Stormwater Technical Memo · MCU23/0096

5             WATER QUALITY ANALYSIS
Stormwater quality modelling is based on split surface areas and their associated export pollutant
load. As per Table 1, above, the roof area increases by approximately 1,200 m2, while the road
area decreases by approximately 1,200m2. In accordance with MUSIC Modelling Guidelines, roof
pollutant export values are significantly less than road pollutant export parameters (see Table 3). As
such, it could be expected that stormwater pollutant loads would decrease with the proposed
developed. Therefore, no additional stormwater quality improvement devices are required.


Table 3. Pollutant Export Parameters.

 Pollutant Export Parameters for Split Catchment Land-use (Log10 values)
      Land         Split   Flow Type                TSS                  TP                      TN
       Use                                Mean        Std. Dev    Mean        Std. Dev    Mean        Std. Dev
                   Roof    Baseflow     N/A           N/A        N/A          N/A        N/A      N/A
                           Stormflow    1.3           0.38       -0.89        0.34       0.37     0.34
 Commercial




                  Roads    Baseflow     0.78          0.39       -0.6         0.5        0.32     0.3
                           Stormflow    2.43          0.38       -0.3         0.34       0.37     0.34
                 Ground    Baseflow     0.78          0.39       -0.6         0.5        0.32     0.3
                           Stormflow    2.16          0.38       -0.39        0.34       0.37     0.34
 Source: Table 3.9 (MUSIC Modelling Guidelines).



6             CONCLUSION

As there have been no significant changes to the overall impervious area associated with the
proposed Arts Centre, it has been determined that no additional detention or stormwater quality
improvement devices are required. This advice is based on the current Masterplan layout (Burling
Brown’s drawing: GSL05-SK-02, Dated 24/2/23) and aligns with QUDM (2017) and MUSIC Modelling
Guidelines (2018) requirements, and Noosa Shire Council requirements.


If Council require further explanation of the above or additional information, please contact the
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Technical Memo | 21-0211TM-SW01-v3 |Good Shepherd                                                Page 4