Chapter 4

1. Chapter 4 Water Supply Will Our Taps Run Dry?

2. Think about this!

3. Think about this!

4. Chapter 4 Water Supply • In this chapter, you will explore these Guiding Questions: • What is water shortage? • Which locations in the world are facing water shortage? • Why does water shortage occur? • How does water shortage impact people and countries? • How can Singapore avoid water shortage?

5. Chapter 4 Water Supply • In this chapter, you will explore these Guiding Questions: • What is water shortage? • Which locations in the world are facing water shortage? • Why does water shortage occur? • How does water shortage impact people and countries? • How can Singapore avoid water shortage?

6. 1. What is water shortage? Hydrological cycle (water cycle) • Continuousmovementof water from the earth’s surface to the atmosphere and back again. Along the way, the water takes on different states • Water cycle is driven by heat energy from the sun Water is a renewable resource — can be naturally replenished

7. 4. Some of the water that falls onto the ground may seep into the soil (infiltration). Water that infiltrates deep into the ground, and is contained in the soil and the underlying rocks, becomes groundwater. 1. Heat from the sun causes water from lakes, rivers, oceans and the surface layers of soil to change to water vapour(evaporation) 3. These water droplets gather together to form clouds. When more water droplets gather, the clouds get too heavy. Thus, water falls back to the earth’s surface (precipitation) 5. The rest of the water that is not absorbed into the ground flows over the earth’s surface, down hills and mountains into rivers, lakes and eventually seas(surface runoff) 2. As the water vapour rises into the atmosphere, it cools and becomes water droplets (condensation) 1. Plants also give out water vapour through their leaves(transpiration) Hydrological cycle

8. 1. What is water shortage? Uses of water • Domestic use • Cooking, cleaning • Drinking • Economic activities • Agriculture: 20% of total water to grow rice, 3% of total water to grow cotton • Industry: To generate electricity and manufacture products

9. 1. What is water shortage? Uses of water Domestic use • Globally, domestic water use accounts for the smallest percentage of all water used • Domestic use • Consumption (e.g. drinking and cooking) • Hygiene (e.g. bathing and flushing the toilet) • Amenity use (e.g. washing the car and watering the garden) The volume and way that water is used may differ from household to household

10. 1. What is water shortage? Domestic use (Singapore)

11. 1. What is water shortage? Domestic use (Canada)

12. 1. What is water shortage? Uses of water Economic use (Agriculture) • Uses the greatest amount of water globally • As the world’s population grows rapidly, more water is needed to grow more crops to feed people • Crucialfor growing fruits, vegetables, grain, coffee, tea, oil palm, rubber and cocoa • In places with abundant rainfall all year round less water is used for agriculture because crops are naturally watered by rain

13. 1. What is water shortage? Uses of water Economic use (Agriculture) • Where rainfall is low or irregular more water is used for agriculture because of irrigation • Irrigation: Water is obtained from water bodies (rivers, lakes, reservoirs and wells) and is sprayed or watered onto crops • Without irrigation, crops will not grow in dry areas such as the deserts of California

14. 1. What is water shortage? Uses of water Economic use (Agriculture) Often, large amounts of water are needed to produce a small quantity of an agricultural product

15. 1. What is water shortage? Uses of water Economic use (Agriculture) • To meet the world’s increasing demand for food, more places are relying on irrigation • More water is used to increase crop yield • Compared to 50 years ago, the amount of water used for irrigation today has increased by 70 % • Area of irrigated land has also doubled

16. 1. What is water shortage? Uses of water Economic use (Industry) • Industrial water use accounts for 22 % of total water used • 57–69 % is used for hydropower and nuclear power generation • 30 –40 % is used for industrial processes such as manufacturing • 0.5–3 % is used for thermal power generation • Major users of water are industries that produce steel, chemicals, paper and petroleum

17. 1. What is water shortage? Uses of water Economic use (Industry) • Used in all manufacturing processes as the processes create lots of heat due to friction and chemical reactions • Needed to cool down the machinery and equipment • Used to clean the machinery and products

18. 1. What is water shortage? Uses of water Economic use (Industry) • Power generation • Large amounts of water are used for the manufacture, maintenance and cooling of generators • Large portion of water is lost through evaporation, absorption and leaks • Thermal power generation • Electricity is produced by steam-powered generators where huge amounts of water are required to produce the steam

19. 1. What is water shortage? Uses of water Economic use (Industry) • Some industrial products are used as raw materials for making other products • Thus, more water is needed to produce the finished product

20. 1. What is water shortage? Uses of water Economic use (Industry) • Tourism industry • In 2012, there were 1.035 billion international visitors • Estimated that the number of international visitors will reach 1.8 billion by 2030 • With steady expansion of the global tourism industry, the demand for water will increase

21. 1. What is water shortage? Uses of water Economic use (Industry)

22. 1. What is water shortage? Water footprint • Water footprint: Total volume of water (m3) used to produce the goods and services for a person in a year which includes all domestic and economic uses of water • Water per capita: Amount of water used per person • Some countries have a bigger water footprint as they use a lot more water per capita than others

23. 1. What is water shortage? Water footprint

24. 1. What is water shortage? Water shortage • Water shortage: Occurs when the level of water usage exceeds the water supply available(water is being used at a rate faster than it can be replenished) • Not everybody has access to clean water • Over 1 billion people in the world do not have enough clean water to drink and this number is predicted to increase

25. 1. What is water shortage? Water shortage Example (New Delhi, India) • Faces water shortage due to the country’s growing population whereby a large number of people has moved from the countryside to the city • Water demand in peak summer months has reached more than 4.35 million m3 a day • However, the city gets only about 3.22 million m3 a day

26. 1. What is water shortage? Water shortage

27. Chapter 4 Water Supply • In this chapter, you will explore these Guiding Questions: • What is water shortage? • Which locations in the world are facing water shortage? • Why does water shortage occur? • How does water shortage impact people and countries? • How can Singapore avoid water shortage?

28. 2. Which locations in the world are facing water shortage? Distribution of water on earth • Water is the most abundant substance on earth’s surface • 71 % of the earth’s surface is covered in water where most of the earth’s water is in the oceans • Only 2.8 % of the earth’s water is fresh water which is found in rivers, lakes and groundwater, in which • 68.6 % is locked up in ice caps and glaciers • 30.1 % is groundwater • 1.3 % is on the surface of the earth, in which • 87 % is in lakes • And the rest is found in rivers and swamps

29. 2. Which locations in the world are facing water shortage? Distribution of water on earth

30. 2. Which locations in the world are facing water shortage? Distribution of water on earth Oceans • The world’s oceans are all interconnected in a single, enormous body of water • Pacific Ocean is the largest, covering 1/3 of the total area of earth’s surface • Waterin the oceans is replenished by precipitation and rivers that flow into the oceans

31. 2. Which locations in the world are facing water shortage? Distribution of water on earth Oceans

32. 2. Which locations in the world are facing water shortage? Distribution of water on earth Groundwater • Is stored underground in the soil and underlying rocks • When rain falls to the ground, some of the water infiltrates the ground until it reaches solid rock • The water then fills up the empty spaces and cracks above that layer of rock • When all these spaces are entirely filled, the ground is filled with water. This water is groundwater. • As more water infiltrates deep into the ground, groundwater storage will increase

33. 2. Which locations in the world are facing water shortage? Distribution of water on earth Groundwater

34. 2. Which locations in the world are facing water shortage? Distribution of water on earth Groundwater

35. 2. Which locations in the world are facing water shortage? Distribution of water on earth Groundwater • People mostly use surface fresh water however, people are increasingly drawing from groundwater in places where there is insufficient surface fresh water • Many countries use groundwater for irrigation • Globally, about 38% of water for irrigation comes from groundwater • Countries with the largest areas irrigated with groundwater are India (390,000 km2), China (190,000 km2) and USA (170,000 km2)

36. 2. Which locations in the world are facing water shortage? Distribution of water on earth Ice caps, glaciers, rivers and lakes • Ice cap: A thick, continuous mass of ice which covers large areas of land • Glacier: A body of ice that moves down a slope due to gravity. It forms when snow accumulates and is compacted to form ice • Almost 69% of the earth’s fresh water is trapped in ice caps and glaciers

37. 2. Which locations in the world are facing water shortage? Ice caps and glaciers are usually far from where people stay and hence inaccessible

38. 2. Which locations in the world are facing water shortage? Distribution of water on earth Ice caps, glaciers, rivers and lakes

39. 2. Which locations in the world are facing water shortage? Distribution of water on earth Ice caps, glaciers, rivers and lakes • River: A large natural stream of fresh water flowing along a definite course into another water body • Source may be a lake, spring or melting glacier • As the river flows downstream, precipitation, groundwater and other smaller streams (tributaries) add to the flow • The end of a river is its mouth where it flows into another body of water such as a lake or the ocean

40. 2. Which locations in the world are facing water shortage? Distribution of water on earth Ice caps, glaciers, rivers and lakes

41. 2. Which locations in the world are facing water shortage? Distribution of water on earth Ice caps, glaciers, rivers and lakes

42. 2. Which locations in the world are facing water shortage? Distribution of water on earth Ice caps, glaciers, rivers and lakes • Lake: A body of water occupying a hollow in the earth’s surface The Great Lakes of North America is the largest group of freshwater lakes on earth

43. 2. Which locations in the world are facing water shortage? Distribution of water on earth Ice caps, glaciers, rivers and lakes

44. 2. Which locations in the world are facing water shortage? Locations in the world facing water shortage • Fresh water is distributed unevenlyacross the world • Fresh water availability of a country is calculated by dividing the country’s total water resources (m3) by its total population • Different levels of fresh water availability: Water security, water vulnerability, water stress, water scarcity

45. 2. Which locations in the world are facing water shortage? Locations in the world facing water shortage • Water security: When a country has adequate and sustainable fresh water for human consumption and use more than 2,500 m3 per capita per year • Water vulnerability: If fresh water availability is between 1,701 and 2,500 m3 • Water stress:If fresh water availability is between 1,001 and 1,700 m3 • Water scarcity: When fresh water availability falls below 1,000 m3

46. 2. Which locations in the world are facing water shortage? Locations in the world facing water shortage

47. 2. Which locations in the world are facing water shortage? Locations in the world facing water shortage

48. 2. Which locations in the world are facing water shortage? Locations in the world facing water shortage • Northern Africa is one of the driest areas in the world • Rainfall is low and unreliable (natural factor) • Most countries in Northern Africa cannot meet their current water demand • Forecasts show that climate change will make the weather hotterand drier —more water will be lost due to higher evaporation rates and reduced infiltration  smaller groundwater supply

49. 2. Which locations in the world are facing water shortage? Locations in the world facing water shortage • Water shortage can also be caused by human activities For example, • Uzbekistan (in Central Asia) used to rely on abundant water supply from the Aral Sea (once the world’s fourth-largest lake) • Due to increasing demand for crops, the increase in irrigation led to a decreasing supply of water Causing water shortage in surrounding countries

50. 2. Which locations in the world are facing water shortage? Locations in the world facing water shortage