecs
22/ P3H 2001 Using the hydrograph, how many hours was
the river in flood
Above this level of
discharge and
flooding will occur
• a/ about 1 hour
• b/ about 3 hours
• c/ about 5 hours
23/ Which of the following river catchment variables will
speed up river discharge
• a/ a dam
• b/ afforestation
• c/ urbanisation
24/ P2F 2002 &P3H suggest 2 possible causes of river
flooding
• a/ A prolonged period of heavy rain and
increased building on the flood plain so
that discharge to rivers is increased.
• b/ Failure of the levees eg. New Orleans,
August 2005.
• c/ A tropical cyclone may be funnelled
through the Bay of Bengal which causes a
storm surge and floods Bangladesh.
25/ P1F & P1H 2004 Describe the causes of a river flood
that you have studied
• a/ Dams have been built, levees have been heightened,
flood storage reservoirs built. Some of the Mississippi’s
tributary rivers have had part of their catchment areas
afforested.
• b/ Mississippi Floods of 1993. Spring snow melt together
with 50 days of heavy rain in the Mid West. Building on
the floodplain has increased runoff and added to the
pressure the levees were under. They were built only to
withstand a limited amount of discharge and eventually
they gave way.
• c/ New Orleans Flood of 2005. Loss of lives, homes and
livelihoods. Estimated 500,000 displaced people. People
injured and ill. Some people looted and America’s
reputation was damaged.
26/ 1998 P3H Using the resource (not provided), suggest 2
ways the flooding in Chichester had an impact upon the
local economy
• a/ damage to farmers crops and the large
bill to clear up the flood damage for the
council
• b/ schools were closed, so that students
could not attend lessons and hand in their
homework
• c/ A mother from the local area, on a trip
into Chichester, found herself and her 5
children stuck in 2 metres of water
27/ P2F & P3H 2001 Using an example describe the effects
of a flood
• a/ The Chichester floods of 1994. Damage to
property, communications cut off and damage to
crops.
• b/ New Orleans Flood of 2005. Loss of lives,
homes and livelihoods. Estimated 500,000
displaced people. People injured and ill. Some
people looted from businesses and America’s
reputation was damaged.
• c/ Mississippi floods of 1993. 28 lives lost and
10$ billion repair costs.
28/ P1f & 1H 2003 Using an example of a flood in an
MEDC, describe its effects on the land and people
• a/ Flooding in Bangladesh 1988; 2400 people killed and
a large part of the country flooded (upto 80% at one
time). Infrastructure and homes were damaged and
crops were lost. 25 million people were made homeless.
Water supply was contaminated so hospitals were
inundated with cases of dysentery, diarrhoea and
cholera.
• b/ Mississippi floods of 1993; 28 lives lost, 36,000 people
were made homeless and evacuated. Transport was
restricted and crops were loss.10$ billion was needed to
repair the flood damage and millions of tonnes of silt and
sand were deposited in the flood zone.
• c/ Mississippi Floods of 1993. Spring snow melt together
with 50 days of heavy rain in the Mid West. Building on
the flood plain has increased runoff and added to the
pressure the levees were under. They were built only to
withstand a limited amount of discharge and eventually
they gave way.
29/ P2F 2002 &P3H suggest 2 ways settlements could be
protected from flooding in the future
• a/ Countries could reduce their emissions of
carbon dioxide thereby reducing the risk of the
ice caps melting and thus flooding occurring.
• b/ Build levees and flood relief channels.
• c/ Countries could build expensive dams, dredge
river beds and increase river channel capacity or
plant trees in large areas of a river’s catchment
to reduce river discharge.
30/ 2004 Explain the advantages that the river restoration
scheme may bring to the area
• a/ The river is dredged of its sediments,
increasing river channel capacity and providing
sand for local beaches and building.
• b/ Few river restoration schemes have been
introduced since most people prefer the
reliability of hard engineering constructions to
protect their properties from flooding.
• c/ The river is allowed to flood naturally, so that
costly hard engineering is unnecessary and the
flood damage less severe in the long term. River
wildlife ecosystems return.
31/ P1H 2005 Flood plain zoning is a soft management
strategy. What does a soft management strategy mean
• a/ It is a method of river flood management
which involves major construction work eg. flood
plain zoning
• b/ It is a method of river flood management
which works or attempts to work with natural
river processes. It does not tend to involve major
construction work eg. flood plain zoning
• c/ It is an easy and cheap form of river
management strategy. For example using
sandbags to prevent flooding
32/ P1F 2005 which of the following are examples of soft
river engineering
• a/ Dredging and flood relief channels.
• b/ Dams and levees.
• c/ River restoration and land use zoning.
33/ P1H 2005 Using the diagram (not provided), describe the flood plain
zoning and explain why strategies such as this are sustainable
•
•
•
a/ This is soft engineering. This involves using planning laws to control
building on flood plains. Its advantage is that it is cheap, but requires
sufficient prediction and investigation into the possibilities of flooding.
b/ Flood plain zoning - This is soft engineering. It involves using planning
laws to control building on flood plains. This is seen as sustainable because
not only does it reduce the impact of flooding, because building damage is
limited, but because the flood plain has not been built upon, surface runoff
to river discharge is less likely to cause flooding. Furthermore, flood plain
zoning and other soft engineering strategies such as afforestation and river
restoration can be seen as sustainable because they are cheaper and have
less impact on the environment. Many believe that some hard engineering
strategies are less sustainable because they are expensive and make
flooding worse. Eg raising the levees – if flooding occurs it is far worse.
Channel dredging may need to take place on a regular basis to maintain
river channel depth as well as the dredging behind dams to maintain
storage capacity.
c/ Flood plain zoning - This is hard engineering. It involves using planning
laws to build on flood plains. This is seen as unsustainable because it
increases the impact of flooding. Furthermore, flood plain zoning and other
hard engineering strategies such as afforestation and river restoration can
also be seen as unsustainable because they are cheaper and have more
impact on the environment. Many believe that some soft engineering
strategies are sustainable because they are expensive and make flooding
worse. Eg raising the levees – if flooding occurs it is far worse. Channel
dredging may need to take place on a regular basis to maintain river
channel depth.