1. Water: Reasons for Water Constraint &
Responses to Rising Demand for Water

2. Objectives Reasons for water constraints
Responses to water constraints
Case study: Singapore

3. Reasons for Water Constraint

4. Water Constraint Water supply is limited
Water consumption (demand) is increasing
Hence there is a water shortage

5. Factors affecting Water Supply
Limited supply of fresh water
Uneven distribution of fresh water
Water pollution
Factors affecting Water Demand
Population growth
Growth of agricultural
Growth of industry
Changes in lifestyle

6. Limited supply of fresh water
Only 1 percent of total amount of water on earth is fresh water

7. Uneven distribution of precipitation
Low precipitation in areas such as North Africa and the Middle East results in the scarcity of water in these regions.

9. Water Pollution Man’s activities affect the quality of water
Waste from factories and homes dumped in rivers
Deforestation causes soil erosion, which pollutes rivers
Sedimentation in stream

10. Citarum River – West Java, Indonesia

11. Reasons for the Rising Demand for Water
Population growth
Growth of agricultural
Growth of industry
Changes in lifestyle

12. Population Growth In the last 80 years Population increased by 3 times
Water demand increased by 6 times

13. Growth of agriculture Increasing world need for food
69% of available freshwater used for irrigation, rearing livestock

14. Growth of industries
15% of the earth’s freshwater is used in industries for :
Cleaning machines
Cooling machines
As a raw material in the food, chemical and paper industries

15. Changes in lifestyle People have become more affluent
Can afford modern appliances, eg washing machines, long baths, air conditioners
This increases demand for water
15% of the world’s freshwater is used in household settings

16. Summary Factors affecting Water Supply Factors affecting Water Demand
Limited supply of fresh water
Uneven distribution of fresh water
Water pollution
Factors affecting Water Demand
Population growth
Growth of agricultural
Growth of industry
Changes in lifestyle

17. Responses to Rising Demand for Water
Increasing price of water
Increasing supply of water
Conserving water

18. Increasing the Price of Water
Water prices
influence the use of water
determined by government officials, water companies, environmental groups and interest groups of consumers
Increasing price of water will slow down the rising demand for water.

19. Expensive water everywhere!
Australia:
China:

20. Increasing Water Supply
Increase catchment areas
International agreements
Use of technology

21. Increasing catchment areas
A catchment area is also known as a drainage basin.
It is the area bounded by hills or mountains.
Surface runoff collects in a catchment area and water is carried by a river and its tributaries to the sea.

22. Managing catchment areas
Restrict logging activities and carry out reforestation programmes
Initiate large water projects that help increase water supply
eg. Three Gorges Dam project in Centre China

23. International Agreement

24. International Agreement
Regional tensions and conflicts among nations can arise over the use of the shared water resource.
Affected countries will suffer from inefficient use or decrease in water supply.
International agreements help to settle or prevent cross-border disputes over water resources.

25. Examples of International Water Agreements
Nile Basin Initiative: 9 African countries that the Nile River runs through
Mekong River Commission: 4 SE Asian countries that the Mekong River runs through

26. Mekong River

27. Nile River – it’s so long I can’t show you the whole thing clearly!

28. Use of technology
Desalination
Recyling water (water reclamation)

29. Desalination
A process that removes salts and other impurities from saltwater.
2 methods:
Distillation
Reverse osmosis

30. Distillation
Seawater is heated – water vapour is collected and channeled into condensers
Incoming seawater is used to cool condensers, on which water vapour will condense to form pure water
Pure water is collected and used

31. Reverse Osmosis
Seawater is pumped at high pressure through a special membrane
In this process, dissolved salts are separated from the water
This occurs because the membrane is very dense, and only allows water molecules to pass through it.

32. Water Reclamation
Reclaiming water is the treatment of wastewater for reuse.

33. Water Conservation
Water conservation can take place in domestic, industrial, commercial and agricultural sectors.
Public education helps to reduce water wastage.
Posters, booklets, flyers, programmes, events.

34. Water Conservation at Home

35. Water Conservation at Home

38. Case study: Water Supply in Singapore

39. The Supply of and Demand for Water in Singapore
The supply of water

40. The Supply of and Demand for Water in Singapore
The demand for water
Sources of water supply:
Local water catchments
Imported water
Reclaimed water (NEWater)
Desalination
Water usage pattern in Singapore households

41. Ensuring a Sustainable Water Supply in Singapore
Mandai Reservior
Sarimbun Reservior
Kranji Reservior
Upper Seletar Reservior
Lower Seletar Reservior
Upper Pierce Reservior
Lower Pierce Reservior
Payan Reservior
Jurong Lake
Bedok Reservoir
MacRitche Reservior
Pandan Reservior
Tengeh Reservior
Local catchment areas

43. Water from our local catchment areas
14 reservoirs supply us with clean water.
Half of Singapore’s total area is used as water catchments
By 2009, the total catchment will be two-thirds of Singapore.
The Reservoir Integration Scheme
The Marina Barrage
An artist’s impression of the Marina Barrage

44. Imported Water
Water is Imported from Malaysia to supplement our water supply.
Two agreements signed between Malaysia and Singapore in 1961 and 1962 are in force up to 2011 and 2061 respectively.

45. Reclaimed Water
Through new technology to further treat the effluent water large volumes of used water has been reclaimed since 2002.
NEWater is mainly used for industrial and commercial purposes with a small amount blended with reservoir water.
With NEWater, Singapore’s water supply has become more sustainable.

46. Desalinated Water
Construction of Singapore’s first desalination plant took place in 2004 and began to operate in 2005.
It can supply 10% of our demand for water.

47. The Four National Taps Strategy
Water conservation plan:
Pricing water to reflect its strategic importance and scarcity
Educating the public to use water efficiently
Getting commercial and industrial premises to install water-saving devices
Encouraging use of alternative sources
Imposing fines on water wastage and unauthorised water usage.