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Where it is located
Lancelot Street flood retarding basin and wetland
is situated on Blacktown Creek at William Lawson Reserve in Lancelot
Street, Blacktown.
What does it look like
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Weir between the pool area (left) and the inlet
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Embankment separating the bypass from the pool
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Aerial View of the wetland and basin
Why was it built
- To improve the quality of water in the upper reaches
of Blacktown Creek by reducing of nutrient levels, faecal coliforms,
sediments and suspended solids and gross solids.
- Maintain the existing capacity to reduce flooding
and compensate for further urban development upstream.
- Create a habitat for native fauna through appropriate
local native flora planting.
- Enhance the aesthetical and recreational potential
of the site.
What does it do? / How does it work?
The wetland consists of four main operating components:-
- For the control of litter and sediments coming
from upstream of the wetland, three gross pollutant traps and
a trash rack have been strategically installed.
- The wetland pool area acts as a first flush capture
area for flows from the main catchment. The vegetation and settlement
enhance the quality of the water before it flows back to the channel
at the outlet.
- The channel captures the first flush in minor storms
and the flow that cannot be treated is bypassed over a weir to
the high flow channel, not affecting the water contained in the
wetland pool area.
- In case of a major storm the system acts as one
basin containing the main flow, only protecting residents from
flooding.
When was it built?
1998/1999
How much did it cost?
Upper Parramatta River Catchment Trust $344,000
Blacktown City Council $534,000
NSW Stormwater Trust $485,000
TOTAL $1,363,000
How was it built?
The wetland was built by excavating 1.5m of an existing dry basin.
A separate pool area was formed via a low embankment that follows
the alignment of the sewer and provides the required depth of protective
cover over the sewer. Within the pool area two deeper open water
areas are provided, the one to the west is designed to ensure that
flow entering the wetland is well distributed, while the area to
the east provides a pool from which water could be pumped for maintenance
purposes.
The separation between the pool and the channel is
a concrete weir that also provides a protective encasement to cover
the existing sewer line.
What environmental measures were
undertaken?
The wetland has been designed with steep sides for constant movement
of water to reduce the opportunities for mosquitoes to breed in
the water body, whilst minimizing the potential for drowning and
other issues of public safety.
Links to other projects
Construction of three gross pollutant traps upstream of the wetland
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