lecture 21- global water poverty Flashcards
How much freshwater resources is accessible for human use?
30%
What is the water scarcity index (WSI)?
A way to quantify water poverty.
* Physical availability of renewable water
* Can be quantified on a percentage scale
What is the formula for WSI?
Rws = W/Q
- Rws: Renewable water supply
- W: Water withdrawal from all sources
- Q: Discharge
What is the water poverty index (WPI)?
- Physical availability of water
- Also accounts for social, economic, and environmental factors
What are the 5 metrics of WPI?
1- Resources
2- Use
3- Capacity (how many resources do we have to invest in infrastructure)
4- Acess
5- Environment (is there pollution? can that water be used?)
Helps to identify the weaknesses of the access of that water- maybe lots of water available but the water is not treated or distributed well.
What is the relationship between freshwater availability and population?
Areas with most freshwater do not necessarily overlap with areas of greatest population.
For example: in South America, huge water, little population, but no infrastructure to treat the water and distribute it = little access.
What are the main strategies for addressing issues with discrepancies between supply and need in freshwater resources?
1- Capturing runoff
2- Moving remote water
3- “Producing” more water
Explain capturing runoff.
1- Dams and reservoirs: Manmade structures designed to hold precipitation not immediately used by human activities.
* 2/3 of the longest rivers are currently dammed.
* Considerable impact on wildlife and local societies.
Explain how capturing runoff creates flooded resevoirs.
Flooded reservoirs: Newly created “blue space” often floods considerable plant life.
* Decomposition releases large amounts of methane
* Newly created wetlands may be a source of methane
Things die because of flooding, which creates a new source of GH- emissions associated with the construction of hydro which is usually perceived as clean.
How does capturing runoff displace local communities?
Human habitation is frequently located next to rivers
History of displacing poor and indigenous communities for reservoir formation.
How does capturing runoff affect the local ecosystems? What has been done to try and mitigate this impact?
The placement of dams can permanently disrupt natural
populations in freshwater ecosystems. Migratory fish species are particularly vulnerable.
Technologies implemented to try to allow fish to bypass dams: Fish ladders and Fish elevators. Success is mixed: fish don’t participate.
How does capturing runoff affect international conflicts?
What happens when you have a river crossing international borders?
Not all countries have friendly agreements. For example: iraq gets most of its freshwater from the rivers that start in turkey and syria- iraq barely gets any fresh water and they can’t do anything about it.
Explain moving remote water.
Moving water from a water-inaccessible area to an area where it will be accessible for human use:
* Pipelines
* Trucks and ships: smaller scale transport
Taking remote water and moving it to your area.
Difference between short and long pipelines:
Mainly short pipelines from reservoirs to nearby human
activities.
Long pipelines are currently not economically feasible.
What are the living conditions of people who lack tap water?
Sources are often far away: multiple trips are required for water needs (50 – 100 L per person!).
Water delivery is often irregular and inconvenient: how can you hold employment and wait for water?
Children and women are typically tasked with collecting water: which interferes with education.
Explain moving more water.
When there is not enough precipitation to capture, or other water cannot be brought in remotely:
* Extract non-renewable sources
* Recycled water
* Desalination
Explain groundwater extraction.
Groundwater: water held underground in soil or spaces between rocks.
Groundwater extraction helps to meet the shortfall in renewable freshwater: can extract non-renewable sources.
What is shallow groundwater?
Groundwater resource that refreshes rapidly from precipitation.
Explain the over-extraction of groundwater.
Overextraction: when water is withdrawn from a groundwater reservoir faster than it can be replaced over an extended period of time.
Overextraction can lead to the disappearance of accessible sources of freshwater. Some surface sources of water are supplied by groundwater reservoirs.
What is the consequence of removing groundwater?
Groundwater takes up physical space
* Supports soils
* A component of elevation
Removal of groundwater sources can result in land subsidence:
* Decrease in elevation
What are the different types of recycled water?
1- Treated water
2- Greywater
3- Reused water
4- Untreated water
Define treated water.
Water that has been chemically treated to remove contaminates for the purpose of use as drinking water.
Define greywater.
Wastewater (generally household) that does not contain toxic chemicals or human fecal matter
* Water from your sink, bath, dishwasher, etc
* Between 50 – 80% of household wastewater is greywater
Define reused water.
Waste water that has been chemically treated for reuse
* Treatment can vary in intensity
Define untreated water
Water that has not been treated to remove harmful contaminants
What is the yuck factor of recycled water?
Can be difficult to convince the population that recycled water is safe to drink. Has defeated proposals for recycled water in many cities globally.
What is desalination?
Removal of salt from salt water, to produce fresh water.
Feasible for a community located close enough to a significant source of salt water.
