Inputs and
Outputs but also
the movement
within the system
Area changes characteristics
For example, a drainage basin in america
would have high evaporation and low
physical output to the see
Inputs and
outputs of a
drainage
basin
INPUTS
Precipitation
rain
snow
Hail
Condensation
Vapour to liquid
Due to the cooling of the vapour
Hills
The cloud rises up
the hill, cools and
falls (Rain shadow
on the other side
Convectional Rain
often occurs near the equator
The heat
causes the air
to rise and
condense very
quickly-
Thunderstorms
occur
Frontal
Cold air meets hot air
Warm air is less
dense so rises,
condenses and falls
as rain
Occurs on surfaces (ground)
Attaches itself to dust particles
OUTPUTS
River discharge
Evaporation
Transpiration
plants
inter basin transfer
When rocks allow water to
flow through them, transferring
the water to another basin
Man made:- Locks, canals
Common example: Escarpment where the
dip encourages the movement of water
underground
Evapotranspiration
Easy pathway for moisture
to return to the
atmosphere
what is the water balance?
Shows the equilibrium in the drainage
basin: Between outputs and Inputs
in England: Input exceeds Output
P = Q + E
P= precipitation
Q= runoff
E= evapotranspiration
Processes and Stores
Soil stores
essential for our food.
highly variable becoming completely
saturated after prolonged rain and dryed out
within weeks with little rain. Farmers often
try to alter the soil storage to suit crops
needs. Drainage can reduce excess moisture
and irrigation tops up soil moisture defiencies
depends on
several factors
such as soil depth,
soil texture, soil
structure and land
use management
practises.
Field capacity: the natural amount of water that the soil can hold.
Ground water stores
in permeable rocks
large stores of ground water are called aquifers and the surface of this underground
water is the water table. This moves up and down depending on the level of water. If
water is extracted, the water table goes down.
Surface storage
any body of water from a puddle to a lake.
Human affect
Human activity can modify the
storage. eg. terracing, a deliberate
design in order to improve the water
balance.
Deforestation- Reduces
the amount of water that
is held above land in the
trees.(reduces stores)
Storm Hydrographs
What affects the
shape?
Lag time. This is the time it
takes for water to move through
the systems and stores of a
basin
a graph that shows discharge and rainfall in a drainage basin
Rain fall is the bar graph, Discharge is the line.
Flooding
Causes
Fluvial flooding: these are
caused by a long period of
rainfall over a large area
or because of rapid
melting of snow or ice.
Flash flooding: This is caused by
excessive and localised rainfall that
accumulates in low-lying areas when
the soil becomes too saturated and
cannot absorb any more water.
Groundwater flooding:
This is caused when
the water table rises
too much and causes
overland flow, this type
can last for days or
weeks
Dam Failure: The
release of huge
amounts of water
caused by design failure
or ageing construction
materials. can also be
caused by earthquakes
or landslides.
Impacts
environment destroyed
Economy loss
Loss of lives
Loss of homes and businesses
Spread of disease
Stategies
Effectiveness?
soft engineering tends to be
cheaper, and works WITH
nature, rather than against it.
Hard engineering needs to be
replaced and often gets damaged.
Not only this but it is often referred
to as an eyesore.