RFI - 20220156 Kauri St SWMP Rev B

                                             Figure 4.2 - Rainfall run-off parameters for SEQ

The source nodes have been created using a split catchment approach, with the roof, driveway and other ground
areas separated with stochastic pollutant generation for each of the surface types as per Table 4.2 - Urban
Residential Split Node Pollutant Generation Parameters. The area and impervious fractions for each catchment are
actual values based on the design plans as shown in Table 4.3 – Catchment Nodes.

Table 4.2 - Urban Residential Split Node Pollutant Generation Parameters

 Flow Type          Surface        TSS LOG¹º                       TP LOG¹º VALUES               TN LOG¹º VALUES
                    Type           Mean      St. Dev               Mean       St. Dev            Mean      St. Dev
 Baseflow           Roof             N/A         N/A                  N/A         N/A              N/A         N/A
                    Driveway         1.00       0.34                 -0.97       0.31              0.20       0.20
                    Ground           1.00       0.34                 -0.97       0.31              0.20       0.20
 Stormflow          Roof             1.30       0.39                 -0.89       0.31              0.26       0.23
                    Driveway         2.43       0.39                 -0.30       0.31              0.26       0.23
                    Ground           2.18       0.39                 -0.47       0.31              0.26       0.23

Table 4.3 – Catchment Nodes

 Node                     Surface Type            Surface Area                Fraction
                                                  (m²)                        impervious (%)
 Driveways                     Driveway                 640                         87.4
 Townhouse                       Roof                   799                          100
 Roofs
 Pod A&B                        Ground                     412                     33.5
 Ground
 Pod C Ground                   Ground                     289                     11.2


The proposed treatment train has been modelled as shown in Figure 4.3 - MUSIC Stormwater Treatment Train. The
proposed attenuation tank required to achieve water quantity targets has not been modelled in the treatment train
as it is not considered a water quality improvement device. As the modelling therefore wont account for the
reduced flow rates entering the bioretention area it is likely to represent a conservative assessment of the
treatment performance able to be achieved. The details of the treatments are described in the following sections.




Project number 20220156                                                                                              Page 13 of 27
File RECOR Stormwater Management Report - 20220156.docx, 2022-10-28 Revision 1

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