RFI - stormwater report

5 Establishment and Operational Phase Management
5.1 Establishment
Experience shows that the critical periods in the life of WSUD vegetated stormwater
systems are the construction and establishment phases. The timing and approach to
these systems must be carefully considered to ensure successful establishment and
long-term performance. Bioretention systems are now common stormwater
treatment devices for new urban developments in South East Queensland. Successful
construction and allowing adequate time for the systems to establish is critical to their
long-term performance and function. Construction of the system is also linked to
having suitable bioretention designs in place to ensure, civil contractors have
appropriate plans to construct to. Applying due care in the design and construction
phase will ensure the function of the system whilst also keeping on-going
maintenance to a minimum. It is highly recommended that the constructed activities
be completed in accordance with the Construction and Establishment Guidelines:
Swales, Bioretention Systems and Wetlands (Apr 2010). This will require a sacrificial
turf layer to be installed to protect the filter media from the building phase.

5.2      Operational
It is not proposed for water quality monitoring of the bioretention system to be
undertaken during the operational phase of its life. The “Maintaining Vegetated
Asset” guideline highlights that water quality monitoring is not recommended to
determine the performance of every vegetated stormwater asset, as it is a specialized
field that is complex and costly. In line with this guideline the on-going monitoring of
water quality from this device is not considered necessary considering the small size
of the development.
The bioretention system will be dedicated to Council, who as the asset custodian, will
be responsible for the on-going maintenance of the water quality device.
Maintenance for the bioretention basin may involve the following:
      1. Scheduled inspections;
      2. Removal of noxious plants or weeds;
      3. Maintaining the desired vegetation;
      4. Repairing erosion;
      5. Unblocking inlets and outlets;
      6. Removing litter and debris;
      7. Managing algal or moss growth;
      8. Maintaining the permeability of the filtration.
Operations and maintenance should be conducted in accordance with the
Maintaining Vegetated Stormwater Assets (Feb 2012) guideline.




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