Appendix E - Integrated Water Management Plan

The model set-up for the post-development scenario is shown in Figure 3, below.. The model structure
has 17 subareas. Subareas 1 to 10 represent areas other than the proposed roofs, whereas subareas 11 to
18 represent the proposed roofs. The runoff from subareas 11 to 18 are conceptually lumped together
before passing through a single conceptual detention volume , before being conjoined with the sum of
the runoffs from subareas 1 to 10.

The corresponding coding of the Urbs catchment file for this post-development scenario can be seen in
Appendix C hereto.



   NORTH
                                                                          1


                                                             11                 12
                                                           VILLA 5            VILLA 6
                                                                      2
   0             SCALE             50 m

                                                            3
   STORMWATER CATCHMENT BDY                                          13
   FOR PROPOSED EXTENSION                                         VILLA 4




                                                  4                  DB       OUT
                               5
                                                      14
                                                  VILLA 3

                         15
                         ENTRY
                 6                   7
                                    LANDSCAPED
                                    PODIUM

                                                  17         8
           9              16
                                               VILLA 2
                          VILLA 1

                                          10

                         COOROY - NOOSA ROAD

Figure 3:      URBS Model Layout For Post-Development Scenario

The pre-development and post-development models shared the same operating parameters – namely, an
alpha parameter of 2.0 and an m parameter of 0.80, with reach factor lengths varying from 1.9 to 2.5 in


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   Brisbane Stormwater Management Pty Ltd Document File: Carramar.Doc