GEOGRAPHY CAMBRIDGE IGCSE: RIVERS PROCESSES AND FEATURES. Presentation suitable for Year 11 Geography students.

1. IGCSEIGCSEGEOGRAPHYGEOGRAPHY
RIVERSRIVERS
PROCESSESPROCESSESANDANDFEATURESFEATURES
PRESENTATION 4PRESENTATION 4

2. THE LIFE OF A RIVERTHE LIFE OF A RIVER
JOURNEY FROMJOURNEY FROM
SOURCE TOSOURCE TO
MOUTHMOUTH
AN EXPLANATIONAN EXPLANATION
OF PROCESSESOF PROCESSES
AND FEATURES

3. What happens when water reaches the ground?What happens when water reaches the ground?
CONDENSATIONCONDENSATION
EVAPORATIONEVAPORATION
PRECIPITATIONPRECIPITATION
SEA
LAND
A SIMPLIFIED WATER CYCLEA SIMPLIFIED WATER CYCLE

4. Key WordsKey Words
EVAPORATIONEVAPORATION
CONDENSATIONCONDENSATION
PRECIPITATIONPRECIPITATION
RUN-OFFRUN-OFF
PERCOLATIONPERCOLATION
GROUND WATERGROUND WATER
WATER STORESWATER STORES
When water vapour changes to liquid (cooling)When water vapour changes to liquid (cooling)
Water in any form that falls to earth e.g. rainWater in any form that falls to earth e.g. rain
When the ground water moves through the landWhen the ground water moves through the land
When water vapour changes to liquid (warming)When water vapour changes to liquid (warming)
The water that is stored within the groundThe water that is stored within the ground
Water that is stored e.g. ground,clouds,air etc.Water that is stored e.g. ground,clouds,air etc.
Water that moves directly along the groundWater that moves directly along the ground
without penetrating.without penetrating.
Put the correct definition to the given word~one has been done for youPut the correct definition to the given word~one has been done for you

5. Detailed Water CycleDetailed Water Cycle

6. Completed Water CycleCompleted Water Cycle

7. River BasinsRiver Basins
• Where a river begins is called the source.source.
• A small river meeting a larger river is called a tributarytributary.
• Where the two rivers join is called the confluenceconfluence
• Where the river flows into the sea is called the mouthmouth.
• The area drained by a river is called the drainage basin.drainage basin.
• The ‘line’ that separates two drainage basins is called the
watershed.watershed.
Key WordsKey Words

8. THE LONG PROFILE OF A RIVERTHE LONG PROFILE OF A RIVER
Upper CourseUpper Course Middle CourseMiddle Course Lower courseLower course
SOURCESOURCE
MOUTHMOUTH

9. Key WordsKey Words
Hydraulic PowerHydraulic Power
CorrasionCorrasion
CorrosionCorrosion
AttritionAttrition
Water/debris isWater/debris is
forced into cracksforced into cracks
Rocks /stonesRocks /stones
erode bed and sideserode bed and sides
of river bank.of river bank.
Rocks getRocks get
smaller bysmaller by
chemical actionchemical action
Rocks get smaller when knocked togetherRocks get smaller when knocked together
Rocks such as chalkRocks such as chalk
and Limestoneand Limestone

10. The Upper Course of a RiverThe Upper Course of a River
• Hydraulic powerHydraulic power
This is the force of the water on the bed and banks of the
river, powerful when in flood, the force of the water
removes material from the bed and banks of the river.
• CorrasionCorrasion
When the river is particularly full, pebbles and boulders
are carried along by the water. These rub against the bed
and banks of the river and wear them away. The process is
called abrasion.
Processes of erosionProcesses of erosion

11. Processes of ErosionProcesses of Erosion
CorrosionCorrosion
River water sometimes causes some rock to slowly dissolve.
(e.g. limestone dissolves in slightly acid water and is carried
away in solution (as a liquid) as calcium hydrogen carbonate).
AttritionAttrition
The pebbles and small rocks being carried by the river -
the load - collide and rub against each other, breaking up
into smaller and smaller pieces. The rough edges become
smooth, forming smaller rounded material. Eventually the
particles are reduced to sand and silt-sized particles

12. Features of the upper course of a riverFeatures of the upper course of a river
The main features of a Waterfall are:
•A steep drop in the river ~ called a higha high
head of waterhead of water
•A plunge poolplunge pool at the base
•Hard, resistant rock at the top~ the cap rockthe cap rock
•Softer rock below that are undercut.undercut.
Waterfalls and gorges are formed over aWaterfalls and gorges are formed over a
long period of time they are characterisedlong period of time they are characterised
by the following: -by the following: -
•Bands of hard and soft rock being erodederoded
at different rates. (softer rock the quickest)
•The river moves back as the erosion takes
place, this is known as recession.recession.
•A gorge and waterfall have steep sidessteep sides

13. Hard cap rockHard cap rock
(resistant)(resistant)
Softer rock isSofter rock is
undercut byundercut by
backwash frombackwash from
falling waterfalling water
Softer less resistant rock isSofter less resistant rock is
easily erodedeasily eroded by fast flowingby fast flowing
water.water.

14. Deep plungeDeep plunge
pool at base ofpool at base of
waterfallwaterfall
Undercutting hasUndercutting has
taken place wheretaken place where
softer rock is foundsofter rock is found

15. Waterfall overWaterfall over
150 metres high150 metres high
Deep plunge pool atDeep plunge pool at
base of waterfallbase of waterfall

16. The middle course of a riverThe middle course of a river
Key wordsKey words
TractionTraction
-large boulders-large boulders
roll along theroll along the
river bedriver bed
SaltationSaltation
-smaller pebbles are bounced along the river bed, picked up-smaller pebbles are bounced along the river bed, picked up
and then dropped as the flow of the river changesand then dropped as the flow of the river changes

17. Key words continuedKey words continued
SuspensionSuspension
-the finer sand and silt-sized particles are carried along in the-the finer sand and silt-sized particles are carried along in the
flow, giving the river a brown appearance.flow, giving the river a brown appearance.
SolutionSolution
-minerals, such as limestone and chalk, are dissolved in the-minerals, such as limestone and chalk, are dissolved in the
water and carried along in the flow, it often cannot be seen.water and carried along in the flow, it often cannot be seen.

18. The middle course of a riverThe middle course of a river
•MeandersMeanders
Erosion onErosion on
outside bendoutside bend
DepositionDeposition
on insideon inside
bendbend

19. Feature of the middle courseFeature of the middle course
A Meander (cross-section)A Meander (cross-section)
Label the diagram with the following words and statements:-Label the diagram with the following words and statements:-
Outside bend, inside bend, erosion, deposition, river cliff,Outside bend, inside bend, erosion, deposition, river cliff,
deepest water and fastest current.deepest water and fastest current.
BBAA
BBAA

20. Feature of the middle courseFeature of the middle course
A Meander (cross-section)A Meander (cross-section)
Outside bend, inside bend, erosion, deposition, river cliff,Outside bend, inside bend, erosion, deposition, river cliff,
deepest water and fastest current.deepest water and fastest current.
BBAA
BBAA

21. The lower course of a riverThe lower course of a river
•Ox-bow lakesOx-bow lakes
•Flood plainsFlood plains

22. Oxbow or ‘cut-off ’ lake
New course of the river
Steep undercut bankRiver straightens at this point
and cuts off the ox-bow
Part of the flood plain