Attachment 3 - Revised Engineering Report (rec. 7.04.2025) MCU24-0165 & OPW24-0222

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TABLE 4: RECOMMENDED RAINFALL-RUNOFF PARAMETERS

 Parameter                                                         Urban Residential
 Rainfall threshold (mm)                                                     1
 Soil storage capacity (mm)                                              500
 Initial storage (% capacity)                                             10
 Field capacity (mm)                                                     200
 Infiltration capacity - Coefficient a                                   211
 Infiltration capacity - Exponent b                                       5.0
 Initial depth (mm)                                                       50
 Daily recharge rate (%)                                                  28
 Daily baseflow rate (%)                                                  27
 Daily deep seepage rate (%)                                                 0
5.6.2.5 Pollutant Export Parameters
The pollutant export parameters for split catchment land use was adopted for MUSIC modelling and
are shown in Table 5.
TABLE 5: POLLUTANT EXPORT PARAMETERS – SPLIT CATCHMENT URBAN RESIDENTIAL LAND USE

     Flow Type         Surface Type      Total Suspended      Total                 Total Nitrogen
                                           Solids (TSS)    Phosphorous                   (TN)
                                           (Log10 mg/L)        (TP)                  (Log10 mg/L)
                                                           (Log10 mg/L)

                                         Mean      Std     Mean        Std          Mean             Std
                                                   Dev                 Dev                           Dev
 Baseflow              Roof               N/A      N/A     N/A         N/A           N/A              N/A
 concentration
 parameters            Road Reserve       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
 concentration
 parameters            Road Reserve       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

5.6.2.6   MUSIC Model Layout
The model node arrangement shown in Figure 8 has been adopted and is representative of the
proposed development.




 15 November 2024                                                                                    Page 13