| Flooding in the upper Parramatta River catchment
occurs when heavy rainfall causes: |
|
a) creeks overtop their banks
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b) drainage systems back up because they can not cope
with the volume of water or ae blocked by rubbish.
|
c) sewers overflow because of illegal connections
and the sewer system can not cope with the increased volumes.
|
|
The worst flooding occurs after prolonged rainfall
when the soil is saturated and the water levels in the creeks
elevated.
Then, if an intense rainfall burst occurs, causing a large
amount of rain within a brief period, flash flooding may occur
with little or no warning.
Why does flooding occur?
Flooding has become a problem in recent years because:
|
|
a) Developments encroach floodplains, obstructing
floodways and causing loss of natural flood storage.
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b) Continued development and redevelopment to higher
density land uses by high land costs in Sydney.
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c) Increased imprevious areas such as roads, roofs
and paving, due to increasing development densities means
more run-off.
|
| |
