Water and its management

1. WATER AND ITS
MANAGEMENT
Chapter 4

2. 4.1 Global water distribution
■ Learning Objectives: Describe the distribution of the Earth`s water
- Oceans
- Fresh water (ice sheets & glaciers, ground water, atmosphere, lakes & rivers)
■ www.usgs.gov – search ‘Where is Earth’s water?’
Follow the link for more information

4. Key term:
Sanitation: the conditions necessary for health, such
as:
1. providing clean drinking water
2. safe disposal of sewage
■ 75% of the Earth`s surface is covered with water.
■ Only 3% of this water is FRESH ( not salty) = usable for humans
■ This 3% = 42 million Km3 of fresh water.
■ Much of this 3% fresh water is locked in the polar ice caps & glaciers.
■ Less than 1% of this fresh water is available for people to use.

5. Distribution of water on Earth
https://www.bbc.co.uk/bitesize/guides/zt3xdmn/revision/1
Water distribution
Saline (oceans) ~97% Fresh water ~3%
■ On average, one person uses about 1.5 million liters
a year for washing and drinking.
■ Half of the fresh water is found in just 6 countries:
Brazil, Russia, Canada, Indonesia,China & Colombia
 Much of the water inChina & Colombia is not safe
for drinking.
 Worldwide, women suffer from collecting water.
 InAfrica & Asia, women walk in average of 6
hours/day to collect water.

6. 4.2The water cycle
Learning Objectives:
Describe and interpret the water cycle
 Precipitation
 surface run off
 Interception
 Infiltration
 Through-flow
 Ground water
 Transpiration
 Evaporation
 condensation

7. 1 386 000 000 KM3
OFWATER ON
EARTH IS FIXED
AMOUNTTHAT
NEITHER
INCREASES NOR
DECREASES.

8. The water, or hydrologic, cycle describes the movement of water as water molecules
make their way from the Earth’s surface to the atmosphere and back again, in some
cases to below the surface. This gigantic system, powered by energy from the Sun, is a
continuous exchange of moisture between the oceans, the atmosphere, and the land.

9. https://youtu.be/vYBjPE0wekw Water cycle

10. 4.3Water usage
Learning Objectives:
Describe the different ways in which fresh water can be
used
1. Domestic
2. Industrial
3. Agricultural

11. 4.4 Water supply
Learning Objectives:
 Describe the sources of fresh water used by people
1. aquifers
2. wells
3. rivers
4. reservoirs
5. desalination plants
KeyTerms:
1. Artesian aquifers
2. Desalination
3. Reserve osmosis

12. 1. Surface water:
a. lakes: good source of water for people
b. Rivers: good source of water for people
 Reservoir
2. Ground water:
Vast majority of water is stored in the spaces of porous rocks (limestones &
sandstones)
 such as, Aquifers
 Wells
If there are insufficient amount of water on surface or under the ground, we
use Saltwater.This water is made safe to human (potable) by Removing the
Salt (DESALINATION)

13. Water from rivers
 reservoir
It can be built behind a Dam by the side of the river, creating store
of water.
Generally this water is not potable for humans.
Reservoir types:
a. service reservoirs has potable water to use
b. Water towers
c. Underground cisterns

14. RESERVOI
R

16. IRRIGATION
RESERVOIR IN
CANADA

18. Water from the ground
 1. Aquifers stores water when water infiltrates and accumulate in porous rocks such
sandstone & limestone. About 30% of fresh water is found in aquifers, it fulfils
many people
The most common way in which water is obtained from aquifers is to sink Wells
 2. Wells. Can be dug in from the ground by hand(lowering down a bucket) in LEDCs
or bored by machinery (motor-driven pump) in MEDCs
 3. Artesian aquifers: Wells stored under pressure are called artesian aquifers.
Water from a well sunk into an artesian aquifer will rise to the surface
without the need for a pump.

22. Water from the sea
To make saltwater suitable to drink by humans, it must be Desalinated
Two processes(methods) can be used to make saltwater potable:
1. Distillation ( water is boiled & released as vapour, leaving salt behind), then
the water vapour is condensed as liquid to be used later.
Desalination by distillation is about
10-30% efficient ???
1. the process produces large quatities of waste,
saltwater ( BRINE) the need to be disposed
2. It can be source of pollution because it needs
energy to operate and to transport
3. it can be costly
4. It can be found in MEDCs and Middle East
countries

23. 2. by Reverse Osmosis ( salt water is pumped at high pressure through
very fine membranes
Reverse Osmosis techniques is mostly used by plants

24. Step 1
Pumps force
seawater through
pipes; this uses
energy
Step 2
Seawater is pumped
through thousands of
pipes to remove salt,
it needs energy

25. RO
This Photo by Unknown author is licensed under CC BY-SA.

26. 4.5 Availability of safe drinking water
around the world
Learning objectives:
 Compare the availability of safe drinking (potable water)
in different parts of the world.
a. between water-rich & water-poor regions and potential
for water conflict
b. access to safe drinking water in urban & rural areas

27.  https://www.worldometers.info/ world meter
■ http://www.growingblue.com/wp-content/uploads/2019/01/Growing-
Blue-ilovepdf-compressed.pdf Water stress in the world map

29. The most important factor when considering a countries`
water wealth is the amount of rain it receives
■ Brazil & Russia are the most water wealthy nations.
■ United Arab Emirates & Kuwait are two of the most water poor.
■ China, which has the largest population in the world at over 1.3
billion, the water availability is about 2800 Km3, this makes
2300 m3/person/year
■ Singapore, which has only 0.60 Km3 of water available, the
supply is only about 110 m3/person/year....
■ That means a water rich country seems to have enough water
for its people

30. The lack of water maybe because of:
■ Physical water scarcity: the lack of water because of low rainfall/and or high levels
of evaporation.
■ Economic water scarcity: the of water is available but Can Not extract it, purify it
and make it available for the population.
Two main principles to ensure use of water:
1. Sanitation systems, which ensure that dirty water does not mix with potable
water.
2. water-treatment processes, which ensure that water supplied to people is safe to
drink
https://youtu.be/XGgYTcPzexE Lack of water

31. Worldwide, sanitation and clean water are not available to everyone.
United nations (UN) said the aim was to halve, the proportion of the population
without sustainable access to safe drinking water and basic sanitation.
2.1 billion people have gained access to improved sanitation.
2.4 billion are still using unimproved sanitation facilities
946 millions of these still practice open defecation.
A child dies every 2.5 minute from diseases linked to open defecation
In LEDCs, less than a quarter of the population has access to safe water.
In Europe & North America, it is taken for granted that 100% have such access.
This varies from country to another, from urban to rural or even from city to a town.

32. Main reasons for this difference are that:
1. there is more wealth and wealthy people in cities.
2. Large numbers of people can act together to pressurize authorities to
provide safe water.
3. It is cheaper to install piped water when many people live close
together than in a scattered rural community.

33. ■ At a larger scale, differences in the availability of water can
also lead to actual conflict: Water Wars

34. ■ There are some tension
over the use of the River
of Jordan.
■ Another tention raised
aroundThe Aral Sea in
Asia

35. Self-Assessment Questions/pg.95
In groups of three, complete the task in 10 minutes

36. 4.6 Multipurpose dam projects
Learning Objectives:
• Describe and evaluate multipurpose dam projects.
- Choice of site
- environmental, economic and social impacts
- sustainability

37. Packwood Lake Hydro
Project
The Packwood Lake
Hydro Project is a
hydroelectric project
owned and operated
by Energy Northwest.
Completed in 1964 the
project was the first
project built by a
group of public power
utilities that later
became Energy
Northwest.

38. In general constructing a dam can be very expensive and
controversial project, a dam may help in:
1. Generation of electricity
2. Flood control
3. Irrigation
4. Tourism & leisure
5. Provision of water (Services)
6. Creation of habitat
7. Access by boat to inaccessible areas

39. Disadvantages of dam projects are:
1. Relocating people
2. Flooding land
3. Disrupting the life cycle of fish and other aquatic
organisms.
4. Altering the water supply for people downstream of the
dam
5. Reducing the enrichment of soil downstream of the dam
6. The dam may become redundant as sediment in the
river sinks at the bottom.

40. ■ https://youtu.be/q8HmRLCgDAI Hydroelectric Power (HEP)
■ https://youtu.be/OC8Lbyeyh-E How it works

41. Where to build a dam?
1. It must be in a river valley for economic reasons
2. The valley should be narrow where the dam is built.;
A wider valley will cost more to build a dam
1. A dam needs to be high up a valley to
produce Hydroelectric power (HEP);
The higher the dam the greater the pressure of water.
1. Dams should be sited away from developed areas, to
reduce the risk of pollution in the reservoir.

42. Are dams sustainable?
■ They are good solution for generating electricity
■ There are problems with their operation on the long run.
■ The reservoir can be silted due to the material left behind..
■ Dams with time can deteriorate and fail.
■ Dams can affect the environment including fish
population.
■ On the other hand, dams are superior alternative to the
burning of fuels because they produce electricity
without emitting greenhouse gases

43. Self-assessment questions/ pg.96
4.7 Water-related diseases
https://water.org/our-impact/water-crisis
https://youtu.be/LSqan1xmMpY
Learning objectives:
• Describe the life cycle of malaria parasite
• Evaluate the strategies to control it.
• Describe strategies to control cholera

44. ■ Water provides a nutrient –rich environment for bacteria and viruses
https://youtu.be/8-sqticNg5o : Cholera
https://youtu.be/f5XKob0lc2A : Malaria
https://youtu.be/N1lKW2CYU68 :Typhoid

45. ■ Two major diseases caused by water contaminated with
human faeces are:
1. Cholera
2. Typhoid
 The crucial element in preventing these diseases being
transmitted with people is to ensure that; Sewage water and
drinking water do not encounter each other.
 Look at the features for Cholera and Typhoid on page 98/CB

47. • Bacteria may enter drinking water from sewage if sanitization is poor.
• If these pathogens (organisms, including bacteria and viruses that can
cause diseases) + the water they live in is untreated, Then.....diseases
can spread.
• Therefore, sanitation is CRUCIAL and preventing them from being
transmitted within a population before delivered to people to drink.
• Hygiene is important as is for washing and cooking food.
• Washing hands from any faecal material.
• Use of efficient latrines is essential.
• BOIL THE WATER to eliminate the harmful organisms.

48. Malaria:
Like cholera & typhoid is water-related disease
■ The organism is an insect called MOSQUITO, lay its eggs in water, where larvae
develop.
■ Mosquitoes can pass malaria on to humans, acting as a vector
■ Malaria occurs in 97(out of 193) countries around the world, mainly in Africa,
Asia and the Americas.
■ These countries are home for 3.8 billion people, almost half of the population
of the whole world.
■ In 2015 there were 214 million cases of Malaria and 438 000 death
■ Symptoms: flue-like, fever and chills at first.The disease can be fatal
■ Malaria can be treated but a much better option is prevention.

50. Figure 4.7
Figure 4.8

51. How can prevent being bitten by mosquitos:
■ Avoiding being outside between dusk and dawn in countries where
malaria mosquitoes are active at night.
■ Wearing clothing that covers most of the body and treat exposed parts
of the body with mosquito-repellent products.
■ Sleeping under a mosquito net treated with insecticides.
■ Spraying the inside of accommodation with insecticides.
■ Spraying insecticide inside building, houses.
■ Draining wetland areas to remove mosquito- breeding sites
■ Pouring oil onto the surface of the water where mosquitoes breed
■ Eradicating malaria means completely removing
the malaria parasite from the population.

54. https://youtu.be/Va_2hCZDYeU

55. MALARIA IS CAUSED BY A PARASITE, WHICH BREEDS IN AN
INSECT, WHICH BREEDS IN WATER.
CHOLERA & TYPHOID ARE BACTERIAL DISEASES.

56. ■ WHO encourages the eradication in sub-Saharan Africa, where
nearly 90% of all cases occur
■ There is the possibility that malaria is favored by Global Warming.
■ Studies are showing that malaria is showing in highland regions of
Kenya, Colombia and Ethiopia.
■ In the first 12 years of the 21st. Century, improvements in diagnosis,
treatment and prevention have led to a 42% deaths from malaria
■ The mosquito vector is evolving resistance to insecticides and
the parasite is also becoming resistant to available drugs.

57. 4.8 Sources, impact and management of water pollution
Learning Objectives:
 Describe and explain the impact of pollution of fresh water on
people and the environment.
1. global inequalities in sewage and water treatment
2. risk of infectious bacterial diseases (typhoid & cholera)
3. accumulation of toxic substances from industrial processes in lakes and
rivers
4. bioaccumulation of toxic substances in food chains
5. the effect of acid rain on organism in rivers and lakes
6. nutrient enrichment leading to eutrophication

58. The three main uses of water are also the three main polluters
1) Domestic waste
i. Sewage treatment
ii. Improved sanitation
iii. Water treatment
2) Industrial processes
i. Toxic compounds from industry
ii. Acid rain
3) Agriculture
i. Eutrophication
ii. Pesticide and herbicide pollution

59. 1) Domestic waste (home & building waste)/ pg100
• Sewage is water matter carried away from houses and buildings in cities
and villages.
• It takes away drains called sewage and dumped or Converted into a form
that is less harmful.
• Sewage is rich in ORGANIC MATTER & MICROBIAL ORGANISMS.
• Sewage is dumped in water, so it must be treated beforehand.

60. I. Sewage treatment:
What is the main aim of sewage treatment?
To reduce the biological oxygen demand (B.O.D) of the sewage.
So what is BOD?
https://youtu.be/v33CgWJ2TZ0
The BOD of sewage :
is the amount of oxygen it would
use up if released directly to the
river or lake

61. Sewage treatment
https://youtu.be/8isr9nSDCK4

62. Sewage treatment process:
Sewage treatment or The activated
sludge process
Main parts of sewage treatment:
1. Sewage outfall: wastewater is taken
through pipes is called sewage.
2. Screening tank: large objects are
removed from sewage using coarse grid.
3. First settling tank:
The solid organic waste will settle at the
bottom of the tank...this called Sludge.
The cleaned water overflows the sides
and taken to the next stage.
Primary treatment: (1,2 and 3)

63. 4. Oxidation (aerobic bacteria stage)
Water is pumped into the tank where oxygen is bubbled through it
This will encourage the growth of bacteria & microbes.
Which in return will dissolved Organic Matter and causes B O D
5. The second settling tank:
Water enters the second settling tank where the bacteria settles at the
bottom …..forming more sludge.
Now, this cleaner water overflows the sides of the tank as Effluent
Secondary treatment:(4 &5)
6. The effluent is discharged into the environment, usually rivers.

64. 7. Sludge digester:
Oxygen- free conditions are created that encourage the growth of bacteria
which can break down the Sludge....releasing methane, which can be
burnt
8. The treated sludge can be dried in sludge lagoons and used as
fertilizers.
9. Some extra treatment may involve further filtering using Chlorine
(Chlorination)

66. ii. Improved Sanitation systems
Improving sanitation can be done by separating the human excreta
from human by:
 A flush toilet:
1. connection to system of sewer pipes(sewerage) that collects
human faeces, urine and wastewater which is removed from the
house.
2. connection to septic system, which consists of an underground,
sealed settling seat.
 A pit Latrine with a platform: dry pit fully covered by a platform
fitted with a seat over a hole.....or just have a hole
 A composting toilet is a dry toilet into which vegetable waste,
straw, grass sawdust and ash are added to the human waste to
produce compost.

71. iii. Water treatment
■ Water that is domestic and is used for drinking, washing and cooking is called
potable water.
■ To make it potable it should go under Coagulation treatment, and that is filtration
and disinfection
■ COAGULANT process steps:
1. Coagulant makes particles in water stick together and settle at the bottom
The container
2. the water then is filtered through sand
3. adding chlorine to the filtered water to kill any pathogens that may remain
( Chlorine is added to the water as disinfectant = Chlorination)

72. The stages in the
treatment of water to
produce potable water
Fig.4.10/pg.102

73. Self-assessment questions pg.101

74. 2) Industrial process:
■ i.Toxic compounds from industry
■ ii. Acid rain

75. Industrial process:
Industry produces & uses a wide range of chemicals that can be harmful to both humans
and the environment.
Industry produces gases that enters the atmosphere, where they dissolve in water and form
acid rain
.i. Toxic compounds from industry
- Biomagnification: the increasing concentration of a substance, such as a toxic chemical,
in the tissues of tolerant organisms at successively higher levels in a food chain.
- The most well-known examples of biomagnification are; Heavy metals and pesticides.
- Many industrial processes involve the use of heavy metals such as lead, mercury and
cadmium. Those toxic substances will be stored in the bodies of plants, animals and
humans....causing illness.
ii. Acid rain
- By 1970 acid rain was considered a serious problem
- DIEBACK: the leaves and branches of trees in many forests of the world were dead

76. DIEBACK

77. ACID RAIN

78. What causes acid rain? Figure 4.13/pg.104
1. When fossil fuels are burned, gases such sulfur dioxide (SO2) and
oxides of nitrogen (NOx) are produced.
2. Sulfur oxides dissolves in water (clouds) producing sulfuric acid
and oxides of nitrogen produces nitric acid.
3. When it rains these acids fall to the ground.
4. The gases can be blown from one country to another
https://youtu.be/1PDjVDIrFec

79. The impact & effect of acid rain on Aquatic ecosystem
■ When water in a river or lake is acidified, the pH makes it
intolerable to organisms
■ Fish organisms will be malformed
■ Acid rain may lead to leaching of heavy metals, such Aluminum
and cause suffocation for fish gills.
■ Some essential minerals for life will be washed away, like Calcium
And Potassium are washed away to rivers & lakes
 This will reduce the algal growth
 Reduce the fertility of surrounding soils
 Affect the whole ecosystem

80. Reducing acid rain
■ Substitute the fossil fuels
■ Low-Sulfur varieties should be used
■ NOx emissions should be reduced by burning with cooler
flame

81. 3) Agriculture Fig.4.14 & 4.15/pg.105
Many chemicals can enter the agriculture and harm humans and environment:
i. Eutrophication:
 Nutrients such nitrate (NO3) and phosphate (SO4) can enter water from
farmland, industry and domestic outputs.
 Organic matter can enter water directly as sewage.
 And, any increase in nitrate & phosphate will cause rapid growth of algae, we
call it the algal bloom
 When the algae die there will be an increase in organic matter in the water.
 This acts as food for bacteria as they decomposed the dead algae
 This bacteria will use up all the oxygen, lowering its levels in water
 This will lead to the death of other organisms in water ...EUTROPHICATION

82. Nutrients enter water
Stimulate algal growth an algal bloom
Algae die
Bacteria decompose dead algae,
increasing the organic matter
Oxygen used up and level is lowered
Fish and many other aquatic animals,
including insect larvae, die
Organic matter from
sewage,manure,paper
waste and many other
sources

84. ii Pesticide and herbicide pollution
• Pesticides are designed to kill living things, but not humans
• But pesticides might harm human in an indirect & negative way.
• Pesticides are generally water-soluble, so water pollution by
these agrochemicals is a major concern
• Insecticides is class of pesticides produced to kill insects...that
Will kill both the target species ( the pest) and the non-target species

85. Pollution control and legislation
■ Governments have been tackling pollution by legislation.
■ Industries in participating countries are required to monitor
the pollution they cause and keep it within set levels
■ The legislation puts pressure on the polluters to find ways to
reduce the pollutants
■ There are fines for exceeding limits
■ Companies may be prosecuted and in extreme cases forced
to close down.
■ Incentives are used to encourage companies to take parts and
pay taxes to reduce the impact of pollution they produce

86. ■ https://www.bbc.co.uk/bitesize/guides/zt3xdmn/revision/1 Water distribution
■ https://www.bbc.co.uk/bitesize/guides/z72v4wx/revision/3Water cycle
■ https://www.bbc.co.uk/bitesize/guides/zqv3dmn/revision/1 water supply
■ www. Worldmeter.info – search for water (water usage & quality)
■ www.klickitpud.com – search for ‘Packwood lake hydro project’
■ https://www.bbc.co.uk/bitesize/guides/zg4tfrd/revision/3 multipurpose dam projects
■ https://www.bbc.co.uk/bitesize/guides/zppdg82/revision/5 River management
■ https://www.bbc.co.uk/bitesize/guides/zyvwxnb/revision/1 water pollution and its recourses
■ https://www.bbc.co.uk/bitesize/guides/zgx382p/revision/2 managing pollution of water
supply
■ http://www.who.int/water-sanitation-health recourses strategies to improve water quality
■ https://www.bbc.co.uk/bitesize/guides/zg2mycw/revision/6 water-related diseases