Engineering Hydrology Plans (IWMP)

2.3 Modelling Approach
2.3.1 MUSIC Parameters
An assessment of stormwater runoff quality from the proposed development site
has been assessed using the Cooperative Research Centre for Catchment
Hydrology’s (CRCCH) Model for Urban Stormwater Improvement Conceptualisation
(MUSIC). MUSIC is a decision support tool, used to plan and design appropriate
urban stormwater management systems at the conceptual level. MUSIC Version
5.1.16, released in 2012, was used in this assessment.
Climate data for the catchment was sourced from the MUSIC model database. The
rainfall and evaporation data template for this site has been based on data from
Nambour from 1/1/1989- 31/12/1998 with six (6) minute rainfall duration.
The “MUSIC Modeling Guidelines” (Water By Design, 2010) was used as the basis for
constructing the MUSIC model. The default parameters of the MUSIC model were
used in representing the treatment nodes (where applicable). Table 3 and Table 4
outline the adopted source node parameters that were used in the MUSIC model.

Table 3: MUSIC Base and Storm Flow Concentration Parameters - Commercial

                                  Total Suspended            Total
                                                                          Total Nitrogen
                                        Solids            Phosphorous
                                                                           (Log10 mg/L)
 Land Use       Parameter           (Log10 mg/L)          (Log10 mg/L)
                                   Storm        Base     Storm    Base    Storm    Base
                                    Flow        Flow      Flow    Flow     Flow    Flow
                  Mean              1.30        0.001    -0.89    0.001   0.37     0.001
   Roof
               Std Deviation        0.38        0.001    0.34     0.001   0.34     0.001
                  Mean              2.43        0.78     -0.30    -0.60   0.37     0.32
   Road
               Std Deviation        0.38        0.39     0.34     0.50    0.34     0.30

Table 4: MUSIC Runoff Generation Parameters - Commercial

                                Parameter                   Commercial
                       Rainfall Threshold (mm)                    1
                          Soil Capacity (mm)                     18
                            Initial Storage (%)                  10
                               Field Capacity                    80
                   Infiltration Capacity Coefficient a           243
                   Infiltration Capacity Coefficient b           0.6
                          Initial Depth (mm)                     50
                          Daily Recharge (%)                      0
                          Daily Drainage (%)                     31
                     Daily Deep Seepage Rate (%)                  0




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