4. Water and its management Flashcards
How much of Earths surface is covered in water
75%
only 3% is fresh and possible usable by humans
The water cycle
- Evaporation
- Condensation
- Precipitation
- Transpiration
- Surface run-off
- Interception
- Infiltration
- Groundwater flow/through flow
Water cycle - Evaporation
liquid water turns into vapour
Water cycle - Condensation
water vapour turns into liquid water
Water cycle - Precipitation
liquid water/ice particles fall to Earth due to gravity
rain/snow/hail
Water cycle - Transpiration
the movement of water up plants and its loss as water vapour from the leaves
Water cycle - Surface run-off
water running over the ground into rivers
Water cycle - Interception
precipitation is stopped from reaching the ground by the presence of of trees/other plants
Water cycle - Infiltration
when water seeps into the ground
Water cycle - Groundwater flow
infiltrated water that flows through rocks
Water cycle - Through flow
infiltrated water that flows through soil
3 reasons why humans water
- domestic purposes
- industrial purposes
- agricultural purposes
Main sources of fresh water for human use
Surface water - lakes, rivers, swamps
Groundwater - water in soil and rocks underground
Aquifer - water stored in porous rocks underground
Sea water - made potable by desalination (removal of salt)
- Water from the sea *
- distillation
- reverse osmosis
- Availability of safe drinking water pg. 94
Purpose of a dam (benefits)
- the provision of water
- generation of electricity
- flood control
- irrigation
- tourism
- habitat for wetland species
Disadvantages of dam projects
- relocating people
- flooding land
- disrupts life cycles of fish/aquatic organisms
- alters water supply for people downstream
- reduces enrichment of soil downstream
Where to build a dam
In a narrow river valley
A wider valley would be more costly
Needs to be quite high up to produce hydroelectric power
(The higher it is, the greater the pressure of the water, more potential energy)
Away from developed areas to avoid pollution
- Are dams sustainable?
pg. 96
- Cholera, typhoid
pg 96
- malaria
pg. 96 - 98
How to avoid mosquito bites
(in countries where malaria mosquitos are active)
- avoid being outside between dusk and dawn
- wear clothing that covers most of your body
- use insect repellent
