Please enable JavaScript.
Coggle requires JavaScript to display documents.
ADELAIDE'S DRINKING WATER CRISIS (CAUSES OF SALINITY (MASS VEGETATION…
ADELAIDE'S DRINKING WATER CRISIS
GEOGRAPHICAL FEATURES
3.750 km long
Drainage basin = 14% of Australian mainland
IMPORTANCE
Primary water supply for 5 states
South Australia
Victoria
New South Wales
Australian Capital Territory
Queensland
Large % of water drawn
Usually 35-40%
Up to 90% when extremely low rain fall
ca. 3 million people dependent on it for their water needs
Domestic use
Agricultural use
Industrial use
PROBLEMS FACED
Declining availability of water
Low Rainfall + high level of evaporation
River holds relatively small amount of water
Use of water exceeds natural replenishment level
Increasing salinity levels
CAUSES OF SALINITY
LOW RAINFALL
PRIMARY salinity
HIGH LEVEL OF EVAPORATION
PRIMARY SALINITY
Caused by natural processes
MASS VEGETATION CLEARING
Land used for farming and timber
No interception of precipitation
unnatural level of rainwater seeps into ground
water tables rise
salts found in deeper layers of earth rise
SECONDARY SALINITY
DRYLAND salinity
EXCESSIVE IRRIGATION
Primary salinity
Water pumped out of river to water crops absorbs the excess salts in the top soils (due to rising water tables)
high salinity water drains back into river
IRRIGATION SALINITY
EFFECTS OF SALINITY
Decreasing fertility of area
Decreasing quality of dinking water
10% of the year does not pass WHO standard
Within 2 decades - 40% of the year (prediction)
Decreasing biodiversity of Coorong wetlands