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An brief introduction to WATER RESOURCES.pptx
- 1. WATER RESOURCES World andSouth Africa
- 2. LEARNING OUTCOMES • Statethe different forms of water in the world. • Describe the distribution of salt water and freshwater. • Describe the hydrological/water cycle. • Explain the significance of oceans.
- 3. WATER IN THEWORLD • Where is most of it? • Earth’s surface or Atmosphere? • Is there more water OR land? • Does ice count as water?
- 4. THE DIFFERENT FORMSOF WATER • Liquid water - wet and fluid • Water vapour - in the air, where it attaches to dust particles(condenses to form clouds.) • Ice - frozen water.
- 5. DISTRIBUTION OF WATERIN THE WORLD
- 6. MEASURING WATER ONEARTH
- 7.
- 8. NATURAL WATER STORAGE •Ice/Glaciers/Snow • Sea/rivers/natural dams/lakes • Water vapour • Ground water
- 9. IMPORTANCE OF NATURALWATER STORAGE • Snow and glacial storage – spring snow-melt replenish rivers in cold countries with high mountains like in Russia. • Shallow groundwater storage – maintain dry season dam levels and river flow in warmer countries like South Africa.
- 10. PROCESSES IN THEWATER CYCLE • Evaporation – water turns into a vapour. • Transpiration – loss of water vapour through stomata from plant leaf surfaces. • Condensation - water vapour changes into a liquid. • Precipitation – any form of condensation that falls on the ground e.g. rain, snow & hail. • Surface run-off – water that flows on earth’s surface after rains or snow melting. • Infiltration - the process by which precipitation soaks into the soil and moves into rocks through cracks and pore spaces.
- 11. KEY CONCEPTS • Drainagebasin (catchment area) – an area drained by the main river and its tributaries. • Tributary – small river or stream that joins a larger river. • River discharge – volume of water passing at a given point in a river in cubic metres per second.
- 12. KEY CONCEPTS • Surfacerun-off – water that flows on earth’s surface after rains. (pg 81-82 handout - runoff) • Infiltration - the process by which precipitation soaks into the soil and moves into rocks through cracks and pore spaces. • Percolation – water passes through permeable rocks (aquifers) underground.
- 13. KEY CONCEPTS Throughflow –downhill water movement within first few centimetres of the soil on the unsaturated zone which is above the water table. Water table– uppermost layer of saturated rock and soil beneath Earth’s surface being recharged by infiltration. Groundwater – water stored underground in soil and rocks below the level of water table.
- 14. Groundwater – waterstored underground in soil and rocks below the level of water table.
- 15. KEY CONCEPTS • Baseflow– part of river flow produced by seeping of groundwater into bed and banks of a river resulting to permanent flow even during the dry season.
- 16. LAND MIS-MANAGEMNET EFFECTSON RIVER FLOW AND GROUNDWATER STORAGE • Damming – increased surface area for evaporation. • Deforestation – increase surface run-off and reduce infiltration. • Destruction of wetlands – increased risks of flooding and more pollutants. • Overstocking – overgrazing thus reduced infiltration. • Over extraction of underground water from boreholes – lower the water table. • Veld fires – less infiltration.
- 17. MAIN OCEANS OFTHE WORLD • Atlantic – colder & salty • Indian – warmer • Pacific – larger • Southern • Arctic
- 18. IMPORTANCE OF OCEANS •Source of oxygen supply • Source of food • Energy resource • Minerals • Mariculture • Moisture • Water transport
- 19. IMPORTANCE OF OCEANS •Source of oxygen supply - phytoplankton e.g. seaweed photosynthesise to release oxygen into the ocean and the atmosphere (50% of atmospheric O2 ).
- 20. IMPORTANCE OF OCEANS •Source of food – fish (source of proteins)& seaweed
- 21. IMPORTANCE OF OCEANS •Energy resource - tidal energy (generated using sea waves at barrages) -oil drilling and gas extraction. (page 316 top class geo text book)
- 22. IMPORTANCE OF OCEANS •Ocean minerals – seafloor is rich in minerals e.g. sodium chloride, magnesium, bromine, diamond, copper, zinc, etc
- 23. IMPORTANCE OF OCEANS •Aquaculture – (especially mariculture i.e. fish farming) farming of aquatic organisms, including fish, molluscs, crustaceans and aquatic plants.
- 24. IMPORTANCE OF OCEANS •Moisture – oceans provide a large surface area for evaporation of sea water into water vapour. • Water vapour is transported by air currents towards the land as onshore winds • Water vapour can rise and condense to form fresh water/rainwater.