Reference Document - Flood & Stormwater Management Plan 28_8_2025

                 Table 3-2: Urban land use (Split Source Nodes) - Pollutant Export Parameters
                                                                   Total Suspended
                                                                                                Total Phosphorous      Total Nitrogen
                                                                         Solids
                                                                                                   (Log10 mg/L)         (Log10 mg/L)
                      Land Use             Parameter                 (Log10 mg/L)
                                                                   Storm          Base           Storm         Base    Storm    Base
                                                                    Flow          Flow            Flow         Flow     Flow    Flow
                                               Mean                  2.18          1.0           -0.47         -0.97   0.26      0.20
                      Ground
                                          Std Deviation              0.39          0.34          0.31          0.31    0.23      0.20
                                               Mean                  2.43          1.0           -0.30         -0.97   0.26      0.20
                        Road
                                          Std Deviation              0.39          0.34          0.31          0.31    0.23      0.20
                                               Mean                  1.30          N/A           -0.89         N/A     0.26      N/A
                        Roof
                                          Std Deviation              0.39          N/A           0.31          N/A     0.23      N/A

                 Table 3-3: MUSIC Runoff Generation Parameters

                                           Parameter                                            Urban

                                  Rainfall Threshold (mm)                                         1
                                       Soil Capacity (mm)                                        500
                                       Initial Storage (%)                                       10
                                         Field Capacity                                          200
                            Infiltration Capacity Coefficient a                                  211
                            Infiltration Capacity Coefficient b                                   5
                                       Initial Depth (mm)                                        50
                                       Daily Recharge (%)                                        28
                                       Daily Drainage (%)                                        27
                               Daily Deep Seepage Rate (%)                                        0



                 3.2.3.      Catchment Areas
                 The development site and external catchment has been split into three catchments containing split source
                 nodes (road, roof and ground) representing total developed area reporting to the bioretention basin. As it
                 is proposed to extend the existing bioretention basin approved with reconfiguration of lot at 25 Pavilion
                 Street, the catchment setup from that approval has also been represented. Table 3-4 outlines the
                 catchment areas and imperviousness represented within the MUSIC model. The stormwater quality
                 catchments are provided in Figure 3-1.

                 Table 3-4: Catchment Areas
                      Catchment           Road (ha)        Roof (ha)         Ground (ha)          Total (ha)

                  1                           0.342           0.250              0.791                1.384
                  Ex1                           -             0.049              0.415                0.464
                  2                           0.157           0.250              0.854                1.261
                  Ex2                                         0.091              0.639                 0.73
                  Impervious %                 60              100                 15                    -




                 23-0167SMP01-V4 | Stormwater Management Plan | 33 Pavilion Street, Pomona                                       Page 30

Document Set ID: 24092538
Version: 1, Version Date: 02/09/2025