1. The HydrologicalThe Hydrological
CycleCycle
Higher GeographyHigher Geography
The HydrosphereThe Hydrosphere

2. The Hydrological CycleThe Hydrological Cycle
 What you need to know:What you need to know:
 Be able to draw a diagram of theBe able to draw a diagram of the
hydrological cycle.hydrological cycle.
 Describe its main elements.Describe its main elements.
 Explain how balance is maintained withinExplain how balance is maintained within
the system.the system.

3. What is the HydrologicalWhat is the Hydrological
Cycle?Cycle?
The hydrological cycle is the system which describes
the distribution and movement of water between the
earth and its atmosphere. The model involves the
continual circulation of water between the oceans, the
atmosphere, vegetation and land.
http://www.metoffice.gov.uk/education/teachers/key-stage3/lessonplan-hydrological-cycle

4. The Hydrological cycleThe Hydrological cycle

5. Describing the Cycle:Describing the Cycle:
 EvaporationEvaporation
Solar energySolar energy
powers the cycle.powers the cycle.
Heat energy fromHeat energy from
the sun causesthe sun causes
evaporationevaporation fromfrom
water surfaceswater surfaces
(rivers, lakes and(rivers, lakes and
oceans) and….oceans) and….

6.  …… transpirationtranspiration fromfrom
plantsplants.. TranspirationTranspiration
is essentiallyis essentially
evaporation of waterevaporation of water
from plant leaves.from plant leaves.
 EvapotranspirationEvapotranspiration ––
water loss to thewater loss to the
atmosphere fromatmosphere from
plants and waterplants and water
surfaces.surfaces.

7. CondensationCondensation
 The warm, moist airThe warm, moist air
(containing(containing waterwater
vapourvapour) rises and, as) rises and, as
it cools,it cools,
condensationcondensation takestakes
place to formplace to form cloudsclouds..

8. AdvectionAdvection
 Wind energy mayWind energy may
move clouds overmove clouds over
land surfacesland surfaces
where …where …

9. PrecipitationPrecipitation
 ……precipitationprecipitation
occurs, either asoccurs, either as
rain or snowrain or snow
depending ondepending on
altitude.altitude.

10.  StemflowStemflow (red(red
arrows) –arrows) –
Precipitation flowsPrecipitation flows
down stems anddown stems and
branches to groundbranches to ground
 ThroughflowThroughflow (yellow)(yellow)
Rate at whichRate at which
precipitation flowsprecipitation flows
through branchesthrough branches

11. Run off / Overland flowRun off / Overland flow
 The rainwaterThe rainwater
flows, either overflows, either over
the ground (the ground (runrun
offoff) into rivers and) into rivers and
back to the ocean,back to the ocean,
or…or…

12. Groundwater flowGroundwater flow
 …… infiltratesinfiltrates
downwards throughdownwards through
the soil and rocksthe soil and rocks
where it is returnedwhere it is returned
to the oceansto the oceans
throughthrough
groundwatergroundwater flow.flow.

13. Groundwater flowGroundwater flow

14. Hydrological Cycle BingoHydrological Cycle Bingo
Also called the hydrological cycle
Split your page into 8 squares and write one word from the list
below in the each square
Condensation Ground Water Infiltration
Evaporation Precipitation Percolation
Run off Evapotranspiration Interception
Saturation The Hydrological Cycle The water table

15. The water cycle balanceThe water cycle balance
 Usually the water cycle is in balance, and theUsually the water cycle is in balance, and the
amount ofamount of precipitationprecipitation falling will slowly soakfalling will slowly soak
into the ground and eventually reach theinto the ground and eventually reach the
rivers.rivers.
 However, if rain falls for a long period of timeHowever, if rain falls for a long period of time
or if the ground is already soaked oror if the ground is already soaked or
saturated with water then the chance ofsaturated with water then the chance of
flooding is increased.flooding is increased.

16. Under the groundUnder the ground

17. A closed systemA closed system
 The hydrological cycle is a good example of aThe hydrological cycle is a good example of a
closed system: the total amount of water isclosed system: the total amount of water is
the same, with virtually no water added to orthe same, with virtually no water added to or
lost from the cycle.lost from the cycle.
 Water just moves from one storage type toWater just moves from one storage type to
another.another.
 Water evaporating from the oceans isWater evaporating from the oceans is
balanced by water being returned throughbalanced by water being returned through
precipitation and surface run off.precipitation and surface run off.

18. Your TurnYour Turn
Write down the meaning of the following words:Write down the meaning of the following words:
 InfiltrateInfiltrate
 Groundwater flowGroundwater flow
 Surface runoffSurface runoff
 EvapotranspirationEvapotranspiration
 Closed systemClosed system
Use the New Higher Geography Textbook p.10 to help
you.
Then complete Activity 1 (a) – (c)

19. Human Inputs to the CycleHuman Inputs to the Cycle
 Although this is a closed system there is aAlthough this is a closed system there is a
natural balance maintained between thenatural balance maintained between the
exchange of water within the systemexchange of water within the system
 Human activities have the potential to lead toHuman activities have the potential to lead to
changes in this balance which will have knockchanges in this balance which will have knock
on impacts.on impacts.
 For example as the earth warms due to globalFor example as the earth warms due to global
warming the rate of exchange in the cyclewarming the rate of exchange in the cycle
(between land and sea and atmosphere) is(between land and sea and atmosphere) is
expected to increase.expected to increase.

20. Human InputsHuman Inputs
 Some aspects of the hydrologic cycle can beSome aspects of the hydrologic cycle can be
utilized by humans for a direct economicutilized by humans for a direct economic
benefitbenefit
 Example: generation of electricityExample: generation of electricity
(hydroelectric power stations and reservoirs)(hydroelectric power stations and reservoirs)
 These are effectively huge artificial lakes andThese are effectively huge artificial lakes and
this will disrupt river hydrology (amount ofthis will disrupt river hydrology (amount of
water in a river)water in a river)

21. Other Human ActivitiesOther Human Activities
 Paving, compacting soils, and altering thePaving, compacting soils, and altering the
nature of the vegetation (includingnature of the vegetation (including
deforestation)deforestation)
 The mining of ground water for use inThe mining of ground water for use in
agriculture and industryagriculture and industry
 Large amounts of water vapour released intoLarge amounts of water vapour released into
the atmosphere from industrial activitythe atmosphere from industrial activity
 Large changes in vegetation by wildfire,Large changes in vegetation by wildfire,
logging, clearance for agriculturelogging, clearance for agriculture

23. ImpactsImpacts
 These human activities can lead toThese human activities can lead to
increase chances of floodingincrease chances of flooding
 Increases in soil erosionIncreases in soil erosion
 A cooling effect on the north west ofA cooling effect on the north west of
Europe (climate change)Europe (climate change)
 Possible higher precipitation levels inPossible higher precipitation levels in
the Arctic but less in the Tropicsthe Arctic but less in the Tropics