Stormwater Management Plan · MCU15/0122

                                                                                     15099 - SBSMP/2
                                                                                               Page 11




5.6.2 Post-Development Unmitigated
Figure 5.1 shows the XP-RAFTS model used to represent the post-development unmitigated site
conditions and Table 5.3 summarises the input parameters used in the model for the post-
development unmitigated site scenario.

Node Roof represents the post-development roof area of the proposed medical centre. Node
Ground represents the exposed car parking areas, the exposed ramp and remainder of the site.
LPD represents the legal point of discharge.




                     Figure 5.1 - XP-RAFTS Post-Development Unmitigated Model
              Table 5.6 – XP-RAFTS Source Node Parameters – Post-Development Site
                                                        Post-Development Site
                                          Roof Node                             Ground Node
       Parameter
                             Sub Catchment 1    Sub Catchment 2     Sub Catchment 1    Sub Catchment 2
                                (Pervious)        (Impervious)         (Pervious)        (Impervious)
    Initial Loss (mm)                0                   0                  0                  0
Continuous Loss (mm/hr)              0                   0                 2.5                 0
  Catchment Area (ha)                0               0.2241              0.0777             0.1307
 Impervious Percentage              0%                100%                 0%                100%
      Vectored Slope                0%                4.4%                7.1%                3%
       Manning's "n"                 0                0.015              0.035               0.015
     IFD Coefficients           Noosaville          Noosaville         Noosaville          Noosaville
   Storage Coefficient             N/A                 N/A                N/A                 N/A


Table 5.7 summaries the post development unmitigated peak flows calculated by XP-RAFTS for
a range of design storms. As a check to ensure the peak flows calculated from XP-RAFTS are
sound, peak flows utilising the Rational Method were calculated and have been also listed in
Table 5.7 (refer Appendix F for detailed Rational Method calculations).




Site Based Stormwater Management Plan
Proposed Medical Development at Cnr Val Crescent & Goodchap Street, Noosaville