water EQ3 Flashcards
define water stress
below 1700 m^3 per person
define water scarcity
below 1000m^3 per person
define absolute water scarcity
less than 500m^3 per person
what is water insecurity
water insecurity occurs when economic, social and environmental requirements for water supplies are not met
what are the two physical causes of water insecurity
-climate variability
-saltwater encroachment
a physical cause of water insecurity is climate variability, explain this
there are significant global variations in the distribution and variation of freshwater resources due to climate variability (arid vs wet). Climate change is amplifying this, changes in runoff and aquifer recharge. warmer climates= increased rates of evaporation and transpiration = less effective precipitation. Warmer waters= encourage the growth of bacteria and other organisms harmful to human health. Thermal pollution can degrade water
a physical cause of water insecurity is saltwater encroachment, explain this
global level sea rise and localised abstraction of groundwater are increasing the risk of saltwater intrusion into many coastal areas. Extensive groundwater pumping reduces the water table and allows saltwater to move into aquifers and soils.
case study for saltwater intrusion and climate variability, the Pacific islands
-35% of Samoas water supply is drawn from aquifers.
-Climate variability associated with ENSO cycles is causing recurrent droughts and floods.
-During the 1997/8 El Nino event, groundwater withdrawal levels in the Marshall islands nearly tripled as a result of drought. Affects crop production.
how is water needed to ensure economic sustainability
-water is needed for food, energy and manufactured products.
-around 20% of all cultivated land is irrigated
-energy production is water intensive
-industrial processes will affect water supply and quality.
-pollution occurs in the industry
what are the complications to the environment due to human activities
a half of wetlands have been lost
disruption of ecosystems through urban sprawl , over abstraction and deforestation and pollution.
may erode an environments capacity to sustain itself
untreated water= breeding ground; disease vectors such as mosquitoes. An inadequate water supply will lead to over abstraction= prolonged periods of drought= desertification
what are the two human causes of water insecurity
overabstraction
water contamination
how does the human cause of over abstraction affect water insecurity
its estimated that over 20% of the worlds aquifers are overexploited. This is due to ever increasing demands due to population growth , rising middle class, water is needed for agriculture
how does the human cause of water contamination affect water insecurity
due to fertilisers and pesticides in farming, industrial production, mining, untreated sewerage and urban runoff and waste water. Some countries dont have water infrastructure to treat water. Eutrophication.
In 2015, over 1 mill m^3 of contaminated water was released into the Animas river
the Nile, Transboundary water conflicts case study
11 countries use the river Nile
-Egypt depend on the Nile for 95% of its H2O needs
- ambitious dam building programmes have the potential to reduce downstream flows.
-The Nile agreement gave Egypt the right to veto power over construction projects.
-It was announced in 2011 that the Grand Ethiopia Renaissance Dam was to be built, this caused tensions between Egypt and Ethiopia but was resolved, Egypt and Sudan signed an agreement
what are the spheres of pressures for water insecurity
Diminishing supply
- climate change
-pollution
-competing users
Rising demands
-population growth
-economic development
competing demands from users
-international issues
-upstream vs downstream
-HEP vs irrigation