Access to Freshwater

Question 1

How many people live without clean drinking water?

Answer 1

1.1 billion people live without clean drinking water

Question 2

How many children died everyday from waterborne disease in 2004?

Answer 2

3,900

Question 3

What is the daily per capita use of water in North America + Japan?

Answer 3

350litres

Question 4

What is the daily per capita use of water in Sub-Saharan Africa?

Answer 4

20litres

Question 5

How much water is needed to produce 1 kg of wheat, rice and beef?

Answer 5

Wheat = 1,000litres
Rise = 1,400litres
Beef = 13,000litres

Question 6

How can we remove salt from water and what are the problems with this?

Answer 6

• Desalinisation plants
• Energy costs are large
• Only currently possible in water-stressed wealthy countries near the sea e.g Israel
• Salt is a by-product + is often returned to ocean, increasing density of water which then sinks + damages ocean-bottom ecosystems

Question 7

What proportion of the human population lives with some level of water scarcity?

Answer 7

40%

Question 8

6 things humans use freshwater for

Answer 8

> Domestic purposes // drinking, cleaning
Agriculture // irrigation, for animals
Industry // manufacture, mining
Hydroelectric power
Transportation // ships on lakes+rivers
Marking boundaries between nation states

Question 9

How much freshwater does Agenda 21 say humans should have access to daily?

Answer 9

40litres

Question 10

What are aquifers?

Answer 10

• An aquifer is a layer of porous rock (holds water) sandwiched between 2 layers of impermeable rock
• Continuously filled by infiltration of precipitation where porous rock reaches surface, but this only in limited areas

Question 11

Can aquifers be used sustainably?

Answer 11

• Water flow in aquifers is v slow and so they are often used unsustainably
• Many aquifers are ‘fossil aquifers’ meaning the recharge source is no longer exposed at surface so can never be refilled. These can never be used sustainably

Question 12

What is the problem with irrigation?

Answer 12

• Irrigation often results in soil degradation
• Much of water used in irrigation evaporates before its absorbed by crops
• Dissolved minerals remain in top layer of the soil making it too saline for further agriculture (salinisation)

Question 13

What is the problem with industries + electricity plants releasing warm water into rivers?

Answer 13

• Warm water holds less dissolved oxygen than cold water
• So aquatic organisms that take their oxygen from water (fish) are negatively affected
• Warm water outflow from power stations changes the species composition in the water

SO USE COOLING TOWERS

Question 14

How can climate change increase inequality of freshwater supplies?

Answer 14

May disrupt rainfall patterns

Can even change monsoon rains

Question 15

5 ways to increase freshwater supplies

Answer 15

> reservoirs
> redistribution
> desalinisation plants removing salt from seawater
> rainwater harvesting systems 
> artificially recharging aquifers

Question 16

3 ways to reduce amounts of freshwater used

Answer 16

> reduce domestic use by using more water-efficient showers, dishwashers, toilets
wash cars in car washes w closed water system// also reduces pollution by oil
grey-water recycling// water from showers, baths etc can be used in garden irrigation + toilets

Question 17

How to reduce problems caused by irrigation

Answer 17

• selecting drought resistant crops can reduce need for irrigation (some areas may be unsuitable for growing crops, graze cattle instead)
• trickle systems instead of spraying water to reduce evaporation