Appendix F - SBSMP

 5.1     Pre- and Post-Development Design Flow Rates (unmitigated)
The table below, provides a summary of the pre-development design flow rates off the Development Area only
calculated using DRAINS:

Table 2 - Comparison of Pre- and Post-Development Design Flow Rates

                                  Q1        Q2        Q5        Q10            Q20        Q50       Q100
                       Area
                               (63% AEP) (50% AEP) (20% AEP) (10% AEP)      (5% AEP)   (2% AEP)   (1% AEP)
                       (ha)
                                 (m3/s)    (m3/s)    (m3/s)    (m3/s)         (m3/s)     (m3/s)     (m3/s)

 External Catchment Only

      External
     Catchment         0.735     0.168      0.227      0.313      0.365       0.434      0.531      0.585


 Development Area Only

 Development Area
                       0.415     0.059      0.089      0.115      0.140       0.167      0.198      0.222
  (Pre-Development)

 Development Area
                       0.415     0.124      0.161      0.207      0.242       0.279      0.327      0.363
  (Post-Development)

       Increase                  0.063      0.072      0.082       0.096      0.109      0.126       0.141
                                (+49%)     (+55%)     (+63%)      (+60%)     (+61%)     (+61%)      (+61%)


Results show that, compared to pre-development design flow rates, without mitigation, there is an increase in
post-development flow rates off the Development Area.




 BR210522_SBSMP_Rev3.docx                                                                               Page 9 of 25