3. Water scarcity and water quality

The varying power of different actors in relation to water management issues

Syllabus:  Physical and economic water scarcity, and the factors that control these including the causes and impacts of droughts; the distinction between water quantity and water quality

Make a note of where the worlds fresh water is located.


Map showing physical and economic water scarcity

Screen Shot 2018-10-07 at 4.47.24 pm
Source: UN

Task: 1

  1. Describe the areas of physical water scarcity shown on the map.
  2. Describe the areas of economic water scarcity shown on the map.

Physical Water Scarcity:
Where the demand for water is greater than the supply of water. Consumption of available water is over 60% of the available supply, or demand is at unsustainable levels. Physical water scarcity does not have to be an arid (dry) environment. Demand for water in arid environments (e.g. deserts) is normally low due to low levels of population density and low levels of economic development. So there may not be a shortage of water in terms of demand and supply from people.

Economic Water Scarcity:
Where there is water physically available, but for some economic reason, it is not possible to fully utilise the source of water. This might because extraction, storage or transportation costs are too high, or because the water is polluted and it is not possible to treat it. Therefore people go without water or rely on unclean/untreated water.

Drought is an extended period of dry weather leading to conditions of extreme dryness.
Absolute drought: A period of 15 consecutive days where average daily rainfall is <0.2mm.
Partial drought: A period of at least 29 consecutive days where average daily rainfall is <0.2mm.

Droughts are caused by:
• climate factors like El Nino or high atmospheric pressure.

Task: 2  –  Watch the videos below and draw an annotated diagram to show the process of El Nino (include the following:  Australia, South America, trade winds, Pacific Ocean).

El Nino – What is it? (4 mins)

Webwhat-is-el-nino-noaa•Droughts can also be caused by mountains (rain shadows)


• cold ocean currents
• or simply the prevailing winds crossing large areas of dry land with little moisture



Some of the impacts of droughts are:
• crop failure
• animal mortality
• health issues related to dehydration
• forest fires
• bans on consumption e.g. hosepipe bans, washing cars, etc

Water quantity (supply)
The supply of water to an area depends on several factors related to the water cycle:
• rates of rainfall
• rates of evaporation
• the use of water by plants
• river and groundwater flows

Currently, there are estimated 6600 cubic metres of freshwater per person globally.
By 2015 this is likely to fall to 4400 (population growth and climate change).

The world’s available freshwater is not distributed evenly either seasonally or year-to-year. 75% of annual rainfall occurs in areas covering 33% of the world’s population.

Water Stress
When the demand for water exceeds supply during a set period of time leading to shortages. Per capita annual water supply of <1700 cubic metres is considered ‘water stress’. Currently, 2.3 billion people live in water-stressed areas, rising to an estimated 3.5 be in 2025.

Regions most affected:
• Africa
• Middle East
• South Asia

Since 1922 the world’s population has tripled, hence demand has increased.
Economic growth bringing rising wealth and consumption) has also increased.
Therefore water use is 600% higher than in 1922. It is projected to increase a further 50% by 2040. as a consequence:
• half of the world’s wetlands have disappeared
• 20% of world fresh land species are/near to extinction
• water tables are falling globally

Water quality
Water quality refers to whether it is suitable for consumption (potable) and for sanitation like washing. The WHO estimates there are 4 million deaths p.a. caused by water-related diseases: cholera, hepatitis and malaria.  The most common causes of reduced water quality (pollution) are:
• organic waste from sewage
• fertilizers and pesticides from agriculture
• heavy metals and acids from industrial processes and waste.
• urban areas are generally better served with good quality water than rural areas.
• Asia, Caribbean and Latin America are generally better served than Africa.
• Some countries with piped water still have poor quality water so people drink bottled
water. e.g. Thailand, Mexico, India.

Syllabus:  Environmental consequences of agricultural activities on water quality, to include pollution (eutrophication) and irrigation (salinization)

Eutrophication is the nutrient enrichment of streams and lakes caused by agricultural
runoff from nitrate fertilizers, phosphates and manure.  Runoff carries excess nutrients to rivers, lakes and other water bodies.  This can cause algal blooms (growth of algae on the surface).  Light is prevented from reaching submerged plants. Anoxia also occurs – reduced levels of oxygen in the water.

This can lead to ‘dead zones’ if large areas are affected. High concentrations of nitrates in water can cause health risks (blue baby syndrome). Other problems of eutrophication include a loss of wildlife/fish; reduced tourism potential and high costs of cleaning water.

There are ways of dealing with eutrophication:
1. Changing agricultural practices to use less / different types of fertilizer or not
applying nitrates on fields near to rivers/lakes.
2. Removing nitrates from water at sewage treatment plants.
3. Draining mud and dead plants from eutrophic lakes/rivers.

Process of Eutrophication

Eutrophication in China
For the two examples below, identify:

  • Location and Geographic context (Place)
  • Sources and nature of pollution (Process and Power)
  • The magnitude of the issue
  • Impacts (SEEP) (Process and Power)
  • Solutions/future prospects (Possibility)



Salinization can be caused by:

1. Groundwater rising to the surface through capillary action. Water is evaporated leaving minerals behind. Irrigating fields can cause groundwater levels to rise.

2. Irrigation which adds a large amount of water to fields. Water evaporates from the field surfaces increasing the mineral concentrations left behind.

3. Groundwater depletion (abstraction) near to coasts. Seawater can then infiltrate the
aquifers (salt-water intrusion). The salty water can then make its way to the surface through being abstracted in wells/boreholes or through capillary action.

Saltwater intrusion

Salinisation is widespread in arid and semi-arid environments where evaporation rates are higher and groundwater extraction in coastal areas is more common.
Salt enrichment of the soil/surface can lead to these salts leaching into rivers/lakes in rivers. Local geology can also play an important role in some contexts. Salinization damages livelihoods for farmers by limiting agriculture yields.


Task:  3

Watch the videos on eutrophication and salination.

Soil Salinity in Australia

What is Eutrophication?

  1.  Describe two ways agriculture can have an impact on water quality.

Syllabus:  Detailed examples to illustrate the role of different stakeholder

Irrigation and the use of fertilizers has positive and negative impacts on various stakeholders.

Increased crop yields and resulting lower food prices help by:
• increasing incomes for farmers
• providing food security for local communities
political stability and social cohesion are improved
• opportunities for wealth and development to multiply out to other businesses

However, some farmers face environmental problems caused by:
• salinization can reduce crop yields over time (Pakistan’s Indus plains water table is 6m
higher than 1922)
eutrophication affects local water users and industries
• groundwater can be depleted (water table drops) causing water shortages.
The water table has fallen 50m in Texas.
agro-businesses benefit from sales of fertilizers supporting unsustainable farming
• governments may have additional costs of dealing with water quality issues
Irrigation changes climates through increased rates of evaporation. This can be positive creating more precipitation in arid areas – but also problematic – more storms (erosion and flooding).
The Earth’s albedo  (reflectivity of the earth’s surface) is also changing as darker vegetation absorbs more insolation than lighter sandy soils. But vegetation cools the surroundings through evapotranspiration.

Task: 4

Agriculture, which accounts for 70 per cent of water withdrawals worldwide, plays a major role in water pollution. Farms discharge large quantities of agrochemicals, organic matter, drug residues, sediments and saline drainage into water bodies. 

  1. Create a simple infographic on the impacts of agriculture on freshwater quality. Check your understanding of the terms used – your infographic must not include any words or phrases you do not understand.
  2. Study the graph below. Describe the trends shown quoting data. What does this graph tell us about the magnitude of the problem and concerns for the future?

Screen Shot 2018-10-07 at 8.49.11 pm.png

Syllabus:  Growing human pressures on lakes and aquifers, including economic growth and population migration

Population growth places pressure on rivers lakes and groundwater (aquifers). Population growth is uneven e.g. rural-urban migration means cities may face more future water stress.
• Agriculture uses 70 of all water taken from rivers, lakes and groundwater.
• Industry uses 20%.
• Domestic / municipal sector = 10%

Growing populations, growing food consumption, growing industrial output all mean water stress is going to grow.

Stress signs are:
• Some rivers no longer reach the oceans due to abstractions e.g. Colorado
• Pollution makes river water unfit for human consumption e.g Ganges, Yangtze
• Ogallala aquifer in the USA is 10% lower since 1960 and it would take 6000 years to
recharge if abstractions were halted.
• Flint river suffered industrial pollution in Michigan, the USA during 2014-6 and many
residents have suffered lead poisoning.
• China’s rapid industrialisation means 300m people do not have access to safe water
and 70% of Chinese rivers are officially polluted.

Task: 5

What is an aquifer? (5-minute video)

Use the video to make notes on each of the following:

  • What is an aquifer and what are their characteristics?
  • What are the two types of aquifers?
  • How does human activity affect water tables and aquifers?
  • What is an artesian well?

Pressure on Lakes – The Aral Sea

The Aral Sea crisis

Place – location and geographic context

Process – what are the pressures and what effects are they having?

Power –  who are the decision makers?

Possibility -how is it being managed?

Task: 6

  1. Watch the two videos and look through the PDF.
  2. Describe the reasons the Aral sea has shrunk in the past 40 years (link to irrigation)
  3. What are the two countries to the North and South of the Aral Sea, describe how each has been affected by the sea shrinking and essentially drying up.

The Aral Sea: The sea that dried up in 40 years – BBC (5 minutes)

Restoring the Aral Sea (8 minutes)

The Aral Sea (PDF/notes)

Syllabus:  Internationally shared water resources as a source of conflict

Syllabus:  Case study of one internationally shared water resource and the role of different stakeholders in attempting to find a resolution

Case study:  The Grand Ethiopian Renaissance Dam

Task: 7

Download the template

Watch the videos on the Grand Ethiopian Renaissance Dam, complete the template using both the videos below and articles.


BBC News:  Damming the Nile

The Grand Ethiopian Renaissance Dam

Talk Africa:  The Grand Ethiopian Renaissance Dam


BBC The ‘Water War’ brewing on the Nile

Quartz Africa

Task: 8

Homework (10 mark question)

With reference to an example of an internationally shared water resource, discuss the role various stakeholders share and any attempts to find a resolution.

Things to include –

The freshwater water resource involved should be clearly identified and located,
as should the countries involved in the water conflict.
Answers should clearly describe the nature of the conflict and explain why it occurs e.g.
• countries both in need of limited water supplies e.g. population sizes/growth
• different demands due to industry or agriculture or electricity generation
• arid climate
• territorial boundary disputes etc
For example, Sudan and Egypt had a conflict over the Nile river, as both are in need of limited water supplies to satisfy the demands of the growing populations.
This conflict resulted in the Nile treaty in 1959. Since then the Egyptians have tried to use desalinization to meet their water needs but still rely heavily on the Nile.
However, Ethiopia and Sudan have created upstream projects to utilise the Nile’s water.
The GERD currently being built by Ethiopia is causing regional conflict This has generated stakeholder conflict. The conflict may be resolved through inter-governmental negotiations (Egypt – Ethiopia – Sudan) as well as working with the United Nations to resolve arguments and help find alternative solutions.
The associated problems for each of the countries, however, are not easily solved.
It must be remembered that attempts to resolve the conflict can lead to further conflict and issues e.g. if Egypt begins accessing the Nubian Aquifer.

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