4.2 Access to freshwater Flashcards
WHO (World Health Organization) estimates that 750 million people around the world don’t have access to safe drinking water. Briefly, why is this so?
- Poor infrastructure and inadequate management of water services
- Lack of knowledge and skills
- Lack of finances
- Lack of political will to make water a priority
Give an example of a natural unequal distribution of freshwater
Ex. Atacama desert in Northern Chile vs Cherrapunji in India
The Atacama Desert is considered to be one of the driest places on the planet, with average annual rainfall of about 1mm
Cherrapunji has a sub-tropical climate with an average annual rainfall of more than 11,700mm.
What is the problem with water vendors as an immediate solution to lack of access to fresh drinking water?
notfair
makes it so that people in rural areas (where this immediate solution would take place) pay more for water than their urban counterparts
How does climate change affect water scarcity
- Water stressed mid latitudes and desert areas will recieve even less water
- High latitudes and equatorial Pacific may experience more precipitation
- Weather patterns are likely to be more extreme with:
- Greater periods of dry spells resulting in drought conditions.
- Increases in intense precipitation potentially leading to flooding
- Melting of glaciers 🧊 will result in higher risk of flooding
- Sea level rise consequently poses the risk of contaminated aquifiers near coastal areas
Why is water demand expected to grow? (HINT: 5)
- growth in population
- increase standard of living
- change to more meat based diet
- growth of industry
- increase urbanization
Define water stress
Water stressis when demand exceeds the available supply over a certain time period or when the quality of water restricts its use
When is a population considered to be water stressed? (number)
when supply is less than 1700 cubic meters per person per year (m3/person/year)
List factors/issues that contribute to water stress
- Over abstraction of groundwater → water is being used at a faster rate than it is being replenished
- in coastal areas this leads to saline intrusion in aquifiers
- Excessive abstraction of surface waters
- like lakes
- contamination of water resources through pollution, fertilization, sewage
- Contamination of water resources increases the cost of clean-up (not every country has the money for that)
- inefficent use of water
- Poor irrigation techniques
- Leakages within the water distribution system
Ways to increase storage of water? (HINT: 3)
- Reservoirs
- Artificial recharge
- Rainfall harvesting schemes
Reservoirs- why and how do they help
- why: to store water during periods of high rainfall to provide a plentiful supply throughout the year.
- How:
- Generation of hydropower
- Flood control
- Fisheries
- Control of water quality (SEDAPAL cannot relate)
What are the potential impacts of building reservoirs
- Change of habitat
- Relocation of people
- Change to the flow of the water
- Loss of fish and mammal migratory routes
Artificial recharge- why and how do they help
- Artificial recharge of aquifiers to increase amount of water stored
How:
- Building a ditch or trench above an aquifer zone to intercept and collect run-off
- The water collected gradually seepsinto the ground and percolates into the aquifier
- water can be pumped directly from rivers or reservoirs into the aquifer via a borehole (a hole drilled into the ground).
- Pumping directly from a river with high sediment loads can cause clogging of boreholes
What are Rainfall harvesting schemes?
collection of precipitation that falls onto roofs
Ways to increse water resources- enhancing water supplies (HINT: 3)
- Desalinisation
- Water redistribution
- Use of greywater
Desalinisation- what is it and limitations
- changing seawater into freshwater
- energy intensive process and therefore usually expensive
- reverse osmosis: water moves through semi permeable membrane and leaves salt behind
