RFI - 20220156 Kauri St SWMP Rev B

          4.2.2 MUSIC modelling results
The proposed treatment train for each site can achieve the required water quality improvements as shown below in
Table 4.5 - MUSIC Modelling results. As the pollutant generation is estimated using stochastic generation, the
pollutant loads can vary between runs however the below results are representative of the compliance achieved by
the treatment train.

                                                    Table 4.5 - MUSIC Modelling results

 Pollutant                                    Sources            Residual        Percentage          Percentage          Complies
                                                                 Load            Target              Reduction

 Total Suspended Solids (kg/yr)                 489.144              54.686            85                     88.82             Yes

 Total Phosphorus (kg/yr)                         0.981               0.204            65                     79.21             Yes

 Total Nitrogen (kg/yr)                           5.494               1.951            45                 64.481                Yes

 Gross Pollutants (kg/yr)                        53.402                  0             90                     100               Yes



          4.2.3 Maintenance Requirements
Periodic maintenance and monitoring of stormwater infrastructure proposed for this development should be
carried out to ensure they are operating effectively during the post-construction phase. After the on-maintenance
period, the responsibility for these maintenance activities shall be the body corporate for the site who may appoint
a suitably qualified maintenance contractor or caretaker to undertake these activities.

The field inlet grates, pits and underground pipes shall be inspected for blockage or damage at least 6 monthly or
after significant rainfall event. Any blockages shall be cleared from the system, and damage assessed to determine
if it impacts on the function of the system or may pose a hazard that will require repair.

The bioretention areas shall be maintained following a schedule of routine inspections undertaken after every
significant rainfall event (30mm of rainfall in a 24-hour period) or on a three (3) monthly basis within the first twelve
(12) months and on a six (6) monthly basis thereafter. The inspection shall ensure the proper functioning and
condition of the bioretention area and ensure that the planting and vegetation health is suitably maintained. An
inspection checklist from the Healthy Waterways Technical Design Guidelines for Southeast Queensland has been
provided in Appendix Bioretention Garden Inspection Checklist that provides the structure for the inspections to
be undertaken.

In addition to regular inspections, the first 4 months of establishment of the bioretention areas requires a watering
frequency of:

    i.    Week 1 - 6 - 5 times per week


   ii.    Week 6-10 – 3 times per week


  iii.    Week 11-15 – 2 times per week


After 5 months, watering frequency shall be adjusted based on the local conditions to ensure plants are
maintained in a healthy state.

The pit inserts (nominally Ecosol litter baskets with 200um screening mesh or approved equivalent) are required to
be maintained in accordance with all manufacturer’s specifications. Indicatively, routine maintenance involving
minor servicing shall initially be carried out 2 to 4 times annually, with the ongoing frequency based upon the first
year’s inspections. A higher frequency may be required depending upon the catchment size and pollutant
generating characteristics of the site’s catchments.



Project number 20220156                                                                                               Page 17 of 27
File RECOR Stormwater Management Report - 20220156.docx, 2022-10-28 Revision 1

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