Unit 2
RIVER LANDSCAPES AND HYDROLOGY
LEARNING AIMS
After studying this unit you should be able to describe:
1. how a drainage basin functions as a system and is part of the hydrological cycle
2. river processes and landforms
3. the damage done by floods
KEY WORDS
drainage basin, watershed, source, mouth, tributary, confluence, channel, hydrological cycle, condensation,
groundwater, evaporation, precipitation, surface water, transpiration, erosion, transportation, deposition, Vshaped valley, waterfall, plunge pool, meander, flood plain, alluvium, debris, demolish, landslide
LEAD-IN
1. What proportion of the earth is covered by water?
2. Do rivers always flow from the north to the south?
3. How often does a 100-year flood occur?
EX 1 – How well do you know the basic vocabulary concerning rivers? There are two lists
below. One gives words used to describe parts of drainage or river basins and the second
gives their meanings. Match up the two lists. Look up the words in a dictionary if you`re not
sure.
A watershed is an area of land drained by a river.
The source
is where a river flows into a lake or the sea.
A river basin is a stream or small river flowing into a larger river.
A tributary
is where a river begins.
A channel
is the edge of a river basin formed by hills or mountains.
The mouth
is the place where the river flows.
A confluence is where two rivers meet and join to form one larger river.
EX 2 – The drainage basin forms part of the hydrological or water cycle which you can see
below. Complete the diagram by putting the correct answer into each box. Choose your
answers from the following list:
Condensation – water vapour in the air changes back into a liquid. It forms small droplets which are visible as
clouds.
Groundwater – the transfer of water through the ground back to the sea.
Evaporation – the transfer and change of water from rivers, lakes and the sea into water vapour in the air.
Precipitation – the transfer of water from the air to the land. Water can fall to earth as rain, hail, sleet or snow.
Surface water – the transfer of water back to the sea over the ground surface.
Transpiration – the transfer and change of water from plants into water vapour in the air.
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Unit 2
EX 3 – Imagine you are a geography teacher and your students ask you these questions
about the drainage basin and the hydrological cycle. In pairs, ask and answer the
questions. Be prepared to roleplay the situation for the class. Use the vocabulary from the
previous page.
1.
2.
3.
4.
Describe how water moves through a drainage basin. Draw a diagram to help you.
What is the hydrological or water cycle?
Describe how the water cycle works. Draw a diagram to help you.
What factors affect the hydrological cycle? Think how climate, vegetation, slopes, soils and rock type
can affect the hydrological cycle. Useful vocabulary: permeable Z!o29lH?ak\or porous
Z!oN9q?r\propustný; impermeable ZHl!o29lH?ak\nepropustný.
EX 4 – You are going to hear part of a geography lecture about river processes and
landforms. The lecture is in three parts.
Part 1
Listen to “how a river shapes the land in its upper course” and write down what the numbers 1, 2, 3 and 4 stand
for. What is the end result?
Example: 1 – Eroding down
Part 2
First put these labels in the correct places in the diagram below. Then listen to “what causes waterfalls” and
check your answers.
Hard rock
Soft rock
Plunge pool
Hard rock breaks off
Eroded material Undercutting Waterfall moves back
Listen again and put the phrases below into the correct order to show how a waterfall may be worn away by a
river.
A. Hard rock collapses.
B. Plunge pool deepened.
C. Soft rock worn away.
D. Waterfall moves back.
E. Hard rock undercut.
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Unit 2
Part 3
Look at the diagram below, which is a simple cross-section of a river bend, and write the labels in the correct
places. Then listen to “what happens on a river bend” and check your answers.
Slowest flow
Deposition
Erosion
River cliff
Gentle slope
Fastest flow
Deep water
Shallow water
EX 5 – With a partner, talk about river processes and landforms. Use the diagrams and
vocabulary from the previous exercise. You can also look at the Recording script Unit 2 for
reference.
1.
Describe how rivers erode their channels. Include these words in your description: pushes, scrapes,
loosens, moves, drops.
2.
Look at the diagram in Ex 4, part 1 again. Show how a valley gets to be V-shaped by describing what
happens at 1, 2, 3 and 4.
3.
Using the diagram in Ex 4, part 2 describe how a waterfall may be worn away by a river.
4.
Look at the diagram in Ex 4, part 3 again and describe why one side of the river bend is different from
the other.
5.
Say two reasons why the flood plain of a valley is good for farming.
6.
Give one problem of farming flood plains. Suggest what could be done to reduce the problem.
EX 6 – Read this newspaper extract about floods in France and answer the questions below.
Floods kill 32 in violent French storms
At least 32 people were killed and 44
missing after violent storms and flash
floods swept the Ardeche, Vaucluse
and Drome regions in S.E. France. Four
helicopters were used to rescue at least
100 people hanging onto debris or
sitting on roofs as 95 kph winds made the
use of small boats almost impossible.
The worst hit area was the small town of
Vaison la Romaine where houses were
demolished by a wall of water. Vehicles
1.
2.
were carried away and in some cases their
passengers were drowned. Falling trees
crushed cars and houses. Many of the
country roads were blocked by
landslides, mud and broken bridges.
Weather experts said that although heavy
rain was common, the latest storms were
exceptional. About 40% of the region`s
annual rainfall had fallen in a matter of
hours.
List the damage done by the storms and flooding.
Why were people in cars at risk, and what weather conditions made the rescue operation
difficult?
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EXTRA PRACTICE
EX 1 – Complete the text below. Fill each space with one word beginning with the letter
given. The words can be either verbs in their correct form or nouns, singular or plural, or
adjectives. All the words have appeared in this unit.
The Water cycle
The sun`s heat causes some water from the sea to (1) e……………. . The water changes from a (2)
l…………. to a (3) g…….. - it forms water vapour. The water vapour gas is absorbed by the air. The
mixture of water vapour and air rises and cools. As it cools the water vapour (4) c……………. and turns
back to water. It creates tiny droplets of water which hang in the air forming (5) c……… . Then the
rain can come or the air may be cooled enough so that other forms of (6) p………………. may be
produced, such as (7) s………. or (8) h………. . The water that is precipitated eventually flows in rivers
back to the sea. Then the water cycle (9) r…………. itself.
From Source to Sea
From the mountain top to the sea, rivers constantly change the surface of the land. On their journeys they
destroy rocks, move boulders, and (10) d…………… sediments, constantly wearing away all of the land
in their paths.
Rivers begin their lives in hills or (11) m……………… . The start of a river is called its (12) s………… .
Once the volume of water in the streams increases, the water carries material along and (13) w………..
away the land surface. The areas in which the streams run form depressions between hills or mountains
known as (14) v………….. . They are usually deep, steep and V-shaped as the fast moving water flows
downhill and (15) c……. down the rock.
When rivers leave the higher ground and enter the flat plains, they (16) s………. down. As the force of the
water is reduced, the (17) s………………. falls to the river bottom and is dumped on the riverbed. Most
of the sediment deposition occurs in the river (18) f……….. plains. Here rivers flow slowly, making Sshaped curves known as (19) m…………. . When rivers flood, they spread out over many miles on
either side of their (20) b………. .
At the end of their lives, rivers flow into a large body of water, such as an (21) o………., bay, or
occasionally a (22) l………. to end their journeys. At this final stage a large amount of sediment can be
deposited to form sand banks and the river water then has to find its way to the (23) s……. in the multichannels that make up a delta or estuary.
The complete river pattern that results is like a tree-structure and is known as the (24) d………… basin.
EX 2 – Read another newspaper article about floods in Bangladesh and answer the
questions below.
1000 die in worst ever floods
heaviest monsoon rains ever to hit Bangladesh have left over 1000 people dead and 25 million
Thehomeless.
Up to 80 per cent of the country is at least one metre deep in floodwater. The rice
crop has been lost and 35 million people now face starvation. The chief export crops of sugar cane
and jute have also been ruined. The only dry places to live are on roof tops - but even these are not
safe as snakes have also sought refuge here. Water and electricity have both been cut off.
Railways and bridges have been swept away. Nearly all of the country`s roads are impassable. Dhaka
airport is under water, preventing foreign help from arriving.
With most of the country`s water supply contaminated, the threat of disease is real. Hospitals are
already full of cases of dysentery and diarrhoea. Yesterday 500 cholera cases were admitted to
Dhaka hospital.
1.
2.
How did the flood affect the people living in Bangladesh?
The cause of annual flooding in Bangladesh is partly due to natural reasons and partly due to human
activities. Think what you know about Bangladesh and give examples for both categories.
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