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4.2 ACCESS TO FRESH WATER - Coggle Diagram
4.2 ACCESS TO FRESH WATER
Water Scarce Issues
Climate: arid & semi arid
Economy water scarcity
Biofuel demand heavy use of water
water resource threatened by various form of pollution
depleted aquifer
Water Scarce Issue
Between urban and rural areas
People living in urban areas are more likely to be connected to piped water
Between the rich and poor
Those with wealth are most likely to have a reliable water supply
Between social groups
Some groups within society may be marginalized
Climate change may disrupt rainfall patterns and further affect this access
Earth's water cycle changes in response to natural variability
Rising temperatures lead to melting glaciers and increase evaporation
The changes in precipitation around the globe are not uniformly increasing or decreasing
Outline how climate change may alter rainfall patterns and therefore effect water supply
Climate change cause shifting biomes which will shift the distributions of precipitation (affect input in hydrological cycle)
Climate change cause extreme weather patterns and rainfall (heavy rainfall, hurricanes, extreme drought etc)
Global warming will increase surrounding temperature, increase rate of evaporation lead to more water vapor in atmosphere and can cause heavy rainfall
Demand of water increases due to
LEDCS
Expanding population
Rising standards of living
Changing agricultural practice
Expanding industry (often heavy)
MEDCS
Wash more frequently
Water their gardens
Wash their cars
Water supplies can be enhanced through
reservoirs
large water body that forms behind a wall constructued across a river or a large valley
in some instances, the reservoir accumulates large amounts to form a human-made lake
main goals:
irrigation
flood control
fisheries
recreational/aesthetic
environmental problems caused by reservoir and dams
change of habitat (terrestrial to aquatic)
extinction of aquatic species
disappearance of birds
lost of forest, wetland and farmland
relocation of people from flooded area
lost of fish and mammal migratory routes by dam wall
redistribution
water is distributed through water networks and grids over longer distances in MEDCs than in LEDCs (expensive)
from area with plentiful supply to areas of shortage
Case study: South Western USA
desalination
the conversion of salt water into fresh water by the extraction of dissolved salts
desalination does not affect water level in rivers
desalination plant are energy intensive with ecological footprint
the plant are expensive and do not offer solution for poorest countries
salt returned to ocean as waste which can be harmful to local marine ecosystem
the intake pipe vacuum up large quantities of plankton and other microbial organisms that make up the base later of marine food chain
artificial recharge of aquifers
aquifer can be replenished artificially in TWO ways:
spreading water over the land in pits, furrow or ditches, creating a small dams in stream channels and deflect surface runoff thus allowing it to infiltrate
recharge wells and injecting water directly into aquifer
advantages
water unable to evaporate when stored underground
sustainable drainage can increase infiltration to grundwater
low treatment costs
reduced water runoff
the technology is appropriate and generally well understood by both the technicians and the general population
disadvantages
it is costly to recharge aquifers artificially. This results in groundwater contamination
potential for contamination of the groundwater from injected surface water runoff, especially from agricultural fields and roads surfaces
during the construction of water traps, disturbances of soil and vegetation cover may cause environmental damage to the project area
rainwater harvesting schemes
is process of collecting rainwater from surfaces on which rain falls, filtering it and storing it for multiple use
advantages
independent water supply
suitable for irrigation
reduces floods and soil erosion
reduces demand on ground water
disadvantages
unpredictable rainfall
regular maintenance
storage limits
grey water recycling
referring to all wastewater generated in buildings from streams without fecal contamination, all streams except wastewater from toilet
ideal for garden watering, with the appropriate precautions, such as using low or no sodium and phosphorus products and applying the water below the surface. Appropriately treated greywater can also be reused indoors for toilet flushing and clothes washing, both significant water consumers
way to use or store water efficiently
domestic
making new building more water efficient (recycling rainwater for sanitation and showers)
expanding metering to encourage households to use water more efficient
education campaign to increase local awareness
agriculture/irrigation
irrigation individual plant rather than of whole fields (drip irrigation)
covering expanses of water with plastic to reduce evaporation
store water underground
selecting drought resistance crop-to reduce the need for irrigation
use biocontrol fertilizer cause less pollution
use biocontrol as natural predator of pests
options for improving irrigation water productivity
technical
managerial
institutional
agronomic