4.2 Access to fresh water

Question 1

What is the definition of “water security”?

Answer 1

The capacity of a population to safeguard sustainable access to adequate quantities of acceptable quality water for sustaining livelihoods, human well-being and socio-economic development.

Question 2

What are the two types of “water scarcity”?

Answer 2

• physical
• economic

Question 3

What is “Physical water scarcity”?

Answer 3

When physical access to water is limited. Demand outstrips a region’s ability to provide the water needed by the population.

Question 3

What is “Economic water scarcity”?

Answer 3

When a population does not have the necessary monetary means to access an adequate source of water (eg. Africa)

Question 4

What does “hydrosphere” refer to?

Answer 4

All forms in which earths water can exist

Question 5

What is the “turnover time”?

Answer 5

Turnover time = time taken for a water molecule to enter and leave a part of the system

–> varies massively and although water is technically renewable, intensive use depletes the storage and restoration takes tens to hundreds of years

Question 6

What is the problem with “water distribution”?

Answer 6

The available freshwater is NOT evenly distributed around the globe
eg. Congo Basin accounts for 30% of Africa’s annual run-off but has less than 10% of its population

Question 7

What is a major issue with freshwater from aquifers?

Answer 7

Water is a finite resource – we are withdrawing water from underground aquifers at a greater rate that it can be replenished!!

Question 8

How does water usage differ in LEDCs?

Answer 8

Water usage is lower in LEDCs

• Some countries can’t afford to retrieve the water (economic water scarcity)
• Water sources are often far away
  –> people have to travel for water, houses aren’t fully connected with water supplies like in MEDCs
• People in MEDCs grow aesthetic gardens –> irrigate! In LEDCs people irrigate only necessary crops/ food

Question 9

What are some reasons as to why water is becoming scarcer?

Answer 9

• Growing population
• Increasing affluence
• Climate change
• Biofuel production
• Agricultural practices
• Low water levels
• Aquifer exhaustion

Question 10

What is “water degradation”?

Answer 10

Both surface and groundwater supplies in many parts of the world are affected by pollution and contamination.

–> Direct contamination - water sources are used as sewers or places to dump pollutants
–> Indirect contamination - contaminants enter the water supply through surface run off or by infiltration into the ground water

Question 11

What are some solutions to “water degradation”?

Answer 11

• Use organic farming methods
• Use highly selective pesticides
• Industry removes pollutants
• Regulate temperature of water
• Legislation and regulation

Question 12

What are the 3 water scarcity solutions?

Answer 12

1. Enhancing water supplies
2. Reducing demand (conservation measures)
3. Preventing degradation of water resources

Question 13

How can we “enhance water supplies”?

Answer 13

• Dams and reservoirs
• Rainwater harvesting
• Desalination
• Grey water recycling

Question 14

What are some advantages and disadvantages of “Dams and reservoirs”?

Answer 14

Natural or artificially created lakes, used to collect and store water during times of high rainfall. Built by damming rivers and flooding suitable valleys.

Strengths:
- hydroelectricity generation
- flood control
- recreational value
- control of water quality

Weaknesses:
- expensive and time consuming to construct
- change to habitat
- relocation of people
- change to water flow

Question 15

What are some advantages and disadvantages of “Rainwater harvesting”?

Answer 15

Rainwater is collected when it falls on the earth e.g. from roofs of buildings. It can be stored in tanks and can be used for domestic purposes, such as cleaning and gardening.

Strengths:
- reduces risk of flooding and soil erosion
- relatively cheap method
- easy to maintain
- reduces demand on groundwater sources

Weaknesses:
- Water must be filtered and disinfected before drinking
- rainfall may be unpredictable
- initial costs may be high
- requires regular maintenance

Question 16

What are some advantages and disadvantages of “Desalination”?

Answer 16

Production of fresh drinking water from seawater.

Strengths:
- reasonable cost where waste energy is available
- becoming more and more common
- does not affect water levels in river and lakes

Weaknesses:
- expensive (unaffordable for LEDCs)
- salt is returned to ocean (can damage marine ecosystems
- intake pipes may take up plankton

Question 17

What are some advantages and disadvantages of “Grey water recycling”?

Answer 17

Grey water is water that has been used but is clean enough to use again – water from baths, showers, washing machine..

Strengths:
- reduces amount of water abstracted.
- reduces amount of wastewater produced and requiring treatment.

Weaknesses:
- not suitable for drinking due to pathogens and contaminants.
- cost of collection and treatment system can be expensive and prohibitive for individual households

Question 18

What are some conservation measures/ reducing water demand?

Answer 18

Increased water efficiency
- Agriculture – improved irrigation techniques e.g. drip irrigation.

Public awareness campaigns
- Showers instead of baths

School education
- Encourages long term changes in behaviour

Economic incentives
- Increasing the cost of water
- Installing water meters

Legislation/ policies for water efficiency
- Regulations that require all new buildings to have low flush toilets, showers and greywater systems

Low water crops
- Changing to crops that require less water to produce – GM?

Vegetarian diet
- Requires less water than meat to produce

Improving water distribution
- Detecting and fixing leaks in the system

Question 19

How can we prevent the degradation of water resources?

Answer 19

Agriculture
- Reduce pesticide and fertiliser use - smallest amount at most appropriate time
- Replace chemical fertilisers with organic ones
- Prevent over-spray e.g. near waterways
- Use highly selective pesticides instead of generic ones or use biological control

Industry
- Legislation to force industry to remove pollutants from wastewater with water treatment before discharge
- Regulate maximum temperatures of released cooling water – cooling towers to evaporate the water