- Created by: rosemustard
- Created on: 01-04-13 14:26
1-Global water supply is linked to three main PHYSICAL factors-
• Rivers Systems
• Distribution of water globally over the earth’s climatic zones- near the equator has high levels of precipitation as in the tropics they suffer from droughts.
• Rainfall varies within season, with very distinct wet and dry seasons
• Responsible are El Niño, or snow pack melting.
• The river systems are responsible for holding and transferring water across continents. -Amazon is responsible for 20% of the world’s water entering the ocean.
• Discharge decreases down stream- evaporation can also decrease water flow.
• Seasonal changes in climate can create significant variations in discharge and produce distinctive river regimes.
• Where the rocks underlying the river basin are impermeable, water will remain on the surface as runoff, creating high-density drainage.
• Permeable soils such as limestone allow water to pass through thus allowing water to flow under ground.
Creating underground aquifers.
Water supply and stress
2-Only 2.5% of water is freshwater and 80% of that is trapped in snowmelt and glaciers.
-There is a correlation between global water demand and population growth, which will cause a number of conflicting issues for both water rich countries such as Canada and Brazil as well as water scarce ones such as Africa, and the Middle east.
-There are three factors, which can be held accountable for water stress levels rising…
water supply and stress.
•-69% of the world’s water •-
1kg of beef needs 10% more water then 1kg of rice •
-17% of the words land is used fro agriculture and most of it mismanages their use of water- Evaporation and fertilizer pollution- eutrophication
-21% of the world’s water.
•-Much more efficient use of water then agriculture, hydroelectric power
•-However can cause significant water pollution problems
•-10% of the world’s water
. •-The amount globally varies from country due to economic development levels-America and UK has high levels due to their consumer lifestyles
. •-Domestic water supply is doubling every 20 years.
-Our water supply comes from 2 sources surface water and groundwater supply.
- -Rivers, lakes and reservoirs.
- -Half of the world’s reservoirs are found in the BRICs or USA.
- -They offer short term economic gain however long-term social and environmental impacts.
- -Underground supplies are the soul drinking supply for 30% of the population.
- -75% of the UKs drinking water comes from aquifers.
- - Over abstraction is occurring in many places –USA- resulting in falling water tables.
Pressure on water supplys
-There is a mismatch between supply and demands in terms of water.
WATER STRESS- annual supply of water drops below 1,7003m per person.
WATER SCARCITY- Below 1,000m3
There are two types of water scarcity, physical and economic.
- PHYSICAL SCARCITY- when more the 75% of a countries river flow is being used.
- ECONOMIC SCARCITY- when blue water flows are limited by economic restrictions put in place for financial gain.
Human impact on water avalibility
AVALIBILITY-having a water supply and distreibution network.
ACCSESS- freedome to use or income to buy water in a particular location.
USAGE- entitlement,understanding of water use and helth impacts.
Human activity is having a negitive effect on the enviroment, especially from a water supply prospective, there are a number of reasons for this including-
- Over obstraction for human needs- domestic, agricultural and for industry.
- Pollution of ground water- sewege disposial contaminates the underground waters supply- expected to cause 135 million deaths by 2020 due to contaminated water desiseses- hepatitis.
- Chemicals from fertilisers used by famers also contaminate groundwater supplys- this can causer eutrphication thus contaminating water supplys.
- Each year there is 400billion tonnes of industry waste which also contributes to water contamination as only a small proportion is disposed of in an enviromentally friendily manner.
- over abstractsion is causing salt water incrusion.
The water poverty index
- 1) resources- The qualoity of surface and grounda water per person, and it's quality.
- 2) Access- The time and distance involved in obtaining a sufficiant SAFE water resource.
- 3)Capacity- How well a cummunity manages its water and health.
- 4)Use- How economically water is used in the home and by agriculture and industry.
- 5)Enviromental-Ecological sustainability ( green water)
Poverty and water poverty go hand in hand- lack of water reduces the posibility for people to escape poverty- grow food- get a job ( have to travel for water)- this caused a SPIRAL OF DECLINE aswell as the POVERTY TRAP.
A demand for water continues to rise so will the price, thus increasing econimoic water scarcity and increasing the amount of people who have to get there water from unsafe and dangerous water supplys.
When the demand for water overtakes supply and several stakeholders wish to use the same resource, there is a potentual for conflict.
Conflicty is most likely where developing countries are involved, water is vitalk as the struffle with there generically large populations and promote industry development
Landlock countrys have additionall issues as readil;ly avalible water sources are far harder as the avalibility of water is far less.
Physical factors affecting water supply
1) Higher temperatures at the equator due to shorter distance from the earth to the sun.
2)Curvature of the earth means the suns rays are more concentrated in some areas around the equator= greater convection rainfall.
3)Circulation cells- Rising air at the equator leaves a void which needs to be filled, air is dragged into the space- the coriolis effect has 3 circulation cells-
Lower pressur zones are created when the air is rising- rainfall is common
Higher pressure zones- Air is sinking- clouds and rainfall is limited.
4) High and low pressure belts.
5) River systems- Down stream means greater volume of water- Bradshaw model.
6) Geology- permeable and impermeable rock.
Economic water scarcity
What factors can cause economic water scarcity-
- Political crisis
- Water Privatisation
- TNCs using water
- Increase usage
- Poverty trap.
12% of the population consume 85% of the water.
1% of the worlds freshwater is easily accessible.
How human activity can make water stress worse-
Key factors which have a negative effect on water supplies as a result of human activity-
- Sewage disposal in developing countries is expected to cause 135 million deaths by 2020.
- In the Uk we added 1,400 million litres of sewage to our rivers daily (although most has been treated).
- Chemical fertilisers contaminate groundwater adding nutrients and making algae grow, causing eutrophication.
- 400 billion tonnes of untreated waste are pumped into river systums untreated each year.
how human activity can make water stress worse-
- Over Extraction
- Over extraction up stream result in dams being built,these trap sediment which reduce the fertility of flood planes.
- Salt water incursion
- Removing water from rivers and groundwater sources can cause issues as in arid areas aquifers are never replenished after being abstracted, on coast lines this can lead to salt water incursion due to the aquifers being replenished by saline water.
How water supply is linked to development- Water p
The water poverty index-
- Water insecurity means not having enough, or sufficient access to safe water.
- Around 20 developing cxountries are classified as 'water scarse'.
Water scarcity happens for two main reasons-
1) Physical scarcity
The water poverty index was established in 2002 and uses 5 parameters:
1)Resource- The quanity of surface and groundwater per person.
2)Access-The time and difference involved in obtaining sufficient and safe water.
3)Capacity-How well the community manages it's water.
4)Use-How economically water is use for domestic, agricultural and industrial purposes.
5)Environmental-ecological sustainability water abstraction from both green and blue supply.
Each of these is scored out of 20 to give a mark out of 100.
How water links to poverty-
What problems can the use of a water source create
- Securing water supplies is vital when supporting irrigation and food production, manufacturing and energy generation.
- However misuse or over use of a water supply can result in a number of issues.
Conflict over the same water source-
- Water conflict occurs when the demand for water overtakes the supply and several stakeholders wish to use the same resource.
- Water conflict is most common in developing countries as water is vital in helping the develop as a nation- thus without water they are stuck in the poverty trap.
- The UN reports that there are 300 water conflicts in the world.
They conflicts include-
- China v India-Brahmaputra river
- Turkey v Syria- Tigris and Euphrates rivers.
- India v Pakistan- Indus river.
Geopolitics of water supply within a country
Often when countries compete water resources international agreements and treaties have been drawn up on how best to manage shared water supplies-
The Helsinki rule- An agreement that international treaties must include concepts such as adequate share and use.
- Natural factors.-Rainfall amounts, share of drainage basin.
- Social and economic needs.-Population size and development level.
- Down stream impacts.-restricting flow and lowering the water table.
- Dependency.-are alternative water resources evaluable?
- Prior use.-Existing Vs Potential use.
- Efficiency.-avoiding waste and mismanagement of water.
issues with developing water pathways
In some places where water supply is limited there is an option to divert previous supplies from one drainage basin to another, However this can cause potential risk-
- Creation of storage lakes can disrupt and destroy habitats.
- Rive flow can decrease.
- Ground water salinisation as a result of the low flow.
- Conflict over the limited water left.
The future of water.
Predictions for water supplies due to dwindling resource levels and climate change have been made, however to an extent the impact can not be predicted.
There are 3 possible scenarios for water by 2025-
1)Business as usual.
Business as usual
Water Changes by 2025-
- Water scarcity will reduce food production.
- Consumption will rise by 50%.
- Household water demand/use will rise by 70%.
- Industrial water demand in developing countries will increase, due to development demands.
- Developing countries will rely on food imports as production has decreased, thus increased hunger/poverty.
- In Many developed countries-USA and China- water will be pumped at higher rates that can be recharged.
Water changes by 2025-
- Global water consumption will increase.
- Demand for domestic water will fall.
- Demand for industrial water will increase by 30%.
- Food production will decline.
- Food prices will increase.
- Conflict over water on a global and regional scale.
Water changes by 2025-
- Global industrial water use will have to fall.
- Global rain-fed crops yields will increase due to improvements in water harvesting and sustainable farming.
- Agricultural and demestic water prices will double.
- Food production to increase slightly.
- Conflict over water increase of a global and regional scale.
How different key players opinions on future water
Different players and decision makers have key roles to play in securing water supplys, these decisions have huge potential to cause or result in conflict-
- Political players- International orginisations,UN, local and regional councils.
- Economic (business)- World back, governments,utility companies.
- Social (human welfare)-Individuals, residents, farmers, consumers- NGOs-water aid.
- Environmental (sustainable development)-Conservationists, planners, NGOs like the WWF.
This involves reducing the amount of water used ( demand) rather than trying to increase water supply.
In the UK around 22% of water doesn't reach the end user due to leakages.
Examples to prevent these leakages include-
1) reducing domestic consumption-
- Reducing domestic consumption.
- Installing water meters in every home.
- Reducing toilet water.
- Planting drought resistant species in gardens.
- Using gray water for gardening and flushing the toilet.
2) Reducing industry consumption-
- Installing efficient systems to reduce water loss.
- Agricultural irrigation-using drip irrigation from tubes reduces the loss of water.
Role of technology in solving future problems.
Technology can help to increase both water supply and access- examples include-
- Desalination- provides 70% of Saudi Arabia's water, however is VERY expensive and energy rich.
- USA uses a reverse osmosis membrane technology to filter salt from brackish water.
Developing countries use simple intermediate technology which is more appropriate-
- Water collecting- catching rainfall or building small dams.
- Wells built by NGOs- water aid.
- Using plastic bottles full of contaminated water and sitting it in the sun for 6 hours to kill the micro-organisms.